In Ruby/Sinatra, how to halt with an ERB template and error message

user_123412 0
Viewed 3292

In my Sinatra project, I'd like to be able to halt with both an error code and an error message:

halt 403, "Message!"

I want this, in turn, to be rendered in an error page template (using ERB). For example:

error 403 do
    erb :"errors/error", :locals => {:message => env['sinatra.error'].message}
end

However, apparently env['sinatra.error'].message (aka the readme and every single website says I should do it) does not expose the message I've provided. (This code, when run, returns the undefined method `message' for nil:NilClass error.)

I've searched for 4-5 hours and experimented with everything and I can't figure out where the message is exposed for me to render via ERB! Does anyone know where it is?

(It seems like the only alternative I can think of is writing this instead of the halt code above, every time I would like to halt:

halt 403, erb(:"errors/error", :locals => {m: "Message!"})

This code works. But this is a messy solution since it involves hardcoding the location of the error ERB file.)

(If you were wondering, this problem is not related to the show_exceptions configuration flag because both set :show_exceptions, false and set :show_exceptions, :after_handler make no difference.)

erb sinatra ruby
2 Answers

In Sinatra v2.0.7+, messages passed to halt are stored in the body of the response. So a halt with an error code and an error message (eg: halt 403, "Message!") can be caught and rendered in an error page template with:

error 403 do
  erb :"errors/error", locals: { message: body[0] }
end
user_20681650
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