Multi tool use

How to Distinguish Button Presses in Tornado?

In the process of teaching myself how to use python's tornado web framework, I am trying to create a simple web server and some web pages. On one of the web pages, I have two buttons: one to log users out and redirect them back to the login page and one to submit a blog post. They are both "post" requests and have their name values in html set to "logout" and "new_post".

My questions is, how can I tell which button was pressed so that the post() method for the page's RequestHandler can perform the correct actions in each case? Is there a way to grab the "name" of the button pressed?

2 Answers
2

When you submit a form with a button click, a parameter with the name of the clicked button gets added to the request.

You can check, if the parameter exists and then do your stuff.

def post(self):

if self.get_argument("logout", None) != None:
# do logout stuff

if self.get_argument("new_post", None) != None:
# do submit a blog post stuff


On Python3 using Tornado, the setup looks as follows with two submit buttons (which is very similar to the above answer).

First the HTML and note both buttons are similar with differing display values. The name parameter is what will be passed to Tornado's POST handler:

<p><input type="submit" class="button" name="basic" value="Basic Query"></p>
<p><input type="submit" class="button" name="advanced" value="Advanced Query"></p>


Next, the POST handler. Using get_argument, you can specify the name and select it if the input is not null. Remember to include the ", None" in get_argument so that it defaults to None should the option not be selected:

def post(self):
if self.get_argument('basic', None) is not None:
self.write('Basic Query')

elif self.get_argument('advanced', None) is not None:
self.write('Advanced Query')


That's it! 2 forms and the ability to differentiate between. Happy coding!

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