Add SSLContext to StreamServer et al

fixes #901

src/gevent/server.py

@@ -20,8 +20,18 @@ class StreamServer(BaseServer):
     """A generic TCP server. Accepts connections on a listening socket and spawns user-provided *handle*
     for each connection with 2 arguments: the client socket and the client address.
 
-    If any of the following keyword arguments are present, then the server assumes SSL mode and uses these arguments
-    to create an SSL wrapper for the client socket before passing it to *handle*:
+    Server can assume an SSL mode via either direct client socket wrapper initialization or socket wrapping via an
+    :class:`SSLContext`.
+
+    If *ssl_context* keyword argument is present, it should contain an :class:`SSLContext`. The following keyword
+    arguments may be used SSLContext mode (subject to Python API version):
+
+    - server_hostname
+    - suppress_ragged_eofs
+    - do_handshake_on_connect
+
+    Otherwise, if any of the following keyword arguments are present, then the server assumes SSL mode and uses these
+    arguments to create an SSL wrapper for the client socket before passing it to *handle*:
 
     - keyfile
     - certfile
@@ -51,9 +61,14 @@ class StreamServer(BaseServer):
         try:
             if ssl_args:
                 ssl_args.setdefault('server_side', True)
-                from gevent.ssl import wrap_socket
-                self.wrap_socket = wrap_socket
-                self.ssl_args = ssl_args
+                if 'ssl_context' in ssl_args:
+                    ssl_context = ssl_args.pop('ssl_context')
+                    self.wrap_socket = ssl_context.wrap_socket
+                    self.ssl_args = ssl_args
+                else:
+                    from gevent.ssl import wrap_socket
+                    self.wrap_socket = wrap_socket
+                    self.ssl_args = ssl_args
             else:
                 self.ssl_args = None
             if backlog is not None:

src/greentest/test__pywsgi.py

@@ -19,7 +19,9 @@
 # THE SOFTWARE.
 # pylint: disable=too-many-lines,unused-argument
 from __future__ import print_function
+
 from gevent import monkey
+
 monkey.patch_all(thread=False)
 
 try:
@@ -740,6 +742,13 @@ class HttpsTestCase(TestCase):
         return [environ['wsgi.input'].read(10)]
 
 
+class HttpsSslContextTestCase(HttpsTestCase):
+    def init_server(self, application):
+        from ssl import create_default_context
+        context = create_default_context()
+        context.load_cert_chain(certfile=self.certfile, keyfile=self.keyfile)
+        self.server = pywsgi.WSGIServer(('127.0.0.1', 0), application, ssl_context=context)
+
 class TestHttps(HttpsTestCase):
 
     if hasattr(socket, 'ssl'):
@@ -752,6 +761,8 @@ class TestHttps(HttpsTestCase):
             result = self.urlopen()
             self.assertEquals(result.body, '')
 
+class TestHttpsWithContext(HttpsSslContextTestCase, TestHttps):
+    pass
 
 class TestInternational(TestCase):
     validator = None  # wsgiref.validate.IteratorWrapper([]) does not have __len__