Flask â URL Building
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The url_for() function is very useful for dynamically building a URL for a specific function. The function accepts the name of a function as first argument, and one or more keyword arguments, each corresponding to the variable part of URL.
The following script demonstrates use of url_for() function.
from flask import Flask, redirect, url_for app = Flask(__name__) @app.route(''/admin'') def hello_admin(): return ''Hello Admin'' @app.route(''/guest/<guest>'') def hello_guest(guest): return ''Hello %s as Guest'' % guest @app.route(''/user/<name>'') def hello_user(name): if name ==''admin'': return redirect(url_for(''hello_admin'')) else: return redirect(url_for(''hello_guest'',guest = name)) if __name__ == ''__main__'': app.run(debug = True)
The above script has a function user(name) which accepts a value to its argument from the URL.
The User() function checks if an argument received matches âadminâ or not. If it matches, the application is redirected to the hello_admin() function using url_for(), otherwise to the hello_guest() function passing the received argument as guest parameter to it.
Save the above code and run from Python shell.
Open the browser and enter URL as − http://localhost:5000/user/admin
The application response in browser is −
Hello Admin
Enter the following URL in the browser − http://localhost:5000/user/mvl
The application response now changes to −
Hello mvl as Guest
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