Libevhtp

Overview

libevhtp 는 libevent 를 이용한 HTTP API 라이브러리이다. libevhtp 를 사용하면 손쉽게 REST 인터페이스를 구현할 수 있다.

홈페이지: https://github.com/ellzey/libevhtp

Functions

생성/삭제

<source lang=c> /**

* @brief creates a new evhtp_t instance
*
* @param evbase the initialized event base
* @param arg user-defined argument which is evhtp_t specific
*
* @return a new evhtp_t structure or NULL on error
*/

evhtp_t * evhtp_new(evbase_t * evbase, void * arg); void evhtp_free(evhtp_t * evhtp); </source> evhtp 인스턴스 생성/삭제 함수

콜백 등록

• Interface

<source lang=c> /**

* @brief sets a callback to be executed on a specific path
*
* @param htp the initialized evhtp_t
* @param path the path to match
* @param cb the function to be executed
* @param arg user-defined argument passed to the callback
*
* @return evhtp_callback_t * on success, NULL on error.
*/

evhtp_callback_t * evhtp_set_cb(evhtp_t * htp, const char * path, evhtp_callback_cb cb, void * arg); </source> 지정된 경로가 호출되었을 때 실행 될 콜백 함수를 지정한다.

• Example

<source lang=c> void testcb(evhtp_request_t *req, void *a) {

   const char *str = a;
   
   evbuffer_add_printf(req->buffer_out, "%s", str);
   evhtp_send_reply(req, EVHTP_RES_OK);

}

evhtp_t *htp = evhtp_new(evbase, NULL);

evhtp_set_cb(htp, "/simple/", testcb, "simple"); </source>

Listen 소켓 설정

• Interface

<source lang=c> /**

* @brief bind to a socket, optionally with specific protocol support
*        formatting. The addr can be defined as one of the following:
*          ipv6:<ipv6addr> for binding to an IPv6 address.
*          unix:<named pipe> for binding to a unix named socket
*          ipv4:<ipv4addr> for binding to an ipv4 address
*        Otherwise the addr is assumed to be ipv4.
*
* @param htp
* @param addr
* @param port
* @param backlog
*
* @return
*/

int evhtp_bind_socket(evhtp_t * htp, const char * addr, uint16_t port, int backlog); </source> Listen 주소를 설정한다. 주소 설정 시, 자동으로 주소 타입을 파싱해서 알맞은 소켓 타입으로 생성한 후, listen 한다. "0.0.0.0" 설정시, localhost 주소를 listen 한다.

• Example

<source lang=c> evhtp_bind_socket(htp, "0.0.0.0", 8081, 1024); </source>

Samples

test_basic

• test_basic.c

<source lang=c>

1. include <stdio.h>
2. include <stdlib.h>
3. include <string.h>
4. include <stdint.h>
5. include <errno.h>
6. include <evhtp.h>

void testcb(evhtp_request_t *req, void *a) {

   const char *str = a;
   
   evbuffer_add_printf(req->buffer_out, "%s", str);
   evhtp_send_reply(req, EVHTP_RES_OK);

}

int main(int argc, char **argv) {

   evbase_t *evbase    = event_base_new();
   evhtp_t *htp        = evhtp_new(evbase, NULL);
   
   evhtp_set_cb(htp, "/simple/", testcb, "simple");
   evhtp_set_cb(htp, "/1/ping", testcb, "one");
   evhtp_set_cb(htp, "/1/ping.json", testcb, "two");

1. ifndef EVHTP_DISABLE_EVTHR

   evhtp_use_threads(htp, NULL, 4, NULL);

1. endif

   evhtp_bind_socket(htp, "0.0.0.0", 8081, 1024);
   
   event_base_loop(evbase, 0);
   
   evhtp_unbind_socket(htp);
   evhtp_free(htp);
   event_base_free(evbase);
   
   return 0;

} </source>

References

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