Index: Misc/NEWS
===================================================================
--- Misc/NEWS	(revision 65550)
+++ Misc/NEWS	(working copy)
@@ -41,6 +41,8 @@
 Library
 -------
 
+- Issue#1346874: Added 100-continue support to httplib
+
 - Changed code in the following modules/packages to remove warnings raised
   while running under the ``-3`` flag: aifc, asyncore, bdb, bsddb,
   ConfigParser, cookielib, DocXMLRPCServer, email, filecmp, fileinput, inspect,
Index: Doc/library/httplib.rst
===================================================================
--- Doc/library/httplib.rst	(revision 65550)
+++ Doc/library/httplib.rst	(working copy)
@@ -84,6 +84,8 @@
 
    .. versionadded:: 2.0
 
+   .. versionchanged:: 2.6
+      *ignore_continue* was added.
 The following exceptions are raised as appropriate:
 
 
@@ -95,6 +97,13 @@
    .. versionadded:: 2.0
 
 
+.. exception:: ExpectationFailed
+
+   A subclass of :exc:`HTTPException`, raised if a server returns a 417
+   (Expectation Failed) after sending an Expect: 100-continue header
+
+   .. versionadded:: 2.6
+
 .. exception:: NotConnected
 
    A subclass of :exc:`HTTPException`.
@@ -415,6 +424,9 @@
    Should be called after a request is sent to get the response from the server.
    Returns an :class:`HTTPResponse` instance.
 
+   .. versionchanged:: 2.6
+      *ignore_continue* was added.
+
    .. note::
 
       Note that you must have read the whole response before you can send a new
Index: Lib/httplib.py
===================================================================
--- Lib/httplib.py	(revision 65550)
+++ Lib/httplib.py	(working copy)
@@ -320,11 +320,13 @@
 
     # See RFC 2616 sec 19.6 and RFC 1945 sec 6 for details.
 
-    def __init__(self, sock, debuglevel=0, strict=0, method=None):
+    def __init__(self, sock, debuglevel=0, strict=0, method=None,
+                 ignore_continue=True):
         self.fp = sock.makefile('rb', 0)
         self.debuglevel = debuglevel
         self.strict = strict
         self._method = method
+        self.ignore_continue = ignore_continue
 
         self.msg = None
 
@@ -380,19 +382,21 @@
             # we've already started reading the response
             return
 
-        # read until we get a non-100 response
-        while True:
-            version, status, reason = self._read_status()
-            if status != CONTINUE:
-                break
-            # skip the header from the 100 response
+        if self.ignore_continue:
+            # read until we get a non-100 response
             while True:
-                skip = self.fp.readline().strip()
-                if not skip:
+                version, status, reason = self._read_status()
+                if status != CONTINUE:
                     break
-                if self.debuglevel > 0:
-                    print "header:", skip
-
+                # skip the header from the 100 response
+                while True:
+                    skip = self.fp.readline().strip()
+                    if not skip:
+                        break
+                    if self.debuglevel > 0:
+                        print "header:", skip
+        else:
+            version, status, reason = self._read_status()
         self.status = status
         self.reason = reason.strip()
         if version == 'HTTP/1.0':
@@ -883,6 +887,11 @@
         if 'accept-encoding' in header_names:
             skips['skip_accept_encoding'] = 1
 
+        expect_continue = False
+        for hdr, val in headers.iteritems():
+            if 'expect' == hdr.lower() and '100-continue' in val.lower():
+                expect_continue = True
+        
         self.putrequest(method, url, **skips)
 
         if body and ('content-length' not in header_names):
@@ -905,10 +914,23 @@
             self.putheader(hdr, value)
         self.endheaders()
 
+        # If an Expect: 100-continue was sent, we need to check for a 417
+        # Expectation Failed to avoid unecessarily sending the body
+        # See RFC 2616 8.2.3
+        if expect_continue:
+            if not body:
+                raise HTTPException("A body is required when expecting "
+                                    "100-continue")
+            resp = self.getresponse(ignore_continue=False)
+            resp.read()
+            self.__state = _CS_REQ_SENT
+            if resp.status == EXPECTATION_FAILED:
+                raise ExpectationFailed
+        
         if body:
             self.send(body)
 
-    def getresponse(self):
+    def getresponse(self, ignore_continue=True):
         "Get the response from the server."
 
         # if a prior response has been completed, then forget about it.
@@ -937,10 +959,12 @@
         if self.debuglevel > 0:
             response = self.response_class(self.sock, self.debuglevel,
                                            strict=self.strict,
-                                           method=self._method)
+                                           method=self._method,
+                                           ignore_continue=ignore_continue)
         else:
             response = self.response_class(self.sock, strict=self.strict,
-                                           method=self._method)
+                                           method=self._method,
+                                           ignore_continue=ignore_continue)
 
         response.begin()
         assert response.will_close != _UNKNOWN
@@ -1107,6 +1131,9 @@
     # or define self.args.  Otherwise, str() will fail.
     pass
 
+class ExpectationFailed(HTTPException):
+    pass
+
 class NotConnected(HTTPException):
     pass
 
Index: Lib/test/test_httplib.py
===================================================================
--- Lib/test/test_httplib.py	(revision 65550)
+++ Lib/test/test_httplib.py	(working copy)
@@ -22,6 +22,9 @@
             raise httplib.UnimplementedFileMode()
         return self.fileclass(self.text)
 
+    def close(self):
+        pass
+
 class NoEOFStringIO(StringIO.StringIO):
     """Like StringIO, but raises AssertionError on EOF.
 
@@ -73,6 +76,32 @@
                 conn.request('POST', '/', body, headers)
                 self.assertEqual(conn._buffer.count[header.lower()], 1)
 
+
+class OneHundredContinueTests(TestCase):
+    def test_continue_sent(self):
+        body = "HTTP/1.1 100 Continue\r\n\r\n"
+        conn = httplib.HTTPConnection('example.com')
+        sock = FakeSocket(body)
+        conn.sock = sock
+
+        body = 'testdata'
+        headers = {'Expect': '100-continue'}
+        conn.request(method='GET', url='/foo', body=body, headers=headers)
+        self.assertTrue(body in sock.data)
+
+    def test_expectation_failed(self):
+        body = "HTTP/1.1 417 Expectation Failed\r\n\r\n"
+        conn = httplib.HTTPConnection('example.com')
+        sock = FakeSocket(body)
+        conn.sock = sock
+
+        body = 'testdata'
+        headers = {'Expect': '100-continue'}
+        self.assertRaises(httplib.ExpectationFailed, conn.request,
+            method='GET', url='/foo', body=body, headers=headers)
+        self.assertTrue(body not in sock.data)
+
+
 class BasicTest(TestCase):
     def test_status_lines(self):
         # Test HTTP status lines
@@ -90,7 +119,7 @@
         self.assertRaises(httplib.BadStatusLine, resp.begin)
 
     def test_partial_reads(self):
-        # if we have a lenght, the system knows when to close itself
+        # if we have a length, the system knows when to close itself
         # same behaviour than when we read the whole thing with read()
         body = "HTTP/1.1 200 Ok\r\nContent-Length: 4\r\n\r\nText"
         sock = FakeSocket(body)
@@ -255,7 +284,7 @@
 
 def test_main(verbose=None):
     test_support.run_unittest(HeaderTests, OfflineTest, BasicTest, TimeoutTest,
-                              HTTPSTimeoutTest)
+                              HTTPSTimeoutTest, OneHundredContinueTests)
 
 if __name__ == '__main__':
     test_main()