Order of the state_machine callback chain

When using state_machine you sometimes need to know whether an object may execute a certain transition. Let's take an arbitrary object such as a blog article as an example that has those states:

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In Ruby (almost) everything is an Object. While this enables a lot of powerful features, this concept might be confusing for developers who have been programming in more static languages, such as Java or C#. This card should help understanding t...

If you need to look at the list of methods that are called upon certain events (like before/after saving etc), do this:

Model._save_callbacks.select {|cb| cb.kind == :before}.map{ |c| c.instance_variable_get :@filter }

Rails 2

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View specs are a powerful tool to test several rendering paths by their cases instead of using a more costing feature spec. This is especially useful because they become quite co...

A while back, I had a requirement to persist a record of which email addresses were sent an email through the system. I expected to find callback support for ActionMailer, but was surprised to find that it didn't exist.

You probably know that you can use CSS selectors to match against elements and their attributes, such as:

a[title] { /* any <a> that has a "title" */ }
a[data-fancy="true"] { /* any <a> that has their "data-fancy" attribute set to "true" *...

Native promises have no methods to inspect their state.

You can use the promiseState function below to check whether a promise is fulfilled, rejected or still pendi...

Use Socket.gethostname. So for a machine whose hostname is "happycat", it will look like this:

>> Socket.gethostname
=> "happycat"

That should work right away for your Rails application. For plain Ruby, you first need to do:

requi...