parser requires basic_fields (API Change):

* `parser` is now templated on Allocator

* `parser` only produces messages using `basic_fields<Allocator>`
  as the Fields type.

* message-oriented read and async_read only work on messages
  using basic_fields as the Fields type.

Actions Required:

* Callers using `parser` with Fields types other than basic_fields
  will need to create their own subclass of basic_parser to work
  with their custom fields type.

CHANGELOG.md

@@ -8,6 +8,16 @@ Version 62:
 * Clear the error faster
 * Avoid explicit operator bool for error
 
+API Changes:
+
+* parser requires basic_fields
+
+Actions Required:
+
+* Callers using `parser` with Fields types other than basic_fields
+  will need to create their own subclass of basic_parser to work
+  with their custom fields type.
+
 --------------------------------------------------------------------------------
 
 Version 61:

example/doc/http_examples.hpp

@@ -464,7 +464,6 @@ do_head_request(
 */
 template<
     bool isRequest,
-    class Fields = fields,
     class SyncWriteStream,
     class SyncReadStream,
     class DynamicBuffer,
@@ -487,10 +486,10 @@ relay(
     char buf[2048];
 
     // Create a parser with a buffer body to read from the input.
-    parser<isRequest, buffer_body, Fields> p;
+    parser<isRequest, buffer_body> p;
 
     // Create a serializer from the message contained in the parser.
-    serializer<isRequest, buffer_body, Fields> sr{p.get()};
+    serializer<isRequest, buffer_body, fields> sr{p.get()};
 
     // Read just the header from the input
     read_header(input, buffer, p, ec);
@@ -684,13 +683,12 @@ write_ostream(
 template<
     class Allocator,
     bool isRequest,
-    class Body,
+    class Body>
-    class Fields>
 void
 read_istream(
     std::istream& is,
     basic_flat_buffer<Allocator>& buffer,
-    message<isRequest, Body, Fields>& msg,
+    message<isRequest, Body, fields>& msg,
     error_code& ec)
 {
     // Create the message parser
@@ -700,7 +698,7 @@ read_istream(
     // a move construction in case the caller has constructed
     // their message in a non-default way.
     //
-    parser<isRequest, Body, Fields> p{std::move(msg)};
+    parser<isRequest, Body> p{std::move(msg)};
 
     do
     {

include/beast/http/impl/parser.ipp

@@ -14,19 +14,19 @@
 namespace beast {
 namespace http {
 
-template<bool isRequest, class Body, class Fields>
+template<bool isRequest, class Body, class Allocator>
 template<class Arg1, class... ArgN, class>
-parser<isRequest, Body, Fields>::
+parser<isRequest, Body, Allocator>::
 parser(Arg1&& arg1, ArgN&&... argn)
     : m_(std::forward<Arg1>(arg1),
         std::forward<ArgN>(argn)...)
 {
 }
 
-template<bool isRequest, class Body, class Fields>
+template<bool isRequest, class Body, class Allocator>
 template<class OtherBody, class... Args, class>
-parser<isRequest, Body, Fields>::
+parser<isRequest, Body, Allocator>::
-parser(parser<isRequest, OtherBody, Fields>&& p,
+parser(parser<isRequest, OtherBody, Allocator>&& p,
         Args&&... args)
     : base_type(std::move(p))
     , m_(p.release(), std::forward<Args>(args)...)

include/beast/http/impl/read.ipp

@@ -300,15 +300,15 @@ upcall:
 //------------------------------------------------------------------------------
 
 template<class Stream, class DynamicBuffer,
-    bool isRequest, class Body, class Fields,
+    bool isRequest, class Body, class Allocator,
         class Handler>
 class read_msg_op
 {
     using parser_type =
-        parser<isRequest, Body, Fields>;
+        parser<isRequest, Body, Allocator>;
 
     using message_type =
-        message<isRequest, Body, Fields>;
+        typename parser_type::value_type;
 
     struct data
     {
@@ -383,11 +383,11 @@ public:
 };
 
 template<class Stream, class DynamicBuffer,
-    bool isRequest, class Body, class Fields,
+    bool isRequest, class Body, class Allocator,
         class Handler>
 void
 read_msg_op<Stream, DynamicBuffer,
-    isRequest, Body, Fields, Handler>::
+    isRequest, Body, Allocator, Handler>::
 operator()(error_code ec)
 {
     auto& d = *d_;
@@ -693,12 +693,12 @@ async_read(
 template<
     class SyncReadStream,
     class DynamicBuffer,
-    bool isRequest, class Body, class Fields>
+    bool isRequest, class Body, class Allocator>
 void
 read(
     SyncReadStream& stream,
     DynamicBuffer& buffer,
-    message<isRequest, Body, Fields>& msg)
+    message<isRequest, Body, basic_fields<Allocator>>& msg)
 {
     static_assert(is_sync_read_stream<SyncReadStream>::value,
         "SyncReadStream requirements not met");
@@ -717,12 +717,12 @@ read(
 template<
     class SyncReadStream,
     class DynamicBuffer,
-    bool isRequest, class Body, class Fields>
+    bool isRequest, class Body, class Allocator>
 void
 read(
     SyncReadStream& stream,
     DynamicBuffer& buffer,
-    message<isRequest, Body, Fields>& msg,
+    message<isRequest, Body, basic_fields<Allocator>>& msg,
     error_code& ec)
 {
     static_assert(is_sync_read_stream<SyncReadStream>::value,
@@ -733,7 +733,7 @@ read(
         "Body requirements not met");
     static_assert(is_body_writer<Body>::value,
         "BodyWriter requirements not met");
-    parser<isRequest, Body, Fields> p{std::move(msg)};
+    parser<isRequest, Body, Allocator> p{std::move(msg)};
     p.eager(true);
     read(stream, buffer, p.base(), ec);
     if(ec)
@@ -744,13 +744,13 @@ read(
 template<
     class AsyncReadStream,
     class DynamicBuffer,
-    bool isRequest, class Body, class Fields,
+    bool isRequest, class Body, class Allocator,
     class ReadHandler>
 async_return_type<ReadHandler, void(error_code)>
 async_read(
     AsyncReadStream& stream,
     DynamicBuffer& buffer,
-    message<isRequest, Body, Fields>& msg,
+    message<isRequest, Body, basic_fields<Allocator>>& msg,
     ReadHandler&& handler)
 {
     static_assert(is_async_read_stream<AsyncReadStream>::value,
@@ -764,7 +764,7 @@ async_read(
     async_completion<ReadHandler,
         void(error_code)> init{handler};
     detail::read_msg_op<AsyncReadStream, DynamicBuffer,
-        isRequest, Body, Fields, handler_type<
+        isRequest, Body, Allocator, handler_type<
             ReadHandler, void(error_code)>>{
                 init.completion_handler, stream, buffer, msg}(
                     error_code{});

include/beast/http/parser.hpp

@@ -14,6 +14,7 @@
 #include <beast/http/type_traits.hpp>
 #include <boost/optional.hpp>
 #include <boost/throw_exception.hpp>
+#include <memory>
 #include <type_traits>
 #include <utility>
 
@@ -23,24 +24,27 @@ namespace http {
 /** An HTTP/1 parser for producing a message.
 
     This class uses the basic HTTP/1 wire format parser to convert
-    a series of octets into a @ref message.
+    a series of octets into a @ref message using the @ref basic_fields
+    container to represent the fields.
 
     @tparam isRequest Indicates whether a request or response
     will be parsed.
 
-    @tparam Body The type used to represent the body.
+    @tparam Body The type used to represent the body. This must
+    meet the requirements of @b Body.
 
-    @tparam Fields The type of container used to represent the fields.
+    @tparam Allocator The type of allocator used with the
+    @ref basic_fields container.
 
     @note A new instance of the parser is required for each message.
 */
 template<
     bool isRequest,
     class Body,
-    class Fields = fields>
+    class Allocator = std::allocator<char>>
 class parser
     : public basic_parser<isRequest,
-        parser<isRequest, Body, Fields>>
+        parser<isRequest, Body, Allocator>>
 {
     static_assert(is_body<Body>::value,
         "Body requirements not met");
@@ -52,14 +56,15 @@ class parser
     friend class parser;
 
     using base_type = basic_parser<isRequest,
-        parser<isRequest, Body, Fields>>;
+        parser<isRequest, Body, Allocator>>;
 
-    message<isRequest, Body, Fields> m_;
+    message<isRequest, Body, basic_fields<Allocator>> m_;
     boost::optional<typename Body::writer> wr_;
 
 public:
     /// The type of message returned by the parser
-    using value_type = message<isRequest, Body, Fields>;
+    using value_type =
+        message<isRequest, Body, basic_fields<Allocator>>;
 
     /// Constructor (default)
     parser() = default;
@@ -126,6 +131,9 @@ public:
 
         @throws std::invalid_argument Thrown when the constructed-from
         parser has already initialized a body writer.
+
+        @note This function participates in overload resolution only
+        if the other parser uses a different body type.
     */
 #if BEAST_DOXYGEN
     template<class OtherBody, class... Args>
@@ -135,13 +143,13 @@ public:
             ! std::is_same<Body, OtherBody>::value>::type>
 #endif
     explicit
-    parser(parser<isRequest, OtherBody, Fields>&& parser,
+    parser(parser<isRequest, OtherBody,
-        Args&&... args);
+        Allocator>&& parser, Args&&... args);
 
     /** Returns the parsed message.
 
-        Depending on the progress of the parser, portions
+        Depending on the parser's progress,
-        of this object may be incomplete.
+        parts of this object may be incomplete.
     */
     value_type const&
     get() const
@@ -151,8 +159,8 @@ public:
 
     /** Returns the parsed message.
 
-        Depending on the progress of the parser, portions
+        Depending on the parser's progress,
-        of this object may be incomplete.
+        parts of this object may be incomplete.
     */
     value_type&
     get()
@@ -163,8 +171,8 @@ public:
     /** Returns ownership of the parsed message.
 
         Ownership is transferred to the caller.
-        Depending on the progress of the parser, portions
+        Depending on the parser's progress,
-        of this object may be incomplete.
+        parts of this object may be incomplete.
 
         @par Requires
 
@@ -253,12 +261,12 @@ private:
 };
 
 /// An HTTP/1 parser for producing a request message.
-template<class Body, class Fields = fields>
+template<class Body, class Allocator = std::allocator<char>>
-using request_parser = parser<true, Body, Fields>;
+using request_parser = parser<true, Body, Allocator>;
 
 /// An HTTP/1 parser for producing a response message.
-template<class Body, class Fields = fields>
+template<class Body, class Allocator = std::allocator<char>>
-using response_parser = parser<false, Body, Fields>;
+using response_parser = parser<false, Body, Allocator>;
 
 } // http
 } // beast

include/beast/http/read.hpp

@@ -614,12 +614,12 @@ async_read(
 template<
     class SyncReadStream,
     class DynamicBuffer,
-    bool isRequest, class Body, class Fields>
+    bool isRequest, class Body, class Allocator>
 void
 read(
     SyncReadStream& stream,
     DynamicBuffer& buffer,
-    message<isRequest, Body, Fields>& msg);
+    message<isRequest, Body, basic_fields<Allocator>>& msg);
 
 /** Read a complete message from a stream.
 
@@ -666,12 +666,12 @@ read(
 template<
     class SyncReadStream,
     class DynamicBuffer,
-    bool isRequest, class Body, class Fields>
+    bool isRequest, class Body, class Allocator>
 void
 read(
     SyncReadStream& stream,
     DynamicBuffer& buffer,
-    message<isRequest, Body, Fields>& msg,
+    message<isRequest, Body, basic_fields<Allocator>>& msg,
     error_code& ec);
 
 /** Read a complete message from a stream asynchronously.
@@ -735,7 +735,7 @@ read(
 template<
     class AsyncReadStream,
     class DynamicBuffer,
-    bool isRequest, class Body, class Fields,
+    bool isRequest, class Body, class Allocator,
     class ReadHandler>
 #if BEAST_DOXYGEN
     void_or_deduced
@@ -746,7 +746,7 @@ async_return_type<
 async_read(
     AsyncReadStream& stream,
     DynamicBuffer& buffer,
-    message<isRequest, Body, Fields>& msg,
+    message<isRequest, Body, basic_fields<Allocator>>& msg,
     ReadHandler&& handler);
 
 } // http

test/http/parser.cpp

@@ -32,7 +32,7 @@ class parser_test
 public:
     template<bool isRequest>
     using parser_type =
-        parser<isRequest, string_body, fields>;
+        parser<isRequest, string_body>;
 
     static
     boost::asio::const_buffers_1