第二章 C语言实例 —制作http服务器 dennis ITeye技术网站

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.gz
cd libevent-2.0.12-stable/
./configure --prefix=/usr/local/libevent-2.0.12-stable/
make
make install
cd ../

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);
}