Class: Rack::Informant

Inherits:
Object
  • Object
show all
Defined in:
lib/rack/informant.rb

Overview

Middleware that “informs on” an application, reporting everything it does to its secret employer. Other middlewares may become hostile if they find out.

After each request is processed, calls the provided block with a hash containing:

* :method - HTTP request method, e.g. 'GET', 'POST'
* :path - path segment of the request (no host, port or querystring),
          e.g. '/info'
* :status - HTTP response status code, e.g. 200, 404
* :runtime - total request processing time (by the server's reckoning) in
             *seconds*, as a float.  e.g. 0.1 == 100 ms.

This middleware is async-safe (i.e. should work correctly for both synchronous requests and asynchronous requests).

Example usage:

require 'rack/informant'
use Rack::Informant do |request|
  # poor man's request logging (use Rack::CommonLogger instead)
  puts "#{request[:method]} #{request[:path]}: #{request[:status]} #{request[:runtime]}"
end

Instance Method Summary collapse

Constructor Details

#initialize(app, &block) ⇒ Informant

Returns a new instance of Informant.



27
28
29
30
 
# File 'lib/rack/informant.rb', line 27

def initialize(app, &block)
  @app = app
  @callback = block || lambda {|*_|}
end

Instance Method Details

#call(env) ⇒ Object 



32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
 
# File 'lib/rack/informant.rb', line 32

def call(env)
  start = Time.now

  if original_callback = env['async.callback']
    env['async.callback'] = proc do |response|
      status, headers, body = response

      inform!(env, start, status, headers, body)

      original_callback.call(response)
    end
  end

  catch :async do
    status, headers, body = @app.call(env)

    # if we got this far, then @app.call didn't throw :async
    return [status, headers, body] if status == -1 # alternative async API

    # if we got *this* far, @app.call is definitely synchronous
    inform!(env, start, status, headers, body)

    return [status, headers, body]
  end

  # we only end up here if @app.call threw :async, so just throw it on.
  throw :async
end