Well my friends, fear not. If you enjoy the sweet freedom of RESTful urls, I’m here to help. Since this is all built on top of WSGI, we can create a some new Middleware to sit before the application to resolve this little issue.

MockHTTPMethodMiddleware

from google.appengine.ext import webapp

class MockHTTPMethodMiddleware(object):
  def __init__(self, app):
    self.app = app

  def __call__(self, environ, start_response):
    method = webapp.Request(environ).get('_method')
    if method:
      environ['REQUEST_METHOD'] = method.upper()
    return self.app(environ, start_response)

The code is pretty simple. So when this middleware is called, it processes the environ into a Request object. From there, I just inspect the params for a key called _method. If that param exists, then it overwrites the REQUEST_METHOD and bam…we have mocked the HTTP method of our choosing.

Putting that code to good use

Let’s pretend that this is our class is something inane like this:

from google.appengine.ext import webapp

class MethodTest(webapp.RequestHandler):
  def get(self):
    self.response.headers["Content-Type"] = 'text/text'
    self.response.out.write("Get")

  def put(self):
    self.response.headers["Content-Type"] = 'text/text'
    self.response.out.write("Put")

So now when you are writing your main method that creates the WSGI application, you would write it something like:

import wsgiref.handlers

def main():
  app = webapp.WSGIApplication(
      [('/', MethodTest)],
      debug=True)
  wsgiref.handlers.CGIHandler().run(MockHTTPMethodMiddleware(app))

if __name__ == "__main__":
  main()

Notice that in the run method arguments, MockHTTPMethodMiddleware takes app as a parameter, thus MockHTTPMethodMiddleware will run before it runs app.

Conclusion

While there wasn’t support out of the box for mocking HTTP methods for browsers, with a little help from a WSGI Middleware class, it’s not too hard to add that functionality in, nor is it hard to add anything else you would want to use.