Forwarding a Shortened URL

00:00 Forward a Shortened URL. Your Python URL shortener app aims to provide shortened URLs that forward to a target URL. This means your app needs to have a route that forwards to the target URL.

00:16 In more technical terms, the forwarding behavior means that you need to redirect HTTP requests with URL.key to the URL.target_url address.

00:30 Update main.py to implement a RedirectResponse. For the redirecting behavior your app needs, you need to use the Request and RedirectResponse classes, so these are added to the imports.

00:42 RedirectResponse returns an HTTP redirect that forwards the request of the client. Next you add the raise_not_found() function. Similar to the raise_bad_request() function that was added earlier on, you’ll use raise_not_found() if the provided URL.key doesn’t match any URLs in your database.

01:06 Unlike raise_bad_request(), where you passed in a message, raise_not_found() always returns the same message. Canonically, you send back the 404 HTTP status code in the HTTPException.

01:26 Next you create the forward_to_target_url() function with an @app.get decorator. When you use the @app.get decorator, you allow GET requests for the URL that you provide as an argument.

01:39 With the argument provided, the forward_to_target_url() function will be called any time a client requests the URL that matches the host and key pattern.

01:56 In these lines, you look for an active URL entry with the provided url_key in your database.

02:10 If a database entry is found, then you return the RedirectResponse with target_url. If no matching database entry is found, then you raise the HTTPException.

02:22 In your browser, try out the behavior you just implemented. First, go to the documentation at the /docs URL seen on-screen and create a POST request to your create_url endpoint.

02:52 Copy the key that you receive in response and try out the forwarding.

03:11 In the example seen on-screen, the URL forwards successfully to realpython.com. That’s almost perfect, but why only almost? Well, although the code works, both create_url() and forward_to_target_url() have shortcomings.

03:28 In the next section of the course, you’ll clean up your code before creating more functionality and endpoints for your Python URL shortener app.