Ruby flew too

Rails has a lovely feature as part of ActiveRecord - Callbacks; to wit: Callbacks are hooks into the life cycle of an Active Record object that allow you to trigger logic before or after an alteration of the object state Basically, that means that you can instruct Rails to execute your own code throughout the process of creating, updating and destroying objects/records. You can, for example, use them to set some default values on create, or perhaps do some last minute validation, or even fire an event just after you've saved a record. The available callbacks are: after_initialize after_find after_touch before_validation after_validation before_save around_save after_save before_create around_create after_create before_update around_update after_update :before_destroy around_destroy after_destroy after_commit after_rollback At the same time, Ruby methods have the concept of implicit return values. That is to say, any method will return the value of the la...

If you work with Ruby on Windows in a corporate environment, sooner or later, you will hit an error when you are trying to install or update Gems. In my case, I simply had to set a few environment variables and I was good to go. RubyGems uses the HTTP_PROXY, HTTP_PROXY_USER and HTTP_PASS by default so if you open up a command prompt and set these as follows, it will use them to find the proxy and authenticate you to your proxy server: set HTTP_PROXY=http://pr.oxy.ip:port set HTTP_PROXY_USER=domain\user.name set HTTP_PASS=sUp3rS3curepAs$w0rd Extra points: A reader sent me a comment that this will only work when the proxy is using basic authentication. If you're having trouble using this method then you can give ntlmaps a shot. It's basically a little bit of python magic that sets up a proxy on your localhost through which you can route traffic and it will handle the authentication with your proxy server for you.

There are always times when you need to override the default RESTful routes in Rails. The most common case for this is mapping a /logout url to a session#destroy controller and action. However, this simple example doesn't really help when you want to achieve something a little more intricate - for example using a completely different url for a resource. Examples include a blog when you want your urls to add blog posts to be /add rather than blogs/new. Or what about a application with a Users model that has different types of users that can be added - perhaps it is a medical database and you have Doctors and Nurses - you want your urls to reflect the kind of person you are adding or editing - so doctor/new or nurse/new rather than users/new. Mapping urls like this is easy. However there is a little gotcha that you have to be aware of. Let's walk through an example and we'll see how to make it work New project We'll create a simple project for this example - a hypoth...

For fun, I thought I would start a new Ruby on Rails project and use MiniTest instead of Test::Unit. Why? Well MiniTest is Ruby 1.9s testing framework dejour, and I suspect we will see more and more new projects adopt it. It has a built in mocking framework and RSpec like contextual syntax. You can probably get away with fewer gems in your Gemfile because of that. Getting started is always the hardest part - let's jump in with a new rails project rails new tddforme --skip-test-unit Standard stuff. MiniTest sits nicely next to Test::Unit, so you can leave it in if you prefer. I've left it out just to keep things neat and tidy for now. Now we update the old Gemfile: group :development, :test do gem "minitest" end and of course, bundle it all up.....from the command line: $ bundle Note that if you start experiencing strange errors when we get in to the generators later on, make sure you read about rails not finding a JavaScript runtime . Fire up...

If any language should have been name after a snake, Javascript should have. It's a slippery little thing I tell you. It slithers and slides and wraps around you. And you have to work like a snake charmer to coax it out of its basket and make it play nicely without biting you. Take, for example the simple idea of passing a variable by ref or by val. Javascript's snakey little implementation means that if you are passing a variable then you'll never pass it by ref. However if you are passing an object, then, hey presto, by ref it is. Bear witness: var globalVar; var anObj = function() { this.value = "default value"; } function changeValue(arg){ arg.value = "Changed by function"; } function changeUp(arg) { arg = "Changed"; } globalVar = "global"; console.log(globalVar); changeUp(globalVar); console.log(globalVar); var myObj = new anObj()...

Some thoughts on the Padrino and Rails . For the past few weeks, I've been working on a small project that is using Padrino rather than Rails. The interesting thing was that the decision for the technology was based on the idea that the project was only going to have a few objects; at most five or six and as such, didn't need something as large, complex or weighty as Rails . However, something as barebones as Sinatra would not allow for some of the more rapid application development that you get from some of the baked in goodness of Rails - things like Sessions, Flash, Form helpers and generators all speed up development fairly considerably. With that in mind, Padrino was the framework of choice. Now Padrino is interesting. It's a great little framework, but, the temptation is to look at it's relative light-weightedness in comparison to Rails and think it will require less learning time or up-front knowledge for someone with little experience of the framework or of so...

Running a fresh copy of Linux Mint and Rails lets you generate a new project with no problems, but you might start to hit issues as soon as you start trying to generate some scaffolding. So for example, if you try rails g scaffold User name:string email:string You'll get something like this: /home/x/.rvm/gems/ruby-1.9.3-p194@rails3.2/gems/execjs-1.4.0/lib/execjs/runtimes.rb:51 in 'autodetect': Could not find a JavaScript runtime. It will also tell you to visit https://github.com/sstephenson/execjs to see a list of available runtimes. Don't be shy now, head over there and take a look. Or, if you just want to hack it, add the following to your Gemfile: gem 'therubyracer' Run your bundle update and you should be good to go.