#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <ctype.h>
#include <strings.h>
#include <string.h>
#include <sys/stat.h>
#include <pthread.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <dirent.h>
#include <time.h>
#include <errno.h> // 添加errno头
文件
#define ISspace(x) isspace((int)(x))
#define SERVER_STRING “Server: jdbhttpd/0.2.0\r\n”
// 函数声明
void* accept_request(void *);
void error_die(const char *);
int get_line(int, char *, int);
void not_found(int);
void serve_file(int, const char *);
void serve_file_post(int, const char *);
int startup(unsigned short *);
void unimplemented(int);
void forbidden(int);
void serve_directory(int, const char *);
void url_decode(char *, const char *);
const char *get_mime_type(const char *);
void log_request(const char *, const char *, int);
void set_socket_timeout(int, int);
//
/ 处理客户端请求 /
//
void* accept_request(void *pclient)
{
int client = (int)pclient;
free(pclient);
set_socket_timeout(client, 2); char
buf[65536]; int numchars; char method[255]; char url[255]; char path[1024]; // 增加路径
长度 char decoded_url[1024]; // 存储解码后的URL size_t i, j; struct stat st; //
获取请求的第一行 numchars = get_line(client,
buf, sizeof(
buf)); i = 0; j = 0; while (!ISspace(
buf[j]) && (i < sizeof(method) - 1)) { method[i] =
buf[j]; i++; j++; } method[i] = '\0'; // 只支持GET和POST方法 if (strcasecmp(method, "GET") && strcasecmp(method, "POST") && strcasecmp(method, "OPTIONS")) { unimplemented(client); return NULL; } // 读取URL i = 0; while (ISspace(
buf[j]) && (j < sizeof(
buf))) j++; while (!ISspace(
buf[j]) && (i < sizeof(url) - 1) && (j < sizeof(
buf))) { url[i] =
buf[j]; i++; j++; } url[i] = '\0'; // URL解码 url_decode(decoded_url, url); // 记录请求日志 log_request(method, decoded_url, client); // 构建
文件路径（使用当前目录） sprintf(path, "web%s", decoded_url); // 防止路径遍历攻击 if (strstr(path, "..")) { forbidden(client); close(client); return NULL; } // 处理目录请求 if (path[strlen(path) - 1] == '/') strcat(path, "Index.html"); // 检查
文件/目录是否存在 if (stat(path, &st) == -1) { // 检查是否存在.html扩展名
文件 char alt_path[1024]; sprintf(alt_path, "%s.html", path); if (stat(alt_path, &st) == 0) { strcpy(path, alt_path); } else { /* 跳过剩余头部 */ while ((numchars > 0) && strcmp("\n",
buf)) numchars = get_line(client,
buf, sizeof(
buf)); not_found(client); close(client); return NULL; } } // 如果是目录 if ((st.st_mode & S_IFMT) == S_IFDIR) { // 检查目录中是否有index.html char index_path[1024]; sprintf(index_path, "%s/Index.html", path); if (stat(index_path, &st) == 0) { strcpy(path, index_path); } else { // 显示目录列表 serve_directory(client, path); close(client); return NULL; } } if (strcasecmp(method, "GET") == 0) { serve_file(client, path); } else if (strcasecmp(method, "POST") == 0) { serve_file_post(client, path); } close(client); return NULL;
}
//
/ URL解码 /
//
void url_decode(char *dest, const char *src) {
char *p = dest;
while (*src) {
if (*src == ‘%’) {
if (src[1] && src[2]) {
char hex[3] = {src[1], src[2], ‘\0’};
*p++ = (char)strtol(hex, NULL, 16);
src += 3;
} else {
*p++ = *src++;
}
} else if (*src == ‘+’) {
*p++ = ’ ';
src++;
} else {
*p++ = *src++;
}
}
*p = ‘\0’;
}
//
/
获取MIME类型 /
//
const char *get_mime_type(const char *filename) {
const char *dot = strrchr(filename, ‘.’);
if (!dot) return “text/plain”;
if (strcasecmp(dot, ".html") == 0 || strcasecmp(dot, ".htm") == 0) return "text/html"; if (strcasecmp(dot, ".css") == 0) return "text/css"; if (strcasecmp(dot, ".js") == 0) return "application/javascript"; if (strcasecmp(dot, ".jpg") == 0 || strcasecmp(dot, ".jpeg") == 0) return "image/jpeg"; if (strcasecmp(dot, ".png") == 0) return "image/png"; if (strcasecmp(dot, ".gif") == 0) return "image/gif"; if (strcasecmp(dot, ".json") == 0) return "application/json"; if (strcasecmp(dot, ".ico") == 0) return "image/x-icon"; return "text/plain";
}
//
/ 记录请求日志 /
//
void log_request(const char *method, const char *url, int client) {
time_t now = time(NULL);
struct tm *tm = localtime(&now);
char timestamp[64];
strftime(timestamp, sizeof(timestamp), “%Y-%m-%d %H:%M:%S”, tm);
struct sockaddr_in addr; socklen_t addr_len = sizeof(addr); getpeername(client, (struct sockaddr*)&addr, &addr_len); char *ip = inet_ntoa(addr.sin_addr); printf("[%s] %s %s %s\n", timestamp, ip, method, url);
}
//
/ 处理目录列表 /
//
void serve_directory(int client, const char *path) {
char
buf[4096];
// 发送HTTP头 sprintf(
buf, "HTTP/1.0 200 OK\r\n"); send(client,
buf, strlen(
buf), 0); sprintf(
buf, SERVER_STRING); send(client,
buf, strlen(
buf), 0); sprintf(
buf, "Content-Type: text/html\r\n"); send(client,
buf, strlen(
buf), 0); sprintf(
buf, "\r\n"); send(client,
buf, strlen(
buf), 0); // 发送HTML头部 sprintf(
buf, "<html><head><title>Index of %s</title></head>", path); send(client,
buf, strlen(
buf), 0); sprintf(
buf, "<body><h1>Index of %s</h1><ul>", path); send(client,
buf, strlen(
buf), 0); // 打开目录 DIR *dir = opendir(path); if (dir) { struct dirent *ent; while ((ent = readdir(dir)) != NULL) { // 跳过隐藏
文件 if (ent->d_name[0] == '.') continue; char full_path[1024]; sprintf(full_path, "%s/%s", path, ent->d_name); struct stat st; stat(full_path, &st); char size_
buf[32]; if (S_ISDIR(st.st_mode)) { strcpy(size_
buf, "[DIR]"); } else { if (st.st_size < 1024) { sprintf(size_
buf, "%ld B", st.st_size); } else if (st.st_size < 1024 * 1024) { sprintf(size_
buf, "%.1f KB", st.st_size / 1024.0); } else { sprintf(size_
buf, "%.1f MB", st.st_size / (1024.0 * 1024)); } } sprintf(
buf, "<li><a href=\"%s\">%s</a> - %s</li>", ent->d_name, ent->d_name, size_
buf); send(client,
buf, strlen(
buf), 0); } closedir(dir); } // 发送HTML尾部 sprintf(
buf, "</ul></body></html>\r\n"); send(client,
buf, strlen(
buf), 0);
}
//
/ 403 Forbidden /
//
void forbidden(int client) {
char
buf[1024];
sprintf(
buf, "HTTP/1.0 403 Forbidden\r\n"); send(client,
buf, strlen(
buf), 0); sprintf(
buf, SERVER_STRING); send(client,
buf, strlen(
buf), 0); sprintf(
buf, "Content-Type: text/html\r\n"); send(client,
buf, strlen(
buf), 0); sprintf(
buf, "\r\n"); send(client,
buf, strlen(
buf), 0); sprintf(
buf, "<html><body><h1>403 Forbidden</h1><p>Access to this resource is denied.</p></body></html>\r\n"); send(client,
buf, strlen(
buf), 0);
}
//
/ 错误处理 /
//
void error_die(const char *sc)
{
perror(sc);
exit(1);
}
//
/ 读取一行 /
//
int get_line(int sock, char *
buf, int size)
{
int i = 0;
char c = ‘\0’;
int n;
while ((i < size - 1) && (c != '\n')) { n = recv(sock, &c, 1, 0); if (n > 0) { if (c == '\r') { n = recv(sock, &c, 1, MSG_PEEK); if ((n > 0) && (c == '\n')) recv(sock, &c, 1, 0); else c = '\n'; }
buf[i] = c; i++; } else c = '\n'; }
buf[i] = '\0'; return(i);
}
//
/ 404 Not Found /
//
void not_found(int client)
{
char
buf[1024];
sprintf(
buf, "HTTP/1.0 404 NOT FOUND\r\n"); send(client,
buf, strlen(
buf), 0); sprintf(
buf, SERVER_STRING); send(client,
buf, strlen(
buf), 0); sprintf(
buf, "Content-Type: text/html\r\n"); send(client,
buf, strlen(
buf), 0); sprintf(
buf, "\r\n"); send(client,
buf, strlen(
buf), 0); sprintf(
buf, "<html><body><h1>404 Not Found</h1><p>The requested URL was not found on this server.</p></body></html>\r\n"); send(client,
buf, strlen(
buf), 0);
}
//
/ 服务静态
文件（修复二进制
文件处理） /
//
void serve_file(int client, const char *filename)
{
FILE *resource = NULL;
int numchars = 1;
char
buf[1024];
size_t bytes_read;
long file_size;
// 丢弃请求头
buf[0] = 'A';
buf[1] = '\0'; while ((numchars > 0) && strcmp("\n",
buf)) numchars = get_line(client,
buf, sizeof(
buf)); // 使用二进制模式打开
文件 resource = fopen(filename, "rb"); if (resource == NULL) { not_found(client); return; } //
获取文件大小 fseek(resource, 0, SEEK_END); file_size = ftell(resource); fseek(resource, 0, SEEK_SET); // 发送HTTP头 const char *content_type = get_mime_type(filename); // 创建并发送头部 char header_
buf[2048]; sprintf(header_
buf, "HTTP/1.0 200 OK\r\n"); send(client, header_
buf, strlen(header_
buf), 0); sprintf(header_
buf, SERVER_STRING); send(client, header_
buf, strlen(header_
buf), 0); sprintf(header_
buf, "Content-Type: %s\r\n", content_type); send(client, header_
buf, strlen(header_
buf), 0); sprintf(header_
buf, "Content-Length: %ld\r\n", file_size); send(client, header_
buf, strlen(header_
buf), 0); sprintf(header_
buf, "\r\n"); send(client, header_
buf, strlen(header_
buf), 0); // 使用二进制模式发送
文件内容 while ((bytes_read = fread(
buf, 1, sizeof(
buf), resource)) > 0) { ssize_t sent = send(client,
buf, bytes_read, MSG_NOSIGNAL); if (sent < 0) { // 处理发送错误（如连接关闭） break; } } fclose(resource);
}
//
/ 服务静态
文件（专为POST请求设计，包含请求体处理） /
//
void serve_file_post(int client, const char *filename)
{
FILE *resource = NULL;
int numchars = 1;
char
buf[1024];
size_t bytes_read;
long file_size;
size_t content_length = 0; // 用于存储请求体
长度
// 1. 读取并处理请求头 while ((numchars > 0) && strcmp("\n",
buf) != 0) { numchars = get_line(client,
buf, sizeof(
buf)); // 解析Content-Length头部 if (strncasecmp(
buf, "Content-Length:", 15) == 0) { char *endptr; unsigned long temp = strtoul(
buf + 15, &endptr, 10); if (endptr !=
buf + 15 && temp <= SIZE_MAX) { content_length = (size_t)temp; } } } // 2. 读取并丢弃请求体 if (content_length > 0) { size_t total_read = 0; struct timeval tv; tv.tv_sec = 5; // 设置5秒超时 tv.tv_usec = 0; setsockopt(client, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)); while (total_read < content_length) { size_t to_read = sizeof(
buf); size_t remaining = content_length - total_read; if (to_read > remaining) { to_read = remaining; } bytes_read = recv(client,
buf, to_read, 0); if (bytes_read <= 0) { if (bytes_read == 0) { break; // 连接关闭 } else if (errno == EAGAIN || errno == EWOULDBLOCK) { fprintf(stderr, "Request body read timeout\n"); break; // 超时 } else { perror("recv failed"); break; // 错误 } } total_read += bytes_read; } // 恢复默认超时设置 tv.tv_sec = 0; tv.tv_usec = 0; setsockopt(client, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)); } // 3. 打开并发送
文件（与serve_file相同） resource = fopen(filename, "rb"); if (resource == NULL) { not_found(client); return; } //
获取文件大小 fseek(resource, 0, SEEK_END); file_size = ftell(resource); fseek(resource, 0, SEEK_SET); // 发送HTTP头 const char *content_type = get_mime_type(filename); char header_
buf[2048]; sprintf(header_
buf, "HTTP/1.0 200 OK\r\n"); send(client, header_
buf, strlen(header_
buf), 0); sprintf(header_
buf, SERVER_STRING); send(client, header_
buf, strlen(header_
buf), 0); sprintf(header_
buf, "Content-Type: %s\r\n", content_type); send(client, header_
buf, strlen(header_
buf), 0); sprintf(header_
buf, "Content-Length: %ld\r\n", file_size); send(client, header_
buf, strlen(header_
buf), 0); sprintf(header_
buf, "\r\n"); send(client, header_
buf, strlen(header_
buf), 0); // 发送
文件内容 while ((bytes_read = fread(
buf, 1, sizeof(
buf), resource)) > 0) { ssize_t sent = send(client,
buf, bytes_read, MSG_NOSIGNAL); if (sent < 0) { // 处理发送错误 break; } } fclose(resource);
}
//
/ 启动服务器 /
//
int startup(unsigned short port)
{
int httpd = 0;
struct sockaddr_in name;
/ 创建socket */
httpd = socket(PF_INET, SOCK_STREAM, 0);
if (httpd == -1)
error_die(“socket”);
memset(&name, 0, sizeof(name));
name.sin_family = AF_INET;
name.sin_port = htons(*port);
name.sin_addr.s_addr = htonl(INADDR_ANY);
/* 绑定地址 */ if (bind(httpd, (struct sockaddr *)&name, sizeof(name)) < 0) error_die("bind"); /* 若预设端口为0，随机取用可用端口*/ if (*port == 0) { socklen_t namelen = sizeof(name); if (getsockname(httpd, (struct sockaddr *)&name, &namelen) == -1) error_die("getsockname"); *port = ntohs(name.sin_port); } /* 监听连接 */ if (listen(httpd, 5) < 0) error_die("listen"); return(httpd);
}
//
/ 501 Not Implemented /
//
void unimplemented(int client)
{
char
buf[1024];
sprintf(
buf, "HTTP/1.0 501 Method Not Implemented\r\n"); send(client,
buf, strlen(
buf), 0); sprintf(
buf, SERVER_STRING); send(client,
buf, strlen(
buf), 0); sprintf(
buf, "Content-Type: text/html\r\n"); send(client,
buf, strlen(
buf), 0); sprintf(
buf, "\r\n"); send(client,
buf, strlen(
buf), 0); sprintf(
buf, "<html><body><h1>501 Not Implemented</h1><p>The requested method is not implemented.</p></body></html>\r\n"); send(client,
buf, strlen(
buf), 0);
}
// 设置套接字发送超时（在主循环accept后调用）
void set_socket_timeout(int sockfd, int timeout_sec) {
struct timeval tv;
tv.tv_sec = timeout_sec; // 超时秒数
tv.tv_usec = 0;
if (setsockopt(sockfd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv)) < 0) { perror("setsockopt SO_SNDTIMEO failed"); }
}
//
/ 主函数 /
//
int main(void)
{
int server_sock = -1;
unsigned short port = 8080;
int client_sock = -1;
struct sockaddr_in client_name;
socklen_t client_name_len = sizeof(client_name);
pthread_t newthread;
server_sock = startup(&port); printf("HTTP server running on port %d\n", port); signal(SIGPIPE, SIG_IGN); while (1) { /* 接受连接 */ client_sock = accept(server_sock,(struct sockaddr *)&client_name,&client_name_len); if (client_sock == -1) { perror("accept"); continue; // 继续接受新连接，而不是退出 } // 动态分配内存传递socket描述符 int *pclient = malloc(sizeof(int)); if (!pclient) { perror("malloc failed"); close(client_sock); continue; } *pclient = client_sock; // 创建线程处理请求（不再在主线程设置超时） if (pthread_create(&newthread, NULL, accept_request, pclient) != 0) { perror("pthread_create"); free(pclient); close(client_sock); } else { // 分离线程，使其结束后自动释放资源 pthread_detach(newthread); } } close(server_sock); return(0);
}
以上是使用多线程方式实现的简单webserver。
现在我想通过I/O多路复用的方式实现在单线程下对请求的并发处理
尽量复用以上代码
本文介绍了一种使用C语言从本地文件中读取全部内容的方法。通过fseek和ftell定位并获取文件大小，利用malloc分配内存空间，最终用fread一次性读取整个文件。此方法适用于需要将文件内容加载到内存进行处理的应用场景。
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