boost/beast/http/serializer.hpp
// // Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // // Official repository: https://github.com/boostorg/beast // #ifndef BOOST_BEAST_HTTP_SERIALIZER_HPP #define BOOST_BEAST_HTTP_SERIALIZER_HPP #include <boost/beast/core/detail/config.hpp> #include <boost/beast/core/buffers_cat.hpp> #include <boost/beast/core/buffers_prefix.hpp> #include <boost/beast/core/buffers_suffix.hpp> #include <boost/beast/core/string.hpp> #include <boost/beast/core/detail/variant.hpp> #include <boost/beast/http/message.hpp> #include <boost/beast/http/chunk_encode.hpp> #include <boost/asio/buffer.hpp> #include <boost/optional.hpp> namespace boost { namespace beast { namespace http { /** Provides buffer oriented HTTP message serialization functionality. An object of this type is used to serialize a complete HTTP message into a sequence of octets. To use this class, construct an instance with the message to be serialized. The implementation will automatically perform chunk encoding if the contents of the message indicate that chunk encoding is required. Chunked output produced by the serializer never contains chunk extensions or trailers, and the location of chunk boundaries is not specified. If callers require chunk extensions, trailers, or control over the exact contents of each chunk they should use the serializer to write just the message header, and then assume control over serializing the chunked payload by using the chunk buffer sequence types @ref chunk_body, @ref chunk_crlf, @ref chunk_header, and @ref chunk_last. @tparam isRequest `true` if the message is a request. @tparam Body The body type of the message. @tparam Fields The type of fields in the message. */ template< bool isRequest, class Body, class Fields = fields> class serializer { public: static_assert(is_body<Body>::value, "Body type requirements not met"); static_assert(is_body_writer<Body>::value, "BodyWriter type requirements not met"); /** The type of message this serializer uses This may be const or non-const depending on the implementation of the corresponding <em>BodyWriter</em>. */ #if BOOST_BEAST_DOXYGEN using value_type = __implementation_defined__; #else using value_type = typename std::conditional< std::is_constructible<typename Body::writer, header<isRequest, Fields>&, typename Body::value_type&>::value && ! std::is_constructible<typename Body::writer, header<isRequest, Fields> const&, typename Body::value_type const&>::value, message<isRequest, Body, Fields>, message<isRequest, Body, Fields> const>::type; #endif private: enum { do_construct = 0, do_init = 10, do_header_only = 20, do_header = 30, do_body = 40, do_init_c = 50, do_header_only_c = 60, do_header_c = 70, do_body_c = 80, do_final_c = 90, #ifndef BOOST_BEAST_NO_BIG_VARIANTS do_body_final_c = 100, do_all_c = 110, #endif do_complete = 120 }; void fwrinit(std::true_type); void fwrinit(std::false_type); template<std::size_t, class Visit> void do_visit(error_code& ec, Visit& visit); using writer = typename Body::writer; using cb1_t = buffers_suffix<typename Fields::writer::const_buffers_type>; // header using pcb1_t = buffers_prefix_view<cb1_t const&>; using cb2_t = buffers_suffix<buffers_cat_view< typename Fields::writer::const_buffers_type,// header typename writer::const_buffers_type>>; // body using pcb2_t = buffers_prefix_view<cb2_t const&>; using cb3_t = buffers_suffix< typename writer::const_buffers_type>; // body using pcb3_t = buffers_prefix_view<cb3_t const&>; using cb4_t = buffers_suffix<buffers_cat_view< typename Fields::writer::const_buffers_type,// header detail::chunk_size, // chunk-size net::const_buffer, // chunk-ext chunk_crlf, // crlf typename writer::const_buffers_type, // body chunk_crlf>>; // crlf using pcb4_t = buffers_prefix_view<cb4_t const&>; using cb5_t = buffers_suffix<buffers_cat_view< detail::chunk_size, // chunk-header net::const_buffer, // chunk-ext chunk_crlf, // crlf typename writer::const_buffers_type, // body chunk_crlf>>; // crlf using pcb5_t = buffers_prefix_view<cb5_t const&>; using cb6_t = buffers_suffix<buffers_cat_view< detail::chunk_size, // chunk-header net::const_buffer, // chunk-size chunk_crlf, // crlf typename writer::const_buffers_type, // body chunk_crlf, // crlf net::const_buffer, // chunk-final net::const_buffer, // trailers chunk_crlf>>; // crlf using pcb6_t = buffers_prefix_view<cb6_t const&>; using cb7_t = buffers_suffix<buffers_cat_view< typename Fields::writer::const_buffers_type,// header detail::chunk_size, // chunk-size net::const_buffer, // chunk-ext chunk_crlf, // crlf typename writer::const_buffers_type, // body chunk_crlf, // crlf net::const_buffer, // chunk-final net::const_buffer, // trailers chunk_crlf>>; // crlf using pcb7_t = buffers_prefix_view<cb7_t const&>; using cb8_t = buffers_suffix<buffers_cat_view< net::const_buffer, // chunk-final net::const_buffer, // trailers chunk_crlf>>; // crlf using pcb8_t = buffers_prefix_view<cb8_t const&>; value_type& m_; writer wr_; boost::optional<typename Fields::writer> fwr_; beast::detail::variant< cb1_t, cb2_t, cb3_t, cb4_t, cb5_t ,cb6_t, cb7_t, cb8_t> v_; beast::detail::variant< pcb1_t, pcb2_t, pcb3_t, pcb4_t, pcb5_t ,pcb6_t, pcb7_t, pcb8_t> pv_; std::size_t limit_ = (std::numeric_limits<std::size_t>::max)(); int s_ = do_construct; bool split_ = false; bool header_done_ = false; bool more_ = false; public: /// Constructor serializer(serializer&&) = default; /// Constructor serializer(serializer const&) = default; /// Assignment serializer& operator=(serializer const&) = delete; /** Constructor The implementation guarantees that the message passed on construction will not be accessed until the first call to @ref next. This allows the message to be lazily created. For example, if the header is filled in before serialization. @param msg A reference to the message to serialize, which must remain valid for the lifetime of the serializer. Depending on the type of Body used, this may or may not be a `const` reference. @note This function participates in overload resolution only if Body::writer is constructible from a `const` message reference. */ explicit serializer(value_type& msg); /// Returns the message being serialized value_type& get() { return m_; } /// Returns the serialized buffer size limit std::size_t limit() { return limit_; } /** Set the serialized buffer size limit This function adjusts the limit on the maximum size of the buffers passed to the visitor. The new size limit takes effect in the following call to @ref next. The default is no buffer size limit. @param limit The new buffer size limit. If this number is zero, the size limit is removed. */ void limit(std::size_t limit) { limit_ = limit > 0 ? limit : (std::numeric_limits<std::size_t>::max)(); } /** Returns `true` if we will pause after writing the complete header. */ bool split() { return split_; } /** Set whether the header and body are written separately. When the split feature is enabled, the implementation will write only the octets corresponding to the serialized header first. If the header has already been written, this function will have no effect on output. */ void split(bool v) { split_ = v; } /** Return `true` if serialization of the header is complete. This function indicates whether or not all buffers containing serialized header octets have been retrieved. */ bool is_header_done() { return header_done_; } /** Return `true` if serialization is complete. The operation is complete when all octets corresponding to the serialized representation of the message have been successfully retrieved. */ bool is_done() { return s_ == do_complete; } /** Returns the next set of buffers in the serialization. This function will attempt to call the `visit` function object with a <em>ConstBufferSequence</em> of unspecified type representing the next set of buffers in the serialization of the message represented by this object. If there are no more buffers in the serialization, the visit function will not be called. In this case, no error will be indicated, and the function @ref is_done will return `true`. @param ec Set to the error, if any occurred. @param visit The function to call. The equivalent function signature of this object must be: @code template<class ConstBufferSequence> void visit(error_code&, ConstBufferSequence const&); @endcode The function is not copied, if no error occurs it will be invoked before the call to @ref next returns. */ template<class Visit> void next(error_code& ec, Visit&& visit); /** Consume buffer octets in the serialization. This function should be called after one or more octets contained in the buffers provided in the prior call to @ref next have been used. After a call to @ref consume, callers should check the return value of @ref is_done to determine if the entire message has been serialized. @param n The number of octets to consume. This number must be greater than zero and no greater than the number of octets in the buffers provided in the prior call to @ref next. */ void consume(std::size_t n); /** Provides low-level access to the associated <em>BodyWriter</em> This function provides access to the instance of the writer associated with the body and created by the serializer upon construction. The behavior of accessing this object is defined by the specification of the particular writer and its associated body. @return A reference to the writer. */ writer& writer_impl() { return wr_; } }; /// A serializer for HTTP/1 requests template<class Body, class Fields = fields> using request_serializer = serializer<true, Body, Fields>; /// A serializer for HTTP/1 responses template<class Body, class Fields = fields> using response_serializer = serializer<false, Body, Fields>; } // http } // beast } // boost #include <boost/beast/http/impl/serializer.hpp> #endif