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Build Your First Flask App
Variable Rules

We’ve seen how the route() decorator can be used to bind one or more static URLs to a view function. But what if we want to handle a set of URLs that may be constantly changing? Let’s take a look at how we can use variable rules to allow for dynamic URLs.

When specifying the URL to bind to a view function, we have the option of making any section of the path between the slashes (/) variable by indicating <variable_name>. These variable parts will then be passed to the view function as arguments. For example:

@app.route('/orders/<user_name>/<int:order_id>') def orders(user_name, order_id): return f'<p>Fetching order #{order_id} for {user_name}.</p>'

Now, URLs like '/orders/john/1' and '/orders/jane/8' can all be handled by the orders() function.

Note that we can also optionally enforce the type of the variable being accepted using the syntax: <converter:variable_name>. The possible converter types are:

string accepts any text without a slash (default)
int accepts positive integers
float accepts positive floating point values
path like string but also accepts slashes
uuid accepts UUID strings



Update the reporter endpoint to handle requests from individual reporter pages whose URL path follows the pattern '/reporter/#'.

Add a variable section called reporter_id to the URL passed to the route() decorator. Use a converter to specify that the variable part must be a positive integer.


Next, update the reporter() function to take a parameter called reporter_id. In the function body, modify the <h2> heading to read Reporter # Bio, where # is the reporter_id.


Run Try visiting various reporter pages such as https://localhost/reporter/1 or https://localhost/reporter/1000!

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