/*
* Copyright (c) 2000-2004 Niels Provos <provos@citi.umich.edu>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _EVHTTP_H_
#define _EVHTTP_H_
#include <event.h>
#ifdef __cplusplus
extern "C" {
#endif
#ifdef WIN32
#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <windows.h>
#undef WIN32_LEAN_AND_MEAN
#endif
/** @file evhttp.h
*
* Basic support for HTTP serving.
*
* As libevent is a library for dealing with event notification and most
* interesting applications are networked today, I have often found the
* need to write HTTP code. The following prototypes and definitions provide
* an application with a minimal interface for making HTTP requests and for
* creating a very simple HTTP server.
*/
/* Response codes */
#define HTTP_OK 200
#define HTTP_NOCONTENT 204
#define HTTP_MOVEPERM 301
#define HTTP_MOVETEMP 302
#define HTTP_NOTMODIFIED 304
#define HTTP_BADREQUEST 400
#define HTTP_NOTFOUND 404
#define HTTP_SERVUNAVAIL 503
struct evhttp;
struct evhttp_request;
struct evkeyvalq;
/** Create a new HTTP server
*
* @param base (optional) the event base to receive the HTTP events
* @return a pointer to a newly initialized evhttp server structure
*/
struct evhttp *evhttp_new(struct event_base *base);
/**
* Binds an HTTP server on the specified address and port.
*
* Can be called multiple times to bind the same http server
* to multiple different ports.
*
* @param http a pointer to an evhttp object
* @param address a string containing the IP address to listen(2) on
* @param port the port number to listen on
* @return a newly allocated evhttp struct
* @see evhttp_free()
*/
int evhttp_bind_socket(struct evhttp *http, const char *address, u_short port);
/**
* Makes an HTTP server accept connections on the specified socket
*
* This may be useful to create a socket and then fork multiple instances
* of an http server, or when a socket has been communicated via file
* descriptor passing in situations where an http servers does not have
* permissions to bind to a low-numbered port.
*
* Can be called multiple times to have the http server listen to
* multiple different sockets.
*
* @param http a pointer to an evhttp object
* @param fd a socket fd that is ready for accepting connections
* @return 0 on success, -1 on failure.
* @see evhttp_free(), evhttp_bind_socket()
*/
int evhttp_accept_socket(struct evhttp *http, int fd);
/**
* Free the previously created HTTP server.
*
* Works only if no requests are currently being served.
*
* @param http the evhttp server object to be freed
* @see evhttp_start()
*/
void evhttp_free(struct evhttp* http);
/** Set a callback for a specified URI */
void evhttp_set_cb(struct evhttp *, const char *,
void (*)(struct evhttp_request *, void *), void *);
/** Removes the callback for a specified URI */
int evhttp_del_cb(struct evhttp *, const char *);
/** Set a callback for all requests that are not caught by specific callbacks
*/
void evhttp_set_gencb(struct evhttp *,
void (*)(struct evhttp_request *, void *), void *);
/**
* Set the timeout for an HTTP request.
*
* @param http an evhttp object
* @param timeout_in_secs the timeout, in seconds
*/
void evhttp_set_timeout(struct evhttp *, int timeout_in_secs);
/* Request/Response functionality */
/**
* Send an HTML error message to the client.
*
* @param req a request object
* @param error the HTTP error code
* @param reason a brief explanation of the error
*/
void evhttp_send_error(struct evhttp_request *req, int error,
const char *reason);
/**
* Send an HTML reply to the client.
*
* @param req a request object
* @param code the HTTP response code to send
* @param reason a brief message to send with the response code
* @param databuf the body of the response
*/
void evhttp_send_reply(struct evhttp_request *req, int code,
const char *reason, struct evbuffer *databuf);
/* Low-level response interface, for streaming/chunked replies */
void evhttp_send_reply_start(struct evhttp_request *, int, const char *);
void evhttp_send_reply_chunk(struct evhttp_request *, struct evbuffer *);
void evhttp_send_reply_end(struct evhttp_request *);
/**
* Start an HTTP server on the specified address and port
*
* DEPRECATED: it does not allow an event base to be specified
*
* @param address the address to which the HTTP server should be bound
* @param port the port number on which the HTTP server should listen
* @return an struct evhttp object
*/
struct evhttp *evhttp_start(const char *address, u_short port);
/*
* Interfaces for making requests
*/
enum evhttp_cmd_type { EVHTTP_REQ_GET, EVHTTP_REQ_POST, EVHTTP_REQ_HEAD };
enum evhttp_request_kind { EVHTTP_REQUEST, EVHTTP_RESPONSE };
/**
* the request structure that a server receives.
* WARNING: expect this structure to change. I will try to provide
* reasonable accessors.
*/
struct evhttp_request {
#if defined(TAILQ_ENTRY)
TAILQ_ENTRY(evhttp_request) next;
#else
struct {
struct evhttp_request *tqe_next;
struct evhttp_request **tqe_prev;
} next;
#endif
/* the connection object that this request belongs to */
struct evhttp_connection *evcon;
int flags;
#define EVHTTP_REQ_OWN_CONNECTION 0x0001
#define EVHTTP_PROXY_REQUEST 0x0002
struct evkeyvalq *input_headers;
struct evkeyvalq *output_headers;
/* address of the remote host and the port connection came from */
char *remote_host;
u_short remote_port;
enum evhttp_request_kind kind;
enum evhttp_cmd_type type;
char *uri; /* uri after HTTP request was parsed */
char major; /* HTTP Major number */
char minor; /* HTTP Minor number */
int response_code; /* HTTP Response code */
char *response_code_line; /* Readable response */
struct evbuffer *input_buffer; /* read data */
ev_int64_t ntoread;
int chunked;
struct evbuffer *output_buffer; /* outgoing post or data */
/* Callback */
void (*cb)(struct evhttp_request *, void *);
void *cb_arg;
/*
* Chunked data callback - call for each completed chunk if
* specified. If not specified, all the data is delivered via
* the regular callback.
*/
void (*chunk_cb)(struct evhttp_request *, void *);
};
/**
* Creates a new request object that needs to be filled in with the request
* parameters. The callback is executed when the request completed or an
* error occurred.
*/
struct evhttp_request *evhttp_request_new(
void (*cb)(struct evhttp_request *, void *), void *arg);
/** enable delivery of chunks to requestor */
void evhttp_request_set_chunked_cb(struct evhttp_request *,
void (*cb)(struct evhttp_request *, void *));
/** Frees the request object and removes associated events. */
void evhttp_request_free(struct evhttp_request *req);
/**
* A connection object that can be used to for making HTTP requests. The
* connection object tries to establish the connection when it is given an
* http request object.
*/
struct evhttp_connection *evhttp_connection_new(
const char *address, unsigned short port);
/** Frees an http connection */
void evhttp_connection_free(struct evhttp_connection *evcon);
/** sets the ip address from which http connections are made */
void evhttp_connection_set_local_address(struct evhttp_connection *evcon,
const char *address);
/** sets the local port from which http connections are made */
void evhttp_connection_set_local_port(struct evhttp_connection *evcon,
unsigned short port);
/** Sets the timeout for events related to this connection */
void evhttp_connection_set_timeout(struct evhttp_connection *evcon,
int timeout_in_secs);
/** Sets the retry limit for this connection - -1 repeats indefnitely */
void evhttp_connection_set_retries(struct evhttp_connection *evcon,
int retry_max);
/** Set a callback for connection close. */
void evhttp_connection_set_closecb(struct evhttp_connection *evcon,
void (*)(struct evhttp_connection *, void *), void *);
/**
* Associates an event base with the connection - can only be called
* on a freshly created connection object that has not been used yet.
*/
void evhttp_connection_set_base(struct evhttp_connection *evcon,
struct event_base *base);
/** Get the remote address and port associated with this connection. */
void evhttp_connection_get_peer(struct evhttp_connection *evcon,
char **address, u_short *port);
/** The connection gets ownership of the request */
int evhttp_make_request(struct evhttp_connection *evcon,
struct evhttp_request *req,
enum evhttp_cmd_type type, const char *uri);
const char *evhttp_request_uri(struct evhttp_request *req);
/* Interfaces for dealing with HTTP headers */
const char *evhttp_find_header(const struct evkeyvalq *, const char *);
int evhttp_remove_header(struct evkeyvalq *, const char *);
int evhttp_add_header(struct evkeyvalq *, const char *, const char *);
void evhttp_clear_headers(struct evkeyvalq *);
/* Miscellaneous utility functions */
/**
Helper function to encode a URI.
The returned string must be freed by the caller.
@param uri an unencoded URI
@return a newly allocated URI-encoded string
*/
char *evhttp_encode_uri(const char *uri);
/**
Helper function to decode a URI.
The returned string must be freed by the caller.
@param uri an encoded URI
@return a newly allocated unencoded URI
*/
char *evhttp_decode_uri(const char *uri);
/**
* Helper function to parse out arguments in a query.
*
* Parsing a uri like
*
* http://foo.com/?q=test&s=some+thing
*
* will result in two entries in the key value queue.
* The first entry is: key="q", value="test"
* The second entry is: key="s", value="some thing"
*
* @param uri the request URI
* @param headers the head of the evkeyval queue
*/
void evhttp_parse_query(const char *uri, struct evkeyvalq *headers);
/**
* Escape HTML character entities in a string.
*
* Replaces <, >, ", ' and & with <, >, ",
* ' and & correspondingly.
*
* The returned string needs to be freed by the caller.
*
* @param html an unescaped HTML string
* @return an escaped HTML string
*/
char *evhttp_htmlescape(const char *html);
#ifdef __cplusplus
}
#endif
#endif /* _EVHTTP_H_ */