我正在尝试创建一个网络服务器，以将png或jpg或html文件发送到浏览器（Firefox）。因此，我执行了已编译的文件，打开浏览器，然后输入要发送的文件，例如“ http://localhost:9191/a.html”，然后该文件显示在浏览器中。
但是当我尝试发送png或jpg文件时，它不起作用！ 只是说'图像“ http://localhost:9191/dog.png”因为包含错误而无法显示。”
我不知道为什么它不起作用 所以我认为我应该在send_data函数中做些什么
有人可以给我一些建议吗？
这是我的代码：
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <pthread.h>
#include <sys/wait.h>
#include <signal.h>
#include <sys/stat.h>
#define BUF_SIZE 1024
#define SMALL_BUF 100
#define DATA_SIZE 100000
void* request_handler(void* arg);
void send_data(FILE* fp, char* ct, char* file_name);
char* content_type(char* file);
void send_error(FILE* fp);
void error_handling(char* message);
void read_childproc(int sig);
int main(int argc, char *argv[])
{
int serv_sock, clnt_sock;
struct sockaddr_in serv_adr, clnt_adr;
int clnt_adr_size;
char buf[BUF_SIZE];
int state;
pid_t pid;
struct sigaction act;
if (argc != 2) {
printf("Usage : %s <port>\n", argv[0]);
exit(1);
}
act.sa_handler = read_childproc;
sigemptyset(&act.sa_mask);
act.sa_flags = 0;
state = sigaction(SIGCHLD, &act, 0);
serv_sock = socket(PF_INET, SOCK_STREAM, 0);
memset(&serv_adr, 0, sizeof(serv_adr));
serv_adr.sin_family = AF_INET;
serv_adr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_adr.sin_port = htons(atoi(argv[1]));
if (bind(serv_sock, (struct sockaddr*)&serv_adr, sizeof(serv_adr)) == -1)
error_handling("bind() error");
if (listen(serv_sock, 20) == -1)
error_handling("listen() error");
while (1)
{
clnt_adr_size = sizeof(clnt_adr);
clnt_sock = accept(serv_sock, (struct sockaddr*)&clnt_adr, &clnt_adr_size);
if (clnt_sock == -1)
continue;
else {
printf("Connection Request : %s:%d\n", inet_ntoa(clnt_adr.sin_addr), ntohs(clnt_adr.sin_port));
}
pid = fork();
if (pid == -1)
{
close(clnt_sock);
continue;
}
if (pid == 0)
{
close(serv_sock);
request_handler(&clnt_sock);
}
else
close(clnt_sock);
}
close(serv_sock);
return 0;
}
void* request_handler(void *arg)
{
int clnt_sock = *((int*)arg);
char req_line[SMALL_BUF];
FILE* clnt_read;
FILE* clnt_write;
char method[10];
char ct[15];
char file_name[30];
clnt_read = fdopen(clnt_sock, "r");
clnt_write = fdopen(dup(clnt_sock), "w"); // duplicate clnt_sock
fgets(req_line, SMALL_BUF, clnt_read);// clnt_read -> req_line
if (strstr(req_line, "HTTP/") == NULL) // find "HTTP/" in req_line
{
send_error(clnt_write);
fclose(clnt_read);
fclose(clnt_write);
return;
}
strcpy(method, strtok(req_line, " /")); // req_line token
strcpy(file_name, strtok(NULL, " /")); //
strcpy(ct, content_type(file_name));
if (strcmp(method, "GET") != 0) // compare method with "GET"
{
send_error(clnt_write);
fclose(clnt_read);
fclose(clnt_write);
return;
}
fclose(clnt_read);
send_data(clnt_write, ct, file_name);
}
void send_data(FILE* fp, char* ct, char* file_name)
{
int size;
char protocol[] = "HTTP/1.1 200 OK\r\n";
char server[] = "Server:Linux Web Server \r\n";
char cnt_len[SMALL_BUF];
char cnt_type[SMALL_BUF];
char buf[DATA_SIZE];
char keep_alive[] = "Keep-Alive: timeout=10, max=15\r\n";
char connection[] = "Connection: Keep-Alive\r\n";
FILE* send_file;
sprintf(cnt_type, "Content-type:%s\r\n\r\n", ct);
send_file = fopen(file_name, "rb");
if (send_file == NULL)
{
send_file = fopen("error404.html", "r");
send_404_error(fp, send_file);
}
else {
fseek(send_file, 0, SEEK_END);
size = ftell(send_file);
fseek(send_file, 0, SEEK_SET);
sprintf(cnt_len, "Content-length:%d\r\n", size);
/* send header data*/
fputs(protocol, fp);
fputs(server, fp);
fputs(cnt_len, fp);
fputs(keep_alive, fp);
fputs(connection, fp);
fputs(cnt_type, fp);
/* send requested data */
while (fgets(buf, size, send_file) != NULL)
{
fputs(buf, fp);
fflush(fp);
}
}
fflush(fp);
fclose(fp);
}
char* content_type(char* file)
{
char extension[SMALL_BUF];
char file_name[SMALL_BUF];
strcpy(file_name, file);
strtok(file_name, ".");
strcpy(extension, strtok(NULL, "."));
if (!strcmp(extension, "html") || !strcmp(extension, "htm"))
return "text/html";
else if (!strcmp(extension, "jpg") || !strcmp(extension, "jpeg"))
return "image/jpg";
else if (!strcmp(extension, "png"))
return "image/png";
else
return "text/plain";
}
void send_404_error(FILE* fp, FILE* fp2)
{
char buf[BUF_SIZE];
char protocol[] = "HTTP/1.1 404 Not Found\r\n";
char cnt_len[] = "Content-length:137\r\n";
char cnt_type[] = "Content-type:text/html\r\n\r\n";
char content[] = "<html><head><title>NETWORK</title></head>"
"<body><font size=+5><br> 404 ERROR </br>"
"</font></body></html>";
fputs(protocol, fp);
fputs(cnt_len, fp);
fputs(cnt_type, fp);
while (fgets(buf, BUF_SIZE, fp2) != NULL)
{
fputs(buf, fp);
fflush(fp);
}
fflush(fp2);
fclose(fp2);
}
void send_error(FILE* fp)
{
char protocol[] = "HTTP/1.0 400 Bad Request\r\n";
char server[] = "Server:Linux Web Server \r\n";
char cnt_len[] = "Content-length:2048\r\n";
char cnt_type[] = "Content-type:text/html\r\n\r\n";
char content[] = "<html><head><title>NETWORK</title></head>"
"<body><font size=+5> <br> 400 ERROR </br>"
"</font></body></html>";
fputs(protocol, fp);
fputs(server, fp);
fputs(cnt_len, fp);
fputs(cnt_type, fp);
fflush(fp);
}
void error_handling(char* message)
{
fputs(message, stderr);
fputc('\n', stderr);
exit(1);
}
void read_childproc(int sig)
{
pid_t pid;
int status;
pid = waitpid(-1, &status, WNOHANG);
printf("removed proc id: %d \n", pid);
}