I get the following error whenever I want to test a 404 HTTP error path in my code:
AssertionError: Content-Length is different from actual app_iter length (512!=60)
I have created a minimal sample that triggers this behavior:
import unittest
import endpoints
from protorpc import remote
from protorpc.message_types import VoidMessage
import webtest
@endpoints.api(name='test', version='v1')
class HelloWorld(remote.Service):
@endpoints.method(VoidMessage, VoidMessage,
path='test_path', http_method='POST',
name='test_name')
def test(self, request):
raise endpoints.NotFoundException("Not found")
class AppTest(unittest.TestCase):
def setUp(self):
app = endpoints.api_server([HelloWorld])
self.testapp = webtest.TestApp(app)
# Test the handler.
def testHelloWorldHandler(self):
response = self.testapp.post('/_ah/spi/HelloWorld.test', extra_environ={
'SERVER_SOFTWARE': 'Development/X', 'CONTENT_TYPE': 'application/json'})
So what am I doing wrong?
This is a known error with App Engine.
Endpoints does not set the correct Content-Length header when you raise an exception:
https://code.google.com/p/googleappengine/issues/detail?id=10544
To fix it there is a diff file included in the link above, or follow my instructions to temporarily patch it by yourself.
1. Open apiserving.py
On a mac you can find the file at:
/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/endpoints-1.0/endpoints
2. Locate the following section (line 467):
It should look like this:
headers_dict = dict([(k.lower(), v) for k, v in headers])
if self.__is_json_error(status, headers_dict):
status, body = self.protorpc_to_endpoints_error(status, body)
3. Change it to this:
headers_dict = dict([(k.lower(), v) for k, v in headers])
if self.__is_json_error(status, headers_dict):
pre_body_length = len(body)
status, body = self.protorpc_to_endpoints_error(status, body)
post_body_length = len(body)
if pre_body_length != post_body_length:
for index, header in enumerate(headers):
header_key, _header_value = header
if header_key == 'content-length':
headers[index] = (header_key, str(post_body_length))
break
4. All done!
Endpoints will return the correct Content-Length, WebOb will be happy and your API tests will be working :)
