parser_callbacks.ipp

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/*
    restinio
*/

/**
 * @brief A helper function to get the pointer to a context object.
 */
[[nodiscard]] inline restinio::impl::http_parser_ctx_t *
get_http_parser_ctx( llhttp_t * parser )
{
    return reinterpret_cast< restinio::impl::http_parser_ctx_t * >(
        parser->data );
}

/*!
    Callbacks used with http parser.
*/

inline int
restinio_url_cb( llhttp_t * parser, const char * at, size_t length )
{
    try
    {
        auto * ctx = get_http_parser_ctx( parser );

        ctx->m_header.append_request_target( at, length );

        if( ctx->m_header.request_target().length() >
                ctx->m_limits.max_url_size() )
        {
            return -1;
        }
    }
    catch( const std::exception & )
    {
        return -1;
    }

    return 0;
}

inline int
restinio_header_field_cb( llhttp_t * parser, const char *at, size_t length )
{
    try
    {
        auto * ctx = get_http_parser_ctx( parser );

        // Maybe there are too many fields?
        if( ctx->m_total_field_count == ctx->m_limits.max_field_count() )
        {
            return -1;
        }

        if( ctx->m_current_field_name.size() + length >
                ctx->m_limits.max_field_name_size() )
        {
            return -1;
        }

        ctx->m_current_field_name.append( at, length );
    }
    catch( const std::exception & )
    {
        return -1;
    }

    return 0;
}

inline int
restinio_header_field_complete_cb( llhttp_t * parser )
{
    try
    {
        auto * ctx = get_http_parser_ctx( parser );

        auto & fields = ctx->m_leading_headers_completed
                ? ctx->m_chunked_info_block.m_trailing_fields
                : ctx->m_header;

        // Note: moving `ctx->m_current_field_name`
        //       also cleans the placeholder, so it
        //       becomes ready to accumulating next field.
        fields.add_field(
            std::move( ctx->m_current_field_name ),
            std::string{} );

        // At this point the number of parsed fields can be incremented.
        ctx->m_total_field_count += 1u;
    }
    catch( const std::exception & )
    {
        return -1;
    }

    return 0;
}


inline void
append_last_field_accessor( http_header_fields_t & fields, string_view_t value )
{
    fields.append_last_field( value );
}

inline int
restinio_header_value_cb( llhttp_t * parser, const char *at, size_t length )
{
    try
    {
        auto * ctx = get_http_parser_ctx( parser );

        http_header_fields_t & fields = ctx->m_leading_headers_completed
                ? ctx->m_chunked_info_block.m_trailing_fields
                : ctx->m_header;

        if( ctx->m_last_value_total_size + length >=
                ctx->m_limits.max_field_value_size() )
        {
            return -1;
        }

        ctx->m_last_value_total_size += length;

        append_last_field_accessor( fields, std::string{ at, length } );
    }
    catch( const std::exception & )
    {
        return -1;
    }

    return 0;
}

inline int
restinio_header_value_complete_cb( llhttp_t * parser )
{
    // Reset value size counter for the next time.
    get_http_parser_ctx( parser )->m_last_value_total_size = 0;
    return 0;
}

inline int
restinio_headers_complete_cb( llhttp_t * parser )
{
    auto * ctx = get_http_parser_ctx( parser );
    // Next time header_name/header_value callback should store
    // values of trailing fields.
    ctx->m_leading_headers_completed = true;

    if( ULLONG_MAX != parser->content_length &&
        0 < parser->content_length )
    {
        // Maximum body size can be checked right now.
        if( parser->content_length > ctx->m_limits.max_body_size() )
        {
            return -1;
        }

        try
        {
            ctx->m_body.reserve(
                    ::restinio::utils::impl::uint64_to_size_t(
                            parser->content_length) );
        }
        catch( const std::exception & )
        {
            return -1;
        }
    }

    return 0;
}


inline int
restinio_body_cb( llhttp_t * parser, const char *at, size_t length )
{
    try
    {
        auto * ctx = get_http_parser_ctx( parser );

        // The total size of the body should be checked.
        const auto total_length = static_cast<std::uint64_t>(
                ctx->m_body.size() ) + length;
        if( total_length > ctx->m_limits.max_body_size() )
        {
            return -1;
        }

        ctx->m_body.append( at, length );
    }
    catch( const std::exception & )
    {
        return -1;
    }

    return 0;
}

inline int
restinio_chunk_header_cb( llhttp_t * parser )
{
    try
    {
        // In on_chunk_header callback parser->content_length contains
        // the size of the next chunk.
        // If that size is 0 then it is the last chunk and it should be
        // ignored.
        if( 0u != parser->content_length )
        {
            auto * ctx = get_http_parser_ctx( parser );

            // Store an info about the new chunk.
            // If there will be an error at the next stage of parsing
            // the incoming request the whole request's data will be dropped.
            // So there is no need to care about that new item in m_chunks.
            ctx->m_chunked_info_block.m_chunks.emplace_back(
                ctx->m_body.size(),
                ::restinio::utils::impl::uint64_to_size_t(parser->content_length),
                std::move( ctx->m_chunk_ext_params ) );
        }
    }
    catch( const std::exception & )
    {
        return -1;
    }

    return 0;
}

inline int
restinio_chunk_complete_cb( llhttp_t * /*parser*/ )
{
    // There is nothing to do.
    return 0;
}

template< typename Http_Methods >
int
restinio_message_complete_cb( llhttp_t * parser )
{
    auto * ctx = get_http_parser_ctx( parser );

    ctx->m_message_complete = true;
    ctx->m_header.method( Http_Methods::from_nodejs( parser->method ) );

    if( 0 == llhttp_get_upgrade( parser ) )
    {
        ctx->m_header.should_keep_alive( 0 != llhttp_should_keep_alive( parser ) );
    }
    else
    {
        ctx->m_header.connection( http_connection_header_t::upgrade );
    }

    return HPE_PAUSED;
}

/*!
 * @name Chunked encoding callbacks.
 *
 * @since v.0.7.0
 */
/// @{
inline int
restinio_chunk_extension_name_cb( llhttp_t * parser, const char * at, size_t length )
{
    try
    {
        auto * ctx = get_http_parser_ctx( parser );

        if( !ctx->m_chunk_ext_params )
        {
            ctx->m_chunk_ext_params = std::make_unique<chunk_ext_params_t>();
        }

        auto * ext_params = ctx->m_chunk_ext_params.get();

        // Maybe there are too many fields?
        if( ext_params->size() == ctx->m_limits.max_field_count() )
        {
            return -1;
        }

        if( ctx->m_current_field_name.size() + length >
                ctx->m_limits.max_field_name_size() )
        {
            return -1;
        }

        ctx->m_current_field_name.append( at, length );
    }
    catch( const std::exception & )
    {
        return -1;
    }

    return 0;
}

inline int
restinio_chunk_extension_name_complete_cb( llhttp_t * parser )
{
    try
    {
        auto * ctx = get_http_parser_ctx( parser );
        auto * ext_params = ctx->m_chunk_ext_params.get();

        ext_params->emplace_back(
            chunk_ext_param_t{ std::move( ctx->m_current_field_name ), {} } );
    }
    catch( const std::exception & )
    {
        return -1;
    }

    return 0;
}

inline int
restinio_chunk_extension_value_cb( llhttp_t * parser, const char * at, size_t length )
{
    try
    {
        auto * ctx = get_http_parser_ctx( parser );
        auto & value_receiver_str =
            ctx->m_chunk_ext_params->back().m_value;

        if( value_receiver_str.size() + length >
                ctx->m_limits.max_field_value_size() )
        {
            return -1;
        }

        value_receiver_str.append( at, length );
    }
    catch( const std::exception & )
    {
        return -1;
    }

    return 0;
}

inline int
restinio_chunk_extension_value_complete_cb( llhttp_t * /*parser*/ )
{
    // There is nothing to do.
    return 0;
}
/// @}