# Can't call link\_to from within a model class **URL:** \ **Category:** Rails\ **Created:** [May 11, 2006, 11:47pm UTC](https://www.ruby-forum.com/t/cant-call-link-to-from-within-a-model-class/60308 "2006-05-11T23:47:05Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![random52k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/7bcc69/32.png) [@random52k](https://www.ruby-forum.com/u/random52k)\ **Post date:** [May 11, 2006, 11:47pm UTC](https://www.ruby-forum.com/t/cant-call-link-to-from-within-a-model-class/60308/1 "2006-05-11T23:47:05Z")
can anyone tell me how to call link\_to from within a model class? I’m trying to do something like the following: validates\_uniqueness\_of :email, :message =\> “address has already been taken. If you’ve forgotten your password, please click " + link\_to(‘here’, :action =\> ‘forgot\_password’, :controller =\> ‘site’) + " to reset it.” although I get the following error when it attempts to validate a form: Session contains objects whose class definition isn’t available. Remember to require the classes for all objects kept in the session. (Original exception: undefined method `link\_to’ for User:Class [NoMethodError]) I’ve also tried doing: class User \< ActiveRecord::Base include ActionView::Helpers::UrlHelper … but calling link\_to produces the same error… I’ve also tried: validates\_uniqueness\_of :email, :message =\> "address has already been taken. If you’ve forgotten your password, please click " + ActionView::Helpers::UrlHelper:link\_to(‘here’, :action =\> ‘forgot\_password’, :controller =\> ‘site’) + " to reset it. but that gives me: Session contains objects whose class definition isn’t available. Remember to require the classes for all objects kept in the session. (Original exception: undefined method `link\_to’ for ActionView::Helpers::UrlHelper:Module [NoMethodError]) if anyone can help me, I’d really appreciate it… Thanks, Mike ---
**Author:** ![random52k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/7bcc69/32.png) [@random52k](https://www.ruby-forum.com/u/random52k)\ **Post date:** [May 11, 2006, 11:56pm UTC](https://www.ruby-forum.com/t/cant-call-link-to-from-within-a-model-class/60308/2 "2006-05-11T23:56:23Z")
On 5/11/2006, “Mike G.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > can anyone tell me how to call link\_to from within a model class? I’m > trying to do something like the following: That would break the model/view/controller paradigm. The model isn’t supposed to know anything about the view (or even how the data is rendered). ---
**Author:** ![random52k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/7bcc69/32.png) [@random52k](https://www.ruby-forum.com/u/random52k)\ **Post date:** [May 12, 2006, 3:33pm UTC](https://www.ruby-forum.com/t/cant-call-link-to-from-within-a-model-class/60308/3 "2006-05-12T15:33:08Z")
On 5/11/06, Deirdre Saoirse M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > On 5/11/2006, “Mike G.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > can anyone tell me how to call link\_to from within a model class? I’m > > trying to do something like the following: > > That would break the model/view/controller paradigm. > > The model isn’t supposed to know anything about the view (or even how > the data is rendered). true, but in my case, my choices are either using link\_to/url\_for or hardcoding a tag, and I wanted to avoid the latter. So yes, I realize this breaks the separation of the model from the view, but since the validation messages are provided by the model, I can’t think of how else I should do this… Thanks, Mike ---
**Author:** ![random52k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/7bcc69/32.png) [@random52k](https://www.ruby-forum.com/u/random52k)\ **Post date:** [May 12, 2006, 3:42pm UTC](https://www.ruby-forum.com/t/cant-call-link-to-from-within-a-model-class/60308/4 "2006-05-12T15:42:27Z")
Ultimately, the built in validation message methods really aren’t good enough for stuff like this. On a recent project in a similar situation, we used @object.errors.full\_messages to get an array containing all the error messages, and then produced custom output based on those errors. Its a lot less clean, but honestly, there’s not much way around it.