Instantiate a Class from a String in Rails
Rails classes need to be called dynamically sometimes. Learn how to do it using the constantize inflector.
Sometimes you want your class names to be dynamic. Rails has a nice constantize inflector that makes this easy.
In the simplest of examples, let's just say you have a "post" string and you want to load the Post class from it. Something like the following should work great.
str = "post"
new_class_instance = str.constantize.newWe can get a little wild. Let's say you have a multi-word string and want to constantize and then instantiate it.
str = "posts controller"
new_class_instance = str.titleize.gsub(/\ /, '').constantize.newEssentially, this just shows you want a properly-cased string (the string equivalent of the class name) before you call constantize.
Keep Reading
Bi-Directional has_and_belongs_to_many on a Single Model in Rails
Bi-directional HABTM relationships are easy in Rails, but when you need to do it on a single model, that's when it gets tricky. Here's one approach.
Order Rails Query by Virtual Attribute
Rails' scopes don't work well with virtual attributes since they resolve to a SQL query. Instead you can throw them in an array and then sort by a virtual attribute.
Convert PDF to Image with Dragonfly and Rails
Converting a PDF to an image using Rails and Dragonfly is actually quite simple. Check it out.