Class: Puppeteer::Bidi::WaitTask

Inherits:
Object
  • Object
show all
Defined in:
lib/puppeteer/bidi/wait_task.rb,
sig/puppeteer/bidi/wait_task.rbs

Overview

WaitTask orchestrates polling for a predicate using Puppeteer's Poller classes. This is a faithful port of Puppeteer's WaitTask implementation: https://github.com/puppeteer/puppeteer/blob/main/packages/puppeteer-core/src/common/WaitTask.ts

Note: signal and AbortSignal are not implemented as they are JavaScript-specific

Instance Method Summary collapse

Constructor Details

#initialize(world, options, fn, *args) ⇒ Object

Corresponds to Puppeteer's WaitTask constructor

Parameters:

  • world (Realm) —

    The realm to execute in (matches Puppeteer's World abstraction)

  • options (Hash) —

    Options for waiting

  • fn (String) —

    JavaScript function to evaluate

  • args (Array) —

    Arguments to pass to the function

Options Hash (options):

  • :polling (String, Numeric) —

    Polling strategy ('raf', 'mutation', or interval in ms)

  • :timeout (Numeric) —

    Timeout in milliseconds

  • :root (ElementHandle) —

    Root element for mutation polling



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# File 'lib/puppeteer/bidi/wait_task.rb', line 20

def initialize(world, options, fn, *args)
  @world = world
  @polling = options[:polling]
  @root = options[:root]

  # Convert function to string format
  # Corresponds to Puppeteer's switch (typeof fn)
  if fn.is_a?(String)
    # Check if the string is already a function (starts with "function ", "(", or "async ")
    # If so, use it as-is. Otherwise, wrap it as an expression.
    if fn.strip.match?(/\A(?:function\s|\(|async\s)/)
      @fn = fn
    else
      @fn = "() => {return (#{fn});}"
    end
  else
    raise ArgumentError, 'fn must be a string'
  end
  @args = args

  # Corresponds to Puppeteer's #timeout and #timeoutError
  @timeout_task = nil
  @generic_error = StandardError.new('Waiting failed')
  @timeout_error = nil

  # Corresponds to Puppeteer's #result = Deferred.create<HandleFor<T>>()
  @result = Async::Promise.new

  # Corresponds to Puppeteer's #poller?: JSHandle<Poller<T>>
  @poller = nil

  # Track the active rerun Async task so we can cancel it when rerunning
  @rerun_task = nil

  # Validate polling interval
  if @polling.is_a?(Numeric) && @polling < 0
    raise ArgumentError, "Cannot poll with non-positive interval: #{@polling}"
  end

  # Corresponds to Puppeteer's this.#world.taskManager.add(this)
  @world.task_manager.add(self)

  # Store timeout value and start timeout task
  # Corresponds to Puppeteer's setTimeout(() => { void this.terminate(this.#timeoutError); }, options.timeout)
  default_timeout = if @world.respond_to?(:default_timeout)
                      @world.default_timeout
                    elsif @world.respond_to?(:page)
                      @world.page.default_timeout
                    end
  @timeout_ms = options.key?(:timeout) ? options[:timeout] : default_timeout
  if @timeout_ms && @timeout_ms > 0
    @timeout_error = Puppeteer::Bidi::TimeoutError.new(
      "Waiting failed: #{@timeout_ms}ms exceeded"
    )
    # Start timeout task in background
    @timeout_task = Async do |task|
      task.sleep(@timeout_ms / 1000.0)
      @timeout_task = nil # prevent stopping in terminate
      terminate(@timeout_error)
    end
  end

  # Start polling
  # Corresponds to Puppeteer's void this.rerun()
  rerun
end

Instance Method Details

#create_interval_poller ⇒ Object

Create IntervalPoller instance Corresponds to Puppeteer's evaluateHandle call for IntervalPoller

Returns:

  • (Object) 


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# File 'lib/puppeteer/bidi/wait_task.rb', line 251

def create_interval_poller
  util_handle = @world.puppeteer_util
  interval = @polling.is_a?(Numeric) ? @polling : 100

  # Corresponds to Puppeteer's evaluateHandle with LazyArg
  script = <<~JAVASCRIPT
    ({IntervalPoller, createFunction}, ms, fn, ...args) => {
      const fun = createFunction(fn);
      return new IntervalPoller(() => {
        return fun(...args);
      }, ms);
    }
  JAVASCRIPT

  @world.evaluate_handle(script, util_handle, interval, @fn, *@args)
end

#create_mutation_poller ⇒ Object

Create MutationPoller instance Corresponds to Puppeteer's evaluateHandle call for MutationPoller

Returns:

  • (Object) 


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# File 'lib/puppeteer/bidi/wait_task.rb', line 233

def create_mutation_poller
  util_handle = @world.puppeteer_util

  # Corresponds to Puppeteer's evaluateHandle with LazyArg
  script = <<~JAVASCRIPT
    ({MutationPoller, createFunction}, root, fn, ...args) => {
      const fun = createFunction(fn);
      return new MutationPoller(() => {
        return fun(...args);
      }, root || document);
    }
  JAVASCRIPT

  @world.evaluate_handle(script, util_handle, @root, @fn, *@args)
end

#create_raf_poller ⇒ Object

Create RAFPoller instance Corresponds to Puppeteer's evaluateHandle call for RAFPoller

Returns:

  • (Object) 


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# File 'lib/puppeteer/bidi/wait_task.rb', line 214

def create_raf_poller
  util_handle = @world.puppeteer_util

  # Corresponds to Puppeteer's evaluateHandle with LazyArg
  script = <<~JAVASCRIPT
    ({RAFPoller, createFunction}, fn, ...args) => {
      const fun = createFunction(fn);
      return new RAFPoller(() => {
        return fun(...args);
      });
    }
  JAVASCRIPT

  handle = @world.evaluate_handle(script, util_handle, @fn, *@args)
  handle
end

#get_bad_error(error) ⇒ Exception?

Check if error should terminate task Corresponds to Puppeteer's getBadError(error: unknown): Error | undefined

Parameters:

  • error (Exception) —

    Error to check

Returns:

  • (Exception, nil) —

    Error if it should terminate, nil if recoverable



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# File 'lib/puppeteer/bidi/wait_task.rb', line 272

def get_bad_error(error)
  return nil unless error

  error_message = error.message

  # Frame detachment is fatal
  # Corresponds to Puppeteer's error.message.includes('Execution context is not available in detached frame')
  if error_message.include?('Execution context is not available in detached frame')
    return StandardError.new('Waiting failed: Frame detached')
  end

  # These are recoverable (realm was destroyed/recreated)
  # Corresponds to Puppeteer's error.message.includes('Execution context was destroyed')
  return nil if error_message.include?('Execution context was destroyed')

  # Corresponds to Puppeteer's error.message.includes('Cannot find context with specified id')
  return nil if error_message.include?('Cannot find context with specified id')

  # Corresponds to Puppeteer's error.message.includes('DiscardedBrowsingContextError')
  return nil if error_message.include?('DiscardedBrowsingContextError')

  # Recoverable when the browsing context is torn down during navigation.
  return nil if error_message.include?('Browsing Context with id')
  return nil if error_message.include?('no such frame')

  # Happens when handles become invalid after realm/navigation changes.
  return nil if error_message.include?('Unable to find an object reference for "handle"')

  # All other errors are fatal
  # Corresponds to Puppeteer's return error;
  error
end

#perform_rerun ⇒ Object

Run a single rerun cycle. Mirrors the async rerun logic from Puppeteer.

Returns:

  • (Object) 


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# File 'lib/puppeteer/bidi/wait_task.rb', line 149

def perform_rerun
  poller = nil
  schedule_rerun = false

  begin
    # Create Poller instance based on polling mode
    # Corresponds to Puppeteer's switch (this.#polling)
    poller = case @polling
             when 'raf'
               create_raf_poller
             when 'mutation'
               create_mutation_poller
             else
               create_interval_poller
             end

    @poller = poller

    # Start the poller
    # Corresponds to Puppeteer's await this.#poller.evaluate(poller => { void poller.start(); });
    poller.evaluate('poller => { void poller.start(); }')

    # Get the result
    # Corresponds to Puppeteer's const result = await this.#poller.evaluateHandle(poller => { return poller.result(); });
    # Note: poller.result() returns a Promise, so we need to await it
    # evaluateHandle with awaitPromise: true will wait for the Promise to resolve
    result_handle = poller.evaluate_handle('poller => { return poller.result(); }')

    # Resolve the result
    # Corresponds to Puppeteer's this.#result.resolve(result);
    @result.resolve(result_handle)

    # Terminate cleanly
    # Corresponds to Puppeteer's await this.terminate();
    terminate
  rescue Async::Stop
    # Propagate cancellation so caller can distinguish from regular errors
    raise
  rescue => error
    # Check if this is a bad error
    # Corresponds to Puppeteer's const badError = this.getBadError(error);
    bad_error = get_bad_error(error)
    if bad_error
      # Corresponds to Puppeteer's this.#genericError.cause = badError;
      @generic_error = StandardError.new(@generic_error.message)
      @generic_error.set_backtrace([bad_error.message] + bad_error.backtrace)
      # Corresponds to Puppeteer's await this.terminate(this.#genericError);
      terminate(@generic_error)
    else
      schedule_rerun = true
    end
    # If badError is nil, it's a recoverable error and we don't terminate
    # Puppeteer would rerun automatically via realm 'updated' event
  ensure
    if poller && @poller.equal?(poller)
      stop_and_dispose_poller(poller)
      @poller = nil
    end
  end

  rerun if schedule_rerun && !@result.resolved?
end

#rerun ⇒ Object

Rerun the polling task Corresponds to Puppeteer's async rerun(): Promise

Returns:

  • (Object) 


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# File 'lib/puppeteer/bidi/wait_task.rb', line 96

def rerun
  # Cancel previous rerun task if one is active
  if (previous_task = @rerun_task)
    @rerun_task = nil if @rerun_task.equal?(previous_task)
    previous_task.stop
  end

  # Launch the rerun asynchronously so it can be cancelled like Puppeteer's AbortController
  @rerun_task = Async do |task|
    begin
      perform_rerun
    rescue Async::Stop
      # Rerun was cancelled; poller cleanup happens in ensure block
    ensure
      @rerun_task = nil if @rerun_task.equal?(task)
    end
  end
end

#result ⇒ Async::Promise

Get the result as a promise Corresponds to Puppeteer's get result(): Promise<HandleFor>

Returns:



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# File 'lib/puppeteer/bidi/wait_task.rb', line 90

def result
  @result
end

#stop_and_dispose_poller(poller) ⇒ Object

Safely stop and dispose a poller handle, ignoring cleanup errors

Parameters:

  • poller (Object)

Returns:

  • (Object) 


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# File 'lib/puppeteer/bidi/wait_task.rb', line 306

def stop_and_dispose_poller(poller)
  return unless poller

  begin
    poller.evaluate('async poller => { await poller.stop(); }')
  rescue StandardError
    # Ignore errors from stopping the poller
  end

  begin
    poller.dispose
  rescue StandardError
    # Ignore dispose errors as they are low-level cleanup
  end
end

#terminate(error = nil) ⇒ Object

Terminate the task Corresponds to Puppeteer's async terminate(error?: Error): Promise

Parameters:

  • error (Exception, nil) (defaults to: nil) —

    Error to reject with

Returns:

  • (Object) 


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# File 'lib/puppeteer/bidi/wait_task.rb', line 118

def terminate(error = nil)
  # Corresponds to Puppeteer's this.#world.taskManager.delete(this)
  @world.task_manager.delete(self)

  # Note: this.#signal?.removeEventListener('abort', this.#onAbortSignal) is skipped
  # AbortSignal is not implemented

  # Clear timeout task
  # Corresponds to Puppeteer's clearTimeout(this.#timeout)
  if @timeout_task
    @timeout_task.stop
    @timeout_task = nil
  end

  # Reject result if not finished
  # Corresponds to Puppeteer's if (error && !this.#result.finished()) { this.#result.reject(error); }
  if error && !@result.resolved?
    @result.reject(error)
  end

  # Stop and dispose poller
  # Corresponds to Puppeteer's if (this.#poller) { ... }
  if @poller
    stop_and_dispose_poller(@poller)
    @poller = nil
  end
end