Functions of class **afb_req**
============================

## General function

### afb_req_is_valid

```C
/**
 * Checks whether the request 'req' is valid or not.
 *
 * @param req the request to check
 *
 * @return 0 if not valid or 1 if valid.
 */
int afb_req_is_valid(
			afb_req_t req);
```

### afb_req_get_api

```C
/**
 * Retrieves the api that serves the request
 *
 * @param req the request whose serving api is queried
 *
 * @return the api serving the request
 */
afb_api_t afb_req_get_api(
			afb_req_t req);
```

### afb_req_get_vcbdata

```C
/**
 * Retrieves the callback data of the verb. This callback data is set
 * when the verb is created.
 *
 * @param req whose verb vcbdata is queried
 *
 * @return the callback data attached to the verb description
 */
void *afb_req_get_vcbdata(
			afb_req_t req);
```

### afb_req_get_called_api

```C
/**
 * Retrieve the name of the called api.
 *
 * @param req the request
 *
 * @return the name of the called api
 *
 * @see afb_api_new_api
 * @see afb_api_add_alias
 */
const char *afb_req_get_called_api(
			afb_req_t req);
```

### afb_req_get_called_verb

```C
/**
 * Retrieve the name of the called verb
 *
 * @param req the request
 *
 * @return the name of the called verb
 */
const char *afb_req_get_called_verb(
			afb_req_t req);
```

### afb_req_addref

```C
/**
 * Increments the count of references of 'req'.
 *
 * @param req the request
 *
 * @return returns the request req
 */
afb_req_t *afb_req_addref(
			afb_req_t req);
```

### afb_req_unref

```C
/**
 * Decrement the count of references of 'req'.
 *
 * @param req the request
 */
void afb_req_unref(
			afb_req_t req);
```


## Logging functions

### afb_req_wants_log_level

```C
/**
 * Is the log message of 'level (as defined for syslog) required for the
 * request 'req'?
 *
 * @param req the request
 * @param level the level to check as defined for syslog:
 *
 *      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
 *
 * @return 0 if not required or a value not null if required
 *
 * @see syslog
 */
int afb_req_wants_log_level(
			afb_req_t req,
			int level);
```

### afb_req_vverbose

```C
/**
 * Send associated to 'req' a message described by 'fmt' and its 'args'
 * 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
 *
 * @param req the request
 * @param level the level of the message
 * @param file the source filename that emits the message or NULL
 * @param line the line number in the source filename that emits the message
 * @param func the name of the function that emits the message or NULL
 * @param fmt the message format as for printf
 * @param args the arguments to the format
 *
 * @see printf
 * @see afb_req_verbose
 */
void afb_req_vverbose(
			afb_req_t req,
			int level, const char *file,
			int line,
			const char * func,
			const char *fmt,
			va_list args);
```

### afb_req_verbose

```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
 *
 * @param req the request
 * @param level the level of the message
 * @param file the source filename that emits the message or NULL
 * @param line the line number in the source filename that emits the message
 * @param func the name of the function that emits the message or NULL
 * @param fmt the message format as for printf
 * @param ... the arguments of the format 'fmt'
 *
 * @see printf
 */
void afb_req_verbose(
			afb_req_t req,
			int level, const char *file,
			int line,
			const char * func,
			const char *fmt,
			...);
```

## Arguments/parameters function

### afb_req_get

```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.
 *
 * @param req the request
 * @param name the name of the argument to get
 *
 * @return a structure describing the retrieved argument for the request
 *
 * @see afb_req_value
 * @see afb_req_path
 */
struct afb_arg afb_req_get(
			afb_req_t req,
			const char *name);
```

### afb_req_value

```C
/**
 * 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
 *
 * @param req the request
 * @param name the name of the argument's value to get
 *
 * @return the value as a string or NULL
 *
 * @see afb_req_get
 * @see afb_req_path
 */
const char *afb_req_value(
			afb_req_t req,
			const char *name);
```

### afb_req_path

```C
/**
 * 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
 *
 * @param req the request
 * @param name the name of the argument's path to get
 *
 * @return the path if any or NULL
 *
 * @see afb_req_get
 * @see afb_req_value
 */
const char *afb_req_path(
			afb_req_t req,
			const char *name);
```

### afb_req_json

```C
/**
 * Gets from the request 'req' the json object hashing the arguments.
 *
 * The returned object must not be released using 'json_object_put'.
 *
 * @param req the request
 *
 * @return the JSON object of the query
 *
 * @see afb_req_get
 * @see afb_req_value
 * @see afb_req_path
 */
struct json_object *afb_req_json(
			afb_req_t req);
```

## Reply functions

The functions **success** and **fail** are still supported.
These functions are now implemented as the following macros:

```C
#define afb_req_success(r,o,i)		afb_req_reply(r,o,NULL,i)
#define afb_req_success_f(r,o,...)	afb_req_reply_f(r,o,NULL,__VA_ARGS__)
#define afb_req_success_v(r,o,f,v)	afb_req_reply_v(r,o,NULL,f,v)
#define afb_req_fail(r,e,i)		afb_req_reply(r,NULL,e,i)
#define afb_req_fail_f(r,e,...)		afb_req_reply_f(r,NULL,e,__VA_ARGS__)
#define afb_req_fail_v(r,e,f,v)		afb_req_reply_v(r,NULL,e,f,v)
```


### afb_req_reply

```C
/**
 * Sends a reply to the request 'req'.
 *
 * The status of the reply is set to 'error' (that must be NULL on success).
 * Its send the object 'obj' (can be NULL) with an
 * informational 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.
 *
 * @param req the request
 * @param obj the replied object or NULL
 * @param error the error message if it is a reply error or NULL
 * @param info an informative text or NULL
 *
 * @see afb_req_reply_v
 * @see afb_req_reply_f
 */
void afb_req_reply(
			afb_req_t req,
			struct json_object *obj,
			const char *error,
			const char *info);
```

### afb_req_reply_v

```C
/**
 * Same as 'afb_req_reply_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.
 *
 * @param req the request
 * @param obj the replied object or NULL
 * @param error the error message if it is a reply error or NULL
 * @param info an informative text containing a format as for vprintf
 * @param args the va_list of arguments to the format as for vprintf
 *
 * @see afb_req_reply
 * @see afb_req_reply_f
 * @see vprintf
 */
void afb_req_reply_v(
			afb_req_t req,
			struct json_object *obj,
			const char *error,
			const char *info,
			va_list args);
```

### afb_req_reply_f

```C
/**
 * Same as 'afb_req_reply' 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.
 *
 * @param req the request
 * @param obj the replied object or NULL
 * @param error the error message if it is a reply error or NULL
 * @param info an informative text containing a format as for printf
 * @param ... the arguments to the format as for printf
 *
 * @see afb_req_reply
 * @see afb_req_reply_v
 * @see printf
 */
void afb_req_reply_f(
			afb_req_t req,
			struct json_object *obj,
			const char *error,
			const char *info,
			...);
```

## Subcall functions



### afb_req_subcall

```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 5 arguments:
 *  1. 'closure' the user defined closure pointer 'closure',
 *  2. 'object'  a JSON object returned (can be NULL)
 *  3. 'error'   a string not NULL in case of error
 *  4. 'info'    a string handling some info (can be NULL)
 *  5. 'req'     the req
 *
 * NOTE: For convenience, *json_object_put* is called on 'object' after the
 * callback returns. So, it is wrong to call *json_object_put* in the callback.
 *
 * @param req      The request
 * @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 flags    The bit field of flags for the subcall as defined by @ref afb_req_subcall_flags_t
 * @param callback The to call on completion
 * @param closure  The closure to pass to the callback
 *
 * The flags are any combination of the following values:
 *
 *    - afb_req_x2_subcall_catch_events = 1
 *
 *        the calling API wants to receive the events from subscription
 *
 *    - afb_req_x2_subcall_pass_events = 2
 *
 *        the original request will receive the events from subscription
 *
 *    - afb_req_x2_subcall_on_behalf = 4
 *
 *        the calling API wants to use the credentials of the original request
 *
 *    - afb_req_x2_subcall_api_session = 8
 *
 *        the calling API wants to use its session instead of the one of the
 *        original request
 *
 * @see also 'afb_req_subcall_sync'
 */
void afb_req_subcall(
			afb_req_t req,
			const char *api,
			const char *verb,
			struct json_object *args,
			int flags,
			void (*callback)(
					void *closure,
					struct json_object *object,
					const char *error,
					const char * info,
					afb_req_t req),
			void *closure);
```

### afb_req_subcall_sync

```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'.
 * This call is synchronous, it waits untill completion of the request.
 * It returns 0 on success or a negative value on error answer.
 *
 * 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.
 *
 * See also:
 *  - 'afb_req_subcall_req' that is convenient to keep request alive automatically.
 *  - 'afb_req_subcall' that doesn't keep request alive automatically.
 *
 * @param req      The request
 * @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 flags    The bit field of flags for the subcall as defined by @ref afb_req_subcall_flags
 * @param object   a pointer where the replied JSON object is stored must be freed using @ref json_object_put (can be NULL)
 * @param error    a pointer where a copy of the replied error is stored must be freed using @ref free (can be NULL)
 * @param info     a pointer where a copy of the replied info is stored must be freed using @ref free (can be NULL)
 *
 * @return 0 in case of success or -1 in case of error
 */
int afb_req_subcall_sync(
			afb_req_t req,
			const char *api,
			const char *verb,
			struct json_object *args,
			int flags,
			struct json_object **object,
			char **error,
			char **info);
```

## Event functions

### afb_req_subscribe

```C
/**
 * Establishes for the client link identified by 'req' a subscription
 * to the 'event'.
 *
 * Establishing subscription MUST be called BEFORE replying to the request.
 *
 * @param req the request
 * @param event the event to subscribe
 *
 * @return 0 in case of successful subscription or -1 in case of error.
 */
int afb_req_subscribe(
			afb_req_t req,
			afb_event_t event);
```

### afb_req_unsubscribe

```C
/**
 * 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.
 *
 * Revoking subscription MUST be called BEFORE replying to the request.
 *
 * @param req the request
 * @param event the event to revoke
 *
 * @return 0 in case of successful subscription or -1 in case of error.
 */
int afb_req_unsubscribe(
			afb_req_t req,
			afb_event_t event);
```

## Session functions

### afb_req_context

```C
/**
 * Manage the pointer stored by the binding for the client session of 'req'.
 *
 * If no previous pointer is stored or if 'replace' is not zero, a new value
 * is generated using the function 'create_context' called with the 'closure'.
 * If 'create_context' is NULL the generated value is 'closure'.
 *
 * When a value is created, the function 'free_context' is recorded and will
 * be called (with the created value as argument) to free the created value when
 * it is not more used.
 *
 * This function is atomic: it ensures that 2 threads will not race together.
 *
 * @param req the request
 * @param replace if not zero an existing value is replaced
 * @param create_context the creation function or NULL
 * @param free_context the destroying function or NULL
 * @param closure the closure to the creation function
 *
 * @return the stored value
 */
void *afb_req_context(
			afb_req_t req,
			int replace,
			void *(*create_context)(void *closure),
			void (*free_context)(void*),
			void *closure);
```

### afb_req_context_get

```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.
 *
 * Shortcut for: afb_req_context(req, 0, NULL, NULL, NULL)
 *
 * @param req the request
 *
 * @return the previously stored value
 */
void *afb_req_context_get(
			afb_req_t req);
```

### afb_req_context_set

```C
/**
 * 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.
 *
 * Shortcut for: afb_req_context(req, 1, NULL, free_context, context)
 *
 *
 * @param req the request
 * @param context the context value to store
 * @param free_context the cleaning function for the stored context (can be NULL)
 */
void afb_req_context_set(
			afb_req_t req,
			void *context,
			void (*free_context)(void*));
```

### afb_req_context_clear

```C
/**
 * 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)
 *
 * @param req the request
 */
void afb_req_context_clear(
			afb_req_t req);
```

### afb_req_session_close

```C
/**
 * Closes the session associated with 'req'
 * and delete all associated contexts.
 *
 * @param req the request
 */
void afb_req_session_close(
			afb_req_t req);
```

### afb_req_session_set_LOA

```C
/**
 * Sets the level of assurance of the session of 'req'
 * to 'level'. The effect of this function is subject of
 * security policies.
 *
 * @param req the request
 * @param level of assurance from 0 to 7
 *
 * @return 0 on success or -1 if failed.
 */
int afb_req_session_set_LOA(
			afb_req_t req,
			unsigned level);
```

## Credential/client functions

### afb_req_has_permission

```C
/**
 * Check whether the 'permission' is granted or not to the client
 * identified by 'req'.
 *
 * @param req the request
 * @param permission string to check
 *
 * @return 1 if the permission is granted or 0 otherwise.
 */
int afb_req_has_permission(
			afb_req_t req,
			const char *permission);
```

### afb_req_get_application_id

```C
/**
 * Get the application identifier of the client application for the
 * request 'req'.
 *
 * Returns the application identifier or NULL when the application
 * can not be identified.
 *
 * The returned value if not NULL must be freed by the caller
 *
 * @param req the request
 *
 * @return the string for the application id of the client MUST BE FREED
 */
char *afb_req_get_application_id(
			afb_req_t req);
```

### afb_req_get_uid

```C
/**
 * Get the user identifier (UID) of the client for the
 * request 'req'.
 *
 * @param req the request
 *
 * @return -1 when the application can not be identified or the unix uid.
 *
 */
int afb_req_get_uid(
			afb_req_t req);
```

### afb_req_get_client_info

```C
/**
 * Get informations about the client of the
 * request 'req'.
 *
 * Returns an object with client informations:
 *  {
 *    "pid": int, "uid": int, "gid": int,
 *    "label": string, "id": string, "user": string,
 *    "uuid": string, "LOA": int
 *  }
 *
 * If some of this information can't be computed, the field of the return
 * object will not be set at all.
 *
 * @param req the request
 *
 * @return a JSON object that must be freed using @ref json_object_put
 */
struct json_object *afb_req_get_client_info(
			afb_req_t req);
```

## Legacy functions

### afb_req_subcall_legacy

```C
/**
 * @deprecated use @ref afb_req_subcall
 *
 * 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'.
 * 'status' is 0 on success or negative when on 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.
 *
 * @param req the request
 * @param api the name of the api to call
 * @param verb the name of the verb to call
 * @param args the arguments of the call as a JSON object
 * @param callback the call back that will receive the reply
 * @param closure the closure passed back to the callback
 *
 * @see afb_req_subcall
 * @see afb_req_subcall_sync
 */
void afb_req_subcall_legacy(
			afb_req_t req,
			const char *api,
			const char *verb,
			struct json_object *args,
			void (*callback)(
					void *closure,
					int iserror,
					struct json_object *result,
					afb_req_t req),
			void *closure);
```

### afb_req_subcall_sync_legacy

```C
/**
 * @deprecated use @ref afb_req_subcall_sync
 *
 * 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 until completion of the request.
 * It returns 0 on success or a negative value on error answer.
 * 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.
 *
 * @param req the request
 * @param api the name of the api to call
 * @param verb the name of the verb to call
 * @param args the arguments of the call as a JSON object
 * @param result the pointer to the JSON object pointer that will receive the result
 *
 * @return 0 on success or a negative value on error answer.
 *
 * @see afb_req_subcall
 * @see afb_req_subcall_sync
 */
int afb_req_subcall_sync_legacy(
			afb_req_t req,
			const char *api,
			const char *verb,
			struct json_object *args,
			struct json_object **result);
```