c语言实现websocket客户端
时间: 2023-10-09 12:17:16 浏览: 50
很抱歉,作为AI语言模型,我无法提供实际的编程服务。不过我可以为您提供一个简单的WebSocket客户端的代码框架,您可以基于此进行相应的开发和实现。
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <openssl/crypto.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
#define BUF_SIZE 1024
int main(int argc, char *argv[]) {
if (argc != 2) {
fprintf(stderr, "Usage: %s ws://example.com\n", argv[0]);
exit(EXIT_FAILURE);
}
char *url = argv[1];
char host[BUF_SIZE], path[BUF_SIZE];
int port = 80;
if (sscanf(url, "ws://%[^/]/%s", host, path) == 2) {
// URL contains host and path
} else if (sscanf(url, "ws://%[^:]:%d/%s", host, &port, path) == 3) {
// URL contains host, port, and path
} else {
fprintf(stderr, "Invalid URL: %s\n", url);
exit(EXIT_FAILURE);
}
struct addrinfo hints, *res;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
char port_str[BUF_SIZE];
snprintf(port_str, sizeof(port_str), "%d", port);
int status = getaddrinfo(host, port_str, &hints, &res);
if (status != 0) {
fprintf(stderr, "getaddrinfo error: %s\n", gai_strerror(status));
exit(EXIT_FAILURE);
}
int sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (sockfd == -1) {
perror("socket error");
exit(EXIT_FAILURE);
}
if (connect(sockfd, res->ai_addr, res->ai_addrlen) == -1) {
perror("connect error");
exit(EXIT_FAILURE);
}
SSL_library_init();
SSL_CTX *ctx = SSL_CTX_new(TLS_client_method());
if (!ctx) {
ERR_print_errors_fp(stderr);
exit(EXIT_FAILURE);
}
SSL *ssl = SSL_new(ctx);
if (!ssl) {
ERR_print_errors_fp(stderr);
exit(EXIT_FAILURE);
}
if (SSL_set_fd(ssl, sockfd) != 1) {
ERR_print_errors_fp(stderr);
exit(EXIT_FAILURE);
}
if (SSL_connect(ssl) != 1) {
ERR_print_errors_fp(stderr);
exit(EXIT_FAILURE);
}
char request[BUF_SIZE];
snprintf(request, sizeof(request), "GET /%s HTTP/1.1\r\n"
"Host: %s\r\n"
"Upgrade: websocket\r\n"
"Connection: Upgrade\r\n"
"Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n"
"Sec-WebSocket-Version: 13\r\n"
"\r\n", path, host);
if (SSL_write(ssl, request, strlen(request)) != strlen(request)) {
ERR_print_errors_fp(stderr);
exit(EXIT_FAILURE);
}
char response[BUF_SIZE];
if (SSL_read(ssl, response, sizeof(response)) == -1) {
ERR_print_errors_fp(stderr);
exit(EXIT_FAILURE);
}
printf("%s", response);
close(sockfd);
SSL_free(ssl);
SSL_CTX_free(ctx);
return 0;
}
```
这个代码框架实现了基本的WebSocket客户端连接,但是需要注意以下几点:
- 代码中的Sec-WebSocket-Key值是一个随机字符串,需要使用base64编码后传输;
- 如果服务器响应Sec-WebSocket-Accept值与客户端发送的值不相等,则表示握手失败;
- WebSocket协议中的数据帧需要进行掩码处理,客户端发送的数据帧需要掩码,服务器返回的数据帧需要解掩码;
- 客户端需要不断地发送Ping帧,以保持连接的活跃性;
- 客户端需要处理服务器发送的Pong帧和Close帧,以保证连接的正常关闭。
希望以上内容能够帮到您。