Class: ApiThrottling

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

Instance Method Summary collapse

Constructor Details

#initialize(app, options = {}) ⇒ ApiThrottling

Returns a new instance of ApiThrottling.



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# File 'lib/api_throttling.rb', line 6

def initialize(app, options={})
  @app = app
  @options = {:requests_per_hour => 60, :cache=>:redis, :auth=>true}.merge(options)
  @handler = Handlers.cache_handler_for(@options[:cache])
  raise "Sorry, we couldn't find a handler for the cache you specified: #{@options[:cache]}" unless @handler
end

Instance Method Details

#auth_required ⇒ Object 



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# File 'lib/api_throttling.rb', line 43

def auth_required
  body_text = "Authorization Required"
  [ 401, { 'Content-Type' => 'text/plain', 'Content-Length' => body_text.size.to_s }, [body_text] ]
end

#bad_request ⇒ Object 



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# File 'lib/api_throttling.rb', line 38

def bad_request
  body_text = "Bad Request"
  [ 400, { 'Content-Type' => 'text/plain', 'Content-Length' => body_text.size.to_s }, [body_text] ]
end

#call(env, options = {}) ⇒ Object 



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# File 'lib/api_throttling.rb', line 13

def call(env, options={})
  if @options[:auth]
    auth = Rack::Auth::Basic::Request.new(env)
    return auth_required unless auth.provided?
    return bad_request unless auth.basic?
  end
  
  begin
   cache = @handler.new(@options[:cache])
   key = generate_key(env, auth)
   cache.increment(key)
   return over_rate_limit if cache.get(key).to_i > @options[:requests_per_hour]
 rescue Errno::ECONNREFUSED
   # If Redis-server is not running, instead of throwing an error, we simply do not throttle the API
   # It's better if your service is up and running but not throttling API, then to have it throw errors for all users
   # Make sure you monitor your redis-server so that it's never down. monit is a great tool for that.
 end
  @app.call(env)
end

#generate_key(env, auth) ⇒ Object 



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# File 'lib/api_throttling.rb', line 33

def generate_key(env, auth)
  return @options[:key].call(env, auth) if @options[:key]
  auth ? "#{auth.username}_#{Time.now.strftime("%Y-%m-%d-%H")}" : "#{Time.now.strftime("%Y-%m-%d-%H")}"
end

#over_rate_limit ⇒ Object 



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# File 'lib/api_throttling.rb', line 48

def over_rate_limit
  body_text = "Over Rate Limit"
  retry_after_in_seconds = (60 - Time.now.min) * 60
  [ 503, 
    { 'Content-Type' => 'text/plain', 
      'Content-Length' => body_text.size.to_s, 
      'Retry-After' => retry_after_in_seconds.to_s 
    }, 
    [body_text]
  ]
end