从零开始一个http服务器（三)
代码地址 ：
git checkout step3 运行： gcc request.h request.c response.h response.c main.c tools/utils.c tools/utils.h && ./a.out 测试: 浏览器打开response 构造
- 观察response结构
- 定义并返回response
- 测试
观察response结构
上一节,我们成功解析了http的request，但是我们在浏览器访问我们的地址http://127.0.0.1:9734/ 还是无法正常显示。这是因为我们没有给浏览器返回它能读懂的信息。这一节我们的目标是让浏览器正确的显示信息。什么样的才是浏览器能读懂的信息呢？不妨我们用telnet来模拟向百度主页发一个http request,来看看百度主页返回的是什么信息。
伪造一个http request的字符串，注意 headers 中的 Host 代表我们要访问的主机地址。GET / HTTP/1.1Host: www.baidu.comUser-Agent: curl/7.54.0Accept: */*Content-Type: application/x-www-form-urlencode
再用telnet连接www.baidu.com 并指定80端口（80为http默认端口，telnet默认端口为23）, telnet www.baidu.com 80
Trying 119.75.216.20...Connected to www.a.shifen.com.Escape character is '^]'.GET / HTTP/1.1Host: www.baidu.comUser-Agent: curl/7.54.0Accept: */*Content-Type: application/x-www-form-urlencodeHTTP/1.1 200 OKAccept-Ranges: bytesCache-Control: private, no-cache, no-store, proxy-revalidate, no-transformConnection: Keep-AliveContent-Length: 2381Content-Type: text/htmlDate: Sat, 18 Aug 2018 02:12:08 GMTEtag: "588604c8-94d"Last-Modified: Mon, 23 Jan 2017 13:27:36 GMTPragma: no-cacheServer: bfe/1.0.8.18Set-Cookie: BDORZ=27315; max-age=86400; domain=.baidu.com; path=/ ...Connection closed by foreign host.
从HTTP/1.1 200 OK开始就是百度放回给我们的结果。让人惊喜的是这种结构和request很类型，除了第一行外。仔细看看:
- 第一行为 http版本号 response返回码 response返回结果描述
- 第二行开始为headers
- 空行后，接body
定义并返回response
根据response的结构有的信息定义我们的结构体.
/* response.h*/#include#include "tools/utils.h"#include "request.h"struct http_response { char * version; char * code; // 状态返回码 char * desc; // 返回描述 struct Map * headers; char * body; };void initHttpResponse(struct http_response * response);void doResponse( struct http_request * request, FILE * stream);void outputToFile( struct http_response * response, FILE * stream);
构造我们的response数据, 我们每次都返回相同的数据.
/* response.c*/#include/* fprintf NULL */#include /* strlen */#include "response.h"#include "request.h"#include "tools/utils.h"void initHttpResponse(struct http_response * response) { response->version = NULL; response->code = NULL; response->desc = NULL; response->headers = NULL; response->body = NULL;}void doResponse(struct http_request * request, FILE * stream) { struct http_response responseInstance; struct http_response * response = &responseInstance; initHttpResponse(response); response->version = "HTTP/1.1"; response->code = "200"; response->desc = "OK"; char * content = "hello everyone"; char content_len[25]; sprintf(content_len, "%lu", strlen(content)); struct Item * item = newItem( "Content-Length", content_len ); struct Map map_instance; initMap(&map_instance); response->headers = &map_instance; mapPush(response->headers, item); response->body = content; outputToFile(response, stream); // clean releaseMap(request->headers);}void outputToFile(struct http_response * response, FILE * stream) { // output version code desc int r = fprintf(stream, "%s %s %s \r\n", response->version, response->code, response->desc ); // output headers struct Map* map = response->headers; struct List* list; struct Item* item; int print_item_cnt = 0; for(int i=0; i table_len; i++) { list = map->table[i]; if(list == NULL) { continue; } item = list->start; while(item != NULL) { fprintf(stream, "%s: %s\r\n", item->key, item->value ); item = item->next; } } // output body if(response->body != NULL) { fprintf(stream, "\r\n%s", response->body); }}
写一个测试用例，将本应向客服端发送的数据输出到stdout
/* test/responseTest.ctest cmd:gcc ../request.h ../request.c ../response.h ../response.c ../tools/utils.h ../tools/utils.c responseTest.c && ./a.out*/#include#include "../request.h" #include "../response.h" int main() { struct http_request request; char data[] = "POST / HTTP/1.1\r\nContent-Length: 3\r\n\r\n111"; struct Map headers; request.headers = &headers; parse_request(&request, data); doResponse(&request, stdout);}
cd 到 test 目录
运行：gcc ../request.h ../request.c ../response.h ../response.c ../tools/utils.h ../tools/utils.c responseTest.c && ./a.out 可以看到正确的输出： ---------------------------method is: POSTurl is: /http version is: HTTP/1.1the headers are :{'Content-Length': ' 3'}body is 111---------------------------HTTP/1.1 200 OKContent-Length: 27hello everyone 现在修改main函数，加上我们的reponse处理逻辑
/**run cmd:gcc request.h request.c response.h response.c main.c tools/utils.c tools/utils.h && ./a.out*/#include#include #include #include #include #include #include #include #include "request.h"#include "response.h"#define MAXREQUESTLEN 50000void initString(char * c, int length) { int i = 0; while(i < length) { *(c + i) = '\0'; i++; }}int main() { int server_sockfd, client_sockfd; socklen_t server_len, client_len; struct sockaddr_in server_address; struct sockaddr_in client_address; server_sockfd = socket(AF_INET, SOCK_STREAM, 0); server_address.sin_family = AF_INET; server_address.sin_addr.s_addr = inet_addr("127.0.0.1"); server_address.sin_port = htons(9734); server_len = sizeof(server_address); bind(server_sockfd, (struct sockaddr *)&server_address, server_len); listen(server_sockfd, 5); while(1) { char ch[MAXREQUESTLEN]; initString(ch, MAXREQUESTLEN); // char send_str[] = "hello world !\n"; client_len = sizeof(client_address); client_sockfd = accept(server_sockfd, (struct sockaddr *)&client_address, &client_len); read(client_sockfd, &ch, MAXREQUESTLEN); printf("%s\n", ch); struct http_request request; struct Map headers; request.headers = &headers; parse_request(&request, ch); FILE* fp = fdopen(client_sockfd, "w+"); doResponse(&request, fp); fflush(fp); fclose(fp); // write(client_sockfd, &send_str, sizeof(send_str)/sizeof(send_str[0])); }}
测试
启动我们的server gcc request.h request.c response.h response.c main.c tools/utils.c tools/utils.h && ./a.out