remwharead/include/uri.hpp

/*  This file is part of remwharead.
 *  Copyright © 2019 tastytea <tastytea@tastytea.de>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef REMWHAREAD_URI_HPP
#define REMWHAREAD_URI_HPP

#include <string>

namespace remwharead
{
    using std::string;

    /*!
     *  @brief  A processed HTML page.
     *
     *  @return true if successful, when cast to bool.
     *
     *  @since  0.7.0
     *
     *  @headerfile uri.hpp remwharead/uri.hpp
     */
    using html_extract = struct html_extract
    {
        bool successful = false;
        string error;
        string title;
        string description;
        string fulltext;

        explicit operator bool();
    };

    /*!
     *  @brief  The result of the call to the archive service.
     *
     *  @return true if successful, when cast to bool.
     *
     *  @since  0.7.0
     *
     *  @headerfile uri.hpp remwharead/uri.hpp
     */
    using archive_answer = struct archive_answer
    {
        bool successful = false;
        string error;
        string uri;

        explicit operator bool();
    };

    /*!
     *  @brief  Download, archive and process an %URI.
     *
     *  @since  0.6.0
     *
     *  @headerfile uri.hpp remwharead/uri.hpp
     */
    class URI
    {
    public:
        /*!
         *  @brief  Construct object and set URL.
         *
         *  Initializes TLS and sets proxy from the environment variable
         *  `http_proxy`, if possible.
         *
         *  @since  0.6.0
         */
        explicit URI(string uri);
        virtual ~URI();

        URI(const URI &other) = default;
        URI &operator=(const URI &other) = default;
        URI(URI &&other) = default;
        URI &operator=(URI &&other) = default;

        /*!
         *  @brief  Download %URI and extract title, description and full text.
         *
         *  @since  0.6.0
         */
        html_extract get();

        /*!
         *  @brief  Save %URI in archive and return archive-URI.
         *
         *  @since  0.6.0
         */
        archive_answer archive();

    protected:
        string _uri;

        /*!
         *  @brief  Make a HTTP(S) request.
         *
         *  @since  0.6.0
         */
        string make_request(const string &uri, bool archive = false) const;

        /*!
         *  @brief  Extract the title from an HTML page.
         *
         *  @since  0.6.0
         */
        string extract_title(const string &html);

        /*!
         *  @brief  Extract the description from an HTML page.
         *
         *  @since  0.6.0
         */
        string extract_description(const string &html);

        /*!
         *  @brief  Removes HTML tags and superflous spaces from an HTML page.
         *
         *  @since  0.6.0
         */
        string strip_html(const string &html);

        /*!
         *  @brief  Remove HTML tags.
         *
         *  @param  html HTML page.
         *  @param  tag  If set, only remove this tag.
         *
         *  @since  0.6.0
         */
        string remove_html_tags(const string &html, const string &tag = "");

        /*!
         *  @brief  Convert HTML entities to UTF-8.
         *
         *  @since  0.6.0
         */
        string unescape_html(string html);

        /*!
         *  @brief  Replace newlines with spaces.
         *
         *  @since  0.6.0
         */
        string remove_newlines(string text);

        /*!
         *  @brief  Set proxy server.
         *
         *  @since  0.8.5
         */
        void set_proxy();
    };
} // namespace remwharead

#endif  // REMWHAREAD_URI_HPP