Python Flask - No 'Access-Control-Allow-Origin'

Question

i get this error when loading a json file :

Failed to load http://localhost/sandbox/data.json?_=1505732125859: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:5000' is therefore not allowed access.

#...
from flask_cors import CORS
app = Flask(__name__)
CORS(app, resources={r"/*": {"origins": "*"}})
@app.route('/')
def index():
    return render_template('index.html')

Tried this solution.. but still getting same error Javascript - No 'Access-Control-Allow-Origin' header is present on the requested resource

Is that python code running on `http://localhost` or `http://localhost:5000`? — Quentin, Sep 18 '17 at 11:02
yes python code is running...output is stored in json file.. when accessing that json using jquery. getting this error — deepak murthy, Sep 18 '17 at 11:44
I was expecting your answer to be "`http://localhost`" or `"http://localhost:5000`". "Yes" doesn't help me help you! — Quentin, Sep 18 '17 at 12:44

score 3 · Answer 1 · answered Sep 18 '17 at 12:48

You've set the CORS permissions on the wrong server.

A webpage on http://localhost:5000 is making a request to http://localhost.

Your headers are granting permission to every site (*) to access the data on http://localhost:5000, but you are trying to access the data on http://localhost.

You need to set the CORS permissions on http://localhost instead.

This answer explains the background.

Python Flask - No 'Access-Control-Allow-Origin'

1 Answers1