Ruby object mass assignment - ruby

Question

Is there any better way to do the below code?
user.name = "abc"
user.email = "abc#test.com"
user.mobile = "12312312"
Something like this will do:
user.prepare do |u|
u.name = "abc"
u.email = "abc#test.com"
u.mobile = "12312312"
end

Answer 1

tap let's you do exactly that:
user.tap do |u|
u.name = "abc"
u.email = "abc#test.com"
u.mobile = "12312312"
end

Answer 2

Alternative option when your attributes come in the form of a hash:
attrs = {
name: "abc",
email: "abc#test.com",
mobile: "12312312"
}
attrs.each { |key, value| user.send("#{key}=", value) }

Answer 3

You could do the following as well:
user.instance_eval do
#name = "abc"
#email = "abc#test.com"
#mobile = "12312312"
end
You can access the instance variables of user inside the block given to instance_eval
You could use the below code if you wish to invoke the accessor methods instead of directly manipulating the instance variables.
user.instance_eval do
self.name = "xyz"
self.email = "abc#test.com"
self.mobile = "12312312"
end
or
user.instance_eval do |o|
o.name = "xyz"
o.email = "abc#test.com"
o.mobile = "12312312"
end

Answer 4

With ActiveRecord objects you can use .assign_attributes or the update
methods:
user.assign_attributes( name: "abc", email: "abc#test.com", mobile: "12312312")
# attributes= is a shorter alias for assign_attributes
user.attributes = { name: "abc", email: "abc#test.com", mobile: "12312312" }
# this will update the record in the database
user.update( name: "abc", email: "abc#test.com", mobile: "12312312" )
# or with a block
user.update( name: "abc", mobile: "12312312" ) do |u|
u.email = "#{u.name}#test.com"
end
.update accepts a block, while assign_attributes does not. If you are simply assigning a hash of literal values - such as those passed by a user in the params then there is no need to use a block.
If you have a plain old ruby object which you want to spice up with mass assignment you can do:
class User
attr_accessor :name, :email, :mobile
def initialize(params = {}, &block)
self.mass_assign(params) if params
yield self if block_given?
end
def assign_attributes(params = {}, &block)
self.mass_assign(params) if params
yield self if block_given?
end
def attributes=(params)
assign_attributes(params)
end
private
def mass_assign(attrs)
attrs.each do |key, value|
self.public_send("#{key}=", value)
end
end
end
This will let you do:
u = User.new(name: "abc", email: "abc#test.com", mobile: "12312312")
u.attributes = { email: "abc#example.com", name: "joe" }
u.assign_attributes(name: 'bob') do |u|
u.email = "#{u.name}#example.com"
end
# etc.

Answer 5

Assuming that 'user' is a class that you control, then you can just define a method to do what you want. For example:
def set_all(hash)
#name, #email, #mobile = hash[:name], hash[:email], hash[:mobile]
end
And then in the rest of your code:
user.set_all(name: "abc", email: "abc#test.com", mobile: "12312312")
If 'user' is an instance of, say, an ActiveRecord model, then I'm a little shaky on the details of how you would get this to work. But the principal still applies: DRY up code by moving the responsibility for the complexity to the receiver.