multi.cpp

#include <iostream>
#include <ostream>

#include "curlcpp/curl_easy.h"
#include "curlcpp/curl_multi.h"
#include "curlcpp/curl_ios.h"

using curl::curl_easy;
using curl::curl_multi;
using curl::curl_ios;
using curl::curl_easy_exception;
using curl::curlcpp_traceback;

/**
 * This example shows how to make multiple requests
 * using curl_multi interface.
 */
int main() {
    std::vector<std::string> urls;
    urls.emplace_back("https://google.com");
    urls.emplace_back("https://facebook.com");
    urls.emplace_back("https://linkedin.com");

    // Create a vector of curl easy handlers.
    std::vector<curl_easy> handlers;

    // Create a vector of curl streams.
    std::vector<curl_ios<std::ostringstream>> streams;

    // Create the curl easy handler and associated the streams with it.
    for (const auto & url : urls) {
        auto *output_stream = new std::ostringstream;
        curl_ios<std::ostringstream> curl_stream(*output_stream);

        curl_easy easy(curl_stream);
        easy.add<CURLOPT_URL>(url.c_str());
        easy.add<CURLOPT_FOLLOWLOCATION>(1L);

        streams.emplace_back(curl_stream);
        handlers.emplace_back(easy);
    }

    // Create a map of curl pointers to output streams.
    std::unordered_map<CURL*, curl_ios<std::ostringstream>*> easy_streams;
    for (int i = 0; i < handlers.size(); ++i) {
        easy_streams[handlers.at(i).get_curl()] = (curl_ios<std::ostringstream>*)&streams.at(i);
    }

    // Add all the handlers to the curl multi object.
    curl_multi multi;
    multi.add(handlers);

    try {
        // Start the transfers.
        multi.perform();

        // Until there are active transfers, call the perform() API.
        while (multi.get_active_transfers()) {
            multi.perform();

            // Extracts the first finished request.
            std::unique_ptr<curl_multi::curl_message> message = multi.get_next_finished();
            if (message != nullptr) {
                const curl_easy *handler = message->get_handler();

                // Get the stream associated with the curl easy handler.
                curl_ios<std::ostringstream> stream_handler = *easy_streams[handler->get_curl()];

                auto content = stream_handler.get_stream()->str();
                auto url = handler->get_info<CURLINFO_EFFECTIVE_URL>();
                auto response_code = handler->get_info<CURLINFO_RESPONSE_CODE>();
                auto content_type = handler->get_info<CURLINFO_CONTENT_TYPE>();
                auto http_code = handler->get_info<CURLINFO_HTTP_CODE>();

                std::cout << "CODE: " << response_code.get()
                          << ", TYPE: " << content_type.get()
                          << ", HTTP_CODE: " << http_code.get()
                          << ", URL: " << url.get()
                          << ", CONTENT: " << content.substr(0, 10) + " ... "
                          << std::endl;
            }
        }

        // Free the memory allocated for easy streams.
        for (auto stream : streams) {
            delete stream.get_stream();
        }

    } catch (curl_easy_exception &error) {
        // If you want to print the last error.
        std::cerr<<error.what()<<std::endl;
    }
    return 0;
}