wait_for_idle has issue with window.URL.createObjectURL

[stoivo]

Hi. great work over here.

In out capybara spec we have used some javascript hook to check if all network is done. I found that ferrum can do it with wait_for_idle so I wanted to see if we can switch over and use that instead.

Some part of application uses JQueryTree.js and that does some funky stuff like below. I don't know why.

var wrk = window.URL.createObjectURL(
  new window.Blob(
    ['self.onmessage = ' + func.toString()],
    {type:"text/javascript"}
  )
);
new window.Worker(wrk);

I have created a script to reproduce the issue

script

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'ferrum', '0.15'
end

require "ferrum"

browser = Ferrum::Browser.new({
  headfull: false,
  logger: Kernel,
})
page = browser.create_page


puts "page request make to blob"
page.goto("about:blank")

# warapped in a IIFE since page.evaluate takes one expresion
page.evaluate(<<~JS)
  (function () {
    const func = function (data, undefined) {}
    var wrk = window.URL.createObjectURL(
      new window.Blob(
        ['self.onmessage = ' + func.toString()],
        {type:"text/javascript"}
      )
    );
    w = new window.Worker(wrk);
  })()
JS

begin
  page.network.wait_for_idle(duration: 1)
rescue Ferrum::TimeoutError => e
  puts e
  puts
  puts "unfinished request from blob"
  pp page.network.traffic.reject(&:finished?)
end

# puts "page request make to fetch"
# page.goto("about:blank")

# page.evaluate(<<~JS)
#   (function () {
#     fetch("https://raw.githubusercontent.com/", {"method": "GET", });
#     fetch("https://raw.githubusercontent.com/rubycdp/ferrum/refs/heads/main/logo.svg", {"method": "GET", });
#   })()
# JS

# begin
#   page.network.wait_for_idle(duration: 1)
# rescue Ferrum::TimeoutError => e
#   puts e
#   puts
#   puts "unfinished request from fetch"
#   pp page.network.traffic.reject(&:finished?)
# end

# puts "page request make to xhr"
# page.goto("https://github.com")

# page.evaluate(<<~JS)
#   (function () {
#     const xhr = new XMLHttpRequest();
#     xhr.open("GET", "https://raw.githubusercontent.com/", true);
#     xhr.send(null);
#   })()
# JS

# begin
#   page.network.wait_for_idle(duration: 1)
# rescue Ferrum::TimeoutError => e
#   puts e
#   puts
#   puts "unfinished request from xhr"
#   pp page.network.traffic.reject(&:finished?)
# end

It prints out event which happens and from what I can understand these are the relevant events for each of my cases

Relevant events when fetching with Blob

{"method":"Network.requestWillBeSent","params":{"requestId":"14F76E4E856E44E2D9708320CC766C31" ....
{"method":"Network.loadingFinished","params":{"requestId":"14F76E4E856E44E2D9708320CC766C31" ...

Relevant events when fetching with fetch

{"method":"Network.requestWillBeSent","params":{"requestId":"29478.2" ...
{"method":"Network.requestWillBeSentExtraInfo","params":{"requestId":"29478.2" ...
{"method":"Network.responseReceivedExtraInfo","params":{"requestId":"29478.2" ...
{"method":"Network.responseReceived","params":{"requestId":"29478.2" ...
{"method":"Network.dataReceived","params":{"requestId":"29478.2" ...
{"method":"Network.loadingFinished","params":{"requestId":"29478.2" ...

Have you seen this before? Do you think this is a bug in ferrum?

Desktop (please complete the following information):

• OS: macOS
• Browser [Chrome Version 128.0.6613.138 (Official Build) (arm64)]
• Version 0.15

[route]

Take a note that wait_for_idle does not raise an error now, it's a breaking change. If you want error use wait_for_idle!