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在了解HTTP协议在应用层的一些通信规则后,我们可以开始写一个简单的http server,这个简单的服务器完成的内容很简单,即当收到客户请求后,会发送一个简单的”hello world”响应。
为了简单起见,这里不对请求的方法等进行判定,默认为GET;也不请求特定资源。
简单起见,这里用简单的单线程迭代服务器,即在一个while循环里面不断接收请求处理请求。
这里的所有的套接字函数都是使用unp中的包裹函数:
int Socket(int ,int,int); void Bind(int ,const struct sockaddr*sa,socklen_t salen); void Listen(int ,int); int Accept(int,struct sockaddr*,socklen_t*); int //创建套接字 Socket(int family , int type,int protocol) { int n; if ( (n = socket(family, type, protocol)) < 0) { printf("socket error\r\n"); return -1; } return(n); } void//绑定套接字 Bind(int fd, const struct sockaddr *sa, socklen_t salen) { if (bind(fd, sa, salen) < 0) { printf("bind error\r\n"); exit(-1); } } void//监听套接字 Listen(int fd, int backlog) { char *ptr; /*4can override 2nd argument with environment variable */ if ( (ptr = getenv("LISTENQ")) != NULL) backlog = atoi(ptr); if (listen(fd, backlog) < 0) { printf("listen error\r\n"); return ; } } int//接收连接 Accept(int fd, struct sockaddr *sa, socklen_t *salenptr) { int n; again: if ( (n = accept(fd, sa, salenptr)) < 0) { #ifdef EPROTO if (errno == EPROTO || errno == ECONNABORTED) #else if (errno == ECONNABORTED) #endif goto again; else { printf("accept error\r\n"); return -1; } } return(n); }
int getRequest(int socket) { int msgLen=0; char buffer[BUFFER_SIZE]; memset (buffer,'\0', BUFFER_SIZE); if ((msgLen = recv(socket, buffer, BUFFER_SIZE, 0)) == -1)//接收TCP流 { printf("Error handling incoming request"); return -1; } //以下仅仅在GDB中调试验证 stringstream ss; ss<<buffer;//请求的所有字符内容 string method;//请求方法 ss>>method; string uri;//请求uri ss>>uri; string version;//http协议版本 ss>>version; //... }
由于在本实现中,不对请求方法做区分,因此这里不对请求内容再做判断,仅仅通过GDB调试解析出的内容是否正确。
构造一个HTTP响应就要按照要求构造响应行,响应头部字段和值,响应的实体(这里为简单的html文本)。
string statusCode("200 OK");//响应状态码 string contentType("text/html");//content-type字段值 string content("<html><head><title>my simple httpserver</title></head><h1>hello zx world</h1></body></html>");//响应实体 string contentSize(std::to_string(content.size()));//响应实体大小 string head("\r\nHTTP/1.1 ");//版本 string ContentType("\r\nContent-Type: ");//头部字段 string ServerHead("\r\nServer: localhost");//头部字段和值 string ContentLength("\r\nContent-Length: ");//头部字段 string Date("\r\nDate: ");//头部字段 string Newline("\r\n"); time_t rawtime; time(&rawtime);//获取时间 string message; //按照http响应的顺序和要求构造响应头部 message+=head; message+=statusCode; message+=ContentType; message+=contentType; message+=ServerHead; message+=ContentLength; message+=contentSize; message+=Date; message+=(string)ctime(&rawtime); message+=Newline; int messageLength=message.size(); int n; n=send(socket,message.c_str(),messageLength,0);//发送响应头 n=send(socket,content.c_str(),content.size(),0);//发送响应实体
vim httptest.cpp
g++ -o httptest httptest.cpp
./httptest
#include <string.h> #include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <sys/socket.h> #include <errno.h> #include <netinet/in.h> #include <sys/stat.h> #include <sys/types.h> #include <pthread.h> #include <sys/wait.h> #include <unistd.h> #include <sstream> #include <iostream> #include <string> #include <vector> using namespace std; #define BUFFER_SIZE 512 int Socket(int ,int,int); void Bind(int ,const struct sockaddr*sa,socklen_t salen); void Listen(int ,int); int Accept(int,struct sockaddr*,socklen_t*); void handleAccept(int); void handleHttp(int); int getRequest(int); int main(int argc,char **argv) { const int port = 1024;//listen port int listenfd=Socket(AF_INET,SOCK_STREAM,0); struct sockaddr_in serverAddr; serverAddr.sin_family=AF_INET; serverAddr.sin_addr.s_addr=INADDR_ANY; serverAddr.sin_port=htons(port); Bind(listenfd,(struct sockaddr*)&serverAddr,sizeof(serverAddr)); Listen(listenfd,5); while(true) { handleAccept(listenfd); } } int Socket(int family , int type,int protocol) { int n; if ( (n = socket(family, type, protocol)) < 0) { printf("socket error\r\n"); return -1; } return(n); } void Bind(int fd, const struct sockaddr *sa, socklen_t salen) { if (bind(fd, sa, salen) < 0) { printf("bind error\r\n"); exit(-1); } } void Listen(int fd, int backlog) { char *ptr; /*4can override 2nd argument with environment variable */ if ( (ptr = getenv("LISTENQ")) != NULL) backlog = atoi(ptr); if (listen(fd, backlog) < 0) { printf("listen error\r\n"); return ; } } int Accept(int fd, struct sockaddr *sa, socklen_t *salenptr) { int n; again: if ( (n = accept(fd, sa, salenptr)) < 0) { #ifdef EPROTO if (errno == EPROTO || errno == ECONNABORTED) #else if (errno == ECONNABORTED) #endif goto again; else { printf("accept error\r\n"); return -1; } } return(n); } void handleAccept(int listenfd) { sockaddr_in clientAddr; socklen_t clientLen=sizeof(clientAddr); int connfd=Accept(listenfd,(sockaddr *)&clientAddr,&clientLen); handleHttp(connfd); close(connfd); } void handleHttp(int connfd) { if(getRequest(connfd)<0) { perror("http request get error"); exit(-1); } } int getRequest(int socket) { int msgLen=0; char buffer[BUFFER_SIZE]; memset (buffer,'\0', BUFFER_SIZE); if ((msgLen = recv(socket, buffer, BUFFER_SIZE, 0)) == -1) { printf("Error handling incoming request"); return -1; } stringstream ss; ss<<buffer; string method; ss>>method; string uri; ss>>uri; string version; ss>>version; // string statusCode("200 OK"); string contentType("text/html"); string content("<html><head><title>my simple httpserver</title></head><h1>hello ykk</h1></body></html>"); string contentSize(std::to_string(content.size())); string head("\r\nHTTP/1.1 "); string ContentType("\r\nContent-Type: "); string ServerHead("\r\nServer: localhost"); string ContentLength("\r\nContent-Length: "); string Date("\r\nDate: "); string Newline("\r\n"); time_t rawtime; time(&rawtime); string message; message+=head; message+=statusCode; message+=ContentType; message+=contentType; message+=ServerHead; message+=ContentLength; message+=contentSize; message+=Date; message+=(string)ctime(&rawtime); message+=Newline; int messageLength=message.size(); int n; n=send(socket,message.c_str(),messageLength,0); n=send(socket,content.c_str(),content.size(),0); return n; }
非常简陋的实现
curl -v localhost:1024
也可以在在 Firefox 中直接访问:
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