Explicitly close response iterators when finished with them; this should help us clean up memory sooner when the iterators aren't fully consumed. Fixes #1314.

3 files changed, 36 insertions, 6 deletions

diff --git a/cherrypy/_cpwsgi.py b/cherrypy/_cpwsgi.py
index 4d1fd704..aaec99f7 100644
--- a/cherrypy/_cpwsgi.py
+++ b/cherrypy/_cpwsgi.py
@@ -13,7 +13,7 @@ import cherrypy as _cherrypy
 from cherrypy._cpcompat import BytesIO, bytestr, ntob, ntou, py3k, unicodestr
 from cherrypy import _cperror
 from cherrypy.lib import httputil
-
+from cherrypy.lib import is_closable_iterator
 
 def downgrade_wsgi_ux_to_1x(environ):
     """Return a new environ dict for WSGI 1.x from the given WSGI u.x environ.
@@ -279,6 +279,8 @@ class AppResponse(object):
     def close(self):
         """Close and de-reference the current request and response. (Core)"""
         self.cpapp.release_serving()
+        if is_closable_iterator(self.iter_response):
+            self.iter_response.close()
 
     def run(self):
         """Create a Request object using environ."""
diff --git a/cherrypy/lib/__init__.py b/cherrypy/lib/__init__.py
index 2c851ec4..a75a53da 100644
--- a/cherrypy/lib/__init__.py
+++ b/cherrypy/lib/__init__.py
@@ -16,6 +16,29 @@ def is_iterator(obj):
         # Types which implement the protocol must return themselves when
         # invoking 'iter' upon them.
         return iter(obj) is obj
+        
+def is_closable_iterator(obj):
+    
+    # Not an iterator.
+    if not is_iterator(obj):
+        return False
+    
+    # A generator - the easiest thing to deal with.
+    import inspect
+    if inspect.isgenerator(obj):
+        return True
+    
+    # A custom iterator. Look for a close method...
+    if not (hasattr(obj, 'close') and callable(obj.close)):
+        return False
+    
+    #  ... which doesn't require any arguments.
+    try:
+        inspect.getcallargs(obj.close)
+    except TypeError:
+        return False
+    else:
+        return True
 
 class file_generator(object):
 
diff --git a/cherrypy/lib/encoding.py b/cherrypy/lib/encoding.py
index 6d54ac8c..fa8387b6 100644
--- a/cherrypy/lib/encoding.py
+++ b/cherrypy/lib/encoding.py
@@ -4,6 +4,7 @@ import time
 import cherrypy
 from cherrypy._cpcompat import basestring, BytesIO, ntob, set, unicodestr
 from cherrypy.lib import file_generator
+from cherrypy.lib import is_closable_iterator
 from cherrypy.lib import set_vary_header
 
 
@@ -32,23 +33,27 @@ def decode(encoding=None, default_encoding='utf-8'):
         if not isinstance(default_encoding, list):
             default_encoding = [default_encoding]
         body.attempt_charsets = body.attempt_charsets + default_encoding
-        
+
 class UTF8StreamEncoder:
     def __init__(self, iterator):
         self._iterator = iterator
-        
+
     def __iter__(self):
         return self
-        
+
     def next(self):
         return self.__next__()
-        
+
     def __next__(self):
         res = next(self._iterator)
         if isinstance(res, unicodestr):
             res = res.encode('utf-8')
         return res
-        
+
+    def close(self):
+        if is_closable_iterator(self._iterator)
+            self._iterator.close()
+
     def __getattr__(self, attr):
         if attr.startswith('__'):
             raise AttributeError(self, attr)