Add read, async_read for message_headers:

fix #172, fix #173

This provides overloads of read and async_read to allow
reading message_headers objects.

CHANGELOG.md

@@ -4,6 +4,7 @@ HTTP
 
 * Make chunk_encode public
 * Add write, async_write, operator<< for message_headers
+* Add read, async_read for message_headers
 
 WebSocket
 

include/beast/http/impl/read.ipp

@@ -9,6 +9,7 @@
 #define BEAST_HTTP_IMPL_READ_IPP_HPP
 
 #include <beast/http/concepts.hpp>
+#include <beast/http/headers_parser_v1.hpp>
 #include <beast/http/parse.hpp>
 #include <beast/http/parser_v1.hpp>
 #include <beast/core/bind_handler.hpp>
@@ -21,6 +22,185 @@ namespace http {
 
 namespace detail {
 
+template<class Stream, class DynamicBuffer,
+    bool isRequest, class Headers,
+        class Handler>
+class read_headers_op
+{
+    using alloc_type =
+        handler_alloc<char, Handler>;
+
+    using parser_type =
+        headers_parser_v1<isRequest, Headers>;
+
+    using message_type =
+        message_headers<isRequest, Headers>;
+
+    struct data
+    {
+        Stream& s;
+        DynamicBuffer& db;
+        message_type& m;
+        parser_type p;
+        Handler h;
+        bool started = false;
+        bool cont;
+        int state = 0;
+
+        template<class DeducedHandler>
+        data(DeducedHandler&& h_, Stream& s_,
+                DynamicBuffer& sb_, message_type& m_)
+            : s(s_)
+            , db(sb_)
+            , m(m_)
+            , h(std::forward<DeducedHandler>(h_))
+            , cont(boost_asio_handler_cont_helpers::
+                is_continuation(h))
+        {
+        }
+    };
+
+    std::shared_ptr<data> d_;
+
+public:
+    read_headers_op(read_headers_op&&) = default;
+    read_headers_op(read_headers_op const&) = default;
+
+    template<class DeducedHandler, class... Args>
+    read_headers_op(
+            DeducedHandler&& h, Stream& s, Args&&... args)
+        : d_(std::allocate_shared<data>(alloc_type{h},
+            std::forward<DeducedHandler>(h), s,
+                std::forward<Args>(args)...))
+    {
+        (*this)(error_code{}, false);
+    }
+
+    void
+    operator()(error_code ec, bool again = true);
+
+    friend
+    void* asio_handler_allocate(
+        std::size_t size, read_headers_op* op)
+    {
+        return boost_asio_handler_alloc_helpers::
+            allocate(size, op->d_->h);
+    }
+
+    friend
+    void asio_handler_deallocate(
+        void* p, std::size_t size, read_headers_op* op)
+    {
+        return boost_asio_handler_alloc_helpers::
+            deallocate(p, size, op->d_->h);
+    }
+
+    friend
+    bool asio_handler_is_continuation(read_headers_op* op)
+    {
+        return op->d_->cont;
+    }
+
+    template<class Function>
+    friend
+    void asio_handler_invoke(Function&& f, read_headers_op* op)
+    {
+        return boost_asio_handler_invoke_helpers::
+            invoke(f, op->d_->h);
+    }
+};
+
+template<class Stream, class DynamicBuffer,
+    bool isRequest, class Headers,
+        class Handler>
+void
+read_headers_op<Stream, DynamicBuffer, isRequest, Headers, Handler>::
+operator()(error_code ec, bool again)
+{
+    auto& d = *d_;
+    d.cont = d.cont || again;
+    while(! ec && d.state != 99)
+    {
+        switch(d.state)
+        {
+        case 0:
+            d.state = 1;
+            async_parse(d.s, d.db, d.p, std::move(*this));
+            return;
+
+        case 1:
+            // call handler
+            d.state = 99;
+            d.m = d.p.release();
+            break;
+        }
+    }
+    d.h(ec);
+}
+
+} // detail
+
+template<class SyncReadStream, class DynamicBuffer,
+    bool isRequest, class Headers>
+void
+read(SyncReadStream& stream, DynamicBuffer& dynabuf,
+    message_headers<isRequest, Headers>& msg)
+{
+    static_assert(is_SyncReadStream<SyncReadStream>::value,
+        "SyncReadStream requirements not met");
+    static_assert(is_DynamicBuffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    error_code ec;
+    beast::http::read(stream, dynabuf, msg, ec);
+    if(ec)
+        throw system_error{ec};
+}
+
+template<class SyncReadStream, class DynamicBuffer,
+    bool isRequest, class Headers>
+void
+read(SyncReadStream& stream, DynamicBuffer& dynabuf,
+    message_headers<isRequest, Headers>& m,
+        error_code& ec)
+{
+    static_assert(is_SyncReadStream<SyncReadStream>::value,
+        "SyncReadStream requirements not met");
+    static_assert(is_DynamicBuffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    headers_parser_v1<isRequest, Headers> p;
+    beast::http::parse(stream, dynabuf, p, ec);
+    if(ec)
+        return;
+    BOOST_ASSERT(p.complete());
+    m = p.release();
+}
+
+template<class AsyncReadStream, class DynamicBuffer,
+    bool isRequest, class Headers,
+        class ReadHandler>
+typename async_completion<
+    ReadHandler, void(error_code)>::result_type
+async_read(AsyncReadStream& stream, DynamicBuffer& dynabuf,
+    message_headers<isRequest, Headers>& m,
+        ReadHandler&& handler)
+{
+    static_assert(is_AsyncReadStream<AsyncReadStream>::value,
+        "AsyncReadStream requirements not met");
+    static_assert(is_DynamicBuffer<DynamicBuffer>::value,
+        "DynamicBuffer requirements not met");
+    beast::async_completion<ReadHandler,
+        void(error_code)> completion(handler);
+    detail::read_headers_op<AsyncReadStream, DynamicBuffer,
+        isRequest, Headers, decltype(
+            completion.handler)>{completion.handler,
+                stream, dynabuf, m};
+    return completion.result.get();
+}
+
+//------------------------------------------------------------------------------
+
+namespace detail {
+
 template<class Stream, class DynamicBuffer,
     bool isRequest, class Body, class Headers,
         class Handler>
@@ -138,8 +318,6 @@ operator()(error_code ec, bool again)
 
 } // detail
 
-//------------------------------------------------------------------------------
-
 template<class SyncReadStream, class DynamicBuffer,
     bool isRequest, class Body, class Headers>
 void

include/beast/http/parse.hpp

@@ -106,8 +106,10 @@ parse(SyncReadStream& stream,
     This operation is implemented in terms of one or more calls to
     the next layer's `async_read_some` function, and is known as a
     <em>composed operation</em>. The program must ensure that the
-    stream performs no other operations until this operation
+    stream performs no other operations until this operation completes.
-    completes.
+    The implementation may read additional octets that lie past the
+    end of the object being parsed. This additional data is stored
+    in the stream buffer, which may be used in subsequent calls.
 
     @param stream The stream from which the data is to be read.
     The type must support the @b AsyncReadStream concept.

include/beast/http/read.hpp

@@ -15,6 +15,144 @@
 namespace beast {
 namespace http {
 
+/** Read HTTP/1 message headers from a stream.
+
+    This function is used to synchronously read message headers from
+    the stream. The call blocks until one of the following conditions
+    is true:
+
+    @li The complete message headers are read in.
+
+    @li An error occurs in the stream or parser.
+
+    This function is implemented in terms of one or more calls
+    to the stream's `read_some` function. The implementation may
+    read additional octets that lie past the end of the message
+    headers being parsed. This additional data is stored in the
+    stream buffer, which may be used in subsequent calls.
+
+    @param stream The stream from which the data is to be read.
+    The type must support the @b `SyncReadStream` concept.
+
+    @param dynabuf A @b `DynamicBuffer` holding additional bytes
+    read by the implementation from the stream. This is both
+    an input and an output parameter; on entry, any data in the
+    stream buffer's input sequence will be given to the parser
+    first.
+
+    @param msg An object used to store the message headers.
+    Any contents will be overwritten. The type must support
+    copy assignment or move assignment.
+
+    @throws system_error Thrown on failure.
+*/
+template<class SyncReadStream, class DynamicBuffer,
+    bool isRequest, class Headers>
+void
+read(SyncReadStream& stream, DynamicBuffer& dynabuf,
+    message_headers<isRequest, Headers>& msg);
+
+/** Read HTTP/1 message headers from a stream.
+
+    This function is used to synchronously read message headers from
+    the stream. The call blocks until one of the following conditions
+    is true:
+
+    @li The complete message headers are read in.
+
+    @li An error occurs in the stream or parser.
+
+    This function is implemented in terms of one or more calls
+    to the stream's `read_some` function. The implementation may
+    read additional octets that lie past the end of the message
+    headers being parsed. This additional data is stored in the
+    stream buffer, which may be used in subsequent calls.
+
+    If the message being received contains a message body, it
+    is the callers responsibility to cause the body to be read
+    in before attempting to read the next message.
+
+    @param stream The stream from which the data is to be read.
+    The type must support the @b `SyncReadStream` concept.
+
+    @param dynabuf A @b `DynamicBuffer` holding additional bytes
+    read by the implementation from the stream. This is both
+    an input and an output parameter; on entry, any data in the
+    stream buffer's input sequence will be given to the parser
+    first.
+
+    @param msg An object used to store the message headers.
+    Any contents will be overwritten. The type must support
+    copy assignment or move assignment.
+
+    @param ec Set to the error, if any occurred.
+*/
+template<class SyncReadStream, class DynamicBuffer,
+    bool isRequest, class Headers>
+void
+read(SyncReadStream& stream, DynamicBuffer& dynabuf,
+    message_headers<isRequest, Headers>& msg,
+        error_code& ec);
+
+/** Start an asynchronous operation to read HTTP/1 message headers from a stream.
+
+    This function is used to asynchronously read a message from the
+    stream. The function call always returns immediately. The asynchronous
+    operation will continue until one of the following conditions is true:
+
+    @li A complete message is read in.
+
+    @li An error occurs in the stream or parser.
+
+    This operation is implemented in terms of one or more calls to
+    the next layer's `async_read_some` function, and is known as a
+    <em>composed operation</em>. The program must ensure that the
+    stream performs no other operations until this operation completes.
+    The implementation may read additional octets that lie past the
+    end of the message headers being parsed. This additional data is
+    stored in the stream buffer, which may be used in subsequent calls.
+
+    If the message being received contains a message body, it
+    is the callers responsibility to cause the body to be read
+    in before attempting to read the next message.
+
+    @param stream The stream to read the message from.
+    The type must support the @b `AsyncReadStream` concept.
+
+    @param dynabuf A @b `DynamicBuffer` holding additional bytes
+    read by the implementation from the stream. This is both
+    an input and an output parameter; on entry, any data in the
+    stream buffer's input sequence will be given to the parser
+    first.
+
+    @param msg An object used to store the message. Any contents
+    will be overwritten. The type must support copy assignment or
+    move assignment.
+
+    @param handler The handler to be called when the request completes.
+    Copies will be made of the handler as required. The equivalent
+    function signature of the handler must be:
+    @code void handler(
+        error_code const& error // result of operation
+    ); @endcode
+    Regardless of whether the asynchronous operation completes
+    immediately or not, the handler will not be invoked from within
+    this function. Invocation of the handler will be performed in a
+    manner equivalent to using `boost::asio::io_service::post`.
+*/
+template<class AsyncReadStream, class DynamicBuffer,
+    bool isRequest, class Body, class Headers,
+        class ReadHandler>
+#if GENERATING_DOCS
+void_or_deduced
+#else
+typename async_completion<
+    ReadHandler, void(error_code)>::result_type
+#endif
+async_read(AsyncReadStream& stream, DynamicBuffer& dynabuf,
+    message_headers<isRequest, Headers>& msg,
+        ReadHandler&& handler);
+
 /** Read a HTTP/1 message from a stream.
 
     This function is used to synchronously read a message from
@@ -41,7 +179,8 @@ namespace http {
     first.
 
     @param msg An object used to store the message. Any
-    contents will be overwritten.
+    contents will be overwritten. The type must support
+    copy assignment or move assignment.
 
     @throws system_error Thrown on failure.
 */
@@ -77,7 +216,8 @@ read(SyncReadStream& stream, DynamicBuffer& dynabuf,
     first.
 
     @param msg An object used to store the message. Any
-    contents will be overwritten.
+    contents will be overwritten. The type must support
+    copy assignment or move assignment.
 
     @param ec Set to the error, if any occurred.
 */
@@ -98,10 +238,13 @@ read(SyncReadStream& stream, DynamicBuffer& dynabuf,
 
     @li An error occurs in the stream or parser.
 
-    This operation is implemented in terms of one or more calls to the
+    This operation is implemented in terms of one or more calls to
-    next layer's `async_read_some` function, and is known as a
+    the next layer's `async_read_some` function, and is known as a
-    <em>composed operation</em>. The program must ensure that the stream
+    <em>composed operation</em>. The program must ensure that the
-    performs no other operations until this operation completes.
+    stream performs no other operations until this operation completes.
+    The implementation may read additional octets that lie past the
+    end of the message being parsed. This additional data is stored
+    in the stream buffer, which may be used in subsequent calls.
 
     @param stream The stream to read the message from.
     The type must support the @b `AsyncReadStream` concept.
@@ -113,7 +256,8 @@ read(SyncReadStream& stream, DynamicBuffer& dynabuf,
     first.
 
     @param msg An object used to store the message. Any contents
-    will be overwritten.
+    will be overwritten. The type must support copy assignment or
+    move assignment.
 
     @param handler The handler to be called when the request completes.
     Copies will be made of the handler as required. The equivalent

test/http/read.cpp

@@ -244,6 +244,52 @@ public:
             failMatrix<false>(res[i], do_yield);
     }
 
+    void testReadHeaders(yield_context do_yield)
+    {
+        static std::size_t constexpr limit = 100;
+        std::size_t n;
+
+        for(n = 0; n < limit; ++n)
+        {
+            test::fail_stream<test::string_stream> fs{n, ios_,
+                "GET / HTTP/1.1\r\n"
+                "Host: localhost\r\n"
+                "User-Agent: test\r\n"
+                "Content-Length: 5\r\n"
+                "\r\n"
+            };
+            request_headers m;
+            try
+            {
+                streambuf sb;
+                read(fs, sb, m);
+                break;
+            }
+            catch(std::exception const&)
+            {
+            }
+        }
+        BEAST_EXPECT(n < limit);
+
+        for(n = 0; n < limit; ++n)
+        {
+            test::fail_stream<test::string_stream> fs(n, ios_,
+                "GET / HTTP/1.1\r\n"
+                "Host: localhost\r\n"
+                "User-Agent: test\r\n"
+                "Content-Length: 0\r\n"
+                "\r\n"
+            );
+            request_headers m;
+            error_code ec;
+            streambuf sb;
+            async_read(fs, sb, m, do_yield[ec]);
+            if(! ec)
+                break;
+        }
+        BEAST_EXPECT(n < limit);
+    }
+
     void testRead(yield_context do_yield)
     {
         static std::size_t constexpr limit = 100;
@@ -335,6 +381,9 @@ public:
         yield_to(std::bind(&read_test::testFailures,
             this, std::placeholders::_1));
 
+        yield_to(std::bind(&read_test::testReadHeaders,
+            this, std::placeholders::_1));
+
         yield_to(std::bind(&read_test::testRead,
             this, std::placeholders::_1));