Validate method

rubyonrails-talk
1

Hi,

I want to validate a string before saving, but I need a custom method because I want to change stuff in the string.

I need to remove all whitespaces (front, back, inside) of @movie.filename How I can do it, @movie is the model to save.

protected def validate # I think I put my code here to modify filename

end

secondly, after I modify my string I want to verify if it contains only : A-Z a-z 0-9 dash - underscore _

I'm not familiar with regular expression is it:

errors.add("filename", "has invalid format") unless filename =~ /[a-zA-Z0-9\-_]*/

BR David

2

Suppose I have a Model called House with a field called name

how can I validate the name field, I tried name in the validate method but it doesn't work, i tried :name, House.name, I don't know how I can validate this field within a validate method, I don't know how I can access it.

3

Suppose I have a Model called House with a field called name how can I validate the name field, I tried name in the validate method

It will be self.name

In reference to your earlier email about string manipulation and validation:

You can put your string manipulations in a before_validate method,

and then declare another function to validate if it is valid.

If you call that check_movie_filename, then you should have a line

validate :check_movie_filename

somewhere in your model.

Read up on ActiveRecord callbacks if you want to learn more about

these mechanisms.

Franz

4

You could just call name in the validate method (assuming you're redefining it) rather than self.name, as self will return the object that validate gets called on. You don't call self.self.name so why call self.name?

5

Putting self makes it clear that I’m using the model’s attribute accessors, and not a local variable within my method.