1 /* 2 * Copyright (c) 2000-2004 Niels Provos <provos (at) citi.umich.edu> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 #ifndef _EVHTTP_H_ 28 #define _EVHTTP_H_ 29 30 #include "event.h" 31 32 #ifdef __cplusplus 33 extern "C" { 34 #endif 35 36 #ifdef WIN32 37 #define WIN32_LEAN_AND_MEAN 38 #include <winsock2.h> 39 #include <windows.h> 40 #undef WIN32_LEAN_AND_MEAN 41 #endif 42 43 /** @file evhttp.h 44 * 45 * Basic support for HTTP serving. 46 * 47 * As libevent is a library for dealing with event notification and most 48 * interesting applications are networked today, I have often found the 49 * need to write HTTP code. The following prototypes and definitions provide 50 * an application with a minimal interface for making HTTP requests and for 51 * creating a very simple HTTP server. 52 */ 53 54 /* Response codes */ 55 #define HTTP_OK 200 56 #define HTTP_NOCONTENT 204 57 #define HTTP_MOVEPERM 301 58 #define HTTP_MOVETEMP 302 59 #define HTTP_NOTMODIFIED 304 60 #define HTTP_BADREQUEST 400 61 #define HTTP_NOTFOUND 404 62 #define HTTP_SERVUNAVAIL 503 63 64 struct evhttp; 65 struct evhttp_request; 66 struct evkeyvalq; 67 68 /** Create a new HTTP server 69 * 70 * @param base (optional) the event base to receive the HTTP events 71 * @return a pointer to a newly initialized evhttp server structure 72 */ 73 struct evhttp *evhttp_new(struct event_base *base); 74 75 /** 76 * Binds an HTTP server on the specified address and port. 77 * 78 * Can be called multiple times to bind the same http server 79 * to multiple different ports. 80 * 81 * @param http a pointer to an evhttp object 82 * @param address a string containing the IP address to listen(2) on 83 * @param port the port number to listen on 84 * @return a newly allocated evhttp struct 85 * @see evhttp_free() 86 */ 87 int evhttp_bind_socket(struct evhttp *http, const char *address, u_short port); 88 89 /** 90 * Makes an HTTP server accept connections on the specified socket 91 * 92 * This may be useful to create a socket and then fork multiple instances 93 * of an http server, or when a socket has been communicated via file 94 * descriptor passing in situations where an http servers does not have 95 * permissions to bind to a low-numbered port. 96 * 97 * Can be called multiple times to have the http server listen to 98 * multiple different sockets. 99 * 100 * @param http a pointer to an evhttp object 101 * @param fd a socket fd that is ready for accepting connections 102 * @return 0 on success, -1 on failure. 103 * @see evhttp_free(), evhttp_bind_socket() 104 */ 105 int evhttp_accept_socket(struct evhttp *http, int fd); 106 107 /** 108 * Free the previously created HTTP server. 109 * 110 * Works only if no requests are currently being served. 111 * 112 * @param http the evhttp server object to be freed 113 * @see evhttp_start() 114 */ 115 void evhttp_free(struct evhttp* http); 116 117 /** Set a callback for a specified URI */ 118 void evhttp_set_cb(struct evhttp *, const char *, 119 void (*)(struct evhttp_request *, void *), void *); 120 121 /** Removes the callback for a specified URI */ 122 int evhttp_del_cb(struct evhttp *, const char *); 123 124 /** Set a callback for all requests that are not caught by specific callbacks 125 */ 126 void evhttp_set_gencb(struct evhttp *, 127 void (*)(struct evhttp_request *, void *), void *); 128 129 /** 130 * Set the timeout for an HTTP request. 131 * 132 * @param http an evhttp object 133 * @param timeout_in_secs the timeout, in seconds 134 */ 135 void evhttp_set_timeout(struct evhttp *, int timeout_in_secs); 136 137 /* Request/Response functionality */ 138 139 /** 140 * Send an HTML error message to the client. 141 * 142 * @param req a request object 143 * @param error the HTTP error code 144 * @param reason a brief explanation of the error 145 */ 146 void evhttp_send_error(struct evhttp_request *req, int error, 147 const char *reason); 148 149 /** 150 * Send an HTML reply to the client. 151 * 152 * @param req a request object 153 * @param code the HTTP response code to send 154 * @param reason a brief message to send with the response code 155 * @param databuf the body of the response 156 */ 157 void evhttp_send_reply(struct evhttp_request *req, int code, 158 const char *reason, struct evbuffer *databuf); 159 160 /* Low-level response interface, for streaming/chunked replies */ 161 void evhttp_send_reply_start(struct evhttp_request *, int, const char *); 162 void evhttp_send_reply_chunk(struct evhttp_request *, struct evbuffer *); 163 void evhttp_send_reply_end(struct evhttp_request *); 164 165 /** 166 * Start an HTTP server on the specified address and port 167 * 168 * DEPRECATED: it does not allow an event base to be specified 169 * 170 * @param address the address to which the HTTP server should be bound 171 * @param port the port number on which the HTTP server should listen 172 * @return an struct evhttp object 173 */ 174 struct evhttp *evhttp_start(const char *address, u_short port); 175 176 /* 177 * Interfaces for making requests 178 */ 179 enum evhttp_cmd_type { EVHTTP_REQ_GET, EVHTTP_REQ_POST, EVHTTP_REQ_HEAD }; 180 181 enum evhttp_request_kind { EVHTTP_REQUEST, EVHTTP_RESPONSE }; 182 183 /** 184 * the request structure that a server receives. 185 * WARNING: expect this structure to change. I will try to provide 186 * reasonable accessors. 187 */ 188 struct evhttp_request { 189 #if defined(TAILQ_ENTRY) 190 TAILQ_ENTRY(evhttp_request) next; 191 #else 192 struct { 193 struct evhttp_request *tqe_next; 194 struct evhttp_request **tqe_prev; 195 } next; 196 #endif 197 198 /* the connection object that this request belongs to */ 199 struct evhttp_connection *evcon; 200 int flags; 201 #define EVHTTP_REQ_OWN_CONNECTION 0x0001 202 #define EVHTTP_PROXY_REQUEST 0x0002 203 204 struct evkeyvalq *input_headers; 205 struct evkeyvalq *output_headers; 206 207 /* address of the remote host and the port connection came from */ 208 char *remote_host; 209 u_short remote_port; 210 211 enum evhttp_request_kind kind; 212 enum evhttp_cmd_type type; 213 214 char *uri; /* uri after HTTP request was parsed */ 215 216 char major; /* HTTP Major number */ 217 char minor; /* HTTP Minor number */ 218 219 int response_code; /* HTTP Response code */ 220 char *response_code_line; /* Readable response */ 221 222 struct evbuffer *input_buffer; /* read data */ 223 ev_int64_t ntoread; 224 int chunked; 225 226 struct evbuffer *output_buffer; /* outgoing post or data */ 227 228 /* Callback */ 229 void (*cb)(struct evhttp_request *, void *); 230 void *cb_arg; 231 232 /* 233 * Chunked data callback - call for each completed chunk if 234 * specified. If not specified, all the data is delivered via 235 * the regular callback. 236 */ 237 void (*chunk_cb)(struct evhttp_request *, void *); 238 }; 239 240 /** 241 * Creates a new request object that needs to be filled in with the request 242 * parameters. The callback is executed when the request completed or an 243 * error occurred. 244 */ 245 struct evhttp_request *evhttp_request_new( 246 void (*cb)(struct evhttp_request *, void *), void *arg); 247 248 /** enable delivery of chunks to requestor */ 249 void evhttp_request_set_chunked_cb(struct evhttp_request *, 250 void (*cb)(struct evhttp_request *, void *)); 251 252 /** Frees the request object and removes associated events. */ 253 void evhttp_request_free(struct evhttp_request *req); 254 255 /** 256 * A connection object that can be used to for making HTTP requests. The 257 * connection object tries to establish the connection when it is given an 258 * http request object. 259 */ 260 struct evhttp_connection *evhttp_connection_new( 261 const char *address, unsigned short port); 262 263 /** Frees an http connection */ 264 void evhttp_connection_free(struct evhttp_connection *evcon); 265 266 /** sets the ip address from which http connections are made */ 267 void evhttp_connection_set_local_address(struct evhttp_connection *evcon, 268 const char *address); 269 270 /** sets the local port from which http connections are made */ 271 void evhttp_connection_set_local_port(struct evhttp_connection *evcon, 272 unsigned short port); 273 274 /** Sets the timeout for events related to this connection */ 275 void evhttp_connection_set_timeout(struct evhttp_connection *evcon, 276 int timeout_in_secs); 277 278 /** Sets the retry limit for this connection - -1 repeats indefnitely */ 279 void evhttp_connection_set_retries(struct evhttp_connection *evcon, 280 int retry_max); 281 282 /** Set a callback for connection close. */ 283 void evhttp_connection_set_closecb(struct evhttp_connection *evcon, 284 void (*)(struct evhttp_connection *, void *), void *); 285 286 /** 287 * Associates an event base with the connection - can only be called 288 * on a freshly created connection object that has not been used yet. 289 */ 290 void evhttp_connection_set_base(struct evhttp_connection *evcon, 291 struct event_base *base); 292 293 /** Get the remote address and port associated with this connection. */ 294 void evhttp_connection_get_peer(struct evhttp_connection *evcon, 295 char **address, u_short *port); 296 297 /** The connection gets ownership of the request */ 298 int evhttp_make_request(struct evhttp_connection *evcon, 299 struct evhttp_request *req, 300 enum evhttp_cmd_type type, const char *uri); 301 302 const char *evhttp_request_uri(struct evhttp_request *req); 303 304 /* Interfaces for dealing with HTTP headers */ 305 306 const char *evhttp_find_header(const struct evkeyvalq *, const char *); 307 int evhttp_remove_header(struct evkeyvalq *, const char *); 308 int evhttp_add_header(struct evkeyvalq *, const char *, const char *); 309 void evhttp_clear_headers(struct evkeyvalq *); 310 311 /* Miscellaneous utility functions */ 312 313 314 /** 315 Helper function to encode a URI. 316 317 The returned string must be freed by the caller. 318 319 @param uri an unencoded URI 320 @return a newly allocated URI-encoded string 321 */ 322 char *evhttp_encode_uri(const char *uri); 323 324 325 /** 326 Helper function to decode a URI. 327 328 The returned string must be freed by the caller. 329 330 @param uri an encoded URI 331 @return a newly allocated unencoded URI 332 */ 333 char *evhttp_decode_uri(const char *uri); 334 335 336 /** 337 * Helper function to parse out arguments in a query. 338 * 339 * Parsing a uri like 340 * 341 * http://foo.com/?q=test&s=some+thing 342 * 343 * will result in two entries in the key value queue. 344 345 * The first entry is: key="q", value="test" 346 * The second entry is: key="s", value="some thing" 347 * 348 * @param uri the request URI 349 * @param headers the head of the evkeyval queue 350 */ 351 void evhttp_parse_query(const char *uri, struct evkeyvalq *headers); 352 353 354 /** 355 * Escape HTML character entities in a string. 356 * 357 * Replaces <, >, ", ' and & with <, >, ", 358 * ' and & correspondingly. 359 * 360 * The returned string needs to be freed by the caller. 361 * 362 * @param html an unescaped HTML string 363 * @return an escaped HTML string 364 */ 365 char *evhttp_htmlescape(const char *html); 366 367 #ifdef __cplusplus 368 } 369 #endif 370 371 #endif /* _EVHTTP_H_ */ 372
