Flask JSON Content Type Validation Decorator
This package contains a Flask routes decorator that validates that the request has a Content-Type header with 'application/json'.
Why?
Whenever you develop a Flask based API with plain vanilla flask routes that
expect to get json data, then trying to access request.get_json()
will return None whenever the Content-Type is not 'application/json' - which
might eventually break your code. Using this decorator will help you keep your
code clean and DRY.
How it works?
Create your custom exception
Below is an example of the exception you might wish to raise:
class CustomError(Exception):
def __init__(self, message, error_code):
self.message = message
self.error_code = error_code
Register your custom error with a flask error handler
The decorator will throw your CustomError
if the content type is not valid,
in which case you can handle and return your customized response.
@app.errorhandler(CustomError)
def custom_error_handler(custom_error):
return flask.jsonify(dict(message=custom_error.message,
error_code=custom_error.error_code)), 400
Decorate your route with the content type validator
import flask
from flask import request
from flask_json_content_type_validator import json_content_type_validator
app = flask.Flask(__name__)
@app.route('/echo-resource')
@json_content_type_validator.validator(
CustomError(message='Missing Content-Type header application/json',
error_code=1000)
)
def echo_resource():
data = dict(**request.get_json())
return flask.jsonify(data)