Railway•7mo ago

CORS issue calling to railway from other domain

Project ID : b1d6fa08-43ff-4114-82f0-f836e0ee2651 Hi, I'm getting this error when trying to call from my frontend to Flask backend server hosted on Railway:


Access to fetch at 'http://c...pp/1980' from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: Redirect is not allowed for a preflight request.

Here is my flask server looks like:

 ------------------ SETUP ------------------
load_dotenv()
app = Flask(__name__)
# this will need to be reconfigured before taking the app to production
cors = CORS(app, resources={r"/*": {"origins": ["http://localhost", "http://localhost:3000", "http://c...pp"]}})
...
# ------------------ START SERVER ------------------

if __name__ == '__main__':
    app.run(debug=True, port=os.getenv("PORT", default=5000))

Do you have any suggestion? Anyway, thank you for building amazing railway!

Solution:

I figured it out. On the front end, I actually called to http://c...pp/1980 though it should be https://c...pp/1980 This was a typo as my code was generated by Copilot My railway server took the http request, redirected to make it https. That's why we got the Redirect is not allowed for a preflight request. error We can mark my problem as solved nơ...

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