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When do you use attr_reader/attr_writer/attr_accessor in Rails models?
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In Ruby, object methods are public by default, while data is private. To access and modify data, we use the attr_reader and attr_writer . attr_accessor is a shortcut method when you need both attr_reader and attr_writer .
attr_reader and attr_writer in Ruby allow us to access and modify instance variables using the . notation by creating getter and setter methods automatically. These methods allow us to access instance variables from outside the scope of the class definition.
attr_accessible is used to identify attributes that are accessible by your controller methods makes a property available for mass-assignment.. It will only allow access to the attributes that you specify, denying the rest.
Attributes are specific properties of an object. Methods are capabilities of an object. In Ruby all instance variables (attributes) are private by default. It means you don't have access to them outside the scope of the instance itself. The only way to access the attribute is using an accessor method.
Never, unless you have specific need for it. Automatic database-backed accessors are created for you, so you don't need to worry.
Any attr_accessors you do create will change the relevant @attr on the rails object, but this will be lost when the object is destroyed, unless you stick it back in the database. Sometimes you do want this behavior, but it's unusual in a rails app.
Now in ruby, it's a different story, and you end up using these very frequently. But I'd be surprised if you need them in rails---especially initially.
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attr_accessor can be used for values you don't want to store in the database directly and that will only exist for the life of the object (e.g. passwords).
attr_reader can be used as one of several alternatives to doing something like this:
def instance_value "my value" end If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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