Bad $schema in request blocks the application

[ppanero]

When the $schema of the application doesn't exists or is not found the resolve_from_url fucntion fails (also because is not found on the store attribute).

The non-graceful failure leaves a SQL connection open that blocks the application and does not allow any consequent query.

Stacktrace:

Traceback (most recent call last):
  File "/usr/lib64/python2.7/site-packages/flask/app.py", line 2309, in __call__
    return self.wsgi_app(environ, start_response)
  File "/usr/lib/python2.7/site-packages/werkzeug/wsgi.py", line 826, in __call__
    return app(environ, start_response)
  File "/usr/lib64/python2.7/site-packages/flask/app.py", line 2309, in __call__
    return self.wsgi_app(environ, start_response)
  File "/usr/lib64/python2.7/site-packages/flask/app.py", line 2295, in wsgi_app
    response = self.handle_exception(e)
  File "/usr/lib64/python2.7/site-packages/flask/app.py", line 1741, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/lib64/python2.7/site-packages/flask/app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/lib64/python2.7/site-packages/flask/app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/lib64/python2.7/site-packages/flask/app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/lib64/python2.7/site-packages/flask/app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/lib64/python2.7/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/usr/lib64/python2.7/site-packages/flask/views.py", line 88, in view
    return self.dispatch_request(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/invenio_rest/views.py", line 240, in dispatch_request
    *args, **kwargs
  File "/usr/lib64/python2.7/site-packages/flask/views.py", line 158, in dispatch_request
    return meth(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/invenio_records_rest/views.py", line 419, in need_record_permission_decorator
    return f(self, record=record, *args, **kwargs)
  File "/usr/lib/python2.7/site-packages/invenio_records_rest/views.py", line 598, in post
    record = self.record_class.create(data, id_=record_uuid)
  File "/usr/lib/python2.7/site-packages/invenio_records/api.py", line 179, in create
    record.validate(**kwargs)
  File "/usr/lib/python2.7/site-packages/invenio_records/api.py", line 126, in validate
    _records_state.validate(self, self['$schema'], **kwargs)
  File "/usr/lib/python2.7/site-packages/invenio_records/ext.py", line 41, in validate
    **kwargs
  File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 541, in validate
    cls(schema, *args, **kwargs).validate(instance)
  File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 129, in validate
    for error in self.iter_errors(*args, **kwargs):
  File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 105, in iter_errors
    for error in errors:
  File "/usr/lib/python2.7/site-packages/jsonschema/_validators.py", line 212, in ref
    scope, resolved = validator.resolver.resolve(ref)
  File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 375, in resolve
    return url, self._remote_cache(url)
  File "/usr/lib/python2.7/site-packages/functools32/functools32.py", line 400, in wrapper
    result = user_function(*args, **kwds)
  File "/usr/lib/python2.7/site-packages/jsonschema/validators.py", line 385, in resolve_from_url
    raise RefResolutionError(exc)
jsonschema.exceptions.RefResolutionError: ('Connection aborted.', BadStatusLine("''",))

I can provide access to a sentry event with breadcrumps etc. Migth be usefull to debug.