Troubleshooting OAuth Redirects: When Your Flask-App Uses the Wrong Strava Application
Implementing third-party authentication can significantly enhance user experience, but it sometimes comes with unexpected hurdles. Recently, developers working with the Strava API encountered a perplexing issue where the OAuth authorization process redirected to an entirely different application. This article explores the problem, potential causes, and best practices to resolve such OAuth redirect anomalies in a Flask-based web application.
The Scenario
Suppose you’re developing a web app with a Flask backend and Vue.js frontend, aiming to incorporate Strava’s API for user authentication and activity data access. Your setup involves registering an OAuth application on Strava and obtaining a Client ID and Secret. When initiating the login flow, your app constructs the authorization URL correctly, yet the user is redirected to an authorization page associated with a different Strava app—one with a conflicting structure and scopes, named “Simon’s Journey Viz.”
This unexpected redirect raises questions:
- Why is the OAuth process presenting a different application’s authorization page?
- Could it be related to the application’s credentials, cache issues, or server configuration?
- How to troubleshoot and ensure the correct OAuth app is used?
Common Causes and Troubleshooting Steps
1. Verify the Client ID and Secret
Ensure that the Client ID included in your authorization URL matches the intended app registered on Strava. Double-check the following:
- The Client ID used in your Flask application’s code.
- The application credentials stored securely, avoiding accidental leaks or misconfigurations.
- That there are no hardcoded or outdated credentials.
“`python
Example snippet
strava_client_id = ‘YOUR_CLIENT_ID’
redirect_uri = ‘https://yourdomain.com/callback’
authorization_url = (
f”https://www.strava.com/oauth/authorize?”
f”client_id={strava_client_id}&response_type=code&redirect_uri={redirect_uri}&scope=read”
)
“`
2. Inspect the Actual Authorization URL in the Browser
Before redirecting, log or print the constructed authorization URL to confirm it references the correct Client ID. Sometimes, a typo or stale variable can cause mismatches.
python
print(f"Authorization URL: {authorization_url}")
3. Clear Browser Cache and Cookies
Browsers may cache certain redirect responses or associate OAuth sessions with previous applications. Clear cache and cookies to eliminate this factor.
