diff --git a/ChangeLog b/ChangeLog
index 400be6f252..19c33a02d6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Fri Sep 10 19:11:13 2010  NAKAMURA, Hiroshi  <nahi@ruby-lang.org>
+
+	* lib/webrick/httprequest.rb (WEBrick::HTTPRequest#continue): add
+	  method for generating HTTP/1.1 100 continue response if the client
+	  expects it, otherwise does nothing.  Patch by Brian Candler.
+	  ref #855.
+
+	* test/webrick/test_httprequest.rb: test added.
+
 Fri Sep 10 17:49:34 2010  NAKAMURA, Hiroshi  <nahi@ruby-lang.org>
 
 	* ext/openssl/lib/openssl/x509-internal.rb: removed unused local
diff --git a/NEWS b/NEWS
index 92b519234b..97ef5c596f 100644
--- a/NEWS
+++ b/NEWS
@@ -46,6 +46,10 @@ with all sufficient information, see the ChangeLog file.
     * IO#winsize
     * IO.console
 
+* webrick
+  * new method:
+    * WEBrick::HTTPRequest#continue for generating '100 continue' response.
+
 === Compatibility issues (excluding feature bug fixes)
 
 * Kernel#respond_to?
diff --git a/lib/webrick/httprequest.rb b/lib/webrick/httprequest.rb
index 28be9fd790..75d26b529a 100644
--- a/lib/webrick/httprequest.rb
+++ b/lib/webrick/httprequest.rb
@@ -122,6 +122,15 @@ module WEBrick
       end
     end
 
+    # Generate HTTP/1.1 100 continue response if the client expects it,
+    # otherwise does nothing.
+    def continue
+      if self['expect'] == '100-continue' && @config[:HTTPVersion] >= "1.1"
+        @socket << "HTTP/#{@config[:HTTPVersion]} 100 continue#{CRLF}#{CRLF}"
+        @header.delete('expect')
+      end
+    end
+
     def body(&block)
       block ||= Proc.new{|chunk| @body << chunk }
       read_body(@socket, block)
diff --git a/test/webrick/test_httprequest.rb b/test/webrick/test_httprequest.rb
index 4a1db38bca..7869c21795 100644
--- a/test/webrick/test_httprequest.rb
+++ b/test/webrick/test_httprequest.rb
@@ -305,6 +305,37 @@ class TestWEBrickHTTPRequest < Test::Unit::TestCase
     assert(req.ssl?)
   end
 
+  def test_continue_sent
+    msg = <<-_end_of_message_
+      POST /path HTTP/1.1
+      Expect: 100-continue
+      
+    _end_of_message_
+    msg.gsub!(/^ {6}/, "")
+    req = WEBrick::HTTPRequest.new(WEBrick::Config::HTTP)
+    req.parse(StringIO.new(msg))
+    assert req['expect']
+    l = msg.size
+    req.continue
+    assert_not_equal l, msg.size
+    assert_match /HTTP\/1.1 100 continue\r\n\r\n\z/, msg
+    assert !req['expect']
+  end
+
+  def test_continue_not_sent
+    msg = <<-_end_of_message_
+      POST /path HTTP/1.1
+      
+    _end_of_message_
+    msg.gsub!(/^ {6}/, "")
+    req = WEBrick::HTTPRequest.new(WEBrick::Config::HTTP)
+    req.parse(StringIO.new(msg))
+    assert !req['expect']
+    l = msg.size
+    req.continue
+    assert_equal l, msg.size
+  end
+
   def test_bad_messages
     param = "foo=1;foo=2;foo=3;bar=x"
     msg = <<-_end_of_message_