Re: [Rails] The role of self and :: within a method of a model

salt is a method? I thought it was an attribute of the model

Also, are you saying that SHA2 is a constant and Diges is a utility class of
ActiveSupport, and because SHA2 was defined within the class and because we
are referencing it outside of the class, it must be defined with the scope
operator ::?

Digest::SHA2

Frederick Cheung-2 wrote:
>
>
>
> On Jan 18, 8:40 pm, JohnMerlino <stoici...@aol.com> wrote:
>> Hey all,
>> I understand that a def self.abc, for example, is a class method, which
>> allows you to call its contents by just referencing model.abc (rather
>> than
>> model.new.abc). However, what is its role when located in a method inside
>> a
>> model like in the code below.
>>
>
> If you call a method without specifying the receiver (ie if you just
> write foo()) then you are implicitly sending that call to the current
> object, ie self. Writing self.foo just makes that explicit. Just about
> the only time it is actually necessary is when calling a setter
> function: if you write
>
> salt = ...
>
> ruby thinks you are trying to set a local variable called salt rather
> than call the current object's salt= method
>
>> Also in the code below, you see :: located in the method. Isn't that used
>> for modules and namespaces? If so, why is it located in the method here.
>> These two things are preventing me from comprehending the below code:
>>
> :: is the scope operator. SecureRandom is nested inside ActiveSupport
> so normally you need to write ActiveSupport::SecureRandom (unless your
> lexical scope includes ActiveSupport or you've included it etc
> (constant resolution is a little gnarly in ruby))
>
> Fred
>
>>     def hash_new_password
>>       # First reset the salt to a new random string.  You could choose a
>>       # longer string here but for a salt, 8 bytes of randomness is
>> probably
>>       # fine.  Note this uses SecureRandom which will use your platform's
>> secure
>>       # random number generator.
>>       self.salt = ActiveSupport::SecureRandom.base64(8)
>>       # Now calculate the hash of the password, with the salt prepended,
>> store
>>       # store that in the database
>>       self.hashed_password = Digest::SHA2.hexdigest(self.salt +
>> @new_password)
>>     end
>>   end
>>
>> Thanks for any suggestions.
>> --
>> View this message in
>> context:http://old.nabble.com/The-role-of-self-and-%3A%3A-within-a-method-of-...
>> Sent from the RubyOnRails Users mailing list archive at Nabble.com.
>
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