客户端发送图像到服务端，服务端对图像进行处理，在将处理后的图像发送到客户端，并且服务端持续监听客户端。

客户端

#include <iostream>
#include <fstream>
#include <vector>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <opencv2/opencv.hpp>

#define PORT 8080
#define BUFFER_SIZE 1024
#define IMAGE_PATH "image.jpg"
#define RESULT_IMAGE_PATH "result.jpg"

int main() {
    int sock = 0, valread;
    struct sockaddr_in serv_addr;
    char buffer[BUFFER_SIZE] = {0};

    // 创建套接字
    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        std::cerr << "Socket creation error" << std::endl;
        return -1;
    }

    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(PORT);

    // 将IPv4地址从文本转换为二进制形式
    if(inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr)<=0) {
        std::cerr << "Invalid address/ Address not supported" << std::endl;
        return -1;
    }

    // 连接到服务器
    if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
        std::cerr << "Connection Failed" << std::endl;
        return -1;
    }

    // 读取图像文件
    std::ifstream file(IMAGE_PATH, std::ios::binary);
    if (!file) {
        std::cerr << "Failed to open file: " << IMAGE_PATH << std::endl;
        return -1;
    }
    std::vector<unsigned char> imageData((std::istreambuf_iterator<char>(file)), std::istreambuf_iterator<char>());

    // 发送图像数据到服务器
    send(sock, imageData.data(), imageData.size(), 0);
    std::cout << "Image sent to server" << std::endl;

    // 关闭发送方向的连接
    shutdown(sock, SHUT_WR);

    // 接收服务器的处理结果
    std::vector<unsigned char> resultData;
    while (true) {
        valread = read(sock, buffer, BUFFER_SIZE);
        if (valread <= 0) {
            break;
        }
        resultData.insert(resultData.end(), buffer, buffer + valread);
    }
    std::ofstream resultFile(RESULT_IMAGE_PATH, std::ios::binary);
    resultFile.write(reinterpret_cast<const char*>(resultData.data()), resultData.size());
    resultFile.close();
    std::cout << "Result image received and saved as: " << RESULT_IMAGE_PATH << std::endl;

    return 0;
}

服务端

#include <iostream>
#include <vector>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <opencv2/opencv.hpp>

#define PORT 8080
#define BUFFER_SIZE 1024

void processImage(const std::vector<unsigned char>& imageData, std::vector<unsigned char>& resultData) {
    cv::Mat image = cv::imdecode(imageData, cv::IMREAD_COLOR);

    // 在这里进行图像处理，这里只是一个示例，将图像水平翻转
    cv::flip(image, image, 1);

    // 将处理后的图像编码为JPEG格式
    std::vector<int> params;
    params.push_back(cv::IMWRITE_JPEG_QUALITY);
    params.push_back(90);
    cv::imencode(".jpg", image, resultData, params);
    sleep(3);
}

int main() {
    int server_fd, new_socket, valread;
    struct sockaddr_in address;
    int opt = 1;
    int addrlen = sizeof(address);
    char buffer[BUFFER_SIZE] = {0};

    // 创建套接字
    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
        perror("socket failed");
        exit(EXIT_FAILURE);
    }

    // 设置套接字选项，允许地址重用
    if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt))) {
        perror("setsockopt");
        exit(EXIT_FAILURE);
    }
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);

    // 绑定套接字到指定端口
    if (bind(server_fd, (struct sockaddr *)&address, sizeof(address))<0) {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }

    // 监听连接
    if (listen(server_fd, 3) < 0) {
        perror("listen");
        exit(EXIT_FAILURE);
    }

    while(1)
    {
        // 接受连接
        if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen))<0) {
            perror("accept");
            exit(EXIT_FAILURE);
        }
        // 从客户端读取图像数据
        std::vector<unsigned char> imageData;
        while (true) {
            valread = read(new_socket, buffer, BUFFER_SIZE);
            if (valread <= 0) {
                break;
            }
            imageData.insert(imageData.end(), buffer, buffer + valread);
        }
        std::cout << "Received " << imageData.size() << " bytes of image data" << std::endl;

        // 处理图像数据
        std::vector<unsigned char> resultData;
        processImage(imageData, resultData);

        // 向客户端发送处理后的结果
        send(new_socket, resultData.data(), resultData.size(), 0);
        std::cout << "Processed image sent to client" << std::endl;
        close(new_socket);
    }
    

    return 0;
}