transfer-encoding.hpp

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/*
 * RESTinio
 */

/*!
 * @file
 * @brief Stuff related to value of Transfer-Encoding HTTP-field.
 *
 * @since v.0.6.9
 */

#pragma once

#include <restinio/helpers/http_field_parsers/basics.hpp>

#include <variant>
#include <tuple>

namespace restinio
{

namespace http_field_parsers
{

//
// transfer_encoding_value_t
//
/*!
 * @brief Tools for working with the value of Transfer-Encoding HTTP-field.
 *
 * This struct represents parsed value of HTTP-field Transfer-Encoding
 * (see https://tools.ietf.org/html/rfc7230#section-3.3.1 and
 * https://tools.ietf.org/html/rfc7230#section-4):
@verbatim
Transfer-Encoding  = 1#transfer-coding
transfer-coding    = "chunked"
                   / "compress"
                   / "deflate"
                   / ("gzip" | "x-gzip")
                   / transfer-extension
transfer-extension = token *( OWS ";" OWS transfer-parameter )
transfer-parameter = token BWS "=" BWS ( token / quoted-string )
@endverbatim
 *
 * @since v.0.6.9
 */
struct transfer_encoding_value_t
{
    //! Enumeration for transfer-coding values from RFC7230.
    enum class known_transfer_coding_t
    {
        chunked,
        compress,
        deflate,
        gzip,
    };

    [[nodiscard]]
    static constexpr known_transfer_coding_t chunked() noexcept
    { return known_transfer_coding_t::chunked; }

    [[nodiscard]]
    static constexpr known_transfer_coding_t compress() noexcept
    { return known_transfer_coding_t::compress; }

    [[nodiscard]]
    static constexpr known_transfer_coding_t deflate() noexcept
    { return known_transfer_coding_t::deflate; }

    [[nodiscard]]
    static constexpr known_transfer_coding_t gzip() noexcept
    { return known_transfer_coding_t::gzip; }

    //! Description of transfer-extension.
    struct transfer_extension_t
    {
        std::string token;
        parameter_with_mandatory_value_container_t transfer_parameters;

        [[nodiscard]]
        bool
        operator==( const transfer_extension_t & o ) const noexcept
        {
            return std::tie(this->token, this->transfer_parameters) ==
                    std::tie(o.token, o.transfer_parameters);
        }
    };

    //! Type for one value from Transfer-Encoding HTTP-field.
    using value_t = std::variant<
            known_transfer_coding_t,
            transfer_extension_t
        >;

    using value_container_t = std::vector< value_t >;

    value_container_t values;

    /*!
     * @brief A factory function for a parser of Transfer-Encoding value.
     *
     * @since v.0.6.9
     */
    [[nodiscard]]
    static auto
    make_parser()
    {
        return produce< transfer_encoding_value_t >(
            non_empty_comma_separated_list_p< value_container_t >(
                produce< value_t >(
                    alternatives(
                        expected_caseless_token_p("chunked")
                            >> just_result( chunked() ),
                        expected_caseless_token_p("compress")
                            >> just_result( compress() ),
                        expected_caseless_token_p("deflate")
                            >> just_result( deflate() ),
                        expected_caseless_token_p("gzip")
                            >> just_result( gzip() ),
                        expected_caseless_token_p("x-gzip")
                            >> just_result( gzip() ),
                        produce< transfer_extension_t >(
                            token_p() >> to_lower() >> &transfer_extension_t::token,
                            params_with_value_p()
                                    >> &transfer_extension_t::transfer_parameters
                        ) >> as_result()
                    )
                )
            ) >> &transfer_encoding_value_t::values
        );
    }

    /*!
     * @brief An attempt to parse Transfer-Encoding HTTP-field.
     *
     * @since v.0.6.9
     */
    [[nodiscard]]
    static expected_t<
        transfer_encoding_value_t,
        restinio::easy_parser::parse_error_t >
    try_parse( string_view_t what )
    {
        return restinio::easy_parser::try_parse( what, make_parser() );
    }
};

} /* namespace http_field_parsers */

} /* namespace restinio */