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3 (C) 2001-2013 Christian Grothoff (and other contributing authors)
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13 General Public License for more details.
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22 * @file include/gnunet_client_lib.h
23 * @brief functions related to accessing services
24 * @author Christian Grothoff
25 * @defgroup client Generic client-side communication with services
29 #ifndef GNUNET_CLIENT_LIB_H
30 #define GNUNET_CLIENT_LIB_H
35 #if 0 /* keep Emacsens' auto-indent happy */
42 * Opaque handle for a connection to a service.
44 struct GNUNET_CLIENT_Connection;
47 * Get a connection with a service.
49 * @param service_name name of the service
50 * @param cfg configuration to use
51 * @return NULL on error (service unknown to configuration)
53 struct GNUNET_CLIENT_Connection *
54 GNUNET_CLIENT_connect (const char *service_name,
55 const struct GNUNET_CONFIGURATION_Handle *cfg);
59 * Destroy connection with the service. This will automatically
60 * cancel any pending "receive" request (however, the handler will
61 * *NOT* be called, not even with a NULL message). Any pending
62 * transmission request will also be cancelled UNLESS the callback for
63 * the transmission request has already been called, in which case the
64 * transmission 'finish_pending_write' argument determines whether or
65 * not the write is guaranteed to complete before the socket is fully
66 * destroyed (unless, of course, there is an error with the server in
67 * which case the message may still be lost).
69 * @param client handle to the service connection
72 GNUNET_CLIENT_disconnect (struct GNUNET_CLIENT_Connection *client);
76 * Type of a function to call when we receive a message
80 * @param msg message received, NULL on timeout or fatal error
82 typedef void (*GNUNET_CLIENT_MessageHandler) (void *cls,
83 const struct GNUNET_MessageHeader
88 * Read from the service.
90 * @param client connection to the service
91 * @param handler function to call with the message
92 * @param handler_cls closure for @a handler
93 * @param timeout how long to wait until timing out
96 GNUNET_CLIENT_receive (struct GNUNET_CLIENT_Connection *client,
97 GNUNET_CLIENT_MessageHandler handler, void *handler_cls,
98 struct GNUNET_TIME_Relative timeout);
102 * Transmit handle for client connections.
104 struct GNUNET_CLIENT_TransmitHandle;
108 * Ask the client to call us once the specified number of bytes
109 * are free in the transmission buffer. May call the notify
110 * method immediately if enough space is available.
112 * @param client connection to the service
113 * @param size number of bytes to send
114 * @param timeout after how long should we give up (and call
115 * @a notify with buf NULL and size 0)?
116 * @param auto_retry if the connection to the service dies, should we
117 * automatically re-connect and retry (within the timeout period)
118 * or should we immediately fail in this case? Pass #GNUNET_YES
119 * if the caller does not care about temporary connection errors,
120 * for example because the protocol is stateless
121 * @param notify function to call
122 * @param notify_cls closure for @a notify
123 * @return NULL if someone else is already waiting to be notified
124 * non-NULL if the notify callback was queued (can be used to cancel
125 * using #GNUNET_CONNECTION_notify_transmit_ready_cancel)
127 struct GNUNET_CLIENT_TransmitHandle *
128 GNUNET_CLIENT_notify_transmit_ready (struct GNUNET_CLIENT_Connection *client,
130 struct GNUNET_TIME_Relative timeout,
132 GNUNET_CONNECTION_TransmitReadyNotify
133 notify, void *notify_cls);
137 * Cancel a request for notification.
139 * @param th handle from the original request.
142 GNUNET_CLIENT_notify_transmit_ready_cancel (struct GNUNET_CLIENT_TransmitHandle
147 * Convenience API that combines sending a request
148 * to the service and waiting for a response.
149 * If either operation times out, the callback
150 * will be called with a "NULL" response (in which
151 * case the connection should probably be destroyed).
153 * @param client connection to use
154 * @param hdr message to transmit
155 * @param timeout when to give up (for both transmission
156 * and for waiting for a response)
157 * @param auto_retry if the connection to the service dies, should we
158 * automatically re-connect and retry (within the timeout period)
159 * or should we immediately fail in this case? Pass #GNUNET_YES
160 * if the caller does not care about temporary connection errors,
161 * for example because the protocol is stateless
162 * @param rn function to call with the response
163 * @param rn_cls closure for @a rn
164 * @return #GNUNET_OK on success, #GNUNET_SYSERR if a request
168 GNUNET_CLIENT_transmit_and_get_response (struct GNUNET_CLIENT_Connection *client,
169 const struct GNUNET_MessageHeader *hdr,
170 struct GNUNET_TIME_Relative timeout,
172 GNUNET_CLIENT_MessageHandler rn,
177 * Handle for a test to check if a service is running.
179 struct GNUNET_CLIENT_TestHandle;
182 * Function called with the result on the service test.
185 * @param result #GNUNET_YES if the service is running,
186 * #GNUNET_NO if the service is not running
187 * #GNUNET_SYSERR if the configuration is invalid
189 typedef void (*GNUNET_CLIENT_TestResultCallback)(void *cls,
194 * Test if the service is running. If we are given a UNIXPATH or a
195 * local address, we do this NOT by trying to connect to the service,
196 * but by trying to BIND to the same port. If the BIND fails, we know
197 * the service is running.
199 * @param service name of the service to wait for
200 * @param cfg configuration to use
201 * @param timeout how long to wait at most
202 * @param cb function to call with the result
203 * @param cb_cls closure for @a cb
204 * @return handle to cancel the test
206 struct GNUNET_CLIENT_TestHandle *
207 GNUNET_CLIENT_service_test (const char *service,
208 const struct GNUNET_CONFIGURATION_Handle *cfg,
209 struct GNUNET_TIME_Relative timeout,
210 GNUNET_CLIENT_TestResultCallback cb, void *cb_cls);
214 * Abort testing for service.
216 * @param th test handle
219 GNUNET_CLIENT_service_test_cancel (struct GNUNET_CLIENT_TestHandle *th);
222 #if 0 /* keep Emacsens' auto-indent happy */
229 /** @} */ /* end of group client */
231 /* ifndef GNUNET_CLIENT_LIB_H */
233 /* end of gnunet_client_lib.h */