content-disposition.hpp

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/*
 * RESTinio
 */

/*!
 * @file
 * @brief Stuff related to value of Content-Disposition HTTP-field.
 *
 * @since v.0.6.1
 */

#pragma once

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

#include <restinio/helpers/http_field_parsers/details/pct_encoded_symbols.hpp>

namespace restinio
{

namespace http_field_parsers
{

namespace content_disposition_details
{

namespace ep_impl = restinio::easy_parser::impl;
namespace hfp_impl = restinio::http_field_parsers::impl;
namespace hfp_details = restinio::http_field_parsers::details;

//
// regular_token_producer_t
//
/*!
 * @brief A producer for token that is a "regular parameter name" in sense of
 * RCF6266 and RCF5987
 *
 * A regular parameter name can't have '*' symbol at the end.
 *
 * See: https://tools.ietf.org/html/rfc5987#section-3.2 and
 * https://tools.ietf.org/html/rfc6266#section-4.1
 *
 * @since v.0.6.1
 */
class regular_token_producer_t
    :   public hfp_impl::token_producer_t
{
public:
    [[nodiscard]]
    expected_t< result_type, parse_error_t >
    try_parse( ep_impl::source_t & from ) const
    {
        ep_impl::source_t::content_consumer_t consumer{ from };
        const auto result = hfp_impl::token_producer_t::try_parse( from );
        if( result )
        {
            if( '*' == *(result->rbegin()) )
            {
                // Regular token can't have the trailing '*'.
                return make_unexpected( parse_error_t{
                        consumer.started_at() + result->size() - 1,
                        error_reason_t::unexpected_character
                    } );
            }

            consumer.commit();
        }

        return result;
    }
};

//
// ext_token_producer_t
//
/*!
 * @brief A producer for token that is an "extended parameter name" in sense of
 * RCF6266 and RCF5987
 *
 * An extended parameter name has '*' symbol at the end.
 *
 * See: https://tools.ietf.org/html/rfc5987#section-3.2 and
 * https://tools.ietf.org/html/rfc6266#section-4.1
 *
 * @since v.0.6.1
 */
class ext_token_producer_t
    :   public hfp_impl::token_producer_t
{
public:
    [[nodiscard]]
    expected_t< result_type, parse_error_t >
    try_parse( ep_impl::source_t & from ) const
    {
        ep_impl::source_t::content_consumer_t consumer{ from };
        const auto result = hfp_impl::token_producer_t::try_parse( from );
        if( result )
        {
            if( '*' != *(result->rbegin()) )
            {
                // Extended token should have the trailing '*'.
                return make_unexpected( parse_error_t{
                        consumer.started_at(),
                        error_reason_t::pattern_not_found
                    } );
            }

            consumer.commit();
        }

        return result;
    }
};

//
// mime_charsetc_predicate_t
//
/*!
 * @brief A preducate for symbol_producer_template that checks that
 * a symbol is mime-charsetc symbol from RCF5987.
 *
 * See: https://tools.ietf.org/html/rfc5987#section-3.2
 *
 * @since v.0.6.1
 */
struct mime_charsetc_predicate_t
{
    [[nodiscard]]
    bool
    operator()( const char actual ) const noexcept
    {
        return hfp_impl::is_alpha(actual)
                || hfp_impl::is_digit(actual)
                || '!' == actual
                || '#' == actual
                || '$' == actual
                || '%' == actual
                || '&' == actual
                || '+' == actual
                || '-' == actual
                || '^' == actual
                || '_' == actual
                || '`' == actual
                || '{' == actual
                || '}' == actual
                || '~' == actual
                ;
    }
};

//
// mime_charsetc_symbol_producer
//
/*!
 * @brief A factory for producer that extracts mime-charsetc symbols.
 *
 * See: https://tools.ietf.org/html/rfc5987#section-3.2
 *
 * @since v.0.6.1
 */
[[nodiscard]]
inline auto
mime_charsetc_symbol_p()
{
    return ep_impl::symbol_producer_template_t< mime_charsetc_predicate_t >{};
}

//
// language_predicate_t
//
/*!
 * @brief A preducate for symbol_producer_template that checks that
 * a symbol is language symbol from RCF5646.
 *
 * @attention
 * In the current version of RESTinio only the presence of characters
 * defined in RFC5646 is checked. But those characters can form illegal
 * sequencies.
 *
 * See: https://tools.ietf.org/html/rfc5646#section-2.1 
 *
 * @since v.0.6.1
 */
struct language_predicate_t
{
    [[nodiscard]]
    bool
    operator()( const char actual ) const noexcept
    {
        return hfp_impl::is_alpha(actual)
                || hfp_impl::is_digit(actual)
                || '-' == actual
                ;
    }
};

//
// language_symbol_producer
//
/*!
 * @brief A factory for producer that extracts language symbols.
 *
 * @since v.0.6.1
 */
[[nodiscard]]
inline auto
language_symbol_p()
{
    return ep_impl::symbol_producer_template_t< language_predicate_t >{};
}

//
// attr_char_predicate_t
//
/*!
 * @brief A preducate for symbol_producer_template that checks that
 * a symbol is attr-char symbol from RCF5987.
 *
 * See: https://tools.ietf.org/html/rfc5987#section-3.2
 *
 * @since v.0.6.1
 */
struct attr_char_predicate_t
{
    [[nodiscard]]
    bool
    operator()( const char actual ) const noexcept
    {
        return hfp_impl::is_alpha(actual)
                || hfp_impl::is_digit(actual)
                || '!' == actual
                || '#' == actual
                || '$' == actual
                || '&' == actual
                || '+' == actual
                || '-' == actual
                || '.' == actual
                || '^' == actual
                || '_' == actual
                || '`' == actual
                || '|' == actual
                || '~' == actual
                ;
    }
};

//
// attr_char_symbol_producer
//
/*!
 * @brief A factory for producer that extracts attr-char symbols.
 *
 * See: https://tools.ietf.org/html/rfc5987#section-3.2
 *
 * @since v.0.6.1
 */
[[nodiscard]]
inline auto
attr_char_symbol_p()
{
    return ep_impl::symbol_producer_template_t< attr_char_predicate_t >{};
}

//
// ext_parameter_value_producer
//
/*!
 * @brief A producer for an "extended parameter value" in sense of
 * RCF6266 and RCF5987
 *
 * This producer return std::string object.
 *
 * It handles the following rules:
@verbatim
ext-value     = mime-charset  "'" [ language ] "'" value-chars

mime-charset  = 1*mime-charsetc
mime-charsetc = ALPHA / DIGIT
              / "!" / "#" / "$" / "%" / "&"
              / "+" / "-" / "^" / "_" / "`"
              / "{" / "}" / "~"

language      = 0*language-char
language-char = ALPHA / DIGIT / "-"

value-chars   = *( pct-encoded / attr-char )

pct-encoded   = "%" HEXDIG HEXDIG

attr-char     = ALPHA / DIGIT
              / "!" / "#" / "$" / "&" / "+" / "-" / "."
              / "^" / "_" / "`" / "|" / "~"
@endverbatim
 *
 * @since v.0.6.1
 */
[[nodiscard]]
inline auto
ext_parameter_value_p()
{
    return produce< std::string >(
            repeat( 1, N, mime_charsetc_symbol_p() >> to_container() ),
            symbol_p( '\'' ) >> to_container(),
            repeat( 0, N, language_symbol_p() >> to_container() ),
            symbol_p( '\'' ) >> to_container(),
            repeat( 0, N,
                alternatives(
                    attr_char_symbol_p() >> to_container(),
                    hfp_details::pct_encoded_symbols_p() >>
                            hfp_details::pct_encoded_symbols_consumer_t{} )
            )
        );
}

} /* namespace content_disposition_details */

//
// content_disposition_value_t
//
/*!
 * @brief Tools for working with the value of Content-Disposition HTTP-field.
 *
 * This struct represents parsed value of HTTP-field Content-Disposition
 * (see https://tools.ietf.org/html/rfc6266).
 *
 * @note
 * - the main value of Content-Disposition field is converted to lower case;
 * - parameter names are converted to lower case during the parsing;
 * - parameter values are left as they are;
 * - values of extended parameters are left as they are (it means that if
 *   there is "filename*=utf-8''Some%20name" then the value of
 *   "filename*" parameter will be "utf-8''Some%20name").
 *
 * @since v.0.6.1
 */
struct content_disposition_value_t
{
    using parameter_t = parameter_with_mandatory_value_t;

    using parameter_container_t = parameter_with_mandatory_value_container_t;

    std::string value;
    parameter_container_t parameters;

    /*!
     * @brief A factory function for a parser of Content-Disposition value.
     *
     * @since v.0.6.1
     */
    [[nodiscard]]
    static auto
    make_parser()
    {
        using namespace content_disposition_details;

        return produce< content_disposition_value_t >(
            token_p() >> to_lower()
                    >> &content_disposition_value_t::value,
            produce< parameter_container_t >(
                repeat( 0, N,
                    produce< parameter_t >(
                        ows(),
                        symbol(';'),
                        ows(),
                        alternatives(
                            sequence(
                                regular_token_producer_t{}
                                        >> to_lower() >> &parameter_t::first,
                                symbol('='),
                                alternatives(
                                    token_p() >> &parameter_t::second,
                                    quoted_string_p() >> &parameter_t::second
                                )
                            ),
                            sequence(
                                ext_token_producer_t{}
                                        >> to_lower() >> &parameter_t::first,
                                symbol('='),
                                ext_parameter_value_p() >> &parameter_t::second
                            )
                        )
                    ) >> to_container()
                )
            ) >> &content_disposition_value_t::parameters
        );
    }

    /*!
     * @brief An attempt to parse Content-Disposition HTTP-field.
     *
     * @since v.0.6.1
     */
    [[nodiscard]]
    static expected_t< content_disposition_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 */