replace Communication\Connection::waitForDelay's usleep with select

[divinity76]

the usleep in

chrome/src/Communication/Connection.php

Lines 212 to 219 in 2b7cb13

	private function waitForDelay(): void
	{
	if ($this->lastMessageSentTime) {
	$currentTime = (int) (\hrtime(true) / 1000 / 1000);
	// if not enough time was spent until last message was sent, wait
	if ($this->lastMessageSentTime + $this->delay > $currentTime) {
	$timeToWait = ($this->lastMessageSentTime + $this->delay) - $currentTime;
	\usleep($timeToWait * 1000);

is problematic, it should be a socket_select() / stream_select(), and the usleep causes laggy/non-smooth video recordings with Page.startScreencast + method:Page.screencastFrame (sample implementation here )

So when I record videos, to make them smooth, I have to replace stuff like

$navigate->waitForNavigation(\HeadlessChromium\Page::NETWORK_IDLE);

with a cpu busyloop like

$target_time = microtime(true) + 5;
while (microtime(true) < $target_time) {
    // calling readData() fast causes smooth video recordings.
    // if there is too much delay in sending Page.screencastFrameAck, chromium will drop frames.
    $page->getSession()->getConnection()->readData();
}

That's a dirty quickfix, and I believe the correct solution would be to replace Communication\Connection::waitForDelay's usleep() with select() , it should be something like

             $timeToWait = ($this->lastMessageSentTime + $this->delay) - $currentTime;
             $timeToWaitSeconds = (int)$timeToWait;
             $fractionMicroseconds = ((int)(($timeToWait - $timeToWaitSeconds) * 1000000));
              $read=[$page->socket]; 
              stream_select($read,null,null,$timeToWaitSeconds, $fractionMicroseconds);

But first issue is to figure out how to get $page's socket handle into function waitForDelay 🤔 and seems the raw socket handle is wrapped inside wrench... suggestions?

[divinity76]

For this to be fixed, \Wrench\Client needs a getSocketResource() method.

Made a PR: chrome-php/wrench#17

Before more progress can be made, it seems we need to wait for the method/PR to be accepted, and wait for a new chrome-php/wrench version to be released 🤔

Here is my investigation notes so far:
class \HeadlessChromium\Communication\Connection has a protected \HeadlessChromium\Communication\Socket\SocketInterface $wsClient;

\HeadlessChromium\Communication\Socket\SocketInterface has no getSocketResource().

\HeadlessChromium\Communication\Socket\Wrench must then create its own getSocketResource(),
returning the resource from protected \Wrench\Client $client;
\Wrench\Client needs a getSocketResource(), returning it's socket resource from protected \Wrench\Socket\ClientSocket $socket;

\Wrench\Socket\ClientSocket inherits $this->socket property from UriSocket...

\Wrench\Socket\UriSocket inherits $this->socket property from \Wrench\Socket\AbstractSocket...

\Wrench\Socket\AbstractSocket has a public function getResource()

that means UriSocket has it too... that means ClientSocket also has it.. \Wrench\Client needs to expose it publicly (or at least protectedly)
it needs a
public function getSocketResource(){return $this->socket->getResource();}

[divinity76]

update: The upcoming Wrench 1.7 will have a new \Wrench\Client::waitForData method which uses select() internally, we should replace \usleep($timeToWait * 1000); with $this->wsClient->waitForData($timeToWait); once Wrench >=1.7 is available.

[GrahamCampbell]

@divinity76 Are you planning on picking up the next step of this, with a PR to this repo?

[GrahamCampbell]

Is this basically what you had in mind as the only change?

[divinity76]

@GrahamCampbell no, I've since lost interest, I made some workaround for my specific problem and moved on.

But yes that's exactly what I had in mind!

[GrahamCampbell]

OK, I can make the change then. I just didn't want to be treading on toes. ;)

[divinity76]

@GrahamCampbell perfect, thanks