#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <nanomsg/nn.h> #include <nanomsg/reqrep.h> #define SERVER_ADDRESS "tcp://127.0.0.1:5555" // 服务器地址 int main() { int sock = nn_socket(AF_SP, NN_REP); // 创建一个REP类型的socket if (sock < 0) { fprintf(stderr, "nn_socket error: %s\n", nn_strerror(nn_errno())); return -1; } if (nn_bind(sock, SERVER_ADDRESS) < 0) { // 绑定服务器地址 fprintf(stderr, "nn_bind error: %s\n", nn_strerror(nn_errno())); nn_close(sock); return -1; } printf("server started, waiting for client...\n"); while (1) { char *buf = NULL; int bytes = nn_recv(sock, &buf, NN_MSG, 0); // 接收客户端请求消息 if (bytes < 0) { fprintf(stderr, "nn_recv error: %s\n", nn_strerror(nn_errno())); nn_close(sock); return -1; } printf("server received: %s\n", buf); if (strcmp(buf, "123") == 0) { // 判断客户端请求消息是否为"123" char *response = "abc"; int response_len = strlen(response) + 1; int bytes = nn_send(sock, response, response_len, 0); // 发送回复消息 if (bytes < 0) { fprintf(stderr, "nn_send error: %s\n", nn_strerror(nn_errno())); nn_close(sock); return -1; } } else { printf("invalid request\n"); } nn_freemsg(buf); // 释放接收到的消息内存 } nn_close(sock); // 关闭socket return 0; } 以上是一个服务端代码，客户端发送内容“123”服务器回复“abc”，我想要更改一下，服务端接受到一段json信息为{"module":"1","from":"2","time":"","service":"get_dp_version","args":[]}时，回复客户端一个json为{"module":"2","from":"3","time":"","service":"response_dp_version","data":{"dp_version":"v0.1"}}，使用libjansson，拼接json和解析json分别单独放在一个函数里。不要都堆在主函数里

好的，以下是修改后的代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <nanomsg/nn.h>
#include <nanomsg/reqrep.h>
#include <jansson.h>

#define SERVER_ADDRESS "tcp://127.0.0.1:5555" // 服务器地址

json_t *create_response_json()
{
    json_t *root = json_object();
    json_object_set_new(root, "module", json_string("2"));
    json_object_set_new(root, "from", json_string("3"));
    json_object_set_new(root, "time", json_string(""));
    json_object_set_new(root, "service", json_string("response_dp_version"));

    json_t *data = json_object();
    json_object_set_new(data, "dp_version", json_string("v0.1"));
    json_object_set_new(root, "data", data);

    return root;
}

int handle_request(const char *request_str, char **response_str)
{
    int ret = -1;
    json_error_t error;
    json_t *request = json_loads(request_str, 0, &error);
    if (!request) {
        fprintf(stderr, "json_loads error: on line %d: %s\n", error.line, error.text);
        goto error;
    }

    const char *module = json_string_value(json_object_get(request, "module"));
    const char *from = json_string_value(json_object_get(request, "from"));
    const char *service = json_string_value(json_object_get(request, "service"));

    if (!module || !from || !service) {
        fprintf(stderr, "invalid request\n");
        goto error;
    }

    if (strcmp(service, "get_dp_version") == 0) {
        json_t *response = create_response_json();
        if (!response) {
            fprintf(stderr, "create_response_json error\n");
            goto error;
        }
        *response_str = json_dumps(response, 0);
        if (!*response_str) {
            fprintf(stderr, "json_dumps error\n");
            goto error;
        }
        ret = 0;
    } else {
        fprintf(stderr, "invalid service: %s\n", service);
    }

error:
    if (request) {
        json_decref(request);
    }
    return ret;
}

int main()
{
    int sock = nn_socket(AF_SP, NN_REP); // 创建一个REP类型的socket
    if (sock < 0) {
        fprintf(stderr, "nn_socket error: %s\n", nn_strerror(nn_errno()));
        return -1;
    }

    if (nn_bind(sock, SERVER_ADDRESS) < 0) { // 绑定服务器地址
        fprintf(stderr, "nn_bind error: %s\n", nn_strerror(nn_errno()));
        nn_close(sock);
        return -1;
    }

    printf("server started, waiting for client...\n");

    while (1) {
        char *buf = NULL;
        int bytes = nn_recv(sock, &buf, NN_MSG, 0); // 接收客户端请求消息
        if (bytes < 0) {
            fprintf(stderr, "nn_recv error: %s\n", nn_strerror(nn_errno()));
            nn_close(sock);
            return -1;
        }

        printf("server received: %s\n", buf);

        char *response = NULL;
        if (handle_request(buf, &response) == 0) {
            int response_len = strlen(response) + 1;
            int bytes = nn_send(sock, response, response_len, 0); // 发送回复消息
            if (bytes < 0) {
                fprintf(stderr, "nn_send error: %s\n", nn_strerror(nn_errno()));
                nn_close(sock);
                free(response);
                return -1;
            }
            free(response);
        }

        nn_freemsg(buf); // 释放接收到的消息内存
    }

    nn_close(sock); // 关闭socket

    return 0;
}

其中，`handle_request`函数用于处理请求消息，如果请求消息合法并且`service`字段为`get_dp_version`，则调用`create_response_json`函数创建回复消息，否则打印错误信息。`create_response_json`函数用于创建回复消息的JSON对象。在主函数中，接收到请求消息后调用`handle_request`函数获取回复消息，并发送回复消息。