Linux c++中实现websocket数据接口和接口调用

在Linux C++中实现WebSocket数据接口和接口调用需要依赖WebSocket库和HTTP库，下面以libwebsockets和libcurl为例进行说明。

1. 实现WebSocket数据接口

使用libwebsockets库可以方便地实现WebSocket数据接口。下面是一个简单的例子：

#include <libwebsockets.h>
#include <iostream>

// WebSocket回调函数
int callback_websocket(struct lws* wsi, enum lws_callback_reasons reason,
                       void* user, void* in, size_t len) {
    switch (reason) {
        case LWS_CALLBACK_CLIENT_ESTABLISHED:
            std::cout << "WebSocket connection established" << std::endl;
            break;
        case LWS_CALLBACK_CLIENT_RECEIVE:
            std::cout << "Received data: " << std::string((char*)in, len)
                      << std::endl;
            break;
        case LWS_CALLBACK_CLIENT_WRITEABLE:
            std::cout << "WebSocket writeable" << std::endl;
            break;
        case LWS_CALLBACK_CLOSED:
            std::cout << "WebSocket connection closed" << std::endl;
            break;
    }
    return 0;
}

int main() {
    struct lws_context_creation_info info;
    struct lws_client_connect_info connect_info;
    struct lws* wsi;
    const char* address = "ws://localhost:8080/path/to/endpoint";

    memset(&info, 0, sizeof(info));
    info.port = CONTEXT_PORT_NO_LISTEN;
    info.protocols = NULL;
    info.gid = -1;
    info.uid = -1;

    struct lws_context* context = lws_create_context(&info);
    if (!context) {
        std::cout << "Failed to create WebSocket context" << std::endl;
        return 1;
    }

    memset(&connect_info, 0, sizeof(connect_info));
    connect_info.context = context;
    connect_info.address = address;
    connect_info.port = 0;
    connect_info.path = "/";
    connect_info.host = lws_canonical_hostname(context);
    connect_info.origin = lws_canonical_hostname(context);
    connect_info.protocol = NULL;
    connect_info.ssl_connection = 0;

    wsi = lws_client_connect_via_info(&connect_info);
    if (!wsi) {
        std::cout << "Failed to create WebSocket connection" << std::endl;
        lws_context_destroy(context);
        return 1;
    }

    while (true) {
        lws_service(context, 0);
    }

    lws_context_destroy(context);
    return 0;
}

2. 实现接口调用

使用libcurl库可以方便地实现接口调用。下面是一个简单的例子：

#include <curl/curl.h>
#include <iostream>

// curl回调函数
size_t callback_curl(void* ptr, size_t size, size_t nmemb, void* user) {
    std::string* response = (std::string*)user;
    response->append((char*)ptr, size * nmemb);
    return size * nmemb;
}

int main() {
    CURL* curl;
    CURLcode res;
    std::string response;

    curl = curl_easy_init();
    if (!curl) {
        std::cout << "Failed to create CURL handle" << std::endl;
        return 1;
    }

    curl_easy_setopt(curl, CURLOPT_URL, "http://localhost:8080/path/to/api");
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, callback_curl);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response);

    res = curl_easy_perform(curl);
    if (res != CURLE_OK) {
        std::cout << "curl_easy_perform() failed: " << curl_easy_strerror(res)
                  << std::endl;
        curl_easy_cleanup(curl);
        return 1;
    }

    std::cout << "Response: " << response << std::endl;

    curl_easy_cleanup(curl);
    return 0;
}

需要注意的是，在实际使用中，需要根据具体的需求来设置各种选项和参数。上面的例子只是一个简单的示例。