class OneApm::Rack::BrowserMonitoring

Constants

OA_ALREADY_INSTRUMENTED_KEY
OA_CHARSET_RE
OA_REMOTE_IP
OA_SCAN_LIMIT
OA_X_UA_COMPATIBLE_RE

Public Instance Methods

autoinstrument_source(response, headers, js_to_inject) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 84
def autoinstrument_source(response, headers, js_to_inject)
  begin
    source = gather_source(response)
    close_old_response(response)
    return nil unless source
    inject_js(source, headers, js_to_inject)
  rescue => e
    OneApm::Manager.logger.debug "Skipping RUM instrumentation on exception.", e
    nil
  end
end
calculate_content_length(source) click to toggle source

String does not respond to 'bytesize' in 1.8.6. Fortunately String#length returns bytes rather than characters in 1.8.6 so we can use that instead.

# File lib/one_apm/rack/browser_monitoring.rb, line 172
def calculate_content_length(source)
  if source.respond_to?(:bytesize)
    source.bytesize
  else
    source.length
  end
end
find_body_end(source) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 150
def find_body_end source
  source.rindex("</body>")
end
find_body_start(beginning_of_source) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 146
def find_body_start(beginning_of_source)
  beginning_of_source.index("<body")
end
find_charset_position(beginning_of_source) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 160
def find_charset_position(beginning_of_source)
  match = OA_CHARSET_RE.match(beginning_of_source)
  match.end(0) if match
end
find_end_of_head_open(beginning_of_source) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 165
def find_end_of_head_open(beginning_of_source)
  head_open = beginning_of_source.index("<head")
  beginning_of_source.index(">", head_open) + 1 if head_open
end
find_x_ua_compatible_position(beginning_of_source) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 155
def find_x_ua_compatible_position(beginning_of_source)
  match = OA_X_UA_COMPATIBLE_RE.match(beginning_of_source)
  match.end(0) if match
end
header_index(source) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 113
def header_index source
  beginning_of_source = source[0..OA_SCAN_LIMIT]
  if body_start = find_body_start(beginning_of_source)
    meta_tag_positions = [
      find_x_ua_compatible_position(beginning_of_source),
      find_charset_position(beginning_of_source)
    ].compact

      if !meta_tag_positions.empty?
        insertion_index = meta_tag_positions.max
      else
        insertion_index = find_end_of_head_open(beginning_of_source) || body_start
      end
    insertion_index
  else
    msg = "Skipping RUM instrumentation. Unable to find <body> tag in first #{OA_SCAN_LIMIT} bytes of document."
    OneApm::Manager.logger.log_once(:warn, :rum_insertion_failure, msg)
    OneApm::Manager.logger.debug(msg)
    nil
  end
end
inject_js(source, headers, js_to_inject) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 96
def inject_js source, headers, js_to_inject
  position = OneApm::Manager.config[:'browser_monitoring.position']
  insertion_index = (position.empty? || position.to_sym != :footer) ? header_index(source) : footer_index(source)
  if insertion_index
    source = source[0...insertion_index] \
      << js_to_inject \
      << source[insertion_index..-1]
    if headers['Content-Length']
      headers['Content-Length'] = calculate_content_length(source).to_s
    end
  else
    OneApm::Manager.logger.debug "Skipping RUM instrumentation. Could not properly determine location to inject script."
  end
  source
end
ip_valid?(env) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 62
def ip_valid?(env)
  whitelist_ips = OneApm::Manager.config[:'browser_monitoring.whitelist_ips']
  return true if whitelist_ips.empty? || env[OA_REMOTE_IP].to_s.empty?
  OneApm::Manager.logger.debug "Remote IP: #{env[OA_REMOTE_IP]}"
  begin
    client = IPAddr.new(env[OA_REMOTE_IP].to_s).to_i 
    whitelist_ips.split(",").any? do |ip|
      low_ip, high_ip = ip.split("-").map(&:strip)
      low = IPAddr.new(low_ip).to_i
      if high_ip
        high = IPAddr.new(high_ip).to_i
        (low..high) === client
      else
        low == client
      end
    end
  rescue => e
    OneApm::Manager.logger.error "Configuration for browser_monitoring.whitelist_ips has problems:#{whitelist_ips}"
    true
  end
end
is_attachment?(headers) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 53
def is_attachment?(headers)
  headers['Content-Disposition'].to_s.include?('attachment')
end
is_html?(headers) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 49
def is_html?(headers)
  headers["Content-Type"] && headers["Content-Type"].include?("text/html")
end
is_streaming?(env) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 57
def is_streaming?(env)
  return false unless defined?(ActionController::Live)
  env['action_controller.instance'].class.included_modules.include?(ActionController::Live)
end
should_instrument?(env, status, headers) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 39
def should_instrument?(env, status, headers)
  OneApm::Manager.config[:'browser_monitoring.auto_instrument'] &&
    status == 200 &&
    !env[OA_ALREADY_INSTRUMENTED_KEY] &&
    is_html?(headers) &&
    !is_attachment?(headers) &&
    !is_streaming?(env) && 
    ip_valid?(env)
end
traced_call(env) click to toggle source
# File lib/one_apm/rack/browser_monitoring.rb, line 20
def traced_call(env)
  result = @app.call(env)   # [status, headers, response]

  js_to_inject = OneApm::Manager.browser_timing_header
  if (js_to_inject != "") && should_instrument?(env, result[0], result[1])
    response_string = autoinstrument_source(result[2], result[1], js_to_inject)

    env[OA_ALREADY_INSTRUMENTED_KEY] = true
    if response_string
      response = ::Rack::Response.new(response_string, result[0], result[1])
      response.finish
    else
      result
    end
  else
    result
  end
end