backend/src/cgi.cpp

/*  This file is part of FediBlock-backend.
 *  Copyright © 2020 tastytea <tastytea@tastytea.de>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, version 3.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "cgi.hpp"
#include "files.hpp"
#include "fs-compat.hpp"
#include "time.hpp"

#include <cgicc/Cgicc.h>
#include <unicode/unistr.h>

#include <algorithm>
#include <chrono>
#include <fstream>
#include <ios>
#include <iostream>
#include <iterator>
#include <sstream>
#include <stdexcept>
#include <string>
#include <string_view>
#include <vector>

namespace FediBlock::cgi
{

using std::back_inserter;
using std::getline;
using std::ios;
using std::ofstream;
using std::runtime_error;
using std::string;
using std::string_view;
using std::stringstream;
using std::transform;
using std::vector;
using std::chrono::system_clock;

entry_type parse_formdata()
{
    entry_type entry;

    cgicc::Cgicc cgi;
    entry.instance = cgi("instance");
    entry.tags = string_to_vector(cgi("tags"));
    transform(entry.tags.begin(), entry.tags.end(), entry.tags.begin(),
              [](const auto &tag) { return tolower(tag); });
    entry.receipts = string_to_vector(cgi("receipts"));
    entry.description = cgi("description");
    entry.report_time = time::to_string(system_clock::now());

    const auto screenshot = cgi.getFile("screenshot");
    if (screenshot != cgi.getFiles().end())
    {
        constexpr size_t size_limit{1024 * 1024 * 2}; // 2 MiB.
        if (screenshot->getDataLength() > size_limit)
        {
            throw runtime_error{"Filesize too big"};
        }

        const string filepath{files::get_tmpdir() / screenshot->getFilename()};
        ofstream file{filepath, ios::binary};
        if (!file.good())
        {
            throw runtime_error{"Could not open temporary file: " + filepath};
        }
        screenshot->writeToStream(file);
        entry.screenshot_filepath = filepath;
    }

    return entry;
}

vector<string> string_to_vector(const string_view str)
{
    vector<string> vec;

    stringstream input{str.data()};
    string element;

    while (getline(input, element, ','))
    {
        if (!element.empty())
        {
            const size_t startpos{element.find_first_not_of(' ')};
            const size_t length{element.find_last_not_of(' ') - startpos + 1};
            vec.push_back(element.substr(startpos, length));
        }
    }

    return vec;
}

vector<string> get_tags()
{
    cgicc::Cgicc cgi;
    vector<cgicc::FormEntry> tags_form;
    vector<string> tags_string;

    cgi.getElement("tags[]", tags_form);
    for (const auto &element : tags_form)
    {
        const string tag{element.getValue()};
        if (!tag.empty())
        {
            tags_string.push_back(tolower(tag));
        }
    }

    return tags_string;
}

string tolower(const string_view str)
{
    string result;

    const auto unistr{icu::UnicodeString(str.data(), "UTF-8").toLower()};
    unistr.toUTF8String(result);

    return result;
}

} // namespace FediBlock::cgi