目前正在尝试使用C编写简单的Web服务器。在线找到一个很酷的代码段。一切都与图像有关。我无法弄清楚为什么它不会出现在浏览器上。 sendfile()返回9109(图像的大小)。
我对这个代码片段在fork()方面做了些什么感到困惑。为什么它需要fork()呢?以及当可能有更多请求进入时我们为什么在循环中关闭客户端?或者,对于每个请求,是否有新的连接?提前谢谢!
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <string.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/sendfile.h>
char webpage[] =
"HTTP/1.1 200 Ok\r\n"
"Content-Type: text/html; charset=UTF-8\r\n\r\n"
"<!DOCTYPE html>\r\n"
"<html><head><title>Test Title</title>\r\n"
"<body>Hello World <img src='test.jpg'/></body>"
"</html>";
int main(int argc, char *argv[]){
struct sockaddr_in server_addr, client_addr;
socklen_t sin_len = sizeof(client_addr);
int fd_server, fd_client;
/* Storing the contents sent by the browser (a request) */
char buf[2048];
int fdimg;
int on = 1;
fd_server = socket(AF_INET, SOCK_STREAM, 0);
if(fd_server < 0){
perror("socket");
exit(1);
}
setsockopt(fd_server, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(int));
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = INADDR_ANY;
server_addr.sin_port = htons(8080);
if(bind(fd_server, (struct sockaddr *) &server_addr, sizeof(server_addr)) == -1){
perror("bind");
close(fd_server);
exit(1);
}
if(listen(fd_server, 10) == -1){
perror("listen");
close(fd_server);
exit(1);
}
while(1){
fd_client = accept(fd_server, (struct sockaddr *) &client_addr, &sin_len);
if(fd_client == -1){
perror("Connection failed...\n");
continue;
}
printf("Got client connection...\n");
if(!fork()){
/* Child process */
/* Close this as the client no longer needs it */
close(fd_server);
memset(buf, 0, 2048);
read(fd_client, buf, 2047); /* 2047 because of null char? */
/* Print the request on the console */
printf("%s\n", buf);
if(!strncmp(buf, "GET /test.jpg", 13)){
printf("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
fdimg = open("test.jpg", O_RDONLY);
int sent = sendfile(fd_client, fdimg, NULL, 10000);
printf("sent: %d", sent);
close(fdimg);
}
else{
write(fd_client, webpage, sizeof(webpage) - 1);
}
close(fd_client);
printf("closing connection...\n");
exit(0);
}
/* Parent process */
close(fd_client);
}
return 0;
}
答案 0 :(得分:1)
这可能是由于浏览器仅在端口80上允许HTTP / 0.9。
HTTP / 0.9和HTTP / 1.1之间的主要区别在于服务器在数据之前发送标头。
尝试在图像响应中添加HTTP / 1.1标头:
char imageheader[] =
"HTTP/1.1 200 Ok\r\n"
"Content-Type: image/jpeg\r\n\r\n";
// ....
if (!strncmp(buf, "GET /test.jpg", 13)) {
printf("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
// Send header first: (Note, should loop in case of partial write or EINTR)
write(fd_client, imageheader, sizeof(imageheader) - 1);
// Send image content
fdimg = open("test.jpg", O_RDONLY);
int sent = sendfile(fd_client, fdimg, NULL, 10000);
printf("sent: %d", sent);
close(fdimg);
}