Question

I’ve been using filters in Sinatra the way it has been declared in the documentation: with no match string, with a match string or with a match regexp. It has been working fine til now. Now, I have a particular use case. Let’s say I have this route:

/resources/1

According to REST, and depending of the request method, this can either be a GET method, PUT method or DELETE method. First question is: How to write filters that are only called when it is a GET request? (currently I’m letting all of them get filtered and only then I test the method. It works, but I don’t like it). Second question, and more important: let’s say a PUT request like this is triggered:

/resources/

This is of course wrong, because the PUT request has no resource id associated. I would like to know if there is something in Sinatra that enables me to do something like this:

before "/resources/", :method => :put do
  error_message
end

just this possibility does not exist (before accepts only one argument). How could I achieve this result at best?

Answer 1

Actually, filters do take conditions. You don’t have to use a condition though, you could use a conditional within the filter:

before "/path/" do
  if request.request_method == "PUT"
    # do something
  end
end

If you want to use a condition, I think you’ll need to write one, perhaps something like this:

set(:accepted_verbs) {|*verbs|
  condition { 
    verbs.any?{|v| v == request.request_method }
  } 
}

before "/path/", :accepted_verbs => ["GET","POST"] do
  # do something
end

before "/path/", :accepted_verbs => ["PUT"] do
  # do something else
end

See conditions for more.