1 /*        $NetBSD: http.h,v 1.7 2024/08/18 20:47:22 christos Exp $    */
2 
3 /*
4  * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
5  * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 #ifndef EVENT2_HTTP_H_INCLUDED_
30 #define EVENT2_HTTP_H_INCLUDED_
31 
32 /* For int types. */
33 #include <event2/util.h>
34 #include <event2/visibility.h>
35 
36 #ifdef __cplusplus
37 extern "C" {
38 #endif
39 
40 /* In case we haven't included the right headers yet. */
41 struct evbuffer;
42 struct event_base;
43 struct bufferevent;
44 struct evhttp_connection;
45 
46 /** @file event2/http.h
47  *
48  * Basic support for HTTP serving.
49  *
50  * As Libevent is a library for dealing with event notification and most
51  * interesting applications are networked today, I have often found the
52  * need to write HTTP code.  The following prototypes and definitions provide
53  * an application with a minimal interface for making HTTP requests and for
54  * creating a very simple HTTP server.
55  */
56 
57 /* Response codes */
58 #define HTTP_OK                         200       /**< request completed ok */
59 #define HTTP_NOCONTENT                  204       /**< request does not have content */
60 #define HTTP_MOVEPERM                   301       /**< the uri moved permanently */
61 #define HTTP_MOVETEMP                   302       /**< the uri moved temporarily */
62 #define HTTP_NOTMODIFIED      304       /**< page was not modified from last */
63 #define HTTP_BADREQUEST                 400       /**< invalid http request was made */
64 #define HTTP_NOTFOUND                   404       /**< could not find content for uri */
65 #define HTTP_BADMETHOD                  405       /**< method not allowed for this uri */
66 #define HTTP_ENTITYTOOLARGE   413       /**<  */
67 #define HTTP_EXPECTATIONFAILED          417       /**< we can't handle this expectation */
68 #define HTTP_INTERNAL           500     /**< internal error */
69 #define HTTP_NOTIMPLEMENTED     501     /**< not implemented */
70 #define HTTP_SERVUNAVAIL      503       /**< the server is not available */
71 
72 struct evhttp;
73 struct evhttp_request;
74 struct evkeyvalq;
75 struct evhttp_bound_socket;
76 struct evconnlistener;
77 struct evdns_base;
78 
79 /**
80  * Create a new HTTP server.
81  *
82  * @param base (optional) the event base to receive the HTTP events
83  * @return a pointer to a newly initialized evhttp server structure or NULL
84  *   on error
85  * @see evhttp_free()
86  */
87 EVENT2_EXPORT_SYMBOL
88 struct evhttp *evhttp_new(struct event_base *base);
89 
90 /**
91  * Binds an HTTP server on the specified address and port.
92  *
93  * Can be called multiple times to bind the same http server
94  * to multiple different ports.
95  *
96  * @param http a pointer to an evhttp object
97  * @param address a string containing the IP address to listen(2) on
98  * @param port the port number to listen on
99  * @return 0 on success, -1 on failure.
100  * @see evhttp_accept_socket()
101  */
102 EVENT2_EXPORT_SYMBOL
103 int evhttp_bind_socket(struct evhttp *http, const char *address, ev_uint16_t port);
104 
105 /**
106  * Like evhttp_bind_socket(), but returns a handle for referencing the socket.
107  *
108  * The returned pointer is not valid after \a http is freed.
109  *
110  * @param http a pointer to an evhttp object
111  * @param address a string containing the IP address to listen(2) on
112  * @param port the port number to listen on
113  * @return Handle for the socket on success, NULL on failure.
114  * @see evhttp_bind_socket(), evhttp_del_accept_socket()
115  */
116 EVENT2_EXPORT_SYMBOL
117 struct evhttp_bound_socket *evhttp_bind_socket_with_handle(struct evhttp *http, const char *address, ev_uint16_t port);
118 
119 /**
120  * Makes an HTTP server accept connections on the specified socket.
121  *
122  * This may be useful to create a socket and then fork multiple instances
123  * of an http server, or when a socket has been communicated via file
124  * descriptor passing in situations where an http servers does not have
125  * permissions to bind to a low-numbered port.
126  *
127  * Can be called multiple times to have the http server listen to
128  * multiple different sockets.
129  *
130  * @param http a pointer to an evhttp object
131  * @param fd a socket fd that is ready for accepting connections
132  * @return 0 on success, -1 on failure.
133  * @see evhttp_bind_socket()
134  */
135 EVENT2_EXPORT_SYMBOL
136 int evhttp_accept_socket(struct evhttp *http, evutil_socket_t fd);
137 
138 /**
139  * Like evhttp_accept_socket(), but returns a handle for referencing the socket.
140  *
141  * The returned pointer is not valid after \a http is freed.
142  *
143  * @param http a pointer to an evhttp object
144  * @param fd a socket fd that is ready for accepting connections
145  * @return Handle for the socket on success, NULL on failure.
146  * @see evhttp_accept_socket(), evhttp_del_accept_socket()
147  */
148 EVENT2_EXPORT_SYMBOL
149 struct evhttp_bound_socket *evhttp_accept_socket_with_handle(struct evhttp *http, evutil_socket_t fd);
150 
151 /**
152  * The most low-level evhttp_bind/accept method: takes an evconnlistener, and
153  * returns an evhttp_bound_socket.  The listener will be freed when the bound
154  * socket is freed.
155  */
156 EVENT2_EXPORT_SYMBOL
157 struct evhttp_bound_socket *evhttp_bind_listener(struct evhttp *http, struct evconnlistener *listener);
158 
159 /**
160  * Return the listener used to implement a bound socket.
161  */
162 EVENT2_EXPORT_SYMBOL
163 struct evconnlistener *evhttp_bound_socket_get_listener(struct evhttp_bound_socket *bound);
164 
165 typedef void evhttp_bound_socket_foreach_fn(struct evhttp_bound_socket *, void *);
166 /**
167  * Applies the function specified in the first argument to all
168  * evhttp_bound_sockets associated with "http". The user must not
169  * attempt to free or remove any connections, sockets or listeners
170  * in the callback "function".
171  *
172  * @param http pointer to an evhttp object
173  * @param function function to apply to every bound socket
174  * @param argument pointer value passed to function for every socket iterated
175  */
176 EVENT2_EXPORT_SYMBOL
177 void evhttp_foreach_bound_socket(struct evhttp *http, evhttp_bound_socket_foreach_fn *function, void *argument);
178 
179 /**
180  * Makes an HTTP server stop accepting connections on the specified socket
181  *
182  * This may be useful when a socket has been sent via file descriptor passing
183  * and is no longer needed by the current process.
184  *
185  * If you created this bound socket with evhttp_bind_socket_with_handle or
186  * evhttp_accept_socket_with_handle, this function closes the fd you provided.
187  * If you created this bound socket with evhttp_bind_listener, this function
188  * frees the listener you provided.
189  *
190  * \a bound_socket is an invalid pointer after this call returns.
191  *
192  * @param http a pointer to an evhttp object
193  * @param bound_socket a handle returned by evhttp_{bind,accept}_socket_with_handle
194  * @see evhttp_bind_socket_with_handle(), evhttp_accept_socket_with_handle()
195  */
196 EVENT2_EXPORT_SYMBOL
197 void evhttp_del_accept_socket(struct evhttp *http, struct evhttp_bound_socket *bound_socket);
198 
199 /**
200  * Get the raw file descriptor referenced by an evhttp_bound_socket.
201  *
202  * @param bound_socket a handle returned by evhttp_{bind,accept}_socket_with_handle
203  * @return the file descriptor used by the bound socket
204  * @see evhttp_bind_socket_with_handle(), evhttp_accept_socket_with_handle()
205  */
206 EVENT2_EXPORT_SYMBOL
207 evutil_socket_t evhttp_bound_socket_get_fd(struct evhttp_bound_socket *bound_socket);
208 
209 /**
210  * Free the previously created HTTP server.
211  *
212  * Works only if no requests are currently being served.
213  *
214  * @param http the evhttp server object to be freed
215  * @see evhttp_start()
216  */
217 EVENT2_EXPORT_SYMBOL
218 void evhttp_free(struct evhttp* http);
219 
220 /** XXX Document. */
221 EVENT2_EXPORT_SYMBOL
222 void evhttp_set_max_headers_size(struct evhttp* http, ev_ssize_t max_headers_size);
223 /** XXX Document. */
224 EVENT2_EXPORT_SYMBOL
225 void evhttp_set_max_body_size(struct evhttp* http, ev_ssize_t max_body_size);
226 
227 /**
228   Set the value to use for the Content-Type header when none was provided. If
229   the content type string is NULL, the Content-Type header will not be
230   automatically added.
231 
232   @param http the http server on which to set the default content type
233   @param content_type the value for the Content-Type header
234 */
235 EVENT2_EXPORT_SYMBOL
236 void evhttp_set_default_content_type(struct evhttp *http,
237           const char *content_type);
238 
239 /**
240   Sets the what HTTP methods are supported in requests accepted by this
241   server, and passed to user callbacks.
242 
243   If not supported they will generate a "405 Method not allowed" response.
244 
245   By default this includes the following methods: GET, POST, HEAD, PUT, DELETE
246 
247   @param http the http server on which to set the methods
248   @param methods bit mask constructed from evhttp_cmd_type values
249 */
250 EVENT2_EXPORT_SYMBOL
251 void evhttp_set_allowed_methods(struct evhttp* http, ev_uint16_t methods);
252 
253 /**
254    Set a callback for a specified URI
255 
256    @param http the http sever on which to set the callback
257    @param path the path for which to invoke the callback
258    @param cb the callback function that gets invoked on requesting path
259    @param cb_arg an additional context argument for the callback
260    @return 0 on success, -1 if the callback existed already, -2 on failure
261 */
262 EVENT2_EXPORT_SYMBOL
263 int evhttp_set_cb(struct evhttp *http, const char *path,
264     void (*cb)(struct evhttp_request *, void *), void *cb_arg);
265 
266 /** Removes the callback for a specified URI */
267 EVENT2_EXPORT_SYMBOL
268 int evhttp_del_cb(struct evhttp *, const char *);
269 
270 /**
271     Set a callback for all requests that are not caught by specific callbacks
272 
273     Invokes the specified callback for all requests that do not match any of
274     the previously specified request paths.  This is catchall for requests not
275     specifically configured with evhttp_set_cb().
276 
277     @param http the evhttp server object for which to set the callback
278     @param cb the callback to invoke for any unmatched requests
279     @param arg an context argument for the callback
280 */
281 EVENT2_EXPORT_SYMBOL
282 void evhttp_set_gencb(struct evhttp *http,
283     void (*cb)(struct evhttp_request *, void *), void *arg);
284 
285 /**
286    Set a callback used to create new bufferevents for connections
287    to a given evhttp object.
288 
289    You can use this to override the default bufferevent type -- for example,
290    to make this evhttp object use SSL bufferevents rather than unencrypted
291    ones.
292 
293    New bufferevents must be allocated with no fd set on them.
294 
295    @param http the evhttp server object for which to set the callback
296    @param cb the callback to invoke for incoming connections
297    @param arg an context argument for the callback
298  */
299 EVENT2_EXPORT_SYMBOL
300 void evhttp_set_bevcb(struct evhttp *http,
301     struct bufferevent *(*cb)(struct event_base *, void *), void *arg);
302 
303 /**
304    Adds a virtual host to the http server.
305 
306    A virtual host is a newly initialized evhttp object that has request
307    callbacks set on it via evhttp_set_cb() or evhttp_set_gencb().  It
308    most not have any listing sockets associated with it.
309 
310    If the virtual host has not been removed by the time that evhttp_free()
311    is called on the main http server, it will be automatically freed, too.
312 
313    It is possible to have hierarchical vhosts.  For example: A vhost
314    with the pattern *.example.com may have other vhosts with patterns
315    foo.example.com and bar.example.com associated with it.
316 
317    @param http the evhttp object to which to add a virtual host
318    @param pattern the glob pattern against which the hostname is matched.
319      The match is case insensitive and follows otherwise regular shell
320      matching.
321    @param vhost the virtual host to add the regular http server.
322    @return 0 on success, -1 on failure
323    @see evhttp_remove_virtual_host()
324 */
325 EVENT2_EXPORT_SYMBOL
326 int evhttp_add_virtual_host(struct evhttp* http, const char *pattern,
327     struct evhttp* vhost);
328 
329 /**
330    Removes a virtual host from the http server.
331 
332    @param http the evhttp object from which to remove the virtual host
333    @param vhost the virtual host to remove from the regular http server.
334    @return 0 on success, -1 on failure
335    @see evhttp_add_virtual_host()
336 */
337 EVENT2_EXPORT_SYMBOL
338 int evhttp_remove_virtual_host(struct evhttp* http, struct evhttp* vhost);
339 
340 /**
341    Add a server alias to an http object. The http object can be a virtual
342    host or the main server.
343 
344    @param http the evhttp object
345    @param alias the alias to add
346    @see evhttp_add_remove_alias()
347 */
348 EVENT2_EXPORT_SYMBOL
349 int evhttp_add_server_alias(struct evhttp *http, const char *alias);
350 
351 /**
352    Remove a server alias from an http object.
353 
354    @param http the evhttp object
355    @param alias the alias to remove
356    @see evhttp_add_server_alias()
357 */
358 EVENT2_EXPORT_SYMBOL
359 int evhttp_remove_server_alias(struct evhttp *http, const char *alias);
360 
361 /**
362  * Set the timeout for an HTTP request.
363  *
364  * @param http an evhttp object
365  * @param timeout_in_secs the timeout, in seconds
366  */
367 EVENT2_EXPORT_SYMBOL
368 void evhttp_set_timeout(struct evhttp *http, int timeout_in_secs);
369 
370 /**
371  * Set the timeout for an HTTP request.
372  *
373  * @param http an evhttp object
374  * @param tv the timeout, or NULL
375  */
376 EVENT2_EXPORT_SYMBOL
377 void evhttp_set_timeout_tv(struct evhttp *http, const struct timeval* tv);
378 
379 /* Read all the clients body, and only after this respond with an error if the
380  * clients body exceed max_body_size */
381 #define EVHTTP_SERVER_LINGERING_CLOSE   0x0001
382 /**
383  * Set connection flags for HTTP server.
384  *
385  * @see EVHTTP_SERVER_*
386  * @return 0 on success, otherwise non zero (for example if flag doesn't
387  * supported).
388  */
389 EVENT2_EXPORT_SYMBOL
390 int evhttp_set_flags(struct evhttp *http, int flags);
391 
392 /* Request/Response functionality */
393 
394 /**
395  * Send an HTML error message to the client.
396  *
397  * @param req a request object
398  * @param error the HTTP error code
399  * @param reason a brief explanation of the error.  If this is NULL, we'll
400  *    just use the standard meaning of the error code.
401  */
402 EVENT2_EXPORT_SYMBOL
403 void evhttp_send_error(struct evhttp_request *req, int error,
404     const char *reason);
405 
406 /**
407  * Send an HTML reply to the client.
408  *
409  * The body of the reply consists of the data in databuf.  After calling
410  * evhttp_send_reply() databuf will be empty, but the buffer is still
411  * owned by the caller and needs to be deallocated by the caller if
412  * necessary.
413  *
414  * @param req a request object
415  * @param code the HTTP response code to send
416  * @param reason a brief message to send with the response code
417  * @param databuf the body of the response
418  */
419 EVENT2_EXPORT_SYMBOL
420 void evhttp_send_reply(struct evhttp_request *req, int code,
421     const char *reason, struct evbuffer *databuf);
422 
423 /* Low-level response interface, for streaming/chunked replies */
424 
425 /**
426    Initiate a reply that uses Transfer-Encoding chunked.
427 
428    This allows the caller to stream the reply back to the client and is
429    useful when either not all of the reply data is immediately available
430    or when sending very large replies.
431 
432    The caller needs to supply data chunks with evhttp_send_reply_chunk()
433    and complete the reply by calling evhttp_send_reply_end().
434 
435    @param req a request object
436    @param code the HTTP response code to send
437    @param reason a brief message to send with the response code
438 */
439 EVENT2_EXPORT_SYMBOL
440 void evhttp_send_reply_start(struct evhttp_request *req, int code,
441     const char *reason);
442 
443 /**
444    Send another data chunk as part of an ongoing chunked reply.
445 
446    The reply chunk consists of the data in databuf.  After calling
447    evhttp_send_reply_chunk() databuf will be empty, but the buffer is
448    still owned by the caller and needs to be deallocated by the caller
449    if necessary.
450 
451    @param req a request object
452    @param databuf the data chunk to send as part of the reply.
453 */
454 EVENT2_EXPORT_SYMBOL
455 void evhttp_send_reply_chunk(struct evhttp_request *req,
456     struct evbuffer *databuf);
457 
458 /**
459    Send another data chunk as part of an ongoing chunked reply.
460 
461    The reply chunk consists of the data in databuf.  After calling
462    evhttp_send_reply_chunk() databuf will be empty, but the buffer is
463    still owned by the caller and needs to be deallocated by the caller
464    if necessary.
465 
466    @param req a request object
467    @param databuf the data chunk to send as part of the reply.
468    @param cb callback funcion
469    @param call back's argument.
470 */
471 EVENT2_EXPORT_SYMBOL
472 void evhttp_send_reply_chunk_with_cb(struct evhttp_request *, struct evbuffer *,
473     void (*cb)(struct evhttp_connection *, void *), void *arg);
474 
475 /**
476    Complete a chunked reply, freeing the request as appropriate.
477 
478    @param req a request object
479 */
480 EVENT2_EXPORT_SYMBOL
481 void evhttp_send_reply_end(struct evhttp_request *req);
482 
483 /*
484  * Interfaces for making requests
485  */
486 
487 /** The different request types supported by evhttp.  These are as specified
488  * in RFC2616, except for PATCH which is specified by RFC5789.
489  *
490  * By default, only some of these methods are accepted and passed to user
491  * callbacks; use evhttp_set_allowed_methods() to change which methods
492  * are allowed.
493  */
494 enum evhttp_cmd_type {
495           EVHTTP_REQ_GET     = 1 << 0,
496           EVHTTP_REQ_POST    = 1 << 1,
497           EVHTTP_REQ_HEAD    = 1 << 2,
498           EVHTTP_REQ_PUT     = 1 << 3,
499           EVHTTP_REQ_DELETE  = 1 << 4,
500           EVHTTP_REQ_OPTIONS = 1 << 5,
501           EVHTTP_REQ_TRACE   = 1 << 6,
502           EVHTTP_REQ_CONNECT = 1 << 7,
503           EVHTTP_REQ_PATCH   = 1 << 8
504 };
505 
506 /** a request object can represent either a request or a reply */
507 enum evhttp_request_kind { EVHTTP_REQUEST, EVHTTP_RESPONSE };
508 
509 /**
510  * Create and return a connection object that can be used to for making HTTP
511  * requests.  The connection object tries to resolve address and establish the
512  * connection when it is given an http request object.
513  *
514  * @param base the event_base to use for handling the connection
515  * @param dnsbase the dns_base to use for resolving host names; if not
516  *     specified host name resolution will block.
517  * @param bev a bufferevent to use for connecting to the server; if NULL, a
518  *     socket-based bufferevent will be created.  This buffrevent will be freed
519  *     when the connection closes.  It must have no fd set on it.
520  * @param address the address to which to connect
521  * @param port the port to connect to
522  * @return an evhttp_connection object that can be used for making requests or
523  *   NULL on error
524  */
525 EVENT2_EXPORT_SYMBOL
526 struct evhttp_connection *evhttp_connection_base_bufferevent_new(
527           struct event_base *base, struct evdns_base *dnsbase, struct bufferevent* bev, const char *address, ev_uint16_t port);
528 
529 /**
530  * Return the bufferevent that an evhttp_connection is using.
531  */
532 EVENT2_EXPORT_SYMBOL
533 struct bufferevent* evhttp_connection_get_bufferevent(struct evhttp_connection *evcon);
534 
535 /**
536  * Return the HTTP server associated with this connection, or NULL.
537  */
538 EVENT2_EXPORT_SYMBOL
539 struct evhttp *evhttp_connection_get_server(struct evhttp_connection *evcon);
540 
541 /**
542  * Creates a new request object that needs to be filled in with the request
543  * parameters.  The callback is executed when the request completed or an
544  * error occurred.
545  */
546 EVENT2_EXPORT_SYMBOL
547 struct evhttp_request *evhttp_request_new(
548           void (*cb)(struct evhttp_request *, void *), void *arg);
549 
550 /**
551  * Enable delivery of chunks to requestor.
552  * @param cb will be called after every read of data with the same argument
553  *           as the completion callback. Will never be called on an empty
554  *           response. May drain the input buffer; it will be drained
555  *           automatically on return.
556  */
557 EVENT2_EXPORT_SYMBOL
558 void evhttp_request_set_chunked_cb(struct evhttp_request *,
559     void (*cb)(struct evhttp_request *, void *));
560 
561 /**
562  * Register callback for additional parsing of request headers.
563  * @param cb will be called after receiving and parsing the full header.
564  * It allows analyzing the header and possibly closing the connection
565  * by returning a value < 0.
566  */
567 EVENT2_EXPORT_SYMBOL
568 void evhttp_request_set_header_cb(struct evhttp_request *,
569     int (*cb)(struct evhttp_request *, void *));
570 
571 /**
572  * The different error types supported by evhttp
573  *
574  * @see evhttp_request_set_error_cb()
575  */
576 enum evhttp_request_error {
577   /**
578    * Timeout reached, also @see evhttp_connection_set_timeout()
579    */
580   EVREQ_HTTP_TIMEOUT,
581   /**
582    * EOF reached
583    */
584   EVREQ_HTTP_EOF,
585   /**
586    * Error while reading header, or invalid header
587    */
588   EVREQ_HTTP_INVALID_HEADER,
589   /**
590    * Error encountered while reading or writing
591    */
592   EVREQ_HTTP_BUFFER_ERROR,
593   /**
594    * The evhttp_cancel_request() called on this request.
595    */
596   EVREQ_HTTP_REQUEST_CANCEL,
597   /**
598    * Body is greater then evhttp_connection_set_max_body_size()
599    */
600   EVREQ_HTTP_DATA_TOO_LONG
601 };
602 /**
603  * Set a callback for errors
604  * @see evhttp_request_error for error types.
605  *
606  * On error, both the error callback and the regular callback will be called,
607  * error callback is called before the regular callback.
608  **/
609 EVENT2_EXPORT_SYMBOL
610 void evhttp_request_set_error_cb(struct evhttp_request *,
611     void (*)(enum evhttp_request_error, void *));
612 
613 /**
614  * Set a callback to be called on request completion of evhttp_send_* function.
615  *
616  * The callback function will be called on the completion of the request after
617  * the output data has been written and before the evhttp_request object
618  * is destroyed. This can be useful for tracking resources associated with a
619  * request (ex: timing metrics).
620  *
621  * @param req a request object
622  * @param cb callback function that will be called on request completion
623  * @param cb_arg an additional context argument for the callback
624  */
625 EVENT2_EXPORT_SYMBOL
626 void evhttp_request_set_on_complete_cb(struct evhttp_request *req,
627     void (*cb)(struct evhttp_request *, void *), void *cb_arg);
628 
629 /** Frees the request object and removes associated events. */
630 EVENT2_EXPORT_SYMBOL
631 void evhttp_request_free(struct evhttp_request *req);
632 
633 /**
634  * Create and return a connection object that can be used to for making HTTP
635  * requests.  The connection object tries to resolve address and establish the
636  * connection when it is given an http request object.
637  *
638  * @param base the event_base to use for handling the connection
639  * @param dnsbase the dns_base to use for resolving host names; if not
640  *     specified host name resolution will block.
641  * @param address the address to which to connect
642  * @param port the port to connect to
643  * @return an evhttp_connection object that can be used for making requests or
644  *   NULL on error
645  */
646 EVENT2_EXPORT_SYMBOL
647 struct evhttp_connection *evhttp_connection_base_new(
648           struct event_base *base, struct evdns_base *dnsbase,
649           const char *address, ev_uint16_t port);
650 
651 /**
652  * Set family hint for DNS requests.
653  */
654 EVENT2_EXPORT_SYMBOL
655 void evhttp_connection_set_family(struct evhttp_connection *evcon,
656           int family);
657 
658 /* reuse connection address on retry */
659 #define EVHTTP_CON_REUSE_CONNECTED_ADDR 0x0008
660 /* Try to read error, since server may already send and close
661  * connection, but if at that time we have some data to send then we
662  * can send get EPIPE and fail, while we can read that HTTP error. */
663 #define EVHTTP_CON_READ_ON_WRITE_ERROR  0x0010
664 /* @see EVHTTP_SERVER_LINGERING_CLOSE */
665 #define EVHTTP_CON_LINGERING_CLOSE      0x0020
666 /* Padding for public flags, @see EVHTTP_CON_* in http-internal.h */
667 #define EVHTTP_CON_PUBLIC_FLAGS_END     0x100000
668 /**
669  * Set connection flags.
670  *
671  * @see EVHTTP_CON_*
672  * @return 0 on success, otherwise non zero (for example if flag doesn't
673  * supported).
674  */
675 EVENT2_EXPORT_SYMBOL
676 int evhttp_connection_set_flags(struct evhttp_connection *evcon,
677           int flags);
678 
679 /** Takes ownership of the request object
680  *
681  * Can be used in a request callback to keep onto the request until
682  * evhttp_request_free() is explicitly called by the user.
683  */
684 EVENT2_EXPORT_SYMBOL
685 void evhttp_request_own(struct evhttp_request *req);
686 
687 /** Returns 1 if the request is owned by the user */
688 EVENT2_EXPORT_SYMBOL
689 int evhttp_request_is_owned(struct evhttp_request *req);
690 
691 /**
692  * Returns the connection object associated with the request or NULL
693  *
694  * The user needs to either free the request explicitly or call
695  * evhttp_send_reply_end().
696  */
697 EVENT2_EXPORT_SYMBOL
698 struct evhttp_connection *evhttp_request_get_connection(struct evhttp_request *req);
699 
700 /**
701  * Returns the underlying event_base for this connection
702  */
703 EVENT2_EXPORT_SYMBOL
704 struct event_base *evhttp_connection_get_base(struct evhttp_connection *req);
705 
706 EVENT2_EXPORT_SYMBOL
707 void evhttp_connection_set_max_headers_size(struct evhttp_connection *evcon,
708     ev_ssize_t new_max_headers_size);
709 
710 EVENT2_EXPORT_SYMBOL
711 void evhttp_connection_set_max_body_size(struct evhttp_connection* evcon,
712     ev_ssize_t new_max_body_size);
713 
714 /** Frees an http connection */
715 EVENT2_EXPORT_SYMBOL
716 void evhttp_connection_free(struct evhttp_connection *evcon);
717 
718 /** Disowns a given connection object
719  *
720  * Can be used to tell libevent to free the connection object after
721  * the last request has completed or failed.
722  */
723 EVENT2_EXPORT_SYMBOL
724 void evhttp_connection_free_on_completion(struct evhttp_connection *evcon);
725 
726 /** sets the ip address from which http connections are made */
727 EVENT2_EXPORT_SYMBOL
728 void evhttp_connection_set_local_address(struct evhttp_connection *evcon,
729     const char *address);
730 
731 /** sets the local port from which http connections are made */
732 EVENT2_EXPORT_SYMBOL
733 void evhttp_connection_set_local_port(struct evhttp_connection *evcon,
734     ev_uint16_t port);
735 
736 /** Sets the timeout in seconds for events related to this connection */
737 EVENT2_EXPORT_SYMBOL
738 void evhttp_connection_set_timeout(struct evhttp_connection *evcon,
739     int timeout_in_secs);
740 
741 /** Sets the timeout for events related to this connection.  Takes a struct
742  * timeval. */
743 EVENT2_EXPORT_SYMBOL
744 void evhttp_connection_set_timeout_tv(struct evhttp_connection *evcon,
745     const struct timeval *tv);
746 
747 /** Sets the delay before retrying requests on this connection. This is only
748  * used if evhttp_connection_set_retries is used to make the number of retries
749  * at least one. Each retry after the first is twice as long as the one before
750  * it. */
751 EVENT2_EXPORT_SYMBOL
752 void evhttp_connection_set_initial_retry_tv(struct evhttp_connection *evcon,
753     const struct timeval *tv);
754 
755 /** Sets the retry limit for this connection - -1 repeats indefinitely */
756 EVENT2_EXPORT_SYMBOL
757 void evhttp_connection_set_retries(struct evhttp_connection *evcon,
758     int retry_max);
759 
760 /** Set a callback for connection close. */
761 EVENT2_EXPORT_SYMBOL
762 void evhttp_connection_set_closecb(struct evhttp_connection *evcon,
763     void (*)(struct evhttp_connection *, void *), void *);
764 
765 /** Get the remote address and port associated with this connection. */
766 EVENT2_EXPORT_SYMBOL
767 void evhttp_connection_get_peer(struct evhttp_connection *evcon,
768     char **address, ev_uint16_t *port);
769 
770 /** Get the remote address associated with this connection.
771  * extracted from getpeername() OR from nameserver.
772  *
773  * @return NULL if getpeername() return non success,
774  * or connection is not connected,
775  * otherwise it return pointer to struct sockaddr_storage */
776 EVENT2_EXPORT_SYMBOL
777 const struct sockaddr*
778 evhttp_connection_get_addr(struct evhttp_connection *evcon);
779 
780 /**
781     Make an HTTP request over the specified connection.
782 
783     The connection gets ownership of the request.  On failure, the
784     request object is no longer valid as it has been freed.
785 
786     @param evcon the evhttp_connection object over which to send the request
787     @param req the previously created and configured request object
788     @param type the request type EVHTTP_REQ_GET, EVHTTP_REQ_POST, etc.
789     @param uri the URI associated with the request
790     @return 0 on success, -1 on failure
791     @see evhttp_cancel_request()
792 */
793 EVENT2_EXPORT_SYMBOL
794 int evhttp_make_request(struct evhttp_connection *evcon,
795     struct evhttp_request *req,
796     enum evhttp_cmd_type type, const char *uri);
797 
798 /**
799    Cancels a pending HTTP request.
800 
801    Cancels an ongoing HTTP request.  The callback associated with this request
802    is not executed and the request object is freed.  If the request is
803    currently being processed, e.g. it is ongoing, the corresponding
804    evhttp_connection object is going to get reset.
805 
806    A request cannot be canceled if its callback has executed already. A request
807    may be canceled reentrantly from its chunked callback.
808 
809    @param req the evhttp_request to cancel; req becomes invalid after this call.
810 */
811 EVENT2_EXPORT_SYMBOL
812 void evhttp_cancel_request(struct evhttp_request *req);
813 
814 /**
815  * A structure to hold a parsed URI or Relative-Ref conforming to RFC3986.
816  */
817 struct evhttp_uri;
818 
819 /** Returns the request URI */
820 EVENT2_EXPORT_SYMBOL
821 const char *evhttp_request_get_uri(const struct evhttp_request *req);
822 /** Returns the request URI (parsed) */
823 EVENT2_EXPORT_SYMBOL
824 const struct evhttp_uri *evhttp_request_get_evhttp_uri(const struct evhttp_request *req);
825 /** Returns the request command */
826 EVENT2_EXPORT_SYMBOL
827 enum evhttp_cmd_type evhttp_request_get_command(const struct evhttp_request *req);
828 
829 EVENT2_EXPORT_SYMBOL
830 int evhttp_request_get_response_code(const struct evhttp_request *req);
831 EVENT2_EXPORT_SYMBOL
832 const char * evhttp_request_get_response_code_line(const struct evhttp_request *req);
833 
834 /** Returns the input headers */
835 EVENT2_EXPORT_SYMBOL
836 struct evkeyvalq *evhttp_request_get_input_headers(struct evhttp_request *req);
837 /** Returns the output headers */
838 EVENT2_EXPORT_SYMBOL
839 struct evkeyvalq *evhttp_request_get_output_headers(struct evhttp_request *req);
840 /** Returns the input buffer */
841 EVENT2_EXPORT_SYMBOL
842 struct evbuffer *evhttp_request_get_input_buffer(struct evhttp_request *req);
843 /** Returns the output buffer */
844 EVENT2_EXPORT_SYMBOL
845 struct evbuffer *evhttp_request_get_output_buffer(struct evhttp_request *req);
846 /** Returns the host associated with the request. If a client sends an absolute
847     URI, the host part of that is preferred. Otherwise, the input headers are
848     searched for a Host: header. NULL is returned if no absolute URI or Host:
849     header is provided. */
850 EVENT2_EXPORT_SYMBOL
851 const char *evhttp_request_get_host(struct evhttp_request *req);
852 
853 /* Interfaces for dealing with HTTP headers */
854 
855 /**
856    Finds the value belonging to a header.
857 
858    @param headers the evkeyvalq object in which to find the header
859    @param key the name of the header to find
860    @returns a pointer to the value for the header or NULL if the header
861      could not be found.
862    @see evhttp_add_header(), evhttp_remove_header()
863 */
864 EVENT2_EXPORT_SYMBOL
865 const char *evhttp_find_header(const struct evkeyvalq *headers,
866     const char *key);
867 
868 /**
869    Removes a header from a list of existing headers.
870 
871    @param headers the evkeyvalq object from which to remove a header
872    @param key the name of the header to remove
873    @returns 0 if the header was removed, -1  otherwise.
874    @see evhttp_find_header(), evhttp_add_header()
875 */
876 EVENT2_EXPORT_SYMBOL
877 int evhttp_remove_header(struct evkeyvalq *headers, const char *key);
878 
879 /**
880    Adds a header to a list of existing headers.
881 
882    @param headers the evkeyvalq object to which to add a header
883    @param key the name of the header
884    @param value the value belonging to the header
885    @returns 0 on success, -1  otherwise.
886    @see evhttp_find_header(), evhttp_clear_headers()
887 */
888 EVENT2_EXPORT_SYMBOL
889 int evhttp_add_header(struct evkeyvalq *headers, const char *key, const char *value);
890 
891 /**
892    Removes all headers from the header list.
893 
894    @param headers the evkeyvalq object from which to remove all headers
895 */
896 EVENT2_EXPORT_SYMBOL
897 void evhttp_clear_headers(struct evkeyvalq *headers);
898 
899 /* Miscellaneous utility functions */
900 
901 
902 /**
903    Helper function to encode a string for inclusion in a URI.  All
904    characters are replaced by their hex-escaped (%22) equivalents,
905    except for characters explicitly unreserved by RFC3986 -- that is,
906    ASCII alphanumeric characters, hyphen, dot, underscore, and tilde.
907 
908    The returned string must be freed by the caller.
909 
910    @param str an unencoded string
911    @return a newly allocated URI-encoded string or NULL on failure
912  */
913 EVENT2_EXPORT_SYMBOL
914 char *evhttp_encode_uri(const char *str);
915 
916 /**
917    As evhttp_encode_uri, but if 'size' is nonnegative, treat the string
918    as being 'size' bytes long.  This allows you to encode strings that
919    may contain 0-valued bytes.
920 
921    The returned string must be freed by the caller.
922 
923    @param str an unencoded string
924    @param size the length of the string to encode, or -1 if the string
925       is NUL-terminated
926    @param space_to_plus if true, space characters in 'str' are encoded
927       as +, not %20.
928    @return a newly allocate URI-encoded string, or NULL on failure.
929  */
930 EVENT2_EXPORT_SYMBOL
931 char *evhttp_uriencode(const char *str, ev_ssize_t size, int space_to_plus);
932 
933 /**
934   Helper function to sort of decode a URI-encoded string.  Unlike
935   evhttp_uridecode, it decodes all plus characters that appear
936   _after_ the first question mark character, but no plusses that occur
937   before.  This is not a good way to decode URIs in whole or in part.
938 
939   The returned string must be freed by the caller
940 
941   @deprecated  This function is deprecated; you probably want to use
942      evhttp_uridecode instead.
943 
944   @param uri an encoded URI
945   @return a newly allocated unencoded URI or NULL on failure
946  */
947 EVENT2_EXPORT_SYMBOL
948 char *evhttp_decode_uri(const char *uri);
949 
950 /**
951   Helper function to decode a URI-escaped string or HTTP parameter.
952 
953   If 'decode_plus' is 1, then we decode the string as an HTTP parameter
954   value, and convert all plus ('+') characters to spaces.  If
955   'decode_plus' is 0, we leave all plus characters unchanged.
956 
957   The returned string must be freed by the caller.
958 
959   @param uri a URI-encode encoded URI
960   @param decode_plus determines whether we convert '+' to space.
961   @param size_out if size_out is not NULL, *size_out is set to the size of the
962      returned string
963   @return a newly allocated unencoded URI or NULL on failure
964  */
965 EVENT2_EXPORT_SYMBOL
966 char *evhttp_uridecode(const char *uri, int decode_plus,
967     size_t *size_out);
968 
969 /**
970    Helper function to parse out arguments in a query.
971 
972    Parsing a URI like
973 
974       http://foo.com/?q=test&s=some+thing
975 
976    will result in two entries in the key value queue.
977 
978    The first entry is: key="q", value="test"
979    The second entry is: key="s", value="some thing"
980 
981    @deprecated This function is deprecated as of Libevent 2.0.9.  Use
982      evhttp_uri_parse and evhttp_parse_query_str instead.
983 
984    @param uri the request URI
985    @param headers the head of the evkeyval queue
986    @return 0 on success, -1 on failure
987  */
988 EVENT2_EXPORT_SYMBOL
989 int evhttp_parse_query(const char *uri, struct evkeyvalq *headers);
990 
991 /**
992    Helper function to parse out arguments from the query portion of an
993    HTTP URI.
994 
995    Parsing a query string like
996 
997      q=test&s=some+thing
998 
999    will result in two entries in the key value queue.
1000 
1001    The first entry is: key="q", value="test"
1002    The second entry is: key="s", value="some thing"
1003 
1004    @param query_parse the query portion of the URI
1005    @param headers the head of the evkeyval queue
1006    @return 0 on success, -1 on failure
1007  */
1008 EVENT2_EXPORT_SYMBOL
1009 int evhttp_parse_query_str(const char *uri, struct evkeyvalq *headers);
1010 
1011 /**
1012  * Escape HTML character entities in a string.
1013  *
1014  * Replaces <, >, ", ' and & with &lt;, &gt;, &quot;,
1015  * &#039; and &amp; correspondingly.
1016  *
1017  * The returned string needs to be freed by the caller.
1018  *
1019  * @param html an unescaped HTML string
1020  * @return an escaped HTML string or NULL on error
1021  */
1022 EVENT2_EXPORT_SYMBOL
1023 char *evhttp_htmlescape(const char *html);
1024 
1025 /**
1026  * Return a new empty evhttp_uri with no fields set.
1027  */
1028 EVENT2_EXPORT_SYMBOL
1029 struct evhttp_uri *evhttp_uri_new(void);
1030 
1031 /**
1032  * Changes the flags set on a given URI.  See EVHTTP_URI_* for
1033  * a list of flags.
1034  **/
1035 EVENT2_EXPORT_SYMBOL
1036 void evhttp_uri_set_flags(struct evhttp_uri *uri, unsigned flags);
1037 
1038 /** Return the scheme of an evhttp_uri, or NULL if there is no scheme has
1039  * been set and the evhttp_uri contains a Relative-Ref. */
1040 EVENT2_EXPORT_SYMBOL
1041 const char *evhttp_uri_get_scheme(const struct evhttp_uri *uri);
1042 /**
1043  * Return the userinfo part of an evhttp_uri, or NULL if it has no userinfo
1044  * set.
1045  */
1046 EVENT2_EXPORT_SYMBOL
1047 const char *evhttp_uri_get_userinfo(const struct evhttp_uri *uri);
1048 /**
1049  * Return the host part of an evhttp_uri, or NULL if it has no host set.
1050  * The host may either be a regular hostname (conforming to the RFC 3986
1051  * "regname" production), or an IPv4 address, or the empty string, or a
1052  * bracketed IPv6 address, or a bracketed 'IP-Future' address.
1053  *
1054  * Note that having a NULL host means that the URI has no authority
1055  * section, but having an empty-string host means that the URI has an
1056  * authority section with no host part.  For example,
1057  * "mailto:user@example.com" has a host of NULL, but "file:///etc/motd"
1058  * has a host of "".
1059  */
1060 EVENT2_EXPORT_SYMBOL
1061 const char *evhttp_uri_get_host(const struct evhttp_uri *uri);
1062 /** Return the port part of an evhttp_uri, or -1 if there is no port set. */
1063 EVENT2_EXPORT_SYMBOL
1064 int evhttp_uri_get_port(const struct evhttp_uri *uri);
1065 /** Return the path part of an evhttp_uri, or NULL if it has no path set */
1066 EVENT2_EXPORT_SYMBOL
1067 const char *evhttp_uri_get_path(const struct evhttp_uri *uri);
1068 /** Return the query part of an evhttp_uri (excluding the leading "?"), or
1069  * NULL if it has no query set */
1070 EVENT2_EXPORT_SYMBOL
1071 const char *evhttp_uri_get_query(const struct evhttp_uri *uri);
1072 /** Return the fragment part of an evhttp_uri (excluding the leading "#"),
1073  * or NULL if it has no fragment set */
1074 EVENT2_EXPORT_SYMBOL
1075 const char *evhttp_uri_get_fragment(const struct evhttp_uri *uri);
1076 
1077 /** Set the scheme of an evhttp_uri, or clear the scheme if scheme==NULL.
1078  * Returns 0 on success, -1 if scheme is not well-formed. */
1079 EVENT2_EXPORT_SYMBOL
1080 int evhttp_uri_set_scheme(struct evhttp_uri *uri, const char *scheme);
1081 /** Set the userinfo of an evhttp_uri, or clear the userinfo if userinfo==NULL.
1082  * Returns 0 on success, -1 if userinfo is not well-formed. */
1083 EVENT2_EXPORT_SYMBOL
1084 int evhttp_uri_set_userinfo(struct evhttp_uri *uri, const char *userinfo);
1085 /** Set the host of an evhttp_uri, or clear the host if host==NULL.
1086  * Returns 0 on success, -1 if host is not well-formed. */
1087 EVENT2_EXPORT_SYMBOL
1088 int evhttp_uri_set_host(struct evhttp_uri *uri, const char *host);
1089 /** Set the port of an evhttp_uri, or clear the port if port==-1.
1090  * Returns 0 on success, -1 if port is not well-formed. */
1091 EVENT2_EXPORT_SYMBOL
1092 int evhttp_uri_set_port(struct evhttp_uri *uri, int port);
1093 /** Set the path of an evhttp_uri, or clear the path if path==NULL.
1094  * Returns 0 on success, -1 if path is not well-formed. */
1095 EVENT2_EXPORT_SYMBOL
1096 int evhttp_uri_set_path(struct evhttp_uri *uri, const char *path);
1097 /** Set the query of an evhttp_uri, or clear the query if query==NULL.
1098  * The query should not include a leading "?".
1099  * Returns 0 on success, -1 if query is not well-formed. */
1100 EVENT2_EXPORT_SYMBOL
1101 int evhttp_uri_set_query(struct evhttp_uri *uri, const char *query);
1102 /** Set the fragment of an evhttp_uri, or clear the fragment if fragment==NULL.
1103  * The fragment should not include a leading "#".
1104  * Returns 0 on success, -1 if fragment is not well-formed. */
1105 EVENT2_EXPORT_SYMBOL
1106 int evhttp_uri_set_fragment(struct evhttp_uri *uri, const char *fragment);
1107 
1108 /**
1109  * Helper function to parse a URI-Reference as specified by RFC3986.
1110  *
1111  * This function matches the URI-Reference production from RFC3986,
1112  * which includes both URIs like
1113  *
1114  *    scheme://[[userinfo]@]foo.com[:port]]/[path][?query][#fragment]
1115  *
1116  *  and relative-refs like
1117  *
1118  *    [path][?query][#fragment]
1119  *
1120  * Any optional elements portions not present in the original URI are
1121  * left set to NULL in the resulting evhttp_uri.  If no port is
1122  * specified, the port is set to -1.
1123  *
1124  * Note that no decoding is performed on percent-escaped characters in
1125  * the string; if you want to parse them, use evhttp_uridecode or
1126  * evhttp_parse_query_str as appropriate.
1127  *
1128  * Note also that most URI schemes will have additional constraints that
1129  * this function does not know about, and cannot check.  For example,
1130  * mailto://www.example.com/cgi-bin/fortune.pl is not a reasonable
1131  * mailto url, http://www.example.com:99999/ is not a reasonable HTTP
1132  * URL, and ftp:username@example.com is not a reasonable FTP URL.
1133  * Nevertheless, all of these URLs conform to RFC3986, and this function
1134  * accepts all of them as valid.
1135  *
1136  * @param source_uri the request URI
1137  * @param flags Zero or more EVHTTP_URI_* flags to affect the behavior
1138  *              of the parser.
1139  * @return uri container to hold parsed data, or NULL if there is error
1140  * @see evhttp_uri_free()
1141  */
1142 EVENT2_EXPORT_SYMBOL
1143 struct evhttp_uri *evhttp_uri_parse_with_flags(const char *source_uri,
1144     unsigned flags);
1145 
1146 /** Tolerate URIs that do not conform to RFC3986.
1147  *
1148  * Unfortunately, some HTTP clients generate URIs that, according to RFC3986,
1149  * are not conformant URIs.  If you need to support these URIs, you can
1150  * do so by passing this flag to evhttp_uri_parse_with_flags.
1151  *
1152  * Currently, these changes are:
1153  * <ul>
1154  *   <li> Nonconformant URIs are allowed to contain otherwise unreasonable
1155  *        characters in their path, query, and fragment components.
1156  * </ul>
1157  */
1158 #define EVHTTP_URI_NONCONFORMANT 0x01
1159 
1160 /** Alias for evhttp_uri_parse_with_flags(source_uri, 0) */
1161 EVENT2_EXPORT_SYMBOL
1162 struct evhttp_uri *evhttp_uri_parse(const char *source_uri);
1163 
1164 /**
1165  * Free all memory allocated for a parsed uri.  Only use this for URIs
1166  * generated by evhttp_uri_parse.
1167  *
1168  * @param uri container with parsed data
1169  * @see evhttp_uri_parse()
1170  */
1171 EVENT2_EXPORT_SYMBOL
1172 void evhttp_uri_free(struct evhttp_uri *uri);
1173 
1174 /**
1175  * Join together the uri parts from parsed data to form a URI-Reference.
1176  *
1177  * Note that no escaping of reserved characters is done on the members
1178  * of the evhttp_uri, so the generated string might not be a valid URI
1179  * unless the members of evhttp_uri are themselves valid.
1180  *
1181  * @param uri container with parsed data
1182  * @param buf destination buffer
1183  * @param limit destination buffer size
1184  * @return an joined uri as string or NULL on error
1185  * @see evhttp_uri_parse()
1186  */
1187 EVENT2_EXPORT_SYMBOL
1188 char *evhttp_uri_join(struct evhttp_uri *uri, char *buf, size_t limit);
1189 
1190 #ifdef __cplusplus
1191 }
1192 #endif
1193 
1194 #endif /* EVENT2_HTTP_H_INCLUDED_ */
1195