Setting Rails ActiveResource headers in a thread safe way

Question

I am making calls to an ActiveResource object inside an engine, and I need to set the headers in a thread safe way.

I have /lib/mymodule.rb in the engine and it looks something like this:

module MyModule
  def self.my_method()
    begin
       data = WebResource.find(:all) # Where WebResource < ActiveResource::Base
    rescue
       data = nil
    end

    return data
  end
end

Then in my views/controllers, I call this method roughly like this:

WebResource.headers[:some_id] = cookies[:some_id]
MyModule::my_method()

After asking this question and doing some reading, it looks like this is not threadsafe because I set headers at the class-level.

What is the best way to set these headers in a thread safe way?

score 2 · Accepted Answer · edited May 23 '17 at 12:27

2

Solved the issue. The solution is influenced by this question. Essentially, I overwrite the self.headers() method to store headers in Thread.current, instead of a class variable.

It looks like this:

class WebResource < ActiveResource::Base

  # ...

  class << self

    def headers
      Thread.current["active.resource.currentthread.headers"] = {} if Thread.current["active.resource.currentthread.headers"].blank?
      Thread.current["active.resource.currentthread.headers"]
    end

  end
end

edited May 23 '17 at 12:27

Community

1
1

answered Sep 20 '12 at 14:02

Oleksi

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ActiveResource now does this by default. It stores headers, site, proxy, basic auth and the connection itself in thread-local variables to make it all thread-safe: https://github.com/rails/activeresource/commit/538588ddba9ffc9bf356790e9186dc7e6adad12f – mltsy Nov 28 '17 at 18:41

Setting Rails ActiveResource headers in a thread safe way

1 Answers1