when creating Response.body from app_iter handle content_length w/ mo…

…re case

tests/test_response.py

@@ -1,5 +1,5 @@
 from StringIO import StringIO
-from nose.tools import eq_, ok_
+from nose.tools import eq_, ok_, assert_raises
 from webob import *
 
 def simple_app(environ, start_response):
@@ -48,6 +48,38 @@ def test_HEAD_closes():
     eq_(res.body, '')
     ok_(app_iter.closed)
 
+def test_content_length():
+    r0 = Response('x'*10, content_length=10)
+
+    req_head = Request.blank('/', method='HEAD')
+    r1 = req_head.get_response(r0)
+    eq_(r1.status_int, 200)
+    eq_(r1.body, '')
+    eq_(r1.content_length, 10)
+
+    req_get = Request.blank('/')
+    r2 = req_get.get_response(r0)
+    eq_(r2.status_int, 200)
+    eq_(r2.body, 'x'*10)
+    eq_(r2.content_length, 10)
+
+    r3 = Response(app_iter=['x']*10)
+    eq_(r3.content_length, None)
+    eq_(r3.body, 'x'*10)
+    eq_(r3.content_length, 10)
+
+    r4 = Response(app_iter=['x']*10, content_length=20) # wrong content_length
+    eq_(r4.content_length, 20)
+    assert_raises(AssertionError, lambda: r4.body)
+
+    req_range = Request.blank('/', range=(0,5))
+    r0.conditional_response = True
+    r5 = req_range.get_response(r0)
+    eq_(r5.status_int, 206)
+    eq_(r5.body, 'xxxxx')
+    eq_(r5.content_length, 5)
+
+
 def test_app_iter_range():
     req = Request.blank('/', range=(2,5))
     for app_iter in [

webob/response.py

@@ -292,9 +292,9 @@ def _content_type_params__del(self, value):
         self.headers['Content-Type'] = self.headers.get('Content-Type', '').split(';', 1)[0]
 
     content_type_params = property(
-    _content_type_params__get, 
-        _content_type_params__set, 
-        _content_type_params__del, 
+        _content_type_params__get,
+        _content_type_params__set,
+        _content_type_params__del,
         doc=_content_type_params__get.__doc__
     )
 
@@ -321,15 +321,25 @@ def _body__get(self):
         """
         if self._body is None:
             if self._app_iter is None:
-                raise AttributeError(
-                    "No body has been set")
+                raise AttributeError("No body has been set")
             try:
-                self._body = ''.join(self._app_iter)
+                body = self._body = ''.join(self._app_iter)
             finally:
                 if hasattr(self._app_iter, 'close'):
                     self._app_iter.close()
             self._app_iter = None
-            self.content_length = len(self._body)
+            if self._request is not None and self._request.method == 'HEAD':
+                assert len(body) == 0, "HEAD responses must be empty"
+            elif len(body) == 0:
+                # if body-length is zero, we assume it's a HEAD response and leave content_lenght alone
+                pass
+            elif self.content_length is None:
+                self.content_length = len(body)
+            elif self.content_length != len(body):
+                raise AssertionError(
+                    "Content-Length is different from actual app_iter length (%r!=%r)"
+                    % (self.content_length, len(body))
+                )
         return self._body
 
     def _body__set(self, value):