diff options
Diffstat (limited to 'docs/afb-application-writing.md')
| -rw-r--r-- | docs/afb-application-writing.md | 230 |
1 files changed, 124 insertions, 106 deletions
diff --git a/docs/afb-application-writing.md b/docs/afb-application-writing.md index cc513b48..cfce7179 100644 --- a/docs/afb-application-writing.md +++ b/docs/afb-application-writing.md @@ -1,8 +1,6 @@ -How to write an application on top of AGL FRAMEWORK -==================================================== +# How to write an application on top of AGL FRAMEWORK -Programming Languages for Applications ------------------------------------------ +## Programming Languages for Applications ### Writing an HTML5 application @@ -11,7 +9,8 @@ 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 +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 @@ -25,14 +24,15 @@ Two examples of HTML5 applications are given: ### Writing a Qt application -Writing Qt applications is also supported. Qt offers standard API to send -request through HTTP or WebSockets. +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: +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 + +A simple "hello world" application in QML ### Writing a "C" application @@ -42,30 +42,30 @@ 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. +**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. +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 -------------------------------------- +### 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 +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". +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. @@ -73,24 +73,27 @@ 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 +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 +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**". +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. +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**. @@ -102,7 +105,9 @@ To ensure security, tokens must be refreshed periodically. In following examples, we suppose that **afb-daemon** is launched with something equivalent to: - $ afb-daemon --port=1234 --token=123456 [...] +```bash +afb-daemon --port=1234 --token=123456 [...] +``` making the expectation that **AuthLogin** binding is requested as default. @@ -110,102 +115,117 @@ making the expectation that **AuthLogin** binding is requested as default. 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"} - } +```bash +$ 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} - } +```bash +$ 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"} - } +```bash +$ 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"} - } +```bash +$ 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" - } - } +```bash +$ 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** +- 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"}} +```bash +$ 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}} +```bash +$ 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}} +```bash +$ 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 ------------------ +### 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 +#### Template of replies This is a template of replies: @@ -223,55 +243,54 @@ This is a template of replies: } ``` -### Field jtype +#### Field jtype of replies The field **jtype** must have a value of type string equal to **"afb-reply"**. -### Field request +#### Field request of replies -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**. +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 +##### 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 +##### Subfield request.info **info** is of type string and represent optional information added to the reply. -#### Subfield request.token +##### Subfield request.token **token** is of type string. It is sent either at session creation or when the token is refreshed. -#### Subfield request.uuid +##### Subfield request.uuid **uuid** is of type string. It is sent at session creation. -#### Subfield request.reqid +##### 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 +#### Field response of replies This field response optionally contains an object returned when request succeeded. -Format of events ----------------- +### 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 +#### Template of event Here is a template of event: @@ -283,11 +302,11 @@ Here is a template of event: } ``` -### Field jtype +#### Field jtype of event The field **jtype** must have a value of type string equal to **"afb-event"**. -### Field event +#### Field event of event The field **event** carries the event's name. @@ -295,7 +314,6 @@ 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 +#### Field data of event This field data if present holds the data carried by the event. - |