There’s an interesting article “HTTP PubSub: Webhooks and PubSubHubBub” that covers working with webhooks and points to a great HTTP / webhook developer utility “PostBin“, which:

“lets you debug web lets you debug web hooks by capturing and logging the asynchronous requests made when events happen. Make a PostBin and register the URL with a web hook provider. All POST requests to the URL are logged for you to see when you browse to that URL.”

The article also shows a very simple pubsub “Hello, World” script, postbin.rb, that nicely demonstrates the basic features of Watercoolr — another HTTP-based pubsub mechanism.

So I thought I’d write the equivalent to postbin.rb, this time demonstrating the same features in Coffeeshop. This way, we can see how things compare. It’s in Python, but that’s neither here nor there.

import httplib, urllib, sys

hubconn = httplib.HTTPConnection('localhost:8888')

hubconn.request("POST", "/channel/") channel = hubconn.getresponse().getheader('Location') print "Created channel %s" % channel

hubconn.request("POST", channel + "subscriber/",  urllib.urlencode({'resource': sys.argv[1]})) subscriber = hubconn.getresponse().getheader('Location') print "Added subscriber %s" % subscriber

while True:   print "Post message:"   msg = sys.stdin.readline()   hubconn.request("POST", channel, msg)   message = hubconn.getresponse().getheader('Location')   print "Message published: %s" % message

I’ve added some print statements to show what’s going on, and to highlight the HTTP resources created and utilised.

Here’s a sample execution:

python postbin.py http://www.postbin.org/1a5m8w0 Created channel /channel/1/ Added subscriber /channel/1/subscriber/2/ Post message: Hello, Webhooks World! Message published: /channel/1/message/ahFxbWFjcm8tY[...]RgDDA Post message:

This message appears in the PostBin bucket as expected. Nice!

As well as showing how useful PostBin is, I hope this demonstrates how the basic features of Coffeeshop work, and perhaps more importantly, shows you that the REST-orientated approach is straightforward and works well.