From f6bc48698587758fb764bae66302002fe148e978 Mon Sep 17 00:00:00 2001 From: José Bollo Date: Wed, 7 Jun 2017 18:40:00 +0200 Subject: Refactor of the documentation --- docs/FAQ.md | 5 + docs/afb-application-writing.md | 301 +++++++++++++ docs/afb-binding-references.md | 672 +++++++++++++++++++++++++++++ docs/afb-binding-writing.md | 465 ++++++++++++++++++++ docs/afb-daemon-options.md | 200 +++++++++ docs/afb-daemon-vocabulary.md | 98 +++++ docs/afb-desktop-package.md | 40 ++ docs/afb-events-guide.md | 371 ++++++++++++++++ docs/afb-migration-v1-to-v2.md | 611 ++++++++++++++++++++++++++ docs/afb-overview.md | 98 +++++ docs/index.md | 1 + docs/pictures/AFB_for_services.svg | 238 +++++++++++ docs/pictures/basis.odg | Bin 0 -> 15170 bytes docs/pictures/basis.svg | 356 ++++++++++++++++ docs/pictures/interconnection.odg | Bin 0 -> 20244 bytes docs/pictures/interconnection.svg | 854 +++++++++++++++++++++++++++++++++++++ docs/pictures/signaling-basis.svg | 145 +++++++ docs/pictures/tic-tac-toe.svg | 289 +++++++++++++ docs/pictures/triskel_iot_bzh.svg | 110 +++++ 19 files changed, 4854 insertions(+) create mode 100644 docs/FAQ.md create mode 100644 docs/afb-application-writing.md create mode 100644 docs/afb-binding-references.md create mode 100644 docs/afb-binding-writing.md create mode 100644 docs/afb-daemon-options.md create mode 100644 docs/afb-daemon-vocabulary.md create mode 100644 docs/afb-desktop-package.md create mode 100644 docs/afb-events-guide.md create mode 100644 docs/afb-migration-v1-to-v2.md create mode 100644 docs/afb-overview.md create mode 120000 docs/index.md create mode 100644 docs/pictures/AFB_for_services.svg create mode 100644 docs/pictures/basis.odg create mode 100644 docs/pictures/basis.svg create mode 100644 docs/pictures/interconnection.odg create mode 100644 docs/pictures/interconnection.svg create mode 100644 docs/pictures/signaling-basis.svg create mode 100644 docs/pictures/tic-tac-toe.svg create mode 100644 docs/pictures/triskel_iot_bzh.svg (limited to 'docs') diff --git a/docs/FAQ.md b/docs/FAQ.md new file mode 100644 index 00000000..5063ed74 --- /dev/null +++ b/docs/FAQ.md @@ -0,0 +1,5 @@ +Frequently Asked Question about AFB-DAEMON +========================================== + + + diff --git a/docs/afb-application-writing.md b/docs/afb-application-writing.md new file mode 100644 index 00000000..cc513b48 --- /dev/null +++ b/docs/afb-application-writing.md @@ -0,0 +1,301 @@ +How to write an application on top of AGL FRAMEWORK +==================================================== + +Programming Languages for Applications +----------------------------------------- + +### Writing an HTML5 application + +Developers of HTML5 applications (client side) can easily create +applications for AGL framework using their preferred +HTML5 framework. + +Developers may also take advantage of powerful server side bindings to improve +application behavior. Server side bindings return an application/json mine-type +and can be accessed though either HTTP or Websockets. + +In a near future, JSON-RPC protocol should be added to complete the current +x-afb-json1 protocol. + +Two examples of HTML5 applications are given: + +- [afb-client](https://gerrit.automotivelinux.org/gerrit/gitweb?p=src/app-framework-demo.git;a=tree;f=afb-client) a simple "hello world" application template + +- [afm-client](https://gerrit.automotivelinux.org/gerrit/gitweb?p=src/app-framework-demo.git;a=tree;f=afm-client) a simple "Home screen" application template + +### Writing a Qt application + +Writing Qt applications is also supported. Qt offers standard API to send +request through HTTP or WebSockets. + +It is also possible to write QML applications. A sample QML application +[token-websock] is available: + +- [token-websock](https://gerrit.automotivelinux.org/gerrit/gitweb?p=src/app-framework-binder.git;a=blob;f=test/token-websock.qml) +a simple "hello world" application in QML + +### Writing a "C" application + +C applications can use afb-daemon binder through a websocket connection. + +The library **libafbwsc** is provided for C clients that need +to connect with an afb-daemon binder. + +The program **afb-client-demo** is the C example that use +**libafbwsc** library. +Source code is available here +[src/afb-client-demo.c](https://gerrit.automotivelinux.org/gerrit/gitweb?p=src/app-framework-binder.git;a=blob;f=src/afb-client-demo.c). + +Current implementation relies on libsystemd and file descriptors. +This model might be review in the future to support secure sockets +and get rid of libsystemd dependency. + +Handling sessions within applications +------------------------------------- + +Applications should understand sessions and token management when interacting +with afb-daemon binder. + +Applications communicate with their private binder(afb-daemon) using +a network connection or potentially any other connection channel. While the +current version does not yet implement Unix socket, this feature might be added +in the near future. Developers need to be warn that HTTP protocol is a none +connected protocol and that using HTTP socket connection to authenticate +clients is not supported. + +For this reason, the binder should authenticate the application +by using a shared secret. The secret is named "token" and the identification +of client is named "session". + +The examples **token-websock.qml** and **afb-client** are demonstrating +how authentication and sessions are managed. + +### Handling sessions + +Bindings and other binder features need to keep track of client +instances. This is especially important for bindings running as services +as they may typically have to keep each client's data separated. + +For HTML5 applications, the web runtime handles the cookie of session +that the binder afb-daemon automatically sets. + +Session identifier can be set using the parameter **uuid** or **x-afb-uuid** in +URI requests. Within current version of the framework session UUID is supported +by both HTTP requests and websocket negotiation. + +### Exchanging tokens + +At application start, AGL framework communicates a shared secret to both binder +and client application. This initial secret is called the "**initial token**". + +For each of its client application, the binder manages a current active +token for session management. This authentication token can be use to restrict +the access to some binding's methods. + +The token must be included in URI request on HTTP or during websockets +connection using parameter **token** or **x-afb-token**. + +To ensure security, tokens must be refreshed periodically. + +### Example of session management + +In following examples, we suppose that **afb-daemon** is launched with something +equivalent to: + + $ afb-daemon --port=1234 --token=123456 [...] + +making the expectation that **AuthLogin** binding is requested as default. + +#### Using curl + +First, connects with the initial token, 123456: + + $ curl http://localhost:1234/api/auth/connect?token=123456 + { + "jtype": "afb-reply", + "request": { + "status": "success", + "token": "0aef6841-2ddd-436d-b961-ae78da3b5c5f", + "uuid": "850c4594-1be1-4e9b-9fcc-38cc3e6ff015" + }, + "response": {"token": "A New Token and Session Context Was Created"} + } + +It returns an answer containing session UUID, 850c4594-1be1-4e9b-9fcc-38cc3e6ff015, +and a refreshed token, 850c4594-1be1-4e9b-9fcc-38cc3e6ff015. + +Check if session and token is valid: + + $ curl http://localhost:1234/api/auth/check?token=0aef6841-2ddd-436d-b961-ae78da3b5c5f\&uuid=850c4594-1be1-4e9b-9fcc-38cc3e6ff015 + { + "jtype": "afb-reply", + "request": {"status":"success"}, + "response": {"isvalid":true} + } + +Refresh the token: + + $ curl http://localhost:1234/api/auth/refresh?token=0aef6841-2ddd-436d-b961-ae78da3b5c5f\&uuid=850c4594-1be1-4e9b-9fcc-38cc3e6ff015 + { + "jtype": "afb-reply", + "request": { + "status":"success", + "token":"b8ec3ec3-6ffe-448c-9a6c-efda69ad7bd9" + }, + "response": {"token":"Token was refreshed"} + } + +Close the session: + + curl http://localhost:1234/api/auth/logout?token=b8ec3ec3-6ffe-448c-9a6c-efda69ad7bd9\&uuid=850c4594-1be1-4e9b-9fcc-38cc3e6ff015 + { + "jtype": "afb-reply", + "request": {"status": "success"}, + "response": {"info":"Token and all resources are released"} + } + +Checking on closed session for uuid should be refused: + + curl http://localhost:1234/api/auth/check?token=b8ec3ec3-6ffe-448c-9a6c-efda69ad7bd9\&uuid=850c4594-1be1-4e9b-9fcc-38cc3e6ff015 + { + "jtype": "afb-reply", + "request": { + "status": "failed", + "info": "invalid token's identity" + } + } + +#### Using afb-client-demo + +> The program is packaged within AGL in the rpm **libafbwsc-dev** + +Here is an example of exchange using **afb-client-demo**: + + $ afb-client-demo ws://localhost:1234/api?token=123456 + auth connect + ON-REPLY 1:auth/connect: {"jtype":"afb-reply","request":{"status":"success", + "token":"63f71a29-8b52-4f9b-829f-b3028ba46b68","uuid":"5fcc3f3d-4b84-4fc7-ba66-2d8bd34ae7d1"}, + "response":{"token":"A New Token and Session Context Was Created"}} + auth check + ON-REPLY 2:auth/check: {"jtype":"afb-reply","request":{"status":"success"},"response":{"isvalid":true}} + auth refresh + ON-REPLY 4:auth/refresh: {"jtype":"afb-reply","request":{"status":"success", + "token":"8b8ba8f4-1b0c-48fa-962d-4a00a8c9157e"},"response":{"token":"Token was refreshed"}} + auth check + ON-REPLY 5:auth/check: {"jtype":"afb-reply","request":{"status":"success"},"response":{"isvalid":true}} + auth refresh + ON-REPLY 6:auth/refresh: {"jtype":"afb-reply","request":{"status":"success", + "token":"e83b36f8-d945-463d-b983-5d8ed73ba529"},"response":{"token":"Token was refreshed"}} + +After closing connection, reconnect as here after: + + $ afb-client-demo ws://localhost:1234/api?token=e83b36f8-d945-463d-b983-5d8ed73ba529\&uuid=5fcc3f3d-4b84-4fc7-ba66-2d8bd34ae7d1 auth check + ON-REPLY 1:auth/check: {"jtype":"afb-reply","request":{"status":"success"},"response":{"isvalid":true}} + +Same connection check using **curl**: + + $ curl http://localhost:1234/api/auth/check?token=e83b36f8-d945-463d-b983-5d8ed73ba529\&uuid=5fcc3f3d-4b84-4fc7-ba66-2d8bd34ae7d1 + {"jtype":"afb-reply","request":{"status":"success"},"response":{"isvalid":true}} + +Format of replies +----------------- + +Replies use javascript object returned as serialized JSON. + +This object contains at least 2 mandatory fields of name **jtype** and +**request** and one optional field of name **response**. + +### Template + +This is a template of replies: + +```json +{ + "jtype": "afb-reply", + "request": { + "status": "success", + "info": "informationnal text", + "token": "e83b36f8-d945-463d-b983-5d8ed73ba52", + "uuid": "5fcc3f3d-4b84-4fc7-ba66-2d8bd34ae7d1", + "reqid": "application-generated-id-23456" + }, + "response": ....any response object.... +} +``` + +### Field jtype + +The field **jtype** must have a value of type string equal to **"afb-reply"**. + +### Field request + +The field **request** must have a value of type object. This request object +has at least one field named **status** and four optional fields named +**info**, **token**, **uuid**, **reqid**. + +#### Subfield request.status + +**status** must have a value of type string. This string is equal to **"success"** +only in case of success. + +#### Subfield request.info + +**info** is of type string and represent optional information added to the reply. + +#### Subfield request.token + +**token** is of type string. It is sent either at session creation +or when the token is refreshed. + +#### Subfield request.uuid + +**uuid** is of type string. It is sent at session creation. + +#### Subfield request.reqid + +**reqid** is of type string. It is sent in response to HTTP requests +that added a parameter of name **reqid** or **x-afb-reqid** at request time. +Value returns in the reply has the exact same value as the one received in the +request. + +### Field response + +This field response optionally contains an object returned when request +succeeded. + +Format of events +---------------- + +Events are javascript object serialized as JSON. + +This object contains at least 2 mandatory fields of name **jtype** and **event** +and one optional field of name **data**. + +### Template + +Here is a template of event: + +```json +{ + "jtype": "afb-event", + "event": "sample_api_name/sample_event_name", + "data": ...any event data... +} +``` + +### Field jtype + +The field **jtype** must have a value of type string equal to **"afb-event"**. + +### Field event + +The field **event** carries the event's name. + +The name of the event is made of two parts separated by a slash: +the name of the name of the API that generated the event +and the name of event within the API. + +### Field data + +This field data if present holds the data carried by the event. + diff --git a/docs/afb-binding-references.md b/docs/afb-binding-references.md new file mode 100644 index 00000000..7d6cdd1d --- /dev/null +++ b/docs/afb-binding-references.md @@ -0,0 +1,672 @@ +Binding Reference +================= + +Structure for declaring binding +------------------------------- + +### struct afb_binding_v2 + +The main structure, of type **afb_binding_v2**, for describing the binding +must be exported under the name **afbBindingV2**. + +This structure is defined as below. + +```C +/* + * Description of the bindings of type version 2 + */ +struct afb_binding_v2 +{ + const char *api; /* api name for the binding */ + const char *specification; /* textual openAPIv3 specification of the binding */ + const struct afb_verb_v2 *verbs; /* array of descriptions of verbs terminated by a NULL name */ + int (*preinit)(); /* callback at load of the binding */ + int (*init)(); /* callback for starting the service */ + void (*onevent)(const char *event, struct json_object *object); /* callback for handling events */ + unsigned noconcurrency: 1; /* avoids concurrent requests to verbs */ +}; +``` + +### struct afb_verb_v2 + +Each verb is described with a structure of type **afb_verb_v2** +defined below: + +```C +/* + * Description of one verb of the API provided by the binding + * This enumeration is valid for bindings of type version 2 + */ +struct afb_verb_v2 +{ + const char *verb; /* name of the verb */ + void (*callback)(struct afb_req req); /* callback function implementing the verb */ + const struct afb_auth *auth; /* required authorisation */ + uint32_t session; /* authorisation and session requirements of the verb */ +}; +``` + +The session flags is an or of the constant defined below: + + - AFB_SESSION_NONE : no flag, synonym to 0 + - AFB_SESSION_LOA_0 : Requires the LOA to be 0 or more, synonym to 0 or AFB_SESSION_NONE + - AFB_SESSION_LOA_1 : Requires the LOA to be 1 or more + - AFB_SESSION_LOA_2 : Requires the LOA to be 2 or more + - AFB_SESSION_LOA_3 : Requires the LOA to be 3 or more + - AFB_SESSION_CHECK : Requires the token to be set and valid + - AFB_SESSION_REFRESH : Implies a token refresh + - AFB_SESSION_CLOSE : Implies cloing the session + +The LOA is set binding by binding using the function **afb_req_session_set_LOA**. + +### struct afb_auth and enum afb_auth_type + +The structure **afb_auth** is used within verb description to +set security requirements. The interpretation of the structure +depends on the value of the field **type**. + +```C +struct afb_auth +{ + const enum afb_auth_type type; + union { + const char *text; + const unsigned loa; + const struct afb_auth *first; + }; + const struct afb_auth *next; +}; +``` +The possible values for **type** is defined here: + +```C +/* + * Enum for Session/Token/Assurance middleware. + */ +enum afb_auth_type +{ + afb_auth_No = 0, /** never authorized, no data */ + afb_auth_Token, /** authorized if token valid, no data */ + afb_auth_LOA, /** authorized if LOA greater than data 'loa' */ + afb_auth_Permission, /** authorized if permission 'text' is granted */ + afb_auth_Or, /** authorized if 'first' or 'next' is authorized */ + afb_auth_And, /** authorized if 'first' and 'next' are authorized */ + afb_auth_Not, /** authorized if 'first' is not authorized */ + afb_auth_Yes /** always authorized, no data */ +}; +``` + +Example: + +```C +static const struct afb_auth _afb_auths_v2_monitor[] = { + { .type = afb_auth_Permission, .text = "urn:AGL:permission:monitor:public:set" }, + { .type = afb_auth_Permission, .text = "urn:AGL:permission:monitor:public:get" }, + { .type = afb_auth_Or, .first = &_afb_auths_v2_monitor[1], .next = &_afb_auths_v2_monitor[0] } +}; +``` + +Functions of class afb_daemon... +------------------------- + +The 3 following functions are linked to libsystemd. +They allow use of **sd_event** features and access +to **sd_bus** features. + +```C +/* + * Retrieves the common systemd's event loop of AFB + */ +struct sd_event *afb_daemon_get_event_loop(); + +/* + * Retrieves the common systemd's user/session d-bus of AFB + */ +struct sd_bus *afb_daemon_get_user_bus(); + +/* + * Retrieves the common systemd's system d-bus of AFB + */ +struct sd_bus *afb_daemon_get_system_bus(); +``` + +The 2 following functions are linked to event management. +Broadcasting an event send it to any possible listener. + +```C +/* + * Broadcasts widely the event of 'name' with the data 'object'. + * 'object' can be NULL. + * + * For convenience, the function calls 'json_object_put' for 'object'. + * Thus, in the case where 'object' should remain available after + * the function returns, the function 'json_object_get' shall be used. + * + * Returns the count of clients that received the event. + */ +int afb_daemon_broadcast_event(const char *name, struct json_object *object); + +/* + * Creates an event of 'name' and returns it. + * + * See afb_event_is_valid to check if there is an error. + */ +struct afb_event afb_daemon_make_event(const char *name); +``` + +The following function is used by logging macros and should normally +not be used. Instead, you should use the macros +**AFB\_ERROR**, **AFB\_WARNING**, **AFB\_NOTICE**, +**AFB\_INFO**, **AFB\_DEBUG** + +```C +/* + * Send a message described by 'fmt' and following parameters + * to the journal for the verbosity 'level'. + * + * 'file', 'line' and 'func' are indicators of position of the code in source files + * (see macros __FILE__, __LINE__ and __func__). + * + * 'level' is defined by syslog standard: + * EMERGENCY 0 System is unusable + * ALERT 1 Action must be taken immediately + * CRITICAL 2 Critical conditions + * ERROR 3 Error conditions + * WARNING 4 Warning conditions + * NOTICE 5 Normal but significant condition + * INFO 6 Informational + * DEBUG 7 Debug-level messages + */ +void afb_daemon_verbose(int level, const char *file, int line, const char * func, const char *fmt, ...); +``` + +The 2 following functions MUST be used to access data of the bindings. + +```C +/* + * Get the root directory file descriptor. This file descriptor can + * be used with functions 'openat', 'fstatat', ... + */ +int afb_daemon_rootdir_get_fd(); + +/* + * Opens 'filename' within the root directory with 'flags' (see function openat) + * using the 'locale' definition (example: "jp,en-US") that can be NULL. + * Returns the file descriptor or -1 in case of error. + */ +int afb_daemon_rootdir_open_locale(const char *filename, int flags, const char *locale); +``` + +The following function is used to queue jobs. + +```C +/* + * Queue the job defined by 'callback' and 'argument' for being executed asynchronously + * in this thread (later) or in an other thread. + * If 'group' is not NUL, the jobs queued with a same value (as the pointer value 'group') + * are executed in sequence in the order of there submission. + * If 'timeout' is not 0, it represent the maximum execution time for the job in seconds. + * At first, the job is called with 0 as signum and the given argument. + * The job is executed with the monitoring of its time and some signals like SIGSEGV and + * SIGFPE. When a such signal is catched, the job is terminated and reexecuted but with + * signum being the signal number (SIGALRM when timeout expired). + * + * Returns 0 in case of success or -1 in case of error. + */ +int afb_daemon_queue_job(void (*callback)(int signum, void *arg), void *argument, void *group, int timeout) +``` + +The following function must be used when a binding depends on other +bindings at its initialisation. + +```C +/* + * Tells that it requires the API of "name" to exist + * and if 'initialized' is not null to be initialized. + * Returns 0 in case of success or -1 in case of error. + */ +int afb_daemon_require_api(const char *name, int initialized) +``` + +Functions of class afb_service... +------------------------- + +The following functions allow services to call verbs of other +bindings for themselves. + +```C +/** + * Calls the 'verb' of the 'api' with the arguments 'args' and 'verb' in the name of the binding. + * The result of the call is delivered to the 'callback' function with the 'callback_closure'. + * + * For convenience, the function calls 'json_object_put' for 'args'. + * Thus, in the case where 'args' should remain available after + * the function returns, the function 'json_object_get' shall be used. + * + * The 'callback' receives 3 arguments: + * 1. 'closure' the user defined closure pointer 'callback_closure', + * 2. 'iserror' a boolean status being true (not null) when an error occured, + * 2. 'result' the resulting data as a JSON object. + * + * @param api The api name of the method to call + * @param verb The verb name of the method to call + * @param args The arguments to pass to the method + * @param callback The to call on completion + * @param callback_closure The closure to pass to the callback + * + * @see also 'afb_req_subcall' + */ +void afb_service_call( + const char *api, + const char *verb, + struct json_object *args, + void (*callback)(void*closure, int iserror, struct json_object *result), + void *callback_closure); + +/** + * Calls the 'verb' of the 'api' with the arguments 'args' and 'verb' in the name of the binding. + * 'result' will receive the response. + * + * For convenience, the function calls 'json_object_put' for 'args'. + * Thus, in the case where 'args' should remain available after + * the function returns, the function 'json_object_get' shall be used. + * + * @param api The api name of the method to call + * @param verb The verb name of the method to call + * @param args The arguments to pass to the method + * @param result Where to store the result - should call json_object_put on it - + * + * @returns 1 in case of success or 0 in case of error. + * + * @see also 'afb_req_subcall' + */ +int afb_service_call_sync( + const char *api, + const char *verb, + struct json_object *args, + struct json_object **result); +``` + +Functions of class afb_event... +------------------------- + +This function checks whether the event is valid. It must be used +when creating events. + +```C +/* + * Checks wether the 'event' is valid or not. + * + * Returns 0 if not valid or 1 if valid. + */ +int afb_event_is_valid(struct afb_event event); +``` + +The two following functions are used to broadcast or push +event with its data. + +```C +/* + * Broadcasts widely the 'event' with the data 'object'. + * 'object' can be NULL. + * + * For convenience, the function calls 'json_object_put' for 'object'. + * Thus, in the case where 'object' should remain available after + * the function returns, the function 'json_object_get' shall be used. + * + * Returns the count of clients that received the event. + */ +int afb_event_broadcast(struct afb_event event, struct json_object *object); + +/* + * Pushes the 'event' with the data 'object' to its observers. + * 'object' can be NULL. + * + * For convenience, the function calls 'json_object_put' for 'object'. + * Thus, in the case where 'object' should remain available after + * the function returns, the function 'json_object_get' shall be used. + * + * Returns the count of clients that received the event. + */ +int afb_event_push(struct afb_event event, struct json_object *object); +``` + +The following function destiys the event. + +```C +/* + * Drops the data associated to the 'event' + * After calling this function, the event + * MUST NOT BE USED ANYMORE. + */ +void afb_event_drop(struct afb_event event); +``` + +This function allows to retrieve the exact name of the event. + +```C +/* + * Gets the name associated to the 'event'. + */ +const char *afb_event_name(struct afb_event event); +``` + +Functions of class afb_req... +------------------------- + +This function checks the validity of the **req**. + +```C +/* + * Checks wether the request 'req' is valid or not. + * + * Returns 0 if not valid or 1 if valid. + */ +int afb_req_is_valid(struct afb_req req); +``` + +The following functions retrieves parameters of the request. + +```C +/* + * Gets from the request 'req' the argument of 'name'. + * Returns a PLAIN structure of type 'struct afb_arg'. + * When the argument of 'name' is not found, all fields of result are set to NULL. + * When the argument of 'name' is found, the fields are filled, + * in particular, the field 'result.name' is set to 'name'. + * + * There is a special name value: the empty string. + * The argument of name "" is defined only if the request was made using + * an HTTP POST of Content-Type "application/json". In that case, the + * argument of name "" receives the value of the body of the HTTP request. + */ +struct afb_arg afb_req_get(struct afb_req req, const char *name); + +/* + * Gets from the request 'req' the string value of the argument of 'name'. + * Returns NULL if when there is no argument of 'name'. + * Returns the value of the argument of 'name' otherwise. + * + * Shortcut for: afb_req_get(req, name).value + */ +const char *afb_req_value(struct afb_req req, const char *name); + +/* + * Gets from the request 'req' the path for file attached to the argument of 'name'. + * Returns NULL if when there is no argument of 'name' or when there is no file. + * Returns the path of the argument of 'name' otherwise. + * + * Shortcut for: afb_req_get(req, name).path + */ +const char *afb_req_path(struct afb_req req, const char *name); + +/* + * Gets from the request 'req' the json object hashing the arguments. + * The returned object must not be released using 'json_object_put'. + */ +struct json_object *afb_req_json(struct afb_req req); +``` + +The following functions emit the reply to the request. + +```C +/* + * Sends a reply of kind success to the request 'req'. + * The status of the reply is automatically set to "success". + * Its send the object 'obj' (can be NULL) with an + * informationnal comment 'info (can also be NULL). + * + * For convenience, the function calls 'json_object_put' for 'obj'. + * Thus, in the case where 'obj' should remain available after + * the function returns, the function 'json_object_get' shall be used. + */ +void afb_req_success(struct afb_req req, struct json_object *obj, const char *info); + +/* + * Same as 'afb_req_success' but the 'info' is a formatting + * string followed by arguments. + * + * For convenience, the function calls 'json_object_put' for 'obj'. + * Thus, in the case where 'obj' should remain available after + * the function returns, the function 'json_object_get' shall be used. + */ +void afb_req_success_f(struct afb_req req, struct json_object *obj, const char *info, ...); + +/* + * Same as 'afb_req_success_f' but the arguments to the format 'info' + * are given as a variable argument list instance. + * + * For convenience, the function calls 'json_object_put' for 'obj'. + * Thus, in the case where 'obj' should remain available after + * the function returns, the function 'json_object_get' shall be used. + */ +void afb_req_success_v(struct afb_req req, struct json_object *obj, const char *info, va_list args); + +/* + * Sends a reply of kind failure to the request 'req'. + * The status of the reply is set to 'status' and an + * informationnal comment 'info' (can also be NULL) can be added. + * + * Note that calling afb_req_fail("success", info) is equivalent + * to call afb_req_success(NULL, info). Thus even if possible it + * is strongly recommanded to NEVER use "success" for status. + */ +void afb_req_fail(struct afb_req req, const char *status, const char *info); + +/* + * Same as 'afb_req_fail' but the 'info' is a formatting + * string followed by arguments. + */ +void afb_req_fail_f(struct afb_req req, const char *status, const char *info, ...); + +/* + * Same as 'afb_req_fail_f' but the arguments to the format 'info' + * are given as a variable argument list instance. + */ +void afb_req_fail_v(struct afb_req req, const char *status, const char *info, va_list args); +``` + +The following functions handle the session data. + +```C +/* + * Gets the pointer stored by the binding for the session of 'req'. + * When the binding has not yet recorded a pointer, NULL is returned. + */ +void *afb_req_context_get(struct afb_req req); + +/* + * Stores for the binding the pointer 'context' to the session of 'req'. + * The function 'free_context' will be called when the session is closed + * or if binding stores an other pointer. + */ +void afb_req_context_set(struct afb_req req, void *context, void (*free_context)(void*)); + +/* + * Gets the pointer stored by the binding for the session of 'req'. + * If the stored pointer is NULL, indicating that no pointer was + * already stored, afb_req_context creates a new context by calling + * the function 'create_context' and stores it with the freeing function + * 'free_context'. + */ +void *afb_req_context(struct afb_req req, void *(*create_context)(), void (*free_context)(void*)); + +/* + * Frees the pointer stored by the binding for the session of 'req' + * and sets it to NULL. + * + * Shortcut for: afb_req_context_set(req, NULL, NULL) + */ +void afb_req_context_clear(struct afb_req req); + +/* + * Closes the session associated with 'req' + * and delete all associated contexts. + */ +void afb_req_session_close(struct afb_req req); + +/* + * Sets the level of assurance of the session of 'req' + * to 'level'. The effect of this function is subject of + * security policies. + * Returns 1 on success or 0 if failed. + */ +int afb_req_session_set_LOA(struct afb_req req, unsigned level); +``` + + +The 4 following functions must be used for asynchronous handling requests. + +```C +/* + * Adds one to the count of references of 'req'. + * This function MUST be called by asynchronous implementations + * of verbs if no reply was sent before returning. + */ +void afb_req_addref(struct afb_req req); + +/* + * Substracts one to the count of references of 'req'. + * This function MUST be called by asynchronous implementations + * of verbs after sending the asynchronous reply. + */ +void afb_req_unref(struct afb_req req); + +/* + * Stores 'req' on heap for asynchrnous use. + * Returns a handler to the stored 'req' or NULL on memory depletion. + * The count of reference to 'req' is incremented on success + * (see afb_req_addref). + */ +struct afb_stored_req *afb_req_store(struct afb_req req); + +/* + * Retrieves the afb_req stored at 'sreq'. + * Returns the stored request. + * The count of reference is UNCHANGED, thus, the + * function 'afb_req_unref' should be called on the result + * after that the asynchronous reply if sent. + */ +struct afb_req afb_req_unstore(struct afb_stored_req *sreq); +``` + +The two following functions are used to associate client with events +(subscription). + +```C +/* + * Establishes for the client link identified by 'req' a subscription + * to the 'event'. + * Returns 0 in case of successful subscription or -1 in case of error. + */ +int afb_req_subscribe(struct afb_req req, struct afb_event event); + +/* + * Revokes the subscription established to the 'event' for the client + * link identified by 'req'. + * Returns 0 in case of successful subscription or -1 in case of error. + */ +int afb_req_unsubscribe(struct afb_req req, struct afb_event event); +``` + +The following functions must be used to make request in the name of the +client (with its permissions). + +```C +/* + * Makes a call to the method of name 'api' / 'verb' with the object 'args'. + * This call is made in the context of the request 'req'. + * On completion, the function 'callback' is invoked with the + * 'closure' given at call and two other parameters: 'iserror' and 'result'. + * 'iserror' is a boolean that indicates if the reply is an error reply. + * 'result' is the json object of the reply, you must not call json_object_put + * on the result. + * + * For convenience, the function calls 'json_object_put' for 'args'. + * Thus, in the case where 'args' should remain available after + * the function returns, the function 'json_object_get' shall be used. + */ +void afb_req_subcall( + struct afb_req req, + const char *api, + const char *verb, + struct json_object *args, + void (*callback)(void *closure, int iserror, struct json_object *result), + void *closure); + +/* + * Makes a call to the method of name 'api' / 'verb' with the object 'args'. + * This call is made in the context of the request 'req'. + * This call is synchronous, it waits untill completion of the request. + * It returns 0 on an error answer and returns 1 when no error was detected. + * The object pointed by 'result' is filled and must be released by the caller + * after its use by calling 'json_object_put'. + * + * For convenience, the function calls 'json_object_put' for 'args'. + * Thus, in the case where 'args' should remain available after + * the function returns, the function 'json_object_get' shall be used. + */ +int afb_req_subcall_sync( + struct afb_req req, + const char *api, + const char *verb, + struct json_object *args, + struct json_object **result); +``` + +The following function is used by logging macros and should normally +not be used. Instead, you should use the macros +**AFB_REQ_ERROR**, **AFB_REQ_WARNING**, **AFB_REQ_NOTICE**, +**AFB_REQ_INFO**, **AFB_REQ_DEBUG** + +```C +/* + * Send associated to 'req' a message described by 'fmt' and following parameters + * to the journal for the verbosity 'level'. + * + * 'file', 'line' and 'func' are indicators of position of the code in source files + * (see macros __FILE__, __LINE__ and __func__). + * + * 'level' is defined by syslog standard: + * EMERGENCY 0 System is unusable + * ALERT 1 Action must be taken immediately + * CRITICAL 2 Critical conditions + * ERROR 3 Error conditions + * WARNING 4 Warning conditions + * NOTICE 5 Normal but significant condition + * INFO 6 Informational + * DEBUG 7 Debug-level messages + */ +void afb_req_verbose(struct afb_req req, int level, const char *file, int line, const char * func, const char *fmt, ...); +``` + +Logging macros +-------------- + +The following macros must be used for logging: + +```C +AFB_ERROR(fmt,...) +AFB_WARNING(fmt,...) +AFB_NOTICE(fmt,...) +AFB_INFO(fmt,...) +AFB_DEBUG(fmt,...) +``` + +The following macros can be used for logging in the context +of a request **req** of type **afb_req**: + +```C +AFB_REQ_ERROR(req,fmt,...) +AFB_REQ_WARNING(req,fmt,...) +AFB_REQ_NOTICE(req,fmt,...) +AFB_REQ_INFO(req,fmt,...) +AFB_REQ_DEBUG(req,fmt,...) +``` + +By default, the logging macros add file, line and function +indication. + +Some definitions can be used to + + diff --git a/docs/afb-binding-writing.md b/docs/afb-binding-writing.md new file mode 100644 index 00000000..dd9a8b56 --- /dev/null +++ b/docs/afb-binding-writing.md @@ -0,0 +1,465 @@ + +Overview of the bindings +======================== + +The ***binder*** serves files through HTTP protocol and offers to +developers the capability to offer application API methods through HTTP or +WebSocket protocol. + +The ***bindings*** are used to add **API** to ***binders***. +This part describes how to write a ***binding*** for ***binder*** +or in other words how to add a new **API** to the system. + +Excepting this summary, this section target developers. + +This section shortly explain how to write a binding +using the C programming language. + +It is convenient to install the ***binder*** on the +desktop used for writing the binding. It allows easy +debug and test. + +Nature of a binding +------------------- + +A ***binding*** is an independent piece of software compiled as a shared +library and dynamically loaded by a ***binder***. + +It is intended to provide one **API** (**A**pplication **P**rogramming +**I**nterface). + +The **API** is designated and accessed through its name. +It contains several **verbs** that implement the ***binding*** +functionnalities. Each of these **verbs** is a **method** that +processes requests of applications and sends result. + +The ***binding***'s methods is invoqued by HTTP or websocket +requests. + +The **methods** of the ***bindings*** are noted **api/verb** +where **api** is the **API** name of the binding and **verb** is +the **method**'s name within the **API**. +This notation comes from HTTP invocations that rely on URL path terminated +with **api/verb**. + +The name of an **API** can be made of any characters except: + + - the control characters (\u0000 .. \u001f) + - the characters of the set { ' ', '"', '#', '%', '&', + '\'', '/', '?', '`', '\x7f' } + +The names if the **verbs** can be any character. + +The binder mkes no distinctions between upper case and lower case +latin letters. So **API/VERB** matches **Api/Verb** or **api/verb**. + +Actually it exists 2 ways of writing ***bindings***. +You can either write: + + - a binding version 1 (not recommanded); + - a binding version 2 (RECOMMANDED). + +A ***binder*** loads and runs any of these version +in any combination. + +This document explain how to write bindings version 2. + + +Sample binding: tuto-1 +====================== + +This is the code of the binding **tuto-1.c**: + +```C + 1 #define AFB_BINDING_VERSION 2 + 2 #include + 3 + 4 void hello(afb_req req) + 5 { + 6 AFB_REQ_DEBUG(req, "hello world"); + 7 afb_req_success(req, NULL, "hello world"); + 8 } + 9 + 10 const afb_verb_v2 verbs[] = { + 11 { .verb="hello", .callback=hello }, + 12 { .verb=NULL } + 13 }; + 14 + 15 const afb_binding_v2 afbBindingV2 = { + 16 .api = "tuto-1", + 17 .verbs = verbs + 18 }; +``` + +Compiling: + +```bash +$ gcc -fPIC -shared tuto-1.c -o tuto-1.so $(pkg-config --cflags-only-I afb-daemon) +``` + +Running: + +```bash +$ afb-daemon --binding tuto-1.so --port 3333 --token '' +``` + +Testing using **curl**: + +```bash +$ curl http://localhost:3333/api/tuto-1/hello +{"jtype":"afb-reply","request":{"status":"success","info":"hello world","uuid":"1e587b54-900b-49ab-9940-46141bc2e1d6"}} +``` + +Testing using **afb-client-demo** (with option -H for +getting a human readable output): + +```bash +$ afb-client-demo -H ws://localhost:3333/api?token=x tuto-1 hello +ON-REPLY 1:tuto-1/hello: OK +{ + "jtype":"afb-reply", + "request":{ + "status":"success", + "info":"hello world", + "uuid":"03a84ad1-458a-4ace-af74-b1da917391b9" + } +} +``` + +This shows basic things: + + - The include to get for creating a binding + - How to declare the API offered by the binding + - How to handle request made to the binding + + +### Getting declarations for the binding + +The lines 1 and 2 show how to get the include file **afb-binding.h**. + +```C + 1 #define AFB_BINDING_VERSION 2 + 2 #include +``` + +You must define the version of ***binding*** that you are using. +This is done line 1 where we define that this is the version 2. + +If you don't define it, a warning message is prompted by the compiler +and the version is switched to version 1. This behaviour is +temporarily and enables to continue to use previously written +***binding*** without change but it will change in some future when +***bindings*** V1 will become obsoletes. + +To include **afb-binding.h** successfuly, the include search path +should be set correctly if needed (not needed only if installed in +/usr/include/afb directory that is the default). + +Setting the include path is easy using **pkg-config**: + +```bash +$ pkg-config --cflags-only-I afb-daemon +``` + +Note for **C++** developers: The ***binder*** currently expose +only **C** language **API**. The file **afb/afb-binding.h** +isn't **C++** ready. You should use the construct **extern "C"** +as below: + +```C + #define AFB_BINDING_VERSION 2 + extern "C" { + #include + } +``` + +Future version of the ***binder*** will include a **C++** +interface. Until it is available, please, use the above +construct. + +### Declaring the API of the binding + +Lines 10 to 18 show the declaration of the ***binding***. + +The ***binder*** knows that this is a ***binding*** version 2 because +it finds the exported symbol **afbBindingV2** that is expected to be +a structure of type **afb_binding_v2**. + +```C + 10 const afb_verb_v2 verbs[] = { + 11 { .verb="hello", .callback=hello }, + 12 { .verb=NULL } + 13 }; + 14 + 15 const afb_binding_v2 afbBindingV2 = { + 16 .api = "tuto-1", + 17 .verbs = verbs + 18 }; +``` + +The structure **afbBindingV2** actually tells that: + + - the exported **API** name is **tuto-1** (line 16) + - the array of verbs is the above defined one + +The exported list of verb is specified by an array of structures, +each describing a verb, ended with a verb NULL (line 12). + +The only defined verb here (line 11) is named **hello** (field **.verb**) +and the function that handle the related request is **hello** +(field **.callback**). + +Note that you can explicitely mark the fact that these are +struct by typing the **struct** as below: + +```C + 10 const struct afb_verb_v2 verbs[] = { + 11 { .verb="hello", .callback=hello }, + 12 { .verb=NULL } + 13 }; + 14 + 15 const struct afb_binding_v2 afbBindingV2 = { + 16 .api = "tuto-1", + 17 .verbs = verbs + 18 }; +``` + +### Handling binder's requests + +As shown above this is by default the common include directory where +the AGL stuff is installed. + +```C + 4 void hello(afb_req req) + 5 { + 6 AFB_REQ_DEBUG(req, "hello world"); + 7 afb_req_success(req, NULL, "hello world"); + 8 } +``` + +When the ***binder*** receives a request for the verb **hello** of +of the api **tuto-1**, it invoque the callback **hello** of the **binding** +with the argument **req** that handles the client request. + +The callback has to treat synchronously or asynchronously the request and +should at the end emit a reply for the request. + +Here, the callback for **tuto-1/hello** replies a successful answer +(ligne 7) to the request **req**. The second parameter (here NULL) +is a json object that is sent to the client with the reply. +The third parameter is also sent with the reply and is a string +called info that can be used as some meta data. + +Here again, you can explicitely mark the fact that +**afb_req** is a structure by declaring **hello** as below: + +```C + 4 void hello(struct afb_req req) +``` + +Sample binding: tuto-2 +====================== + +The second tutorial shows many important feature that can +commonly be used when writting a ***binding***: initialisation, +getting arguments, sending replies, pushing events. + +This is the code of the binding **tuto-2.c**: + +```C + 1 #include + 2 #include + 3 + 4 #define AFB_BINDING_VERSION 2 + 5 #include + 6 + 7 afb_event event_login, event_logout; + 8 + 9 void login(afb_req req) + 10 { + 11 json_object *args, *user, *passwd; + 12 char *usr; + 13 + 14 args = afb_req_json(req); + 15 if (!json_object_object_get_ex(args, "user", &user) + 16 || !json_object_object_get_ex(args, "password", &passwd)) { + 17 AFB_REQ_ERROR(req, "login, bad request: %s", json_object_get_string(args)); + 18 afb_req_fail(req, "bad-request", NULL); + 19 } else if (afb_req_context_get(req)) { + 20 AFB_REQ_ERROR(req, "login, bad state, logout first"); + 21 afb_req_fail(req, "bad-state", NULL); + 22 } else if (strcmp(json_object_get_string(passwd), "please")) { + 23 AFB_REQ_ERROR(req, "login, unauthorized: %s", json_object_get_string(args)); + 24 afb_req_fail(req, "unauthorized", NULL); + 25 } else { + 26 usr = strdup(json_object_get_string(user)); + 27 AFB_REQ_NOTICE(req, "login user: %s", usr); + 28 afb_req_session_set_LOA(req, 1); + 29 afb_req_context_set(req, usr, free); + 30 afb_req_success(req, NULL, NULL); + 31 afb_event_push(event_login, json_object_new_string(usr)); + 32 } + 33 } + 34 + 35 void action(afb_req req) + 36 { + 37 json_object *args, *val; + 38 char *usr; + 39 + 40 args = afb_req_json(req); + 41 usr = afb_req_context_get(req); + 42 AFB_REQ_NOTICE(req, "action for user %s: %s", usr, json_object_get_string(args)); + 43 if (json_object_object_get_ex(args, "subscribe", &val)) { + 44 if (json_object_get_boolean(val)) { + 45 AFB_REQ_NOTICE(req, "user %s subscribes to events", usr); + 46 afb_req_subscribe(req, event_login); + 47 afb_req_subscribe(req, event_logout); + 48 } else { + 49 AFB_REQ_NOTICE(req, "user %s unsubscribes to events", usr); + 50 afb_req_unsubscribe(req, event_login); + 51 afb_req_unsubscribe(req, event_logout); + 52 } + 53 } + 54 afb_req_success(req, json_object_get(args), NULL); + 55 } + 56 + 57 void logout(afb_req req) + 58 { + 59 char *usr; + 60 + 61 usr = afb_req_context_get(req); + 62 AFB_REQ_NOTICE(req, "login user %s out", usr); + 63 afb_event_push(event_logout, json_object_new_string(usr)); + 64 afb_req_session_set_LOA(req, 0); + 65 afb_req_context_clear(req); + 66 afb_req_success(req, NULL, NULL); + 67 } + 68 + 69 int preinit() + 70 { + 71 AFB_NOTICE("preinit"); + 72 return 0; + 73 } + 74 + 75 int init() + 76 { + 77 AFB_NOTICE("init"); + 78 event_login = afb_daemon_make_event("login"); + 79 event_logout = afb_daemon_make_event("logout"); + 80 if (afb_event_is_valid(event_login) && afb_event_is_valid(event_logout)) + 81 return 0; + 82 AFB_ERROR("Can't create events"); + 83 return -1; + 84 } + 85 + 86 const afb_verb_v2 verbs[] = { + 87 { .verb="login", .callback=login }, + 88 { .verb="action", .callback=action, .session=AFB_SESSION_LOA_1 }, + 89 { .verb="logout", .callback=logout, .session=AFB_SESSION_LOA_1 }, + 90 { .verb=NULL } + 91 }; + 92 + 93 const afb_binding_v2 afbBindingV2 = { + 94 .api = "tuto-2", + 95 .specification = NULL, + 96 .verbs = verbs, + 97 .preinit = preinit, + 98 .init = init, + 99 .noconcurrency = 0 + 100 }; +``` + +Compiling: + +```bash +$ gcc -fPIC -shared tuto-2.c -o tuto-2.so $(pkg-config --cflags --libs afb-daemon) +``` + +Running: + +```bash +$ afb-daemon --binding tuto-2.so --port 3333 --token '' +``` + +Testing: + +```bash +$ afb-client-demo -H localhost:3333/api?token=toto +tuto-2 login {"help":true} +ON-REPLY 1:tuto-2/login: ERROR +{ + "jtype":"afb-reply", + "request":{ + "status":"bad-request", + "uuid":"e2b24a13-fc43-487e-a5f4-9266dd1e60a9" + } +} +tuto-2 login {"user":"jose","password":"please"} +ON-REPLY 2:tuto-2/login: OK +{ + "jtype":"afb-reply", + "request":{ + "status":"success" + } +} +tuto-2 login {"user":"jobol","password":"please"} +ON-REPLY 3:tuto-2/login: ERROR +{ + "jtype":"afb-reply", + "request":{ + "status":"bad-state" + } +} +tuto-2 action {"subscribe":true} +ON-REPLY 4:tuto-2/action: OK +{ + "response":{ + "subscribe":true + }, + "jtype":"afb-reply", + "request":{ + "status":"success" + } +} +``` + +In an other terminal: + +```bash +$ afb-client-demo -H localhost:3333/api?token=toto +tuto-2 login {"user":"jobol","password":"please"} +ON-REPLY 1:tuto-2/login: OK +{ + "jtype":"afb-reply", + "request":{ + "status":"success", + "uuid":"a09f55ff-0e89-4f4e-8415-c6e0e7f439be" + } +} +tuto-2 logout true +ON-REPLY 2:tuto-2/logout: OK +{ + "jtype":"afb-reply", + "request":{ + "status":"success" + } +} +``` + +It produced in the first terminal: + +```bash +ON-EVENT tuto-2/login: +{ + "event":"tuto-2\/login", + "data":"jobol", + "jtype":"afb-event" +} +ON-EVENT tuto-2/logout: +{ + "event":"tuto-2\/logout", + "data":"jobol", + "jtype":"afb-event" +} +``` + diff --git a/docs/afb-daemon-options.md b/docs/afb-daemon-options.md new file mode 100644 index 00000000..39cf0bdb --- /dev/null +++ b/docs/afb-daemon-options.md @@ -0,0 +1,200 @@ + +Launching options of afb-daemon +--------------------- + +The launch options for binder **afb-daemon** are: + + --help + + Prints help with available options + + --version + + Display version and copyright + + --verbose + + Increases the verbosity, can be repeated + + --quiet + + Decreases the verbosity, can be repeated + + --port=xxxx + + HTTP listening TCP port [default 1234] + + --workdir=xxxx + + Directory where the daemon must run [default: $PWD if defined + or the current working directory] + + --uploaddir=xxxx + + Directory where uploaded files are temporarily stored [default: workdir] + + --rootdir=xxxx + + Root directory of the application to serve [default: workdir] + + --roothttp=xxxx + + Directory of HTTP served files. If not set, files are not served + but apis are still accessibles. + + --rootbase=xxxx + + Angular Base Root URL [default /opa] + + This is used for any application of kind OPA (one page application). + When set, any missing document whose url has the form /opa/zzz + is translated to /opa/#!zzz + + --rootapi=xxxx + + HTML Root API URL [default /api] + + The bindings are available within that url. + + --alias=xxxx + + Maps a path located anywhere in the file system to the + a subdirectory. The syntax for mapping a PATH to the + subdirectory NAME is: --alias=/NAME:PATH. + + Example: --alias=/icons:/usr/share/icons maps the + content of /usr/share/icons within the subpath /icons. + + This option can be repeated. + + --apitimeout=xxxx + + binding API timeout in seconds [default 20] + + Defines how many seconds maximum a method is allowed to run. + 0 means no limit. + + --cntxtimeout=xxxx + + Client Session Timeout in seconds [default 3600] + + --cache-eol=xxxx + + Client cache end of live [default 100000 that is 27,7 hours] + + --session-max=xxxx + + Maximum count of simultaneous sessions [default 10] + + --ldpaths=xxxx + + Load bindings from given paths separated by colons + as for dir1:dir2:binding1.so:... [default = $libdir/afb] + + You can mix path to directories and to bindings. + The sub-directories of the given directories are searched + recursively. + + The bindings are the files terminated by '.so' (the extension + so denotes shared object) that contain the public entry symbol. + + --binding=xxxx + + Load the binding of given path. + + --token=xxxx + + Initial Secret token to authenticate. + + If not set, no client can authenticate. + + If set to the empty string, then any initial token is accepted. + + --random-token + + Generate a random starting token. See option --exec. + + --mode=xxxx + + Set the mode: either local, remote or global. + + The mode indicate if the application is run locally on the host + or remotely through network. + + --dbus-client=xxxx + + Transparent binding to a binder afb-daemon service through dbus. + + It creates an API of name xxxx that is implemented remotely + and queried via DBUS. + + --dbus-server=xxxx + + Provides a binder afb-daemon service through dbus. + + The name xxxx must be the name of an API defined by a binding. + This API is exported through DBUS. + + --ws-client=xxxx + + Transparent binding to a binder afb-daemon service through a WebSocket. + + The value of xxxx is either a unix naming socket, of the form "unix:path/api", + or an internet socket, of the form "host:port/api". + + --ws-server=xxxx + + Provides a binder afb-daemon service through WebSocket. + + The value of xxxx is either a unix naming socket, of the form "unix:path/api", + or an internet socket, of the form "host:port/api". + + --foreground + + Get all in foreground mode (default) + + --daemon + + Get all in background mode + + --no-httpd + + Forbids HTTP serve + + --exec + + Must be the last option for afb-daemon. The remaining + arguments define a command that afb-daemon will launch. + The sequences @p, @t and @@ of the arguments are replaced + with the port, the token and @. + + --tracereq=xxxx + + Trace the processing of requests in the log file. + + Valid values are 'no' (default), 'common', 'extra' or 'all'. + + --traceditf=xxxx + + Trace the accesses to functions of class daemon. + + Valid values are 'no' (default), 'common', 'extra' or 'all'. + + --tracesvc=xxxx + + Trace the accesses to functions of class service. + + Valid values are 'no' (default) or 'all'. + + --traceevt=xxxx + + Trace the accesses to functions of class event. + + Valid values are 'no' (default), 'common', 'extra' or 'all'. + + --call=xxx + + Call a binding at start (can be be repeated). + The values are given in the form API/VERB:json-args. + + Example: --call 'monitor/set:{"verbosity":{"api":"debug"}}' diff --git a/docs/afb-daemon-vocabulary.md b/docs/afb-daemon-vocabulary.md new file mode 100644 index 00000000..c3b7c1ea --- /dev/null +++ b/docs/afb-daemon-vocabulary.md @@ -0,0 +1,98 @@ + +Vocabulary for AFB-DAEMON +========================= + +## Binding + +A shared library object intended to add a functionality to an afb-daemon +instance. It implements an API and may provide a service. + +Binding made for services can have specific entry point called after +initialisation and before serving. + +## Event + +Message with data propagated from the services to the client and not expecting +any reply. + +The current implementation allows to widely broadcast events to all clients. + +## Level of assurance (LOA) + +This level that can be from 0 to 3 represent the level of +assurance that the services can expect from the session. + +The exact definition of the meaning of these levels and how to use it remains to +be achieved. + +## Plugin + +Old name for binding, see binding. + +## Request + +A request is an invocation by a client to a binding method using a message +transferred through some protocol: HTTP, WebSocket, DBUS... and served by +***afb-daemon*** + +## Reply/Response + +This is a message sent to client as the result of the request. + +## Service + +Service are made of bindings running by their side on their binder. +It can serve many client. Each one attached to one session. + +The framework establishes connection between the services and +the clients. Using DBus currently but other protocols are considered. + +## Session + +A session is meant to be the unique instance context of a client, +which identify that instance across requests. + +Each session has an identifier. Session identifier generated by afb-daemon are +UUIDs. + +Internally, afb-daemon offers a mechanism to attach data to sessions. +When the session is closed or disappears, the data attached to that session +are freed. + +## Token + +The token is an identifier that the client must give to be authenticated. + +At start, afb-daemon get an initial token. This initial token must be presented +by incoming client to be authenticated. + +A token is valid only for a period. + +The token must be renewed periodically. When the token is renewed, afb-daemon +sends the new token to the client. + +Tokens generated by afb-daemon are UUIDs. + +## UUID + +It stand for Universal Unique IDentifier. + +It is designed to create identifier in a way that avoid has much as possible +conflicts. It means that if two different instances create an UUID, the +probability that they create the same UUID is very low, near to zero. + +## x-afb-reqid + +Argument name that can be used with HTTP request. When this argument is given, +it is automatically added to the "request" object of the answer. + +## x-afb-token + +Argument name meant to give the token without ambiguity. +You can also use the name **token** but it may conflicts with others arguments. + +## x-afb-uuid + +Argument name for giving explicitly the session identifier without ambiguity. +You can also use the name **uuid** but it may conflicts with others arguments. + diff --git a/docs/afb-desktop-package.md b/docs/afb-desktop-package.md new file mode 100644 index 00000000..775f4ee5 --- /dev/null +++ b/docs/afb-desktop-package.md @@ -0,0 +1,40 @@ + +Desktop packages for binder developement +======================================== + +It exists packages of the ***binder*** (afb-daemon) +for common desktop linux distributions. + + - Fedora + - Ubuntu + - Debian + - Suse + +Installing the developement package of the ***binder*** +allows to write ***bindings*** that runs on the destop +computer of the developper. + +It is very convenient to quickly write and debug a binding. + +Retriving compiling option with pkg-config +========================================== + +The ***binder*** afb-daemon provides a configuration +file for **pkg-config**. +Typing the command + + pkg-config --cflags afb-daemon + +Print flags use for compilation: + + $ pkg-config --cflags afb-daemon + -I/opt/local/include -I/usr/include/json-c + +For linking, you should use + + $ pkg-config --libs afb-daemon + -ljson-c + +It automatically includes the dependency to json-c. +This is activated through **Requires** keyword in pkg-config. + diff --git a/docs/afb-events-guide.md b/docs/afb-events-guide.md new file mode 100644 index 00000000..b6e4557c --- /dev/null +++ b/docs/afb-events-guide.md @@ -0,0 +1,371 @@ +Guide for developing with events +================================ + +Signaling agents are services that send events to any clients that +subscribed for receiving it. The sent events carry any data. + +To have a good understanding of how to write a signaling agent, the +actions of subscribing, unsubscribing, producing, sending and receiving +events must be described and explained. + +Overview of events +------------------ + +The basis of a signaling agent is shown in the following figure: + +![scenario of using events](pictures/signaling-basis.svg) + +This figure shows the main role of the signaling framework for the events +propagation. + +For people not familiar with the framework, a signaling agent and +a “binding” are similar. + +### Subscribing and unsubscribing + +Subscribing is the action that makes a client able to receive data from a +signaling agent. Subscription must create resources for generating the data, and +for delivering the data to the client. These two aspects are not handled by the +same piece of software. Generating the data is the responsibility of the +developer of the signaling agent while delivering the data is handled by the +framework. + +When a client subscribes for data, the agent must: + +1. check that the subscription request is correct; +2. establish the computation chain of the required data, if not already + done; +3. create a named event for the computed data, if not already done; +4. ask the framework to establish the subscription to the event for the + request; +5. optionally give indications about the event in the reply to + the client. + +The first two steps are not involving the framework. They are linked to +the business logic of the binding. The request can be any description of +the requested data and the computing stream can be of any nature, this +is specific to the binding. + +As said before, the framework uses and integrates **libsystemd** and its event +loop. Within the framework, **libsystemd** is the standard API/library for +bindings expecting to setup and handle I/O, timer or signal events. + +Steps 3 and 4 are bound to the framework. + +The agent must create an object for handling the propagation of produced +data to its clients. That object is called “event” in the framework. An +event has a name that allows clients to distinguish it from other +events. + +Events are created using the ***afb\_daemon\_make\_event*** function +that takes the name of the event. Example: + +```C + event = afb_daemon_make_event(name); +``` + +Once created, the event can be used either to push data to its +subscribers or to broadcast data to any listener. + +The event must be used to establish the subscription for the requesting +client. This is done using the ***afb\_req\_subscribe*** function +that takes the current request object and event and associates them +together. Example: + +```C + rc = afb_req_subscribe(req, event); +``` + +When successful, this function make the connection between the event and +the client that emitted the request. The client becomes a subscriber of +the event until it unsubscribes or disconnects. The +***afb\_req\_subscribe*** function will fail if the client +connection is weak: if the request comes from a HTTP link. To receive +signals, the client must be connected. The AGL framework allows connections +using WebSocket. + +The name of the event is either a well known name or an ad hoc name +forged for the use case. + +Let's see a basic example: client A expects to receive the speed in km/h +every second while client B expects the speed in mph twice a second. In +that case, there are two different events because it is not the same +unit and it is not the same frequency. Having two different events +allows to associate clients to the correct event. But this doesn't tell +any word about the name of these events. The designer of the signaling +agent has two options for naming: + +1. names can be the same (“speed” for example) with sent data + self describing itself or having a specific tag (requiring from + clients awareness about requesting both kinds of speed isn't safe). +2. names of the event include the variations (by example: + “speed-km/h-1Hz” and “speed-mph-2Hz”) and, in that case, sent data + can self describe itself or not. + +In both cases, the signaling agent might have to send the name of the +event and/or an associated tag to its client in the reply of the +subscription. This is part of the step 5 above. + +The framework only uses the event (not its name) for subscription, +unsubscription and pushing. + +When the requested data is already generated and the event used for +pushing it already exists, the signaling agent must not instantiate a +new processing chain and must not create a new event object for pushing +data. The signaling agent must reuse the existing chain and event. + +Unsubscribing is made by the signaling agent on a request of its client. +The ***afb\_req\_unsubscribe*** function tells the framework to +remove the requesting client from the event's list of subscribers. +Example: + +```C + afb_req_unsubscribe(req, event); +``` + +Subscription count does not matter to the framework: subscribing the +same client several times has the same effect that subscribing only one +time. Thus, when unsubscribing is invoked, it becomes immediately +effective. + +#### More on naming events + +Within the AGL framework, a signaling agent is a binding that has an API +prefix. This prefix is meant to be unique and to identify the binding +API. The names of the events that this signaling agent creates are +automatically prefixed by the framework, using the API prefix of the +binding. + +Thus, if a signaling agent of API prefix ***api*** creates an event +of name ***event*** and pushes data to that event, the subscribers +will receive an event of name ***api/event***. + +### Generating and pushing signals and data + +This of the responsibility of the designer of the signaling agent to +establish the processing chain for generating events. In many cases, +this can be achieved using I/O or timer or signal events inserted in the +main loop. For this case, the AGL framework uses **libsystemd** and +provide a way to integrates to the main loop of this library using +afb\_daemon\_get\_event\_loop. Example: + +```C + sdev = afb_daemon_get_event_loop(); + rc = sd_event_add_io(sdev, &source, fd, EPOLLIN, myfunction, NULL); +``` + +In some other cases, the events are coming from D-Bus. In that case, the +framework also uses **libsystemd** internally to access D-Bus. It provides +two methods to get the available D-Bus objects, already existing and +bound to the main**libsystemd**event loop. Use either +***afb\_daemon\_get\_system\_bus*** or +***afb\_daemon\_get\_user\_bus*** to get the required instance. Then +use functions of **libsystemd** to handle D-Bus. + +In some rare cases, the generation of the data requires to start a new +thread. + +When a data is generated and ready to be pushed, the signaling agent +should call the function ***afb\_event\_push***. Example: + +```C + rc = afb_event_push(event, JSON); + if (rc == 0) { + stop_generating(event); + afb_event_drop(event); + } +``` + +The function ***afb\_event\_push*** pushes json data to all the +subscribers. It then returns the count of subscribers. When the count is +zero, there is no subscriber listening for the event. The example above +shows that in that case, the signaling agent stops to generate data for +the event and delete the event using afb\_event\_drop. This is one +possible option. Other valuable options are: do nothing and continue to +generate and push the event or just stop to generate and push the data +but keep the event existing. + +### Receiving the signals + +Understanding what a client expects when it receives signals, events or +data shall be the most important topic of the designer of a signaling +agent. The good point here is that because JSON[^1] is the exchange +format, structured data can be sent in a flexible way. + +The good design is to allow as much as possible the client to describe +what is needed with the goal to optimize the processing to the +requirements only. + +### The exceptional case of wide broadcast + +Some data or events have so much importance that they can be widely +broadcasted to alert any listening client. Examples of such an alert +are: + +- system is entering/leaving “power safe” mode +- system is shutting down +- the car starts/stops moving +- ... + +An event can be broadcasted using one of the two following methods: +***afb\_daemon\_broadcast\_event*** or +***afb\_event\_broadcast***. + +Example 1: + +```C + afb_daemon_broadcast_event(name, json); +``` + +Example 2: + +```C + event = afb_daemon_make_event(name); + . . . . + afb_event_broadcast(event, json); +``` + +As for other events, the name of events broadcasted using +***afb\_daemon\_broadcast\_event*** are automatically prefixed by +the framework with API prefix of the binding (signaling agent). + +Reference of functions +---------------------- + +### Function afb\_event afb\_daemon\_make\_event + +The function ***afb\_daemon\_make\_event*** that is defined as below: + +```C +/* + * Creates an event of 'name' and returns it. + */ +struct afb_event afb_daemon_make_event(const char *name); +``` + +The correct way to create the event at initialisation is to call the function +***afb\_daemon\_make\_event*** within the initialisation +function referenced by the field ***init*** of the structure ***afbBindingV2***. + +### Function afb\_event\_push + +The function ***afb\_event\_push*** is defined as below: + +```C +/* + * Pushes the 'event' with the data 'object' to its observers. + * 'object' can be NULL. + * + * For convenience, the function calls 'json_object_put' for object'. + * Thus, in the case where 'object' should remain available after + * the function returns, the function 'json_object_get' shall be used. + * + * Returns the count of clients that received the event. + */ +int afb_event_push(struct afb_event event, struct json_object *object); +``` + +As the function ***afb\_event\_push*** returns 0 when there is no +more subscriber, a binding can remove such unexpected event using the +function ***afb\_event\_drop***. + +### Function afb\_event\_drop + +The function ***afb\_event\_drop*** is defined as below: + +```C +/* + * Drops the data associated to the event + * After calling this function, the event + * MUST NOT BE USED ANYMORE. + */ +void afb_event_drop(struct afb_event event); +``` + +### Function afb\_req\_subscribe + +The function ***afb\_req\_subscribe*** is defined as below: + +```C +/* + * Establishes for the client link identified by 'req' a subscription + * to the 'event'. + * Returns 0 in case of successful subscription or -1 in case of error. + */ +int afb_req_subscribe(struct afb_req req, struct afb_event event); +``` + +The subscription adds the client of the request to the list of subscribers +to the event. + +### Function afb\_req\_unsubscribe + +The function ***afb\_req\_unsubscribe*** is defined as +below: + +```C +/* + * Revokes the subscription established to the 'event' for the client + * link identified by 'req'. + * Returns 0 in case of successful unsubscription or -1 in case of error. + */ +int afb_req_unsubscribe(struct afb_req req, struct afb_event event); +``` + +The unsubscription removes the client of the request of the list of subscribers +to the event. +When the list of subscribers to the event becomes empty, +the function ***afb\_event\_push*** will return zero. + +### Function afb\_event\_broadcast + +The function ***afb\_event\_broadcast*** is defined as below: + +```C +/* + * Broadcasts widely the 'event' with the data 'object'. + * 'object' can be NULL. + * + * For convenience, the function calls 'json_object_put' for 'object'. + * Thus, in the case where 'object' should remain available after + * the function returns, the function 'json_object_get' shall be used. + * + * Returns the count of clients that received the event. + */ +int afb_event_broadcast(struct afb_event event, struct json_object *object); +``` + +This uses an existing event (created with ***afb\_daemon\_make\_event***) +for broadcasting an event having its name. + + +### Function afb\_daemon\_broadcast\_event + +The function ***afb\_daemon\_broadcast\_event*** is defined as below: + +```C +/* + * Broadcasts widely the event of 'name' with the data 'object'. + * 'object' can be NULL. + * + * For convenience, the function calls 'json_object_put' for 'object'. + * Thus, in the case where 'object' should remain available after + * the function returns, the function 'json_object_get' shall be used. + * + * Returns the count of clients that received the event. + */ +int afb_daemon_broadcast_event(const char *name, struct json_object *object); +``` + +The name is given here explicitly. The name is automatically prefixed +with the name of the binding. For example, a binding of prefix "xxx" +would broadcat the event "xxx/name". + +### Function onevent (field of afbBindingV2) + +Binding can designate an event handling function using the field **onevent** +of the structure **afbBindingV2**. This function is called when an event is +broadcasted or when an event the binding subscribed to is pushed. +That allow a service to react to an event and do what it is to do if this is +relevant for it (ie: car back camera detects imminent collision and broadcast +it, then appropriate service enable parking brake.). diff --git a/docs/afb-migration-v1-to-v2.md b/docs/afb-migration-v1-to-v2.md new file mode 100644 index 00000000..487c259d --- /dev/null +++ b/docs/afb-migration-v1-to-v2.md @@ -0,0 +1,611 @@ +Migration from binding V1 to binding V2 +======================================= + +The ***binding*** interface evolved from version 1 to version 2 +for the following reasons: + + - integration of the security requirements within the bindings + - simplification of the API (after developer feedbacks) + - removal of obscur features, cleanup + +The ***binder*** can run ***bindings*** v1 and/or v2 in any combination. +Thus moving from v1 to v2 is not enforced. There is no real need. + +More, it is possible to write a dual ***binding***: a ***binding*** that +implements the version 1 AND the version 2. + +However, IT IS HIGHLY RECOMMANDED TO SWITCH TO ONLY VERSION 2: + + - any new developement SHOULD start using ***binding*** V2 + - existing ***bindings*** SHOULD migrate to the version 2 + +This guide covers the migration of bindings from version 1 to version 2. + +It also explains some of the rationale taken when migrating from version 1 to version 2. + +In the future, if ***binding*** api evolves to fresh versions (3, 4, ...) +it might be necessarily to write bindings implementing more than +just one version. For example, a ***binding*** being v2 AND v3 will resolve +the issue of running on older AND newer version of AGL. This should always +be possible even if more complicated. + +Important things to known when migrating +---------------------------------------- + +One of the most important change when migrating from v1 to v2 is +that many functions use an hidden *common* variable. +This affects the functions of the following classes: + + - functions of class **daemon**: + * functions starting with **afb_daemon_...** + * functions for logging: **ERROR**, **WARNING**, **NOTICE**, **INFO**, **DEBUG** + - functions of class **service**: + * functions starting with **afb_service_...** + - callback functions: + * the register function (that is removed) + * the service init function + * the onevent function + +For these functions, the first parameter is now implicit. + +Let takes an example. For ***binding*** v1 you had to write: + +```C + afb_daemon_broadcast_event(afbitf->daemon, reason, description); +``` + +For ***binding*** v2, you simply write: + +```C + afb_daemon_broadcast_event(reason, description); +``` + +This simplification is possible because the header files included for the bindings +now provide a common variable for storing the **daemon** and **service** data. + +As a programmer, you shouldn't care much about that hidden variable. +It simplifies the job, that's all and that is the reason of the change. + +An other important difference is between the version 1 and the version 2 is +on how the ***binding***'s **API** is documented. The version 2 enphasis the +**OpenAPI v3** description of the **API**. For this reason, to avoid +duplication of descriptions, only one description is expected: the **OpenAPI** one. + +Task list for the migration +--------------------------- + +This task list is: + + 1. Enforce use of binding v2 by setting **AFB_BINDING_VERSION** + 2. Rewrite the main structure and the list of exported verbs + 3. Adapt the init and callback functions + 4. Removes the first parameter of functions of classes **daemon** + and **service** + 5. Consider where to emit logs for requests + 6. Take care of store/unstore changes + 7. Consider use of synchronous (sub)call requests + 8. Optionnaly, removes explicit struct + +The remaining chapters explain these task with more details. + +Enforce use of binding v2 by setting AFB_BINDING_VERSION +-------------------------------------------------------- + +By defining **AFB_BINDING_VERSION** to **2** you switch to version 2. +This is done as below. + +```C +#define AFB_BINDING_VERSION 2 +#include +``` + +After that you will get many errors when compiling. + +Rewrite the main structures and the list of exported verbs +--------------------------------------------------------- + +The structures describing the ***binding** changed from version 1 to version 2. + +The structure for describing verbs changed to include security +requirements. In version 1 it was: + +```C +struct afb_verb_desc_v1 +{ + const char *name; /* name of the verb */ + enum afb_session_flags_v1 session; /* authorisation and session requirements of the verb */ + void (*callback)(struct afb_req req); /* callback function implementing the verb */ + const char *info; /* textual description of the verb */ +}; +``` + +In version 2 it becomes: + +```C +struct afb_verb_v2 +{ + const char *verb; /* name of the verb */ + void (*callback)(struct afb_req req); /* callback function implementing the verb */ + const struct afb_auth *auth; /* required authorisation */ + uint32_t session; /* authorisation and session requirements of the verb */ +}; + +``` + +The migration of instances of that structure requires the following actions: + + - rename field **name** to **verb** + - remove field **info** + - adapt field **session** if needed + - set field **auth** to NULL + +Example: + +```C + { .name= "new", .session= AFB_SESSION_NONE, .callback= new, .info= "Starts a new game" } +``` + +Becomes + +```C + { .verb = "new", .session = AFB_SESSION_NONE, .callback = new, .auth = NULL } +``` + +The field **auth** can be set to a value describing the requested +authorisation. + +The main describing structure also changed. In version 1 it was: + +```C +struct afb_binding_desc_v1 +{ + const char *info; /* textual information about the binding */ + const char *prefix; /* required prefix name for the binding */ + const struct afb_verb_desc_v1 *verbs; /* array of descriptions of verbs terminated by a NULL name */ +}; +``` + +In version 2 it becomes: + +```C +struct afb_binding_v2 +{ + const char *api; /* api name for the binding */ + const char *specification; /* textual specification of the binding */ + const struct afb_verb_v2 *verbs; /* array of descriptions of verbs terminated by a NULL name */ + int (*preinit)(); /* callback at load of the binding */ + int (*init)(); /* callback for starting the service */ + void (*onevent)(const char *event, struct json_object *object); /* callback for handling events */ + unsigned noconcurrency: 1; /* avoids concurrent requests to verbs */ +}; +``` + +The migration of instances of that structure requires the following actions: + + - declare, expore, name the structure as ```const struct afb_binding_v2 afbBindingV2``` + - rename the field **prefix** to **api** + - remove the field **info** + - setup the fields **preinit**, **init**, **onevent** accordling to the next section + - set the field **noconcurrency** to the right value: + * to 1 if you want to avoid concurrent calls to verbs. + * to 0 if you allow concurrent calls to verbs. + +Example: + +```C +static const struct afb_binding plugin_desc = { + .type = AFB_BINDING_VERSION_1, + .v1 = { + .info = "Minimal Hello World Sample", + .prefix = "hello", + .verbs = verbs + } +``` +Becomes: + +```C +const struct afb_binding_v2 afbBindingV2 = { + .api = "hello", + .specification = NULL, + .verbs = verbs, + .preinit = preinit, + .init = init +}; +``` + +The **binder** now relies only on the exported names +to deduce the type of the binding. This make the main +structure more simple. + +Adapt the init and callback functions +------------------------------------- + +The ***bindings*** version 1 defined 3 exported functions: + + - **afbBindingV1Register** + - **afbBindingV1ServiceInit** + - **afbBindingV1ServiceEvent** + +These function should not be exported any more and there definition changed. + +The function **afbBindingV1Register** is no more used to describe the binding. +When a binding has to take actions when it is loaded, it must set the field +**preinit** of the structure **afbBindingV2**. This field, this preinit, might +be used to check features at load. When it returns a negative number, the +***binder*** stops before initializing any ***binding***. + +The function **afbBindingV1ServiceInit** is replaced by the field **init** +of the structure **afbBindingV2**. The init function should return 0 in case +of success or a negative error code in case of problem. It is called during +initialisation of services. + +The function **afbBindingV1ServiceEvent**is replaced by the field **onevent** +of the structure **afbBindingV2**. + +The two functions **afbBindingV1Register** and **afbBindingV1ServiceInit**, +were taking as parameter the ***binder*** interface and the service interface respectively. +These interfaces are now managed hiddenly for the **binding** by the **binder**. +So the variable that ***bindings*** version used to store the ***binder*** interface +and the service interface are no more needed and can be removed. + +Example: + +```C +const struct afb_binding_interface *interface; +struct afb_service service; + +static const struct afb_binding plugin_desc = { + .type = AFB_BINDING_VERSION_1, + .v1 = { + .info = "Minimal Hello World Sample", + .prefix = "hello", + .verbs = verbs + } +} + +const struct afb_binding *afbBindingV1Register (const struct afb_binding_interface *itf) +{ + interface = itf; + NOTICE(interface, "binding register"); + return &plugin_desc; +} + +int afbBindingV1ServiceInit(struct afb_service svc) +{ + service = svc; + NOTICE(interface, "binding init"); + return 0; +} + +void afbBindingV1ServiceEvent(const char *event, struct json_object *object) +{ + NOTICE(interface, "onevent %s", event); +} +``` + +Becomes: + +```C +static int preinit() +{ + AFB_NOTICE("binding preinit (was register)"); + return 0; +} + +static int init() +{ + AFB_NOTICE("binding init"); + return 0; +} + +static void onevent(const char *event, struct json_object *object) +{ + AFB_NOTICE("onevent %s", event); +} + +const struct afb_binding_v2 afbBindingV2 = { + .api = "hello", + .specification = NULL, + .verbs = verbs, + .preinit = preinit, + .init = init, + .onevent = onevent +}; +``` + +The two functions **afbBindingV1Register** and **afbBindingV1ServiceInit**, +were taking as parameter the ***binder*** interface and the service interface respectively. +These interfaces are now managed hiddenly for the **binding** by the **binder**. +So the variable that ***bindings*** version used to store the ***binder*** interface +and the service interface are no more needed and can be removed. + +On the above example the folowing lines were removed: +```C +const struct afb_binding_interface *interface; +struct afb_service service; + + interface = itf; + + service = svc; +``` + + + +Removes the first parameter of functions of classes **daemon** and **service** +------------------------------------------------------------------------------ + +As explained before, many functions loose there first +arguments, this are the functions of the following classes: + + - functions of class **daemon**: + * functions starting with **afb_daemon_...** + * functions for logging: **ERROR**, **WARNING**, **NOTICE**, **INFO**, **DEBUG** + - functions of class **service**: + * functions starting with **afb_service_...** + - callback functions: + * the register function (that is removed) + * the service init function + * the onevent function + +For these functions, the first parameter is now implicit. + +Example: + +```C + afb_daemon_broadcast_event(afbitf->daemon, reason, description); +``` + +Becomes: + +```C + afb_daemon_broadcast_event(reason, description); +``` + +Also, to avoid possible conflicts, we introduced prefixed logging functions: +the macros **ERROR**, **WARNING**, **NOTICE**, **INFO**, **DEBUG** have now +a prefixed version: **AFB\_ERROR**, **AFB\_WARNING**, **AFB\_NOTICE**, +**AFB\_INFO**, **AFB\_DEBUG**. It is now recommanded to use the prefixed version. + +Example: + +```C + NOTICE(interface, "hello plugin comes to live"); +``` + +Become: + +```C + NOTICE("hello plugin comes to live"); +``` + +or, better: + +```C + AFB_NOTICE("hello plugin comes to live"); +``` + +To remove definition of the unprefixed versions of logging macros **ERROR**, **WARNING**, +**NOTICE**, **INFO**, **DEBUG** and just define **AFB_BINDING_PRAGMA_NO_VERBOSE_UNPREFIX** +before to include **afb/afb-binding.h**. + +```C +#define AFB_BINDING_PRAGMA_NO_VERBOSE_UNPREFIX +#define AFB_BINDING_VERSION 2 +#include +``` + +Consider where to emit logs for requests +---------------------------------------- + +The ***bindings*** v2 now allows to emit log messages associated to ***requests***. +This feature is valuable when debugging because it allows to return +side informations associated to a ***request***. + +The defined macros for logging to requests are: **AFB_REQ_ERROR**, +**AFB_REQ_WARNING**, **AFB_REQ_NOTICE**, **AFB_REQ_INFO**, **AFB_REQ_DEBUG**. + +We encourage the use of these new logging facilities everywhere it makes sense. + +Example: + +```C + INFO(afbitf, "method 'new' called for boardid %d", board->id); +``` + +Might become: + +```C + AFB_REQ_INFO(req, "method 'new' called for boardid %d", board->id); +``` + +Take care of store/unstore change +--------------------------------- + +For efficiency, the version 2 redefined how storing/unstoring of +requests works. Storing request is needed for asynchronous handling +of requests. + +For ***bindings*** version, the signature of the functions were: + +```C +struct afb_req *afb_req_store(struct afb_req req); +struct afb_req afb_req_unstore(struct afb_req *req); +``` + +For version 2 it becomes + +```C +struct afb_stored_req *afb_req_store(struct afb_req req); +struct afb_req afb_req_unstore(struct afb_stored_req *sreq); +``` + +Where the structure ```struct afb_stored_req``` is opaque. + +It should require few code change. + +Also check the following chapter that explain that asynchronous (sub)calls +can be replaced by synchronous one, avoiding the need to store/unstore +requests. + +Consider use of synchronous (sub)call requests +---------------------------------------------- + +***Bindings*** can emit requests for themselves (calls) or for +their clients (subcalls). With ***bindings*** version 2 comes +also synchronous requests for both cases. + +So when migrating to bindings version 2, a developper can consider +to replace the asynchronous requests (with asynchronous call back) +by synchronous ones. + +See functions ***afb_service_call_sync*** and ***afb_req_subcall_sync***. + +Optionnaly, removes explicit struct +----------------------------------- + +The new definitions now includes **typedefs** for common +structures, as shown on below sample: + +```C +typedef struct afb_daemon afb_daemon; +typedef struct afb_event afb_event; +typedef struct afb_arg afb_arg; +typedef struct afb_req afb_req; +typedef struct afb_service afb_service; +``` + +So you can remove the keyword **struct** if it bores you. + +Example: + +```C +static void verb(struct afb_req req) +{ + ... +} +``` + +Might become: + +```C +static void verb(afb_req req) +{ + ... +} +``` + +Example of migration +-------------------- + +The first ***binding*** that migrated from v1 to v2 was +the sample **HelloWorld**. Here is shown the differences between +the version 1 and the version 2. + +```diff +diff --git a/bindings/samples/HelloWorld.c b/bindings/samples/HelloWorld.c +index c6fa779..505aee3 100644 +--- a/bindings/samples/HelloWorld.c ++++ b/bindings/samples/HelloWorld.c +@@ -21,9 +21,9 @@ + + #include + ++#define AFB_BINDING_VERSION 2 + #include + +-const struct afb_binding_interface *interface; + static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; + + struct event +@@ -79,7 +80,7 @@ static int event_add(const char *tag, const char *name) + strcpy(e->tag, tag); + + /* make the event */ +- e->event = afb_daemon_make_event(interface->daemon, name); ++ e->event = afb_daemon_make_event(name); + if (!e->event.closure) { free(e); return -1; } + + /* link */ +@@ -140,7 +141,7 @@ static void pingBug (struct afb_req request) + static void pingEvent(struct afb_req request) + { + json_object *query = afb_req_json(request); +- afb_daemon_broadcast_event(interface->daemon, "event", json_object_get(query)); ++ afb_daemon_broadcast_event("event", json_object_get(query)); + ping(request, json_object_get(query), "event"); + } + +@@ -288,38 +289,43 @@ static void exitnow (struct afb_req request) + exit(0); + } + ++static int preinit() ++{ ++ AFB_NOTICE("hello binding comes to live"); ++ return 0; ++} ++ ++static int init() ++{ ++ AFB_NOTICE("hello binding starting"); ++ return 0; ++} ++ + // NOTE: this sample does not use session to keep test a basic as possible + // in real application most APIs should be protected with AFB_SESSION_CHECK +-static const struct afb_verb_desc_v1 verbs[]= { +- {"ping" , AFB_SESSION_NONE, pingSample , "Ping Application Framework"}, +- {"pingfail" , AFB_SESSION_NONE, pingFail , "Fails"}, +- {"pingnull" , AFB_SESSION_NONE, pingNull , "Return NULL"}, +- {"pingbug" , AFB_SESSION_NONE, pingBug , "Do a Memory Violation"}, +- {"pingJson" , AFB_SESSION_NONE, pingJson , "Return a JSON object"}, +- {"pingevent", AFB_SESSION_NONE, pingEvent , "Send an event"}, +- {"subcall", AFB_SESSION_NONE, subcall , "Call api/verb(args)"}, +- {"subcallsync", AFB_SESSION_NONE, subcallsync , "Call api/verb(args)"}, +- {"eventadd", AFB_SESSION_NONE, eventadd , "adds the event of 'name' for the 'tag'"}, +- {"eventdel", AFB_SESSION_NONE, eventdel , "deletes the event of 'tag'"}, +- {"eventsub", AFB_SESSION_NONE, eventsub , "subscribes to the event of 'tag'"}, +- {"eventunsub",AFB_SESSION_NONE, eventunsub , "unsubscribes to the event of 'tag'"}, +- {"eventpush", AFB_SESSION_NONE, eventpush , "pushs the event of 'tag' with the 'data'"}, +- {"exit", AFB_SESSION_NONE, exitnow , "exits from afb-daemon"}, +- {NULL} ++static const struct afb_verb_v2 verbs[]= { ++ { "ping" , pingSample , NULL, AFB_SESSION_NONE }, ++ { "pingfail" , pingFail , NULL, AFB_SESSION_NONE }, ++ { "pingnull" , pingNull , NULL, AFB_SESSION_NONE }, ++ { "pingbug" , pingBug , NULL, AFB_SESSION_NONE }, ++ { "pingJson" , pingJson , NULL, AFB_SESSION_NONE }, ++ { "pingevent", pingEvent , NULL, AFB_SESSION_NONE }, ++ { "subcall", subcall , NULL, AFB_SESSION_NONE }, ++ { "subcallsync", subcallsync, NULL, AFB_SESSION_NONE }, ++ { "eventadd", eventadd , NULL, AFB_SESSION_NONE }, ++ { "eventdel", eventdel , NULL, AFB_SESSION_NONE }, ++ { "eventsub", eventsub , NULL, AFB_SESSION_NONE }, ++ { "eventunsub", eventunsub , NULL, AFB_SESSION_NONE }, ++ { "eventpush", eventpush , NULL, AFB_SESSION_NONE }, ++ { "exit", exitnow , NULL, AFB_SESSION_NONE }, ++ { NULL} + }; + +-static const struct afb_binding plugin_desc = { +- .type = AFB_BINDING_VERSION_1, +- .v1 = { +- .info = "Minimal Hello World Sample", +- .prefix = "hello", +- .verbs = verbs +- } ++const struct afb_binding_v2 afbBindingV2 = { ++ .api = "hello", ++ .specification = NULL, ++ .verbs = verbs, ++ .preinit = preinit, ++ .init = init + }; + +-const struct afb_binding *afbBindingV1Register (const struct afb_binding_interface *itf) +-{ +- interface = itf; +- NOTICE(interface, "hello plugin comes to live"); +- return &plugin_desc; +-} +``` \ No newline at end of file diff --git a/docs/afb-overview.md b/docs/afb-overview.md new file mode 100644 index 00000000..67e5b0d1 --- /dev/null +++ b/docs/afb-overview.md @@ -0,0 +1,98 @@ + +Overview of the binder +====================== + +The ***binder*** provides the way to connect applications to +the services that it needs. It provides a fast way +to securely offer APIs to applications written in +any language and running almost anywhere. + +The ***binder*** is developped for AGL. + +The ***binder*** is the usual name. +The binary is named **afb-daemon**. + +The name **afb-daemon** stands for ***Application +Framework Binder Daemon***. The word *daemon*, here, +denote the fact that the ***binder*** makes witchcraft to +connect applications to their expected services (note that usually +the term of daemon denotes background process but not here). + +Each ***binder*** **afb-daemon** is in charge to bind +one instance of an application or service to the rest +of the system, applications and services. +Within AGL, the connexion between services and/or +applications is tuned by the AGL framework and +the AGL system. + +The basis of the binder +======================= + +The following figure shows main concepts linked to the ***binder***. + + +![Figure: binder basis](pictures/basis.svg) + +The shown elements are: + +* The SECURITY CONTEXT + + The primary intend of any ***binder*** is to provide + a secured environment for any application. On AGL, the + **security context** is ensured by [Smack][Smack] a security context, + the security context of the application or service. + +* The BINDER + + This is the central element. It makes possible to run HTML5 + applications and provides the unified access to APIs provided + by the ***bindings***. + + Running a pure HTML5 application doesn't require any ***binding***. + in that case , the ***binder*** acts as a simple HTTP server for + the web runtime. + +* The BINDINGs + + A ***binding*** adds one **API** to the ***binder***. + + An **API** is a set of **verbs** that can be called + using either REST over HTTP or a kind of JSON RPC. + + ***bindings*** are either: + + - dynamically loaded libraries in the ***binder*** process + - remote service running on the same host + - remote service running on other hosts + + When acting as an HTTP server, the binder treats the language + settings of the HTTP resquests to provide internationalized + content as specified by + [widget specifications](https://www.w3.org/TR/widgets/#internationalization-and-localization). + +* The APPLICATION + + An ***application*** connects to the binder to get access to + the **API** that it provides or to get its HTTP services to access + resources. + +Interconnection of binders +========================== + +The AGL framework interprets the **widget/application** manifests +to setup the ***bindings*** configuration of the ***binders***. + +The figure below shows that ***binders*** are interconnected. + + +![Figure: binder interconnection](pictures/interconnection.svg) + +The figure shows 4 several **application/service**: **A**, **B**, +**C** and **D**. + +The application **A** might use an **API** that is shown as a +local ***binbing*** but that in reality runs within the context +of **D**. + +The framework AGL takes care of making the plumbing working. + diff --git a/docs/index.md b/docs/index.md new file mode 120000 index 00000000..81c25433 --- /dev/null +++ b/docs/index.md @@ -0,0 +1 @@ +afb-overview.md \ No newline at end of file diff --git a/docs/pictures/AFB_for_services.svg b/docs/pictures/AFB_for_services.svg new file mode 100644 index 00000000..6e536c50 --- /dev/null +++ b/docs/pictures/AFB_for_services.svg @@ -0,0 +1,238 @@ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Isolated security context + + + + + + + + APPLICATION + + + + + + + + binderAFB-DAEMON + + + + + + + + BINDINGS + + + + + + + + + + + + + + + + + + + + + D-Bus & CYNARA + + + + + + + + Isolated security context A + + + + + + + + binderAFB-DAEMON + + + + + + + + serviceBINDINGS A + + + + + + + + + + + + + + + Isolated security context B + + + + + + + + binderAFB-DAEMON + + + + + + + + serviceBINDINGS B + + + + + + + + + + + + + + + Isolated security context C + + + + + + + + binderAFB-DAEMON + + + + + + + + serviceBINDINGS C + + + + + + + + + + + + + + \ No newline at end of file diff --git a/docs/pictures/basis.odg b/docs/pictures/basis.odg new file mode 100644 index 00000000..6025fdbf Binary files /dev/null and b/docs/pictures/basis.odg differ diff --git a/docs/pictures/basis.svg b/docs/pictures/basis.svg new file mode 100644 index 00000000..0d42d764 --- /dev/null +++ b/docs/pictures/basis.svg @@ -0,0 +1,356 @@ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + APPLICATION + + + + + + + + BINDERafb-daemon + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + BINDING + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + BINDING + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + BINDING + + + + + + + + + + + + + + + + + + SECURITYCONTEXT + + + + + + http + + + + + + ws + + + + + + + + \ No 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