cigar_example documentation - RuntimeError: Unable to use callback invalid closure/function specified.

[sdg9]

I'm using Django 1.6.2, django-rest-framework 2.3.12, and python 3.3.4

Running the cigar_example locally errors out when trying to view the swagger documentation at http://127.0.0.1:8000/. http://127.0.0.1:8000/api/cigars/ loads properly (when including trailing slash) and the remainder of the documentation loads properly if I remove the cigars route in cigar_example/restapi/urls.py.

The documentation page gives the error - Unable to read api 'cigars' from path http://127.0.0.1:8000/api-docs/api/cigars (server returned undefined)
The stack trace is below.
[08/Mar/2014 11:59:59] "GET /api-docs/ HTTP/1.1" 200 215
Internal Server Error: /api-docs/api/cigars
Traceback (most recent call last):
File "D:\Development\virtualenv\aws-django\lib\site-packages\django\core\handlers\base.py", line 114, in get_response
response = wrapped_callback(request, _callback_args, *_callback_kwargs)
File "D:\Development\virtualenv\aws-django\lib\site-packages\django\views\generic\base.py", line 69, in view
return self.dispatch(request, _args, *_kwargs)
File "D:\Development\virtualenv\aws-django\lib\site-packages\django\views\decorators\csrf.py", line 57, in wrapped_view
return view_func(_args, *_kwargs)
File "D:\Development\virtualenv\aws-django\lib\site-packages\rest_framework\views.py", line 399, in dispatch
response = self.handle_exception(exc)
File "D:\Development\virtualenv\aws-django\lib\site-packages\rest_framework\views.py", line 396, in dispatch
response = handler(request, _args, *_kwargs)
File "D:\Development\virtualenv\aws-django\lib\site-packages\rest_framework_swagger\views.py", line 84, in get
'apis': generator.generate(apis),
File "D:\Development\virtualenv\aws-django\lib\site-packages\rest_framework_swagger\docgenerator.py", line 21, in generate
'operations': self.get_operations(api),
File "D:\Development\virtualenv\aws-django\lib\site-packages\rest_framework_swagger\docgenerator.py", line 41, in get_operations
for method_introspector in introspector:
File "D:\Development\virtualenv\aws-django\lib\site-packages\rest_framework_swagger\introspectors.py", line 285, in iter
methods = self._resolve_methods()
File "D:\Development\virtualenv\aws-django\lib\site-packages\rest_framework_swagger\introspectors.py", line 294, in _resolve_methods
raise RuntimeError('Unable to use callback invalid closure/function specified.')
RuntimeError: Unable to use callback invalid closure/function specified.
[08/Mar/2014 11:59:59] "GET /api-docs/api/manufacturers HTTP/1.1" 200 3514
[08/Mar/2014 11:59:59] "GET /api-docs/api/custom HTTP/1.1" 200 931
[08/Mar/2014 11:59:59] "GET /api-docs/api/countries HTTP/1.1" 200 2694
[08/Mar/2014 12:00:00] "GET /api-docs/api/cigars HTTP/1.1" 500 122324

[hashstat]

The problem is that func_code and func_closure were renamed code and closure in Python 3. Below is a patch that allows the introspection to work with both Python 2.x and 3.x.

--- old/introspectors.py
+++ new/introspectors.py
@@ -287,14 +287,20 @@
             yield ViewSetMethodIntrospector(self, methods[method], method)

     def _resolve_methods(self):
-        if not hasattr(self.pattern.callback, 'func_code') or \
-                not hasattr(self.pattern.callback, 'func_closure') or \
-                not hasattr(self.pattern.callback.func_code, 'co_freevars') or \
-                'actions' not in self.pattern.callback.func_code.co_freevars:
+        callback = self.pattern.callback
+        try:
+            try:
+                closure = callback.func_closure
+            except AttributeError:
+                closure = callback.__closure__
+            try:
+                code = callback.func_code
+            except AttributeError:
+                code = callback.__code__
+            freevars = code.co_freevars
+        except AttributeError:
             raise RuntimeError('Unable to use callback invalid closure/function specified.')
-
-        idx = self.pattern.callback.func_code.co_freevars.index('actions')
-        return self.pattern.callback.func_closure[idx].cell_contents
+        return closure[freevars.index('actions')].cell_contents


 class ViewSetMethodIntrospector(BaseMethodIntrospector):

The 2to3 tool automatically handles renaming the attributes, rendering the inner try-except blocks unnecessary. The code could become:

    def _resolve_methods(self):
        callback = self.pattern.callback
        try:
            closure = callback.func_closure
            freevars = callback.func_code.co_freevars
        except AttributeError:
            raise RuntimeError('Unable to use callback invalid closure/function specified.')
        return closure[freevars.index('actions')].cell_contents

[linuxlewis]

+1

[jeffself]

I've updated the _resolve_methods method in my introspectors.py to look like this:

def _resolve_methods(self):
    callback = self.pattern.callback
    try:
        closure = callback.func_closure
        freevars = callback.func_code.co_freevars
    except AttributeError:
        raise RuntimeError('Unable to use callback invalid closure/function specified.')
    return closure[freevars.index('actions')].cell_contents
    idx = self.pattern.callback.__code__.co_freevars.index('actions')
    return self.pattern.callback.__closure__[idx].cell_contents

However, I'm still getting a 'Unable to use callback invalid closure/function specified.' error. I'm running Python 3.4.1. Any thoughts?

[jason-kane]

Did github mangle your code somehow? The snippet doesn't make very much sense to me.

I'm using (with Python 3.4):

    def _resolve_methods(self):
        callback = self.pattern.callback
        try:
            try:
                closure = callback.func_closure
            except AttributeError:
                closure = callback.__closure__
            try:
                code = callback.func_code
            except AttributeError:
                code = callback.__code__
            freevars = code.co_freevars
        except AttributeError:
            raise RuntimeError('Unable to use callback invalid closure/function specified.')

        return closure[freevars.index('actions')].cell_contents

[jeffself]

Yeah, not sure what happened there. Here's what I've got:

def _resolve_methods(self):
    callback = self.pattern.callback
    try:
        closure = callback.func_closure
        freevars = callback.func_code.co_freevars
    except AttributeError:
        raise RuntimeError('Unable to use callback invalid closure/function specified.')
    return closure[freevars.index('actions')].cell_contents

Still getting same error message.

[jason-kane]

As far as I know that is supposed to work but I don't trust the 2to3 black magic. Try the long winded explicit version I posted above.

[jeffself]

Works! Thanks!

[johansja]

Thanks for the snippet too. I am wondering if this will be patched into the code someday?

[nielsole]

Hey, this worked to let the error message go away, but instead I now get a Value error:
tuple.index(x): x not in tuple
from this line
return closure[freevars.index('actions')].cell_contents
freevars only contains: ('view_func',)
I used the code from @jason-kane .
Did anyone else experience this problem?

[jason-kane]

Haven't seen that; it looks like there must be something missing in the function it is trying to introspect. 'actions' looks like it comes from DRF itself not the swagger addition. Does the DRF browser work?

[nielsole]

I am using Django 1.7 and DRF 2.4.3. The DRF browser works fine.

[jason-kane]

looks like #123 is biting you. Symptoms are identical to #129

[nielsole]

you are right. Did not see them. Thank you. Too bad this repository is not maintained.

[jason-kane]

I added what looks like a suitable fix to pull request #85 ; I haven't actually tried it against DRF 2.4.3 yet.

[FlogFr]

sorry but still having the issue from installing by pip. Is it merged and updated to pypi ?

[allardhoeve]

Same here. Doesn't work with Django REST Framework 2.4.3 and Django 1.7.

[ariovistus]

fixed in develop.