As mentioned, we can also pass variables to the URL, as seen in the examples discussed in chapter9_3.py:
...
@app.route('/routers/<hostname>')
def router(hostname):
return 'You are at %s' % hostname
@app.route('/routers/<hostname>/interface/<int:interface_number>')
def interface(hostname, interface_number):
return 'You are at %s interface %d' % (hostname, interface_number)
...
Note that in the /routers/<hostname> URL, we pass the <hostname> variable as a string; <int:interface_number> will specify that the variable should only be an integer:
$ http GET http://172.16.1.173:5000/routers/host1
...
You are at host1
$ http GET http://172.16.1.173:5000/routers/host1/interface/1
...
You are at host1 interface 1
# Throws exception
$ http GET http://172.16.1.173:5000/routers/host1/interface/one
HTTP/1.0 404 NOT FOUND
...
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<title>404 Not Found</title>
<h1>Not Found</h1>
<p>The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.</p>
The converter includes integers, float, and path (accepts slashes).
Besides matching static routes, we can also generate URLs on the fly. This is very useful when we do not know the endpoint variable in advance or if the endpoint is based on other conditions, such as the values queried from a database. Let's take a look at an example of it.