Narrow the use of Fields parameters:

Every interface or implementation which operates on a templated
type Fields is evaluated to determine if basic_fields<Allocator>
is more appropriate, and changed if so.

example/doc/http_examples.hpp

@@ -47,12 +47,12 @@ namespace http {
 template<
     class SyncStream,
     class DynamicBuffer,
-    class Body, class Fields>
+    class Body, class Allocator>
 void
 send_expect_100_continue(
     SyncStream& stream,
     DynamicBuffer& buffer,
-    request<Body, Fields>& req,
+    request<Body, basic_fields<Allocator>>& req,
     error_code& ec)
 {
     static_assert(is_sync_stream<SyncStream>::value,

example/server-framework/multi_port.hpp

@@ -273,12 +273,12 @@ public:
 
         @param req The upgrade request.
     */
-    template<class Body, class Fields>
+    template<class Body>
     void
     on_upgrade(
         socket_type&& sock,
         endpoint_type ep,
-        beast::http::request<Body, Fields>&& req)
+        beast::http::request<Body>&& req)
     {
         // Create the connection and call the version of
         // run that takes the request since we have it already
@@ -304,12 +304,12 @@ public:
 
         @param req The upgrade request.
     */
-    template<class Body, class Fields>
+    template<class Body>
     void
     on_upgrade(
         ssl_stream<socket_type>&& stream,
         endpoint_type ep,
-        beast::http::request<Body, Fields>&& req)
+        beast::http::request<Body>&& req)
     {
         std::make_shared<async_wss_con>(
             std::move(stream),

example/server-framework/rfc7231.hpp

@@ -26,9 +26,10 @@ namespace rfc7231 {
 
     @see https://tools.ietf.org/html/rfc7231#section-5.1.1
 */
-template<class Body, class Fields>
+template<class Body, class Allocator>
 bool
-is_expect_100_continue(beast::http::request<Body, Fields> const& req)
+is_expect_100_continue(beast::http::request<
+    Body, beast::http::basic_fields<Allocator>> const& req)
 {
     return beast::iequals(
         req[beast::http::field::expect], "100-continue");

example/server-framework/service_list.hpp

@@ -98,9 +98,9 @@ public:
 
         @code
 
-        template<class Body, class Fields>
+        template<class Body>
         void
-        send(response<Body, Fields>&&);
+        send(response<Body>&&);
 
         @endcode
 
@@ -112,13 +112,13 @@ public:
     */
     template<
         class Stream,
-        class Body, class Fields,
+        class Body,
         class Send>
     bool
     respond(
         Stream&& stream,
         endpoint_type const& ep,
-        beast::http::request<Body, Fields>&& req,
+        beast::http::request<Body>&& req,
         Send const& send) const
     {
         return try_respond(
@@ -135,13 +135,13 @@ private:
     */
     template<
         class Stream,
-        class Body, class Fields,
+        class Body,
         class Send>
     bool
     try_respond(
         Stream&&,
         endpoint_type const&,
-        beast::http::request<Body, Fields>&&,
+        beast::http::request<Body>&&,
         Send const&,
         C<sizeof...(Services)> const&) const
     {
@@ -155,14 +155,14 @@ private:
     //
     template<
         class Stream,
-        class Body, class Fields,
+        class Body,
         class Send,
         std::size_t I>
     bool
     try_respond(
         Stream&& stream,
         endpoint_type const& ep,
-        beast::http::request<Body, Fields>&& req,
+        beast::http::request<Body>&& req,
         Send const& send,
         C<I> const&) const
     {

example/server-framework/ws_async_port.hpp

@@ -90,9 +90,9 @@ public:
     // This overload handles the case where we
     // already have the WebSocket Upgrade request.
     //
-    template<class Body, class Fields>
+    template<class Body>
     void
-    run(beast::http::request<Body, Fields> const& req)
+    run(beast::http::request<Body> const& req)
     {
         // Call the overload of accept() which takes
         // the request by parameter, instead of reading
@@ -352,12 +352,12 @@ public:
 
         @param req The upgrade request.
     */
-    template<class Body, class Fields>
+    template<class Body>
     void
     on_upgrade(
         socket_type&& sock,
         endpoint_type ep,
-        beast::http::request<Body, Fields>&& req)
+        beast::http::request<Body>&& req)
     {
         std::make_shared<async_ws_con>(
             std::move(sock),

example/server-framework/ws_sync_port.hpp

@@ -93,9 +93,9 @@ public:
 
     // Run the connection from an already-received Upgrade request.
     //
-    template<class Body, class Fields>
+    template<class Body>
     void
-    run(beast::http::request<Body, Fields>&& req)
+    run(beast::http::request<Body>&& req)
     {
         BOOST_ASSERT(beast::websocket::is_upgrade(req));
 
@@ -104,7 +104,7 @@ public:
         // so we have to write it out by manually specifying the lambda.
         //
         std::thread{
-            lambda<Body, Fields>{
+            lambda<Body>{
                 impl().shared_from_this(),
                 std::move(req)
         }}.detach();
@@ -168,11 +168,11 @@ private:
     // we write out the lambda ourselves. This is similar to what
     // the compiler would generate anyway.
     //
-    template<class Body, class Fields>
+    template<class Body>
     class lambda
     {
         std::shared_ptr<sync_ws_con_base> self_;
-        beast::http::request<Body, Fields> req_;
+        beast::http::request<Body> req_;
         
     public:
         // Constructor
@@ -181,7 +181,7 @@ private:
         //
         lambda(
             std::shared_ptr<sync_ws_con_base> self,
-            beast::http::request<Body, Fields>&& req)
+            beast::http::request<Body>&& req)
             : self_(std::move(self))
             , req_(std::move(req))
         {
@@ -407,12 +407,12 @@ public:
 
         @param req The upgrade request.
     */
-    template<class Body, class Fields>
+    template<class Body>
     void
     on_upgrade(
         socket_type&& sock,
         endpoint_type ep,
-        beast::http::request<Body, Fields>&& req)
+        beast::http::request<Body>&& req)
     {
         // Create the connection object and run it,
         // transferring ownership of the ugprade request.

example/server-framework/ws_upgrade_service.hpp

@@ -67,13 +67,13 @@ public:
     */
     template<
         class Stream,
-        class Body, class Fields,
+        class Body,
         class Send>
     bool
     respond(
         Stream&& stream,
         endpoint_type const& ep,
-        beast::http::request<Body, Fields>&& req,
+        beast::http::request<Body>&& req,
         Send const&) const
     {
         // If its not an upgrade request, return `false`

example/server-framework/wss_ports.hpp

@@ -291,12 +291,12 @@ public:
 
         @param req The upgrade request.
     */
-    template<class Body, class Fields>
+    template<class Body>
     void
     on_upgrade(
         ssl_stream<socket_type>&& stream,
         endpoint_type ep,
-        beast::http::request<Body, Fields>&& req)
+        beast::http::request<Body>&& req)
     {
         // Create the connection object and run it,
         // transferring ownership of the ugprade request.
@@ -415,12 +415,12 @@ public:
 
         @param req The upgrade request.
     */
-    template<class Body, class Fields>
+    template<class Body>
     void
     on_upgrade(
         ssl_stream<socket_type>&& stream,
         endpoint_type ep,
-        beast::http::request<Body, Fields>&& req)
+        beast::http::request<Body>&& req)
     {
         std::make_shared<async_wss_con>(
             std::move(stream),