Making a non blocking HTTP request in a Rails app

Question

Is anyone aware of a way to make outgoing non blocking HTTP requests from within Rails? I will need the response body eventually and am trying to avoid bringing up new frameworks to keep things simple.

Thanks

Familiarize

Possible duplicate of What is the preferred way of performing non blocking I/O in Ruby? – Cyr

Answer 1

You can do something like this:

def async_post
  Thread.new do
    uri = URI('https://somewhere.com/do_something')
    response = Net::HTTP.post_form(uri, 'param1' => '1', 'param2' => '2')
    # do something with the response
  end
  # Execution continues before the response is received
end

Serf

Answer 2

To simulate the non-blocking part, set a low read_timeout. Also be prepared to catch the resulting timeout error:

request = Net::HTTP::Get.new(url)
http = Net::HTTP.new(url.host, url.port)

http.read_timeout = 1

begin
  http.request(request)
rescue Timeout::Error => e
end

I don't know of a basic rails mechanism that will both make a non-blocking call and receive the response. Rails is very much tied to the request/response cycle, so usually the basic controller execution path will have ended before the HTTP call returns.

Archlute

"low timeout" != "non-blocking" – Bridgers

Absolutely nothing about a low timeout "simulates" non-blocking IO. Now you're doing blocking IO with tons of timeouts and failed requests, the worst of all worlds. – Agitprop

Answer 3

You're looking for "background jobs" or "background workers." There are a variety of gems for this. This blog post has a good overview of what's out there. delayed_job is very popular right now.

Mephitis