CODEWITHSUNDEEP
pythonflaskpython-requestsmarshmallow
Ani
Ani

Reputation: 351

flask + marshmallow schema complains 'missing data for required field'

I have a simple flask server (with no sqlalchemy at this stage) and it is unable to parse request for a mandatory field

Server python code -->

from flask import request, jasonify, make_response, abort
from marshmallow import Schema, fields

class MySchema(Schema):
      ref_date=fields.Str(required=True)

schema_instance = MySchema()
@app.route('/functions/regression',method=['GET'])
def perform_regression():
     print('ref_date: ', request.args.get('ref_date'))
     errors = schema_instance.validate(request.form)
     if errors:
         abort(400, str(errors))

app.run()

I have a client python code as follows -->

import requests
res = requests.get("http://127.0.0.1:5000/functions/regression?ref_date='20200205'")
print(res.status_code, res.text)

I am always getting error message "Missing data for required field".

Any pointers? I do get the parameters correctly on the server as can be seen with request.args.get() but after this Schema returns the error.

Upvotes: 0

Views: 4176

Answers (2)

Ani
Ani

Reputation: 351

Based on suggestion of Igor, the following works

from flask import request, jasonify, make_response, abort
from marshmallow import Schema, fields

class MySchema(Schema):
    ref_date=fields.Str(required=True)

schema_instance = MySchema()
@app.route('/functions/regression',method=['GET'])
def perform_regression():
    print('ref_date: ', request.args.get('ref_date'))
    errors = schema_instance.validate(request.args) #<--fix here
    if errors:
        abort(400, str(errors))

app.run()

Upvotes: 1

Ihor Pomaranskyy
Ihor Pomaranskyy

Reputation: 5611

Serializer expects your data to be in request payload, not in request parameters.

So, you have two options:

  1. Instead of GET, use PUT or POST request and put data in payload (as {"ref_date": "20200205"})
  2. In your method, put request parameters into some dictionary and use it instead of request.form.

Basically, the problem is that request.form has no data, so serializer throws error about missing required field.

Upvotes: 0

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