Sky Bill Proxy

Overview

The application is made up of a REST proxy written in Ruby using the sinatra framework, and a webpage constructed using HTML, CSS, JavaScript, jQuery and mustache.

The simple proxy makes a REST call to a service providing the customers billing information in JSON format. This is checked and then returned to the calling webpage.

There are several pros and cons with this appraoch:

Pros

• The proxy server need not render any content, this means that the HTML etc can be served by a web server and cached as it doesn't change
• The CPU load on the server is relatively small and the rendering effort is carried out on the client
• With a suitable JavaScript framework, e.g. Bootstrap, a page can be designed that is responsive and re-sizes to any device

Cons

• The proxy is I/O bound and each connection waits until the REST call to the bill server is complete
• Sinatra doesn't provide an easy way to handle multiple connections, we rely on the Ruby Webserver for this
• Really this is alot of code for a reverse proxy - we should just use nginx :D

Configuration

Yaml Configuration

Environment

There are several environment variables that the application makes use of. More can be added by including those in the configuration file. Only the RACK_ENV environment variable is mandatory in the sense that it is always present for any RACK application.

RACK_ENV

This is a standard variable used to communicate the environment in which a RACK application is running. The values this variable can take the following values

• development
• test
• production

For normal development work locally the value of this variable is obviously "development". When running tests however it has been set to "test" in the Rakefile to force that configuration.

When running under heroku the value "production" is set.

Running

Check out the code

git clone https://github.com/fionahiklas/skybill-sinatra.git

Install Gems

Run the following

gem install bundler --user-install
export PATH=~/.gem/ruby/2.0.0/bin:$PATH

cd <base of cloned code>

bundle install --path ~/.gem

Start using rack

Run the following command to start the server

rackup

You can then access the index page at the following URL

http://localhost:9292/html/index.html

Tests

Ruby

The ruby tests make use of rack-test and test/unit, they can be executed with the following command

rake test

You can also test the server (sinatra front-end) and client (makes calls to Skybill REST endpoint) code separately using the following commands

QUnit

The Qunit tests for the front-end can be executed by loading each html page under the test/qunit directory into a web browser of your choice (I used firefox).

In order to do this, however, you must be running the Ruby server so that it can serve the HTML files. It isn't possible for QUnit/JavaScript to load the template files without there being a real server, I tried doing this from file:/// URLs but it doesn't work properly.

Start the server:

rackup

Use for following URLs for the QUnit tests

• http://localhost:9292/qunit/skybill_ready_test.html
• http://localhost:9292/qunit/top_level_template_test.html

Further Development

Using NGinx

This is MUCH faster in terms of proxying the skybill REST endpoint. This would mean we could throw away the Ruby code.

UI

This could be MUCH neater and also using JQuery UI to collapse certain sections. The loading process needs some animation while the JSON is retrieved.

Tests

The QUnit tests need to cover much more of the functionality.