Flask Get Request validate failed

[CharmingZhou]

from pydantic import BaseModel
from typing import List
class Query(BaseModel):
    query: str
    
@test_bp.route("/test_route")
@validate(query=Query)
def test_route(query:Query):
    return {}

my code is very simple, but when i send 'http://127.0.0.1:8800/test_route?query=1'，I will receive

{
  "validation_error": {
    "query_params": [
      {
        "loc": [
          "query"
        ], 
        "msg": "str type expected", 
        "type": "type_error.str"
      }
    ], 
  }
}

I try add more detail in core.py

try:
                    q = query_model(**query_params)
                except ValidationError as ve:
                    err["query_params"] = ve.errors()
                    err["value"] = query_params

I will get

"value": {
      "query": [
        "1"
      ]
    }

So I'm very doubt why query becomes list rather than str.

My python requrement is

python3.6
pydantic==1.7.3
flask-pydantic-spec==0.1.3
Flask==1.1.2
dataclasses==0.8

Looking forward to a reply！

[bauerji]

Hello,

this is interesting. When I add your code into the example app provided in the repository it works fine.

Could you post your whole code? Also in your requirements there is flask-pydantic-spec==0.1.3 and no flask-pydantic. Maybe there could be some kind of interference with these two libraries.

Jirka

[CharmingZhou]

sorry，flask-pydantic-spec==0.1.3 is other test library. Right requirement is Flask-Pydantic==0.4.0

[bauerji]

I am not able to reproduce your problem. Could you please share a whole minimal example that still produces the error?

[CharmingZhou]

I am not able to reproduce your problem. Could you please share a whole minimal example that still produces the error?
Here is a minimal example:

from flask import Flask
from flask import Blueprint

app = Flask(__name__)

from pydantic import BaseModel
from flask_pydantic import validate
from typing import List
class Query(BaseModel):
    query: str
    
test_bp = Blueprint("test",__name__)
@test_bp.route("/test_route", methods=["GET"])
@validate(query=Query)
def test_route(query:Query):
    return {}

if __name__ == "__main__":
    app.register_blueprint(test_bp)
    app.run(host="0.0.0.0", port="8888")

[yasinyildiza]

Same thing happened to me.

With a little investigation, I think, I found the root cause.

In convert_query_params, this line

    return {
        **query_params,

should be

    return {
        **query_params.to_dict(flat=True), # flat=True is the default

because when request.args is unpacked, dict values become list rather than str; in other words, explicit cast is done with to_dict(flat=False).

[bauerji]

I am sorry guys, I am running the exact same code as @CharmingZhou posted and still no error (tried both python 3.6 and 3.9). Could You please @yasinyildiza share your minimal example together with your environment setup?

[yasinyildiza]

@bauerji

Python
3.6.2

pip freeze

click==7.1.2
dataclasses==0.8
Flask==1.1.2
Flask-Pydantic==0.6.0
itsdangerous==1.1.0
Jinja2==2.11.3
MarkupSafe==1.1.1
pydantic==1.7.3
Werkzeug==1.0.1

code

import flask
import flask_pydantic
import pydantic


class Query(pydantic.BaseModel):
    query: str


app = flask.Flask(__name__)


@app.route('/test')
@flask_pydantic.validate(query=Query)
def test(query:Query):
    return flask.jsonify({'query': query.dict()})


if __name__ == '__main__':
    app.run(port=5000, debug=True)

I also tried to run the tests after setting up the dev environment (following Contributing instructions). This is the result:

18 failed, 55 passed, 1 warning

[bauerji]

@yasinyildiza @CharmingZhou
It seems that there is a problem with specifically python 3.6.2 version. Unfortunately github won't let me to run tests in github actions using this version see this.

I will try to solve this issue, however I would recommend You to upgrade to at least the newest 3.6 version (3.6.13 at the moment).

[bauerji]

@yasinyildiza @CharmingZhou

this issue should not occur anymore since release 0.6.1

Feel free to reopen or create new issue if the problem persists.

Jirka

[yasinyildiza]

I tested with 0.6.1, and it is working very well.
Thanks a lot @bauerji