libcurl 发送 post 请求，请求体为 json 格式

傷城~ 2021-09-25 00:48 1175阅读 0赞

# libcurl 发送 post 请求，请求体为 json 格式 #

## 安装 libcurl ##

sudo apt install libcurl

## 使用 libcurl ##

使用 `jsoncpp` 创建 json 格式字符串，如果没有安装 `jsoncpp` 可以使用 `apt install jsoncpp` 安装

#define CURL_STATICLIB
    #include <curl/curl.h>
    #include <jsoncpp/json/json.h>
    #include <stdio.h>
    #include <string>
    #include <iostream>
    #include <chrono>
    
    size_t ReceiveData(void *contents, size_t size, size_t nmemb, void *stream)
    { 
        std::string *str = (std::string *)stream;
        (*str).append((char *)contents, size * nmemb);
        return size * nmemb;
    }
    
    CURLcode HttpPost(const std::string &url, const std::string &data, std::string &response, int timeout = 300)
    { 
        CURLcode res;
        CURL *curl = curl_easy_init();
        struct curl_slist *headers = NULL;
        headers = curl_slist_append(headers, "Content-Type:application/json;charset=UTF-8");
    
        if (curl == NULL)
        { 
            return CURLE_FAILED_INIT;
        }
    	
    	// 设置请求地址
        curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
        // 设置请求头信息
        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
        // 不显示接收头信息
        curl_easy_setopt(curl, CURLOPT_HEADER, 0);
        // 设置请求超时时间
        curl_easy_setopt(curl, CURLOPT_TIMEOUT_MS, timeout);
        // 设置请求体
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, data.c_str());
        // 设置接收函数
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, ReceiveData);
        // 设置接收内容
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&response);
        
        res = curl_easy_perform(curl);
        curl_easy_cleanup(curl);
        return res;
    }
    
    int main()
    {    
        auto start = std::chrono::system_clock::now();
        Json::Value root;
        root["text"] = "喂喂喂，你好。";
        std::string url = "http://192.168.1.79:9001/api/asr/csc/";
        std::string response;
        CURLcode res = HttpPost(url, root.toStyledString(), response);
        std::chrono::duration<double> duration = std::chrono::system_clock::now() - start;
        std::cout << "Post used time: " << duration.count() << "\n";
        if (res != CURLE_OK)
        { 
            fprintf(stderr, "Failed: %s\n", curl_easy_strerror(res));
        }
        duration = std::chrono::system_clock::now() - start;
        std::cout << "total used time: " << duration.count() << "\n";
        Json::Reader reader;
        Json::Value output;
        reader.parse(response, output);
        std::cout << "checked_sentence: " << output["checked_sentence"].toStyledString() << "\n";
        return 0;
    }

## 编译 ##

g++ -std=c++11 main.cc -lcurl -ljsoncpp -o main

## 参考文章 ##

[libcurl 使用示例][libcurl]

[libcurl]: https://curl.se/libcurl/c/example.html