How to pass variables to render_to_string?

Question

Trying to do the following

@message = render_to_string ( :sender => sender, :template => "template" )          

But when accessing @sender in template it turns out to be nil:NilClass. Double checked if I pass the right variable and it's totally fine. Maybe there are other way to pass variables to render_to_string?

Solution 1

It might be the syntax you're using. Try using the :locals argument:

@m = render_to_string :template => "template", :locals => {:sender => sender}

Then you just need to access sender (without an @) as a local variable inside the template.

Solution 2

Here's Jason Kim's solution he wrote in a comment which worked for me:

ActionController::Base.new.render_to_string(
  "user_mailer/welcome_email.html.erb", locals: { :@user => user}
)

Please mind the :@user => value bit.

---

In Rails 5 (atm in beta):

ApplicationController.render(
  file: 'path',
  assigns: { foo: 'bar' }
)

More here

Solution 3

Try this:

ac = ActionController::Base.new()  
ac.render_to_string(:partial => 'path to your partial',:locals => {:varable => your variables})

Solution 4

In rails 4.0.2 this worked:

render_to_string(partial: 'path/to/partial', locals: { argument: 'value'}

Solution 5

I was trying to render a different format of partial in render_to_string. The thing which really worked for me was:

render_to_string(:partial => 'partial_file.html', :locals => {:variable => variable}, :format => :html)

where the name of the file was _partial_file.html.erb.

View more solutions

Comments

[Peter Brown]

Just noticed you were trying to access sender as @sender in your view. Not sure about your original code, but if you use the locals syntax, it will be a local variable (not an instance variable) and will be accessed without the @

[MrYoshiji]

Your solution actually work. You can pass locals as you said and access them as local variables, not instance variables.

[Jason Kim]

I've been trying to use render_to_string from model. In order to use with as instance variable, I had to do ActionController::Base.new.render_to_string(:template => "template", :locals => {:@sender => sender})

[Sergey Alekseev]

Doesn't work in the latest 4-2-stable github.com/rails/rails/commit/…