Class: Rack::Bug::SpeedTrace::TraceApp

Inherits:
Object
  • Object
show all
Defined in:
lib/rack/bug/speedtracer/trace-app.rb

Constant Summary collapse

TRACER_PATH = 
/^\/speedtracer/.freeze
CONTENT_TYPE = 
'application/json;charset=UTF-8'.freeze
FourOhFour = 
[404, {"Content-Type" => "text/html"}, "App tracker doesn't know that path or id"].freeze

Instance Method Summary collapse

Constructor Details

#initialize(db) ⇒ TraceApp

Returns a new instance of TraceApp.



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# File 'lib/rack/bug/speedtracer/trace-app.rb', line 9

def initialize(db)
  @db = db
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/rack/bug/speedtracer/trace-app.rb', line 13

def call(env)
  return FourOhFour unless env['PATH_INFO'].match(TRACER_PATH)

  resp = Rack::Response.new('', 200)
  resp['Content-Type'] = CONTENT_TYPE

  case env['REQUEST_METHOD']
  when 'HEAD' then
    # SpeedTracer dispatches HEAD requests to verify the
    # tracer endpoint when it detects the X-TraceUrl
    # header for the first time. After the initial load
    # the verification is cached by the extension.
    #
    # By default, we'll return 200.

  when 'GET' then
    # GET requests for specific trace are generated by
    # the extension when the user expands the network
    # resource tab. Hence, server-side tracer data is
    # request on-demand, and we need to store it for
    # some time.

    qs = Rack::Utils.parse_query(env['QUERY_STRING'])
    if qs['id'] && @db[qs['id']]
      resp.write @db[qs['id']].to_json
    else
      # Invalid request or missing request trace id
      return FourOhFour
    end
  else
    # SpeedTracer should only issue GET & HEAD requests
    resp.status = 400
  end

  return resp.finish
end