OpenRCT2/src/openrct2/network/Http.cpp

/*****************************************************************************
 * Copyright (c) 2014-2018 OpenRCT2 developers
 *
 * For a complete list of all authors, please refer to contributors.md
 * Interested in contributing? Visit https://github.com/OpenRCT2/OpenRCT2
 *
 * OpenRCT2 is licensed under the GNU General Public License version 3.
 *****************************************************************************/

#include "Http.h"

#include <cstring>
#include <exception>
#include <memory>
#include <thread>

#ifndef DISABLE_HTTP

#    include "../Version.h"
#    include "../core/Console.hpp"

#    ifdef _WIN32
// cURL includes windows.h, but we don't need all of it.
#        define WIN32_LEAN_AND_MEAN
#    endif
#    include <curl/curl.h>

#    define OPENRCT2_USER_AGENT "OpenRCT2/" OPENRCT2_VERSION

namespace OpenRCT2::Network::Http
{
    Http::Http()
    {
        curl_global_init(CURL_GLOBAL_DEFAULT);
    }

    Http::~Http()
    {
        curl_global_cleanup();
    }

    static size_t writeData(const char* src, size_t size, size_t nmemb, void* userdata)
    {
        size_t realsize = size * nmemb;
        Response* res = static_cast<Response*>(userdata);
        res->body += std::string(src, src + realsize);

        return realsize;
    }

    static size_t header_callback(const char* src, size_t size, size_t nitems, void* userdata)
    {
        size_t realsize = nitems * size;
        Response* res = static_cast<Response*>(userdata);

        auto line = std::string(src, src + realsize);
        auto pos = line.find(':');
        if (pos != std::string::npos)
        {
            std::string key = line.substr(0, pos);
            // substract 4 chars for ": " and "\r\n"
            std::string value = line.substr(pos + 2, line.size() - pos - 4);
            res->header[key] = value;
        }

        return realsize;
    }

    struct WriteThis
    {
        const char* readptr;
        size_t sizeleft;
    };

    static size_t read_callback(void* dst, size_t size, size_t nmemb, void* userp)
    {
        WriteThis* wt = static_cast<WriteThis*>(userp);
        size_t buffer_size = size * nmemb;

        if (wt->sizeleft)
        {
            size_t copy_this_much = wt->sizeleft;
            if (copy_this_much > buffer_size)
                copy_this_much = buffer_size;
            memcpy(dst, wt->readptr, copy_this_much);

            wt->readptr += copy_this_much;
            wt->sizeleft -= copy_this_much;
            return copy_this_much;
        }

        return 0;
    }

    Response Do(const Request& req)
    {
        CURL* curl = curl_easy_init();
        std::shared_ptr<void> _(nullptr, [curl](...) { curl_easy_cleanup(curl); });

        if (!curl)
            throw std::runtime_error("Failed to initialize curl");

        Response res;
        WriteThis wt;

        if (req.method == Method::POST || req.method == Method::PUT)
        {
            wt.readptr = req.body.c_str();
            wt.sizeleft = req.body.size();

            curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);
            curl_easy_setopt(curl, CURLOPT_READDATA, &wt);
            curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)wt.sizeleft);
        }

        if (req.forceIPv4)
            curl_easy_setopt(curl, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4);

        if (req.method == Method::POST)
            curl_easy_setopt(curl, CURLOPT_POST, 1L);

        if (req.method == Method::PUT)
            curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);

        curl_easy_setopt(curl, CURLOPT_URL, req.url.c_str());
        curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, true);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writeData);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void*)&res);
        curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, header_callback);
        curl_easy_setopt(curl, CURLOPT_HEADERDATA, (void*)&res);
        curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, true);
        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, true);
        curl_easy_setopt(curl, CURLOPT_USERAGENT, OPENRCT2_USER_AGENT);

        curl_slist* chunk = nullptr;
        std::shared_ptr<void> __(nullptr, [chunk](...) { curl_slist_free_all(chunk); });
        for (auto header : req.header)
        {
            std::string hs = header.first + ": " + header.second;
            chunk = curl_slist_append(chunk, hs.c_str());
        }
        if (req.header.size() != 0)
        {
            if (chunk == nullptr)
            {
                throw std::runtime_error("Failed to set headers");
            }
            curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
        }

        CURLcode curl_code = curl_easy_perform(curl);
        if (curl_code != CURLE_OK)
        {
            throw std::runtime_error("Failed to perform request");
        }

        // gets freed by curl_easy_cleanup
        char* content_type;
        long code;
        curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &code);
        curl_easy_getinfo(curl, CURLINFO_CONTENT_TYPE, &content_type);
        res.status = static_cast<Status>(code);
        res.content_type = std::string(content_type);

        return res;
    }

    void DoAsync(const Request& req, std::function<void(Response& res)> fn)
    {
        auto thread = std::thread([=]() {
            Response res;
            try
            {
                res = Do(req);
            }
            catch (std::exception& e)
            {
                res.error = e.what();
                return;
            }
            fn(res);
        });
        thread.detach();
    }

    size_t DownloadPark(const char* url, void** outData)
    {
        // Download park to buffer in memory
        Request request;
        request.url = url;
        request.method = Method::GET;

        Response res;
        try
        {
            res = Do(request);
            if (res.status != Status::OK)
                std::runtime_error("bad http status");
        }
        catch (std::exception& e)
        {
            Console::Error::WriteLine("Failed to download '%s', cause %s", request.url.c_str(), e.what());
            *outData = nullptr;
            return 0;
        }

        size_t dataSize = res.body.size() - 1;
        void* data = malloc(dataSize);
        if (data == nullptr)
        {
            Console::Error::WriteLine("Failed to allocate memory for downloaded park.");
            return 0;
        }

        memcpy(data, res.body.c_str(), dataSize);
        *outData = data;

        return dataSize;
    }

} // namespace OpenRCT2::Network::Http

#endif