emailQt/CurlHandler.cpp

#include "CurlHandler.hpp"

CurlHandler::CurlHandler()
    : initialRes{}, initialCurl(curl_easy_init(), curl_easy_cleanup) {
}

CurlHandler::~CurlHandler() {
    for (auto &t: v)
        t.join();
}

void CurlHandler::configure(const ParametersProvider::settings &sett) {
    url.append("imaps://");
    url += sett.imapS;
    url += "/INBOX?ALL";
    setts = sett;

    setupCurl(initialCurl.get(), initialChunk, url);
}

std::vector<std::string> *CurlHandler::fetch() {
    initialRes = curl_easy_perform(initialCurl.get());
    if (initialRes != CURLE_OK) {
        return &decodedMessages;
    }

    // We prepare to query the server.
    url.erase(url.end() - 4, url.end());
    url += "/;MAILINDEX=";

    std::string temp;
    std::stringstream s(initialChunk);

    size_t count = 0;
    while (getline(s, temp, ' ')) {
        // SELECT and *
        if (count < 2) {
            count++;
            continue;
        }
        messagesId.emplace_back(temp);
    }

    // We will query the server number by number.
    // The messagesId vector contains all Email GUIDs.
    v.reserve(messagesId.size());
    decodedMessages.resize(messagesId.size());
    count = 0;

    // 10 messages max
    // By default, even if the thread's function parameter specifies a reference,
    // a copy is made. To specify that you want a reference, use std::ref.
    for (auto i{messagesId.rbegin()}; i != messagesId.rbegin() + 10 && i != messagesId.rend(); ++i)
        v.emplace_back(&CurlHandler::query, this, std::ref(*i), count++);

    return &decodedMessages;
}

void CurlHandler::query(std::string &c, size_t count) {
    std::unique_ptr<CURL, decltype(&curl_easy_cleanup)> localCurl(curl_easy_init(), curl_easy_cleanup);
    CURLcode localCode;
    c.erase(std::remove(c.begin(), c.end(), '\r'), c.end());
    c.erase(std::remove(c.begin(), c.end(), '\n'), c.end());
    setupCurl(localCurl.get(), decodedMessages[count], url + c);

    localCode = curl_easy_perform(localCurl.get());
    if (localCode != CURLE_OK) {
        // ...
    }

    emit threadFinished(count, std::stoi(c));
}

void CurlHandler::setupCurl(CURL *ptr, std::string &m, std::string const &ur) const {
    curl_easy_setopt(ptr, CURLOPT_USERNAME, setts.userS.c_str());
    curl_easy_setopt(ptr, CURLOPT_PASSWORD, setts.passS.c_str());

    curl_easy_setopt(ptr, CURLOPT_PORT, setts.port);
    curl_easy_setopt(ptr, CURLOPT_TIMEOUT, curlTimeoutSeconds);

    // The callback function will receive the string ref as its userdata
    // and therefore save the data there.
    curl_easy_setopt(ptr, CURLOPT_USE_SSL, (long) CURLUSESSL_ALL);
    curl_easy_setopt(ptr, CURLOPT_WRITEDATA, (void *) &m);
    curl_easy_setopt(ptr, CURLOPT_WRITEFUNCTION, cb);

    // Necessary on some servers
    curl_easy_setopt(ptr, CURLOPT_USERAGENT, "libcurl-agent/1.0");

    curl_easy_setopt(ptr, CURLOPT_URL, ur.c_str());

#ifdef DEBUG
    curl_easy_setopt(ptr, CURLOPT_VERBOSE, 1L);
#else
    curl_easy_setopt(ptr.get(), CURLOPT_VERBOSE, 0L);
#endif
}

size_t cb(char *data, size_t size, size_t numberOfMembers, void *userdata) {
    size_t realSize = size * numberOfMembers;
    auto *mem = static_cast<std::string *> (userdata);
    mem->append(data, realSize);
    return realSize;
}