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用C语言在Linux中使用http协议发送文本消息

1. 用C语言在Linux中使用http协议创建一个服务端程序，输出hello,world

  1. LinServer.c
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// LinServer.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define PORT 8080
#define BUFFER_SIZE 1024

void handle_request(int client_socket) {
    char buffer[BUFFER_SIZE];
    int bytes_received = recv(client_socket, buffer, sizeof(buffer) - 1, 0);
    if (bytes_received > 0) {
        buffer[bytes_received] = '\0'; // 添加字符串结束符
        printf("Received request:\n%s\n", buffer);

        // 简单的HTTP响应
        const char* response_header = "HTTP/1.1 200 OK\r\n"
            "Content-Type: text/plain\r\n"
            "Connection: close\r\n"
            "\r\n";
        const char* response_body = "Hello, World!";

        // 发送响应
        send(client_socket, response_header, strlen(response_header), 0);
        send(client_socket, response_body, strlen(response_body), 0);
    }

    // 关闭客户端套接字
    close(client_socket);
}

int main() {
    int server_socket, client_socket;
    struct sockaddr_in server, client;
    socklen_t client_len = sizeof(client);

    // 创建套接字
    server_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (server_socket < 0) {
        perror("Could not create socket");
        return 1;
    }

    // 设置服务器信息
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = INADDR_ANY; // 监听所有IP
    server.sin_port = htons(PORT);

    // 绑定套接字
    if (bind(server_socket, (struct sockaddr*)&server, sizeof(server)) < 0) {
        perror("Bind failed");
        close(server_socket);
        return 1;
    }

    // 开始监听
    listen(server_socket, SOMAXCONN);
    printf("Server listening on port %d...\n", PORT);

    // 主循环，接受客户端连接
    while (1) {
        client_socket = accept(server_socket, (struct sockaddr*)&client, &client_len);
        if (client_socket < 0) {
            perror("Accept failed");
            continue;
        }

        // 处理请求
        handle_request(client_socket);
    }

    // 关闭服务器套接字
    close(server_socket);
    return 0;
}

  1. 使用浏览器访问10.0.2.107:8080

  2. 结果浏览器中成功显示”Hello, World!”

2. 用C语言在Linux中使用http协议创建一个服务端程序,根据路径返回不同的响应

  1. LinServer.c
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// LinServer.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define PORT 8080
#define BUFFER_SIZE 1024

void handle_request(int client_socket) {
    char buffer[BUFFER_SIZE];
    int bytes_received = recv(client_socket, buffer, sizeof(buffer) - 1, 0);
    if (bytes_received > 0) {
        buffer[bytes_received] = '\0'; // 添加字符串结束符
        printf("Received request:\n%s\n", buffer);

        // 解析请求行
        char method[16], path[256], version[16];
        sscanf(buffer, "%s %s %s", method, path, version);

        // 响应内容
        const char* response_header;
        const char* response_body;

        // 根据路径返回不同的响应
        if (strcmp(path, "/") == 0) {
            response_header = "HTTP/1.1 200 OK\r\n"
                "Content-Type: text/plain\r\n"
                "Connection: close\r\n"
                "\r\n";
            response_body = "Welcome to the home page!";
        }
        else if (strcmp(path, "/hello") == 0) {
            response_header = "HTTP/1.1 200 OK\r\n"
                "Content-Type: text/plain\r\n"
                "Connection: close\r\n"
                "\r\n";
            response_body = "Hello, World!";
        }
        else {
            response_header = "HTTP/1.1 404 Not Found\r\n"
                "Content-Type: text/plain\r\n"
                "Connection: close\r\n"
                "\r\n";
            response_body = "404 Not Found";
        }

        // 发送响应
        send(client_socket, response_header, strlen(response_header), 0);
        send(client_socket, response_body, strlen(response_body), 0);
    }

    // 关闭客户端套接字
    close(client_socket);
}

int main() {
    int server_socket, client_socket;
    struct sockaddr_in server, client;
    socklen_t client_len = sizeof(client);

    // 创建套接字
    server_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (server_socket < 0) {
        perror("Could not create socket");
        return 1;
    }

    // 设置服务器信息
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = INADDR_ANY; // 监听所有IP
    server.sin_port = htons(PORT);

    // 绑定套接字
    if (bind(server_socket, (struct sockaddr*)&server, sizeof(server)) < 0) {
        perror("Bind failed");
        close(server_socket);
        return 1;
    }

    // 开始监听
    listen(server_socket, SOMAXCONN);
    printf("Server listening on port %d...\n", PORT);

    // 主循环，接受客户端连接
    while (1) {
        client_socket = accept(server_socket, (struct sockaddr*)&client, &client_len);
        if (client_socket < 0) {
            perror("Accept failed");
            continue;
        }

        // 处理请求
        handle_request(client_socket);
    }

    // 关闭服务器套接字
    close(server_socket);
    return 0;
}

  1. 使用浏览器访问会不同路径会显示不同结果
    • 10.0.2.107:8080显示Welcome to the home page!
    • http://10.0.2.107:8080/hello显示Hello, World!
    • 访问其他路径显示404 Not Found
  2. 结果符合预期

3. 用C语言在Linux中使用http协议创建一个客户端程序访问服务器根路径

  1. 编写LinClient.c
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// LinClient.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define SERVER "10.0.2.107" // 服务器地址
#define PORT 8080            // 服务器端口
#define BUFFER_SIZE 1024

int main() {
    int sock;
    struct sockaddr_in server;
    char request[BUFFER_SIZE], response[BUFFER_SIZE];
    int bytes_received;

    // 创建套接字
    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        perror("Could not create socket");
        return 1;
    }

    // 设置服务器信息
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = inet_addr(SERVER);
    server.sin_port = htons(PORT);

    // 连接到服务器
    if (connect(sock, (struct sockaddr*)&server, sizeof(server)) < 0) {
        perror("Connect failed");
        close(sock);
        return 1;
    }

    // 构建HTTP GET请求
    sprintf(request, "GET / HTTP/1.1\r\n"
                     "Host: %s:%d\r\n"
                     "Connection: keep-alive\r\n"
                     "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36\r\n"
                     "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8\r\n"
                     "Accept-Encoding: gzip, deflate\r\n"
                     "Accept-Language: en-US,en;q=0.9\r\n"
                     "\r\n", SERVER, PORT);

    // 发送请求
    send(sock, request, strlen(request), 0);

    // 接收响应
    while ((bytes_received = recv(sock, response, sizeof(response) - 1, 0)) > 0) {
        response[bytes_received] = '\0'; // 添加字符串结束符
        printf("%s", response); // 打印响应
    }

    // 关闭套接字
    close(sock);
    return 0;
}

  1. 运行LinServer 后再运行LinClient

  2. 运行结果，握手成功,

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    HTTP/1.1 200 OK
    Content-Type: text/plain
    Connection: close

    Welcome to the home page!

4. 用C语言在Linux中使用http协议创建一个客户端程序访问服务器路径/hello

  1. LinClient.c
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// LinClient.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define SERVER "10.0.2.107" // 服务器地址
#define PORT 8080            // 服务器端口
#define BUFFER_SIZE 1024

int main() {
    int sock;
    struct sockaddr_in server;
    char request[BUFFER_SIZE], response[BUFFER_SIZE];
    int bytes_received;

    // 创建套接字
    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        perror("Could not create socket");
        return 1;
    }

    // 设置服务器信息
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = inet_addr(SERVER);
    server.sin_port = htons(PORT);

    // 连接到服务器
    if (connect(sock, (struct sockaddr*)&server, sizeof(server)) < 0) {
        perror("Connect failed");
        close(sock);
        return 1;
    }

    // 构建HTTP GET请求
    sprintf(request, "GET /hello HTTP/1.1\r\n"
                     "Host: %s:%d\r\n"
                     "Connection: keep-alive\r\n"
                     "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36\r\n"
                     "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8\r\n"
                     "Accept-Encoding: gzip, deflate\r\n"
                     "Accept-Language: en-US,en;q=0.9\r\n"
                     "\r\n", SERVER, PORT);

    // 发送请求
    send(sock, request, strlen(request), 0);

    // 接收响应
    while ((bytes_received = recv(sock, response, sizeof(response) - 1, 0)) > 0) {
        response[bytes_received] = '\0'; // 添加字符串结束符
        printf("%s", response); // 打印响应
    }

    // 关闭套接字
    close(sock);
    return 0;
}

  1. 运行LinServer 后再运行LinClient

  2. 运行结果符合预期

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    HTTP/1.1 200 OK
    Content-Type: text/plain
    Connection: close

    Hello, World!

5. 使用POST请求而非GET请求

GET与POST用途：

  • GET请求：通常用于获取资源或数据（如网页、图片等）。
  • POST请求：通常用于提交数据（如表单提交、文件上传等），并可能导致服务器状态的改变。
  1. LinClient.c
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// LinClient.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define SERVER "10.0.2.107" // 服务器地址
#define PORT 8080          // 服务器端口
#define BUFFER_SIZE 1024

int main() {
    int sock;
    struct sockaddr_in server;
    char request[BUFFER_SIZE], response[BUFFER_SIZE];
    int bytes_received;

    // 创建套接字
    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        perror("Could not create socket");
        return 1;
    }

    // 设置服务器信息
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = inet_addr(SERVER);
    server.sin_port = htons(PORT);

    // 连接到服务器
    if (connect(sock, (struct sockaddr*)&server, sizeof(server)) < 0) {
        perror("Connect failed");
        close(sock);
        return 1;
    }

    // 构建HTTP POST请求
    const char* post_data = "param1=value1&param2=value2"; // 要发送的数据
    sprintf(request, "POST /hello HTTP/1.1\r\n"
        "Host: %s\r\n"
        "Content-Type: application/x-www-form-urlencoded\r\n"
        "Content-Length: %lu\r\n"
        "Connection: close\r\n\r\n"
        "%s", SERVER, strlen(post_data), post_data);

    // 发送请求
    send(sock, request, strlen(request), 0);

    // 接收响应
    while ((bytes_received = recv(sock, response, sizeof(response) - 1, 0)) > 0) {
        response[bytes_received] = '\0'; // 添加字符串结束符
        printf("%s", response); // 打印响应
    }

    // 关闭套接字
    close(sock);
    return 0;
}

  1. 运行LinServer 后再运行LinClient

  2. 运行结果符合预期

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    HTTP/1.1 200 OK
    Content-Type: text/plain
    Connection: close

    Hello, World!k

6.使用http协议可以让两个程序互相发送文本消息

  1. LinServer.c
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// LinServer.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define PORT 8080
#define BUFFER_SIZE 1024

void handle_request(int client_socket) {
    char buffer[BUFFER_SIZE];
    int bytes_received = recv(client_socket, buffer, sizeof(buffer) - 1, 0);
    if (bytes_received > 0) {
        buffer[bytes_received] = '\0'; // 添加字符串结束符
        printf("Received request:\n%s\n", buffer);

        // 解析请求体
        char* body = strstr(buffer, "\r\n\r\n");
        if (body != NULL) {
            body += 4; // 跳过"\r\n\r\n"
            printf("Received message: %s\n", body);
        }

        // 响应内容
        const char* response_header = "HTTP/1.1 200 OK\r\n"
            "Content-Type: text/plain\r\n"
            "Connection: close\r\n\r\n";
        const char* response_body = "Message received!";

        // 发送响应
        send(client_socket, response_header, strlen(response_header), 0);
        send(client_socket, response_body, strlen(response_body), 0);
    }

    // 关闭客户端套接字
    close(client_socket);
}

int main() {
    int server_socket, client_socket;
    struct sockaddr_in server, client;
    socklen_t client_len = sizeof(client);

    // 创建套接字
    server_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (server_socket < 0) {
        perror("Could not create socket");
        return 1;
    }

    // 设置服务器信息
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = INADDR_ANY; // 监听所有IP
    server.sin_port = htons(PORT);

    // 绑定套接字
    if (bind(server_socket, (struct sockaddr*)&server, sizeof(server)) < 0) {
        perror("Bind failed");
        close(server_socket);
        return 1;
    }

    // 开始监听
    listen(server_socket, SOMAXCONN);
    printf("Server listening on port %d...\n", PORT);

    // 主循环，接受客户端连接
    while (1) {
        client_socket = accept(server_socket, (struct sockaddr*)&client, &client_len);
        if (client_socket < 0) {
            perror("Accept failed");
            continue;
        }

        // 处理请求
        handle_request(client_socket);
    }

    // 关闭服务器套接字
    close(server_socket);
    return 0;
}
  1. LinClient.c
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//LinClient.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define SERVER "10.0.2.107" // 服务器地址
#define PORT 8080          // 服务器端口
#define BUFFER_SIZE 1024

int main() {
    int sock;
    struct sockaddr_in server;
    char request[BUFFER_SIZE], response[BUFFER_SIZE];
    int bytes_received;

    // 创建套接字
    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        perror("Could not create socket");
        return 1;
    }

    // 设置服务器信息
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = inet_addr(SERVER);
    server.sin_port = htons(PORT);

    // 连接到服务器
    if (connect(sock, (struct sockaddr*)&server, sizeof(server)) < 0) {
        perror("Connect failed");
        close(sock);
        return 1;
    }

    // 构建HTTP POST请求
    const char* message = "Hello, this is a message!";
    sprintf(request, "POST / HTTP/1.1\r\n"
        "Host: %s\r\n"
        "Content-Type: text/plain\r\n"
        "Content-Length: %lu\r\n"
        "Connection: close\r\n\r\n"
        "%s", SERVER, strlen(message), message);

    // 发送请求
    send(sock, request, strlen(request), 0);

    // 接收响应
    while ((bytes_received = recv(sock, response, sizeof(response) - 1, 0)) > 0) {
        response[bytes_received] = '\0'; // 添加字符串结束符
        printf("%s", response); // 打印响应
    }

    // 关闭套接字
    close(sock);
    return 0;
}

  1. 运行LinServer 后再运行LinClient
  2. 运行成功