Posts Tagged: ruby

Rails Engine to produce a photography portfolio/brochureware site.

I was asked to provide a flexible photography portfolio site – brochure type site.

Given Rails was on my “fad” list, I decided to have a go that way.

What I came up with was a ‘generic’ Rails Engine to do the work of pulling the galleries etc together. This was then used inside a specific Rails app which just had the photos/galleries/comments. The aim being that the site owner can arrange things as they want and then do a commit/push to heroku to update their site.

The Engine is open source, available on github here.

Its a bit dated now, using Rails 3.0.9 – although should be easy to update, as its quite simple :) – the Gemfile only has Rails, Capybara and sqlite3 – not sure why the last 2 are there – as no DB is used.

The controllers do the work of responding to various user requests – using the folder/image structure found in the host app to define the site structure.

In the model directory, there are several classes.  photo – is used to wrap each photo image, including a related thumbnail and caption. project – wraps a directory, tracking what images are in it. site_config – this handles parsing the overall site configuration, which is held in a YAML file in the host Rails app.

The lib directory defines the basic engine configuration – how it hooks into the host app.

Under test/dummy there is a minimal rails app using the engine – for testing.  Although I cant see a sample config file – perhaps it relied on the defaults :)

At the time, it seemed a good way to produce the site.  I’ve not had to use it again yet, and that will be the test of how ‘generic’ it is…

Ruby via the backdoor…

At work, our team does not do much development – we support a third party’s product.  Most work is around the edges, integrating it with the rest of the systems.

Some of that work is in Java, but recently I had a chance to sneak in a little Ruby (or  JRuby to be specific).

Why Ruby/JRuby? To me, the main reason is that its a more succinct way of expressing the program logic and combined with the JVM integration features of JRuby, it was an obvious choice.

The premise was we wanted to make the extension of a component flexible/scriptable and ruby seemed like a good fit.

Here are some of the highlights of what was done…

The requirement was to publish data from one source to a webservice.

The initial cut was a pipeline of classes that transformed the source data into target format and then calling the webservice. The problem with this solution was that the webservice was very slow – only able to handle around 16 calls per second – compared to the 100 messages per second that were coming from the source.

This was addressed by adding some threading via calling out to Java’s concurrent utilities

A threadpool was created (num_threads specifies number of threads to run):

@exec = java.util.concurrent.Executors.new_fixed_thread_pool $props["im.num_threads"].to_i

And then for each message that came in, its handling is passed to the threadpool

@exec.execute do
... # do work, happens in a separate thread

This meant we could hammer the webservice with a lot more calls, however the downside is that we need to be wary of concurrent issues.

Some of the processes in the pipeline were completely standalone and so were wrapped in Java ThreadLocal objects.

@time_formatter = $jruby_obj.threadLocal { }

Where the process was not standalone, but had shared data structures, then a mutex was used to ensure only one process accessed the structure at a time.

# create the mutex object - once for the shared object
@mutex =

# then when we need to control access to some data we do this
@mutex.synchronize do

Now, by specifying 20-30 threads, were do 100+ calls per second to the webservice :)

How to test a local gem (when no internet available)


I frequently use my laptop on the train with little or no internet connectivity.

Thus, when testing locally developed gems, besides running their own test suites, its good to test them with my/an app that uses the gem.  But I want to do this without pushing the gem onto rubygems/github and then pulling it down again.

These are my notes on how I tried to do it – but I did not get it working…

Firstly, I use RVM and Bundler – so any solution needs to be compatible with that.

From this ascii/rails-cast, it seems there should be a rake task of “rake install” which will install into the current ruby/gem environment.

So, the plan is:

  • to switch to my app’s ruby/gemset
  • rake install my dev gem
  • test the app.

However, even though the gem list showed the new gem version, it was not being used.  Perhaps I need to run bundle update…



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