How to use delete() method in Google App Engine Python's request handler

Question

In GAE Python, I could use

class MyRequestHandler(webapp.RequestHandler):
    def get(self):
        pass #Do Something...
    def post(self):
        pass #Do Something...

To handle GET and POST request. But how can I handle DELETE and PUT? I see delete() and put() in API documentation, but I don't know how to write a form to simulate DELETE and PUT.

I know in Rails, I can use post method with a hidden field in form to simulate the requests like this:

<input type="hidden" name="_method" value="delete" />

and Rails handles the dirty works automatically.

Is there any similar way to do it in GAE python?

I searched this in Google, but no luck.

Thanks.

Answer 1

You can implement this simulation yourself of course, In pseudo code (I'm not familiar with GAE specifics):

def post(self):
    if request.get('_method', '') == 'delete':
        return self.post()

If you want to truely test PUT and DELETE you will have to find a way to actually use these methods in stead of simulating them. You can use curl for this, for example, i.e.

$ curl -X DELETE url
$ curl -T file url # for PUT

See the curl documentation / manpage for more information.

Answer 2

You can use the request method which accepts all the methods like get,post,delete and put. Then you can check it for the request type accordingly.

Check this:

http://gdata-python-client.googlecode.com/svn/trunk/pydocs/gdata.urlfetch.html

<form method="post" action="">
 <input type="hidden" name="_method" value="put" />
 <input type="text" name="name" value="" />
 <input type="submit" value="Save" />
</form> 

def post(self):
    method= self.request.get("_method")
    if method == 'put':
       #call put() function as required

you can go through this as well for the put specification.

http://code.google.com/appengine/docs/python/tools/webapp/requesthandlerclass.html#RequestHandler_put

Answer 3

The HTML specification doesn't allow a form to use the DELETE method, and you probably can't get a browser to send an HTTP DELETE request with a form. The delete() method of a RequestHandler subclass would generally be used for a RESTful web application with a client that knows how to send DELETE requests, rather than using ordinary HTML forms. (For a browser-based client, you can send DELETE requests in javascript using XMLHttpRequest.)

Answer 4

First, you need to create a new RequestHandler subclass :

from google.appengine.ext import webapp

class RESTfulHandler(webapp.RequestHandler):
  def post(self, *args):
    method = self.request.get('_method')

    if method == "put":
      self.put(*args)
    elif method == "delete":
      self.delete(*args)
    else:
      self.error(405) # Method not allowed

Then your handler will inherit from it :

class MyHandler(RESTfulHandler):
  def get(self):
    ...
  def delete(self):
    ...
  def put(self):
    ...
  def post(self):
    ...

Here is another example using the X-HTTP-Method-Override header used by most JavaScript libraries : http://github.com/sork/webapp-handlers/blob/master/restful.py