How to validate a Pydantic model which represents a list of model instances ?

[jossefaz]

I got these models

from pydantic import BaseModel

class MyModel(BaseModel):
    name: str
    id: int

class ListOfMyModels(BaseModel):
    __root__: List[MyModel]

From the docs this is the official way to instantiate a model who is a list of models

However, when I try to validate this at route level I get an error:

@spectree_app.validate(json=ListOfMyModels)

output traceback

../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/werkzeug/test.py:1137: in put
    return self.open(*args, **kw)
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/flask/testing.py:220: in open
    follow_redirects=follow_redirects,
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/werkzeug/test.py:1072: in open
    response = self.run_wsgi_app(request.environ, buffered=buffered)
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/werkzeug/test.py:943: in run_wsgi_app
    rv = run_wsgi_app(self.application, environ, buffered=buffered)
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/werkzeug/test.py:1229: in run_wsgi_app
    app_rv = app(environ, start_response)
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/flask/app.py:2088: in __call__
    return self.wsgi_app(environ, start_response)
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/flask/app.py:2073: in wsgi_app
    response = self.handle_exception(e)
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/flask/app.py:2070: in wsgi_app
    response = self.full_dispatch_request()
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/flask/app.py:1515: in full_dispatch_request
    rv = self.handle_user_exception(e)
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/flask/app.py:1513: in full_dispatch_request
    rv = self.dispatch_request()
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/flask/app.py:1499: in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/flask/views.py:83: in view
    return self.dispatch_request(*args, **kwargs)
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/flask/views.py:157: in dispatch_request
    return meth(*args, **kwargs)
common/auth.py:97: in decorator
    return func(*args, **kwargs)
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/spectree/spec.py:139: in sync_validate
    **kwargs,
common/spectree_app.py:51: in validate
    self.request_validation(request, query, json, headers, cookies)

self = <common.spectree_app.CustomFlaskPlugin object at 0x107193408>
request = <LocalProxy unbound>, query = None
json = <class 'resources.schemas.my_models.ListOfMyModels'>
headers = None, cookies = None

    def request_validation(self, request, query, json, headers, cookies):
        req_query = request.args or {}
        if request.mimetype in self.FORM_MIMETYPE:
            req_json = request.form or {}
            if request.files:
                req_json = dict(
                    list(request.form.items()) + list(request.files.items())
                )
        else:
            req_json = request.get_json(silent=True) or {}
        req_headers = request.headers or {}
        req_cookies = request.cookies or {}
        request.context = Context(
            query.parse_obj(req_query.items()) if query else None,
>           json.parse_obj(req_json.items()) if json else None,
            headers.parse_obj(req_headers.items()) if headers else None,
            cookies.parse_obj(req_cookies.items()) if cookies else None,
        )
E       AttributeError: 'list' object has no attribute 'items'

How to get rid of this ?

[kemingy]

Which version are you using?

I think it's already supported.

• refer to support list resp with List[Model] #222

You can use List[MyModel] directly instead of creating a dummy one.

[yedpodtrzitko]

@kemingy it seems like this scenario is really broken. #222 is adding support for list in response, but the error in subject here is a list in request. I might take a look into it.

[jossefaz]

@kemingy : Thanks for your answer.
However, I would like to have a model that representing a list, instead of using the typing module.
But even after giving the typing module a shot, I got another error :

@spectree_app.validate(json=List[MyModel])

output traceback

../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/spectree/spec.py:227: in decorate_validation
    model_key = self._add_model(model=model)
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/spectree/spec.py:258: in _add_model
    model_key = get_model_key(model=model)
../../../../.pyenv/versions/fry5/lib/python3.7/site-packages/spectree/utils.py:244: in get_model_key
    return f"{model.__name__}.{hash_module_path(module_path=model.__module__)}"
../../../../.pyenv/versions/3.7.12/lib/python3.7/typing.py:707: in __getattr__
    raise AttributeError(attr)
E   AttributeError: __name__

I use the last version (1.1.0)

[kemingy]

My bad. It doesn't support the List[MyModel] for requests JSON. Only supports in the response.

You should be able to run the original code with version 1.1.0.

[yedpodtrzitko]

@jossefaz from the traceback in first message looks like outdated version of request_validation(). So either you have overriden it based on code from some older release, or the version you have installed isnt really 1.1.0. The default function has changed noticably (notice for example the form.parse_obj() which is absent in your traceback).

spectree/spectree/plugins/flask_plugin.py

Lines 135 to 159 in 98f2e1d

	def request_validation(self, request, query, json, form, headers, cookies):
	"""
	req_query: werkzeug.datastructures.ImmutableMultiDict
	req_json: dict
	req_headers: werkzeug.datastructures.EnvironHeaders
	req_cookies: werkzeug.datastructures.ImmutableMultiDict
	"""
	req_query = get_multidict_items(request.args)
	req_headers = dict(iter(request.headers)) or {}
	req_cookies = get_multidict_items(request.cookies) or {}
	has_data = request.method not in ("GET", "DELETE")
	use_json = json and has_data and request.mimetype == "application/json"
	use_form = (
	form
	and has_data
	and any([x in request.mimetype for x in self.FORM_MIMETYPE])
	)
	request.context = Context(
	query.parse_obj(req_query) if query else None,
	json.parse_obj(request.get_json(silent=True) or {}) if use_json else None,
	form.parse_obj(self._fill_form(request)) if use_form else None,
	headers.parse_obj(req_headers) if headers else None,
	cookies.parse_obj(req_cookies) if cookies else None,
	)