第二章 C语言实例 —制作http服务器

rtxbc

任务:
   1.制作http服务器，读取url提交的相关数据.
   2.把读到的数据推入到队列中.
 
 
条件:
使用libevent的类库,所以先安装libevent
 
tar zxvf libevent-2.0.12-stable.tar.gzcd libevent-2.0.12-stable/./configure --prefix=/usr/local/libevent-2.0.12-stable/makemake installcd ../  
 
1.服务端简易代码如下
 
#include <stdio.h>#include <stdlib.h>#include <err.h>#include <event.h>#include <evhttp.h>void http_handle(struct evhttp_request *req, void *arg); /*  HTTP Request Handle  */int main(){    struct evhttp *httpd;    event_init();    httpd = evhttp_start("0.0.0.0", 2345);    if (httpd == NULL) {        fprintf(stderr, "Error: Unable to listen on %s:%d\n\n");        exit(1);        }       evhttp_set_timeout(httpd, 2000);    evhttp_set_gencb(httpd, http_handle, NULL);    event_dispatch();    evhttp_free(httpd);    return 0;}void http_handle(struct evhttp_request *req, void *arg){    struct evbuffer *buf;    buf = evbuffer_new();    /*  Response the client  */    evhttp_send_reply(req, HTTP_OK, "OK", buf);    //evbuffer_add_printf(buf, "%s", "HTTPSQS_AUTH_FAILED");    /*  Release the memory  */    evbuffer_free(buf);    fprintf(stderr,"Send \n");} 
编译：(编译时把libevent的类库中的.so文件和.h文件连接进来)
 
gcc http.c -L/usr/local/libevent-2.0.12-stable/lib/ -levent -I/usr/local/libevent-2.0.12-stable/include/ 
测试
在服务器端，执行编译后的文件a.out
./a.out 
客户端进行访问(也可以使用浏览器访问，但是要打开端口号2345——vi /etc/sysconfig/iptables)
[www@zhoubc data]$ curl http://127.0.0.1:2345 
此时再看服务端,变成如下状态
 
[www@zhoubc queue]$ ./a.out Send   
2.处理http请求,重写htt_handle方法
 
void http_handle(struct evhttp_request *req, void *arg){    struct evbuffer *buf;    buf = evbuffer_new();    /*  Analyst the URI  */    char *decode_uri = strdup((char*) evhttp_request_uri(req));    struct evkeyvalq http_query;    evhttp_parse_query(decode_uri, &http_query);    free(decode_uri);    /*  URI Parameter  */    const char *http_input_opt = evhttp_find_header (&http_query, "opt"); /* Operation Type */    const char *http_input_name = evhttp_find_header (&http_query, "name"); /* Queue Name */    const char *http_input_data = evhttp_find_header (&http_query, "data"); /* Data With GET */    /*  header  */    evhttp_add_header(req->output_headers, "Content-Type", "text/plain");    evhttp_add_header(req->output_headers, "Connection", "keep-alive");    evhttp_add_header(req->output_headers, "Cache-Control", "no-cache");    evhttp_add_header(req->output_headers, "author", "Dennis .Z Ritchie");    if(http_input_opt != NULL && http_input_name != NULL && strlen(http_input_name) < 300){        /*  GET Method,OUT The Queue  */        if(strcmp(http_input_opt,"put") == 0){            int buffer_data_len = EVBUFFER_LENGTH(req->input_buffer);            if(buffer_data_len > 0){ /* POST METHOD */                char *input_value_data = EVBUFFER_DATA(req->input_buffer); /* Submited Data */                fprintf(stderr,"%s \n",input_value_data);            }else if(http_input_data != NULL){                fprintf(stderr,"%s \n",http_input_data);            }        }else if(strcmp(http_input_opt,"get") == 0){        }    }    /*  Response the client  */    evhttp_send_reply(req, HTTP_OK, "OK", buf);    //evbuffer_add_printf(buf, "%s", "HTTPSQS_AUTH_FAILED");    /*  Release the memory  */    evhttp_clear_headers(&http_query);    evbuffer_free(buf);}