Calling /api/<model>/<id>/<attribute> where <attribute> is not a relation bombs with an unhelpful AttributeError

[jcmcken]

Curl command that I run:

curl http://localhost:5000/api/v1/data/1/id

...where data is my collection_name, /api/v1 is my url_prefix, and id is just the name of the primary key column.

I get this exception:

AttributeError: 'ColumnProperty' object has no attribute 'uselist'

I don't think this is a proper usage of the API, but the error is not helpful. If it's not a valid endpoint, API should raise a 400-level http code, not a 500.

A different AttributeError is raised (with 500 HTTP code) if you call with an attribute that doesn't even exist for the given model, which also seems to be a bug.

Full traceback for the first issue:

Traceback (most recent call last):
  File "/data/sandbox/apps/myapp/venv/lib/python2.6/site-packages/flask/app.py", line 1701, in __call__
    return self.wsgi_app(environ, start_response)
  File "/data/sandbox/apps/myapp/venv/lib/python2.6/site-packages/flask/app.py", line 1689, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/data/sandbox/apps/myapp/venv/lib/python2.6/site-packages/flask/app.py", line 1687, in wsgi_app
    response = self.full_dispatch_request()
  File "/data/sandbox/apps/myapp/venv/lib/python2.6/site-packages/flask/app.py", line 1360, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/data/sandbox/apps/myapp/venv/lib/python2.6/site-packages/flask/app.py", line 1358, in full_dispatch_request
    rv = self.dispatch_request()
  File "/data/sandbox/apps/myapp/venv/lib/python2.6/site-packages/flask/app.py", line 1344, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/data/sandbox/apps/myapp/venv/lib/python2.6/site-packages/flask_restless/views.py", line 112, in decorator
    return func(*args, **kw)
  File "/data/sandbox/apps/myapp/venv/lib/python2.6/site-packages/flask/views.py", line 83, in view
    return self.dispatch_request(*args, **kwargs)
  File "/data/sandbox/apps/myapp/venv/lib/python2.6/site-packages/flask/views.py", line 150, in dispatch_request
    return meth(*args, **kwargs)
  File "/data/sandbox/apps/myapp/venv/lib/python2.6/site-packages/flask_restless/views.py", line 935, in get
    if is_like_list(instance, relationname):
  File "/data/sandbox/apps/myapp/venv/lib/python2.6/site-packages/flask_restless/helpers.py", line 228, in is_like_list
    return instance._sa_class_manager[relation].property.uselist
AttributeError: 'ColumnProperty' object has no attribute 'uselist'

My requirements file:

Flask==0.9
Flask-Restless==0.11.0
Flask-SQLAlchemy==0.16
FormEncode==1.2.6
Jinja2==2.7
MarkupSafe==0.18
SQLAlchemy==0.8.1
Werkzeug==0.8.3
python-dateutil==2.1
six==1.3.0
wsgiref==0.1.2

[jfinkels]

This is definitely a bug.

There may be a way to fix it, but I think a major overhaul of the part of the code that creates API objects (specifically the code in APIManager.create_api_blueprint()) is in order, to specify one API object per endpoint instead of one API object per /api/collectionname and all its sub-endpoints.

[daniel-j-h]

Bumping this issue, because I had to learn about it the hard way.

Has there been any progress towards solving this issue?

Without debug mode this raises an 500 HTTP error code, which - still - is not very nice.
Is there a sensible workaround in the meantime?

[jfinkels]

This is fixed on the master branch. You now get an error response with the message No such relation: "id"