Question

我正在尝试制作一个C服务器，该服务器将接受输入并能够通过html格式将其吐回给用户，其中服务器用作用户界面。 我目前无法弄清的当前问题是，为什么C服务器在localhost：3838上以文本形式显示HTML代码，而不是将其显示为适当的网页。

如何解决此问题，并使它能够将用户命令发送回服务器并发出正确的响应？我是通过使用recieve然后将消息放入缓冲区，解析该消息，然后将该响应放入缓冲区以使用send发送回来来实现的？

CSERVER.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <signal.h>

#define PORT "3838" //port being connected to 
#define MAXLEN 800
#define BACKLOG 10 //number of pending connections to be held in queue

//format of html page 

char header []= 
"<!DOCTYPE html>\n"
"<html>\n"
"<head>\n"
"<title>Web-Based Remote Command Server</title>\n"
"</head>\n"
"<body>\n\n";
char input []= 
"<form action= \"/run\" method= \"get\"> \n"
"Command: <input type=\"text\" size=\"100\" name=\"command\">\n"
"<input type=\"submit\" value=\"Run\">\n"
"</form>";
char output []= "<p>Command that was run:</p>\n"
"<pre>Your server will include the command that was just run here.</pre>\n\n"
"<p>Standard Output:</p>\n""<pre>Your server will include the stdout results here.</pre>\n\n"
"<p>Standard Error:</p>\n"
"<pre>Your server will include the stderr results here.</pre>\n\n"
"</body>\n""</html>";

char *buff = header; 

void sigchld_handler(int s)
{
    (void)s; // quiet unused variable warning

    // waitpid() might overwrite errno, so we save and restore it:
    int saved_errno = errno;

    while(waitpid(-1, NULL, WNOHANG) > 0);

    errno = saved_errno;
}


void *get_in_addr(struct sockaddr *sa)
{
    if (sa->sa_family == AF_INET) {
        return &(((struct sockaddr_in*)sa)->sin_addr);
    }

    return &(((struct sockaddr_in6*)sa)->sin6_addr);
}


int main (void){
    int sockfd;
    int new_fd; 
    struct addrinfo hints;
    struct addrinfo *serverinfo; 
    struct addrinfo *p;
    struct sockaddr_storage client_addr;
    socklen_t addrsize;
    struct sigaction sa;
    int yes = 1;
    char s[INET6_ADDRSTRLEN];
    int status;

    memset(&hints, 0, sizeof hints); //makes struct empty 
    hints.ai_family = AF_UNSPEC; //IPv4 or v6 
    hints.ai_socktype = SOCK_STREAM; //TCP type need 
    hints.ai_flags = AI_PASSIVE; //Fill in IP for us 


    //if can't get address info print error 
    if((status = getaddrinfo(NULL, PORT, &hints, &serverinfo)) != 0){
        fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(status));
        return 1;
    }


    for(p = serverinfo; p != NULL; p = p->ai_next){
        if((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1){
            perror("server: socket");
            continue;
        }

        if(setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1){
            perror("setsockopt");
            exit(1);
        }

        if(bind(sockfd, p->ai_addr, p->ai_addrlen) == -1){
            close(sockfd);
            perror("server: bind");
            continue;
        }

        break;
    }

    freeaddrinfo(serverinfo);

    if(p == NULL){
        fprintf(stderr, "server: failed to bind\n");
        exit(1);
    }

    if(listen(sockfd, BACKLOG) == -1){
        perror("listen");
        exit(1);
    }

    sa.sa_handler = sigchld_handler; // reap all dead processes
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_RESTART;
    if (sigaction(SIGCHLD, &sa, NULL) == -1) {
        perror("sigaction");
        exit(1);
    }

    printf("server: waiting for connections....\n");

    while(1){
        addrsize = sizeof client_addr;
        new_fd = accept(sockfd, (struct sockaddr *)&client_addr, &addrsize);
        if(new_fd == -1){
            perror("Did not accept");
            continue;
        }

        inet_ntop(client_addr.ss_family, get_in_addr((struct sockaddr *)&client_addr), s, sizeof s);
        printf("server: got connection from %s\n", s);

        if(!fork()){
            close(sockfd);
int bufsize = 1024;
char *buffer = malloc(bufsize);
recv(new_fd, buffer, bufsize, 0);
write(new_fd, "HTTP/1.1 200 OK\n", 16);
write(new_fd, "Content-length: 46\n", 19);
write(new_fd, "Content-type: text/html\n\n", 25);
write(new_fd, "<html><head>\n<title>The Web Page</title>\n</head>\n</html>", 46);
            if(send(new_fd, header, MAXLEN, 0) == -1)
                perror("send");
            close(new_fd);
            exit(0);
        }
        close(new_fd);
    }

    return 0;


}

Answer 1

您需要像这样添加响应头：

例如，SO为此页面发送的响应标头是：

HTTP/2.0 200 OK
cache-control: private
content-type: text/html; charset=utf-8
content-encoding: gzip
x-frame-options: SAMEORIGIN
x-request-guid: 599a5768-3cc6-4b94-86e1-e1d1daa8acd5
strict-transport-security: max-age=15552000
content-security-policy: upgrade-insecure-requests
accept-ranges: bytes
date: Tue, 07 May 2019 13:17:15 GMT
via: 1.1 varnish
x-served-by: cache-lcy19237-LCY
x-cache: MISS
x-cache-hits: 0
x-timer: S1557235035.073229,VS0,VE89
vary: Accept-Encoding,Fastly-SSL
x-dns-prefetch-control: off
content-length: 35669
X-Firefox-Spdy: h2

服务器显示文本而不是HTML

1 个答案: