LFE Docs

Configuring Your Server

Now that our webhook is ready to deliver messages, we’ll set up a basic Sinatra server to handle incoming payloads.

Recall that we specifically set our webhook URL to http://localhost:4567/payload. Since we’re developing locally, we’ll need to expose our local development environment to the Internet, so that GitHub can send out messages, and our local server can process them.

Note: you can download the complete source code for this project from the platform-samples repo.

Using ngrok

First, we’ll install a program to expose our local host to the Internet. We’ll use ngrok to do this. ngrok is a free download available for all major operating systems.

When you’re done with that, you can expose your localhost by running ./ngrok 4567 on the command line. You should see a line that looks something like this:

Forwarding    http://7e9ea9dc.ngrok.com -> 127.0.0.1:4567

Copy that funky *.ngrok.com URL! We’re now going to go back to the Payload URL and pasting this server into that field. It should look something like http://7e9ea9dc.ngrok.com/payload.

By doing this, we’ve set ourselves up to expose our localhost at path /payload to the Internet.

Writing the server

Now comes the fun part! We want our server to listen to POST requests, at /payload, because that’s where we told GitHub our webhook URL was. Since ngrok is exposing our local environment, we don’t need to set up a real server somewhere online, and can happily test out our code locally.

Let’s set up a little Sinatra app to do something with the information. Our initial setup might look something like this:

require 'sinatra'
require 'json'

post '/payload' do
  push = JSON.parse(request.body.read)
  puts "I got some JSON: #{push.inspect}"
end

(If you’re unfamiliar with how Sinatra works, we recommend reading the Sinatra guide.)

Start this server up.

Since we set up our webhook to listen to events dealing with Issues, go ahead and create a new Issue on the repository you’re testing with. Once you create it, switch back to your terminal. You should see something like this in your output:

~/Developer/platform-samples/hooks/ruby/configuring-your-server $ ruby server.rb
== Sinatra/1.4.4 has taken the stage on 4567 for development with backup from Thin
>> Thin web server (v1.5.1 codename Straight Razor)
>> Maximum connections set to 1024
>> Listening on localhost:4567, CTRL+C to stop
I got some JSON: {"action"=>"opened", "issue"=>{"url"=>"...

Success! You’ve successfully configured your server to listen to webhooks. Your server can now process this information any way you see fit. For example, if you were setting up a “real” web application, you might want to log some of the JSON output to a database.

For additional information on working with webhooks for fun and profit, head on over to the Testing Webhooks guide.