Validating integer in controller

rubyonrails-talk
1

I'm teaching Ruby on Rails right now, and I will save some values to a plain text file. That works, but I want to validate the variables. Normally I put the validation in the model, but right now I want to check the variables before saving into the text file. I tried to use:

[code]validates_numericality_of params[:size][/code]

but then I get the following error:

undefined method `validates_numericality_of' for #<ReportLinesController:0x44ef120>.

What should I do?

2

Sjoerd Schunselaar wrote:

I'm teaching Ruby on Rails right now, and I will save some values to a plain text file. That works, but I want to validate the variables. Normally I put the validation in the model, but right now I want to check the variables before saving into the text file. I tried to use:

[code]validates_numericality_of params[:size][/code]

but then I get the following error:

undefined method `validates_numericality_of' for #<ReportLinesController:0x44ef120>.

What should I do?

I've now fixed it with a custom method:

def isInteger()     print (params[:aantal].to_i)     if ((params[:aantal].to_i) != 0)       print "gaaaa"       return true

    else       print "gooo"       return false     end

Is there something better?

3

validates_numericality_of should work for classes that inherit from ActiveRecord::Base. Does yours?

4

The important point is that the validation logic comes from ActiveRecord, not ActionController, so you can't just add a validation call like validates_numericality_of anywhere you want. From a big- picture perspective this makes sense: validation is business logic and is properly separated into the model. If you're teaching RoR and not taking these MVC concepts into consideration you really need to revise things quickly.

You might be able to mix in the ActiveRecord::Validations module into your models so that you can get ActiveRecord-like validation without actually using ActiveRecord. Another alternative might be to consider writing a text-file-adapter for ActiveRecord but I suspect you don't have time for that.

Good luck.

5

That validator method is defined in ActiveRecord--from which all your models will derive. So it's available in models no problem, but if you want to bring it in to a controller, you're going to have to torture the framework. :wink:

Think of it as rails' way of encouraging you to do your validations in the model.

6

AndyV wrote:

The important point is that the validation logic comes from ActiveRecord, not ActionController, so you can't just add a validation call like validates_numericality_of anywhere you want. From a big- picture perspective this makes sense: validation is business logic and is properly separated into the model. If you're teaching RoR and not taking these MVC concepts into consideration you really need to revise things quickly.

You might be able to mix in the ActiveRecord::Validations module into your models so that you can get ActiveRecord-like validation without actually using ActiveRecord. Another alternative might be to consider writing a text-file-adapter for ActiveRecord but I suspect you don't have time for that.

Good luck.

On May 5, 9:36�am, Sjoerd Schunselaar <rails-mailing-l...@andreas-

Thank you, for your answer! I changed it and use a model for the file load en saving so I can validate the value.

7

Excellent! Keep spreading the good word about Ruby and Rails!