Add support for messaging between different browsing contexts #29803

jgraham · 2021-07-27T13:33:11Z

This will be split up to land, and will have one or more associated RFCs.

The features added are:

Support for giving contexts known ids through a uuid parameter in the URL.
Support for executing script in remote contexts using testdriver, and an implementation for wptrunner based on WebDriver.
Support for cross-context messaging based on send/poll/recv methods in testdriver, using the server stash as a backend.

hiroshige-g · 2021-09-13T17:44:03Z

html/browsers/browsing-the-web/back-forward-cache/resources/executor.html

+// This ensures that no subsequent commands will be buffered in the underlying
+// websocket before the navigation starts. This has to be done in the caller
+// to avoid a race condition between the caller sending a new command and the
+// socket being closed.


In #28950,

I have something similar to closeAllChannelSockets() that suspends polling network requests on the remote context side,

but no pause()-ish things, relying on that the caller doesn't send any new commands until the page becomes inactive

so I'm curious how pause() works.
Particularly, are both of pause() and closeAllChannelSockets() needed?
Is there a race condition between these two?

hiroshige-g · 2021-09-13T17:45:54Z

html/browsers/browsing-the-web/back-forward-cache/resources/executor.html

+  },
+  {once: true});
+
+async function navigateTo(url) {


As there are ways to trigger navigation other than location.href (e.g. form submission), I'd keep prepateNavigation() and execute_script() for navigation purpose.

foolip

This is a lot! I've reviewed up to infrastructure/channels/serialize_child.html...

html/browsers/browsing-the-web/back-forward-cache/resources/executor.html

html/cross-origin-opener-policy/navigate-to-aboutblank.https.html

infrastructure/channels/serialize_child.html

foolip

I have reviewed infrastructure/ and resources/, only took me 2+ hours.

html/cross-origin-opener-policy/resources/executor-channel.html

infrastructure/channels/child_script.html

foolip · 2021-12-03T09:18:49Z

infrastructure/channels/serialize_child.html

+
+let lastData;
+
+// Hack: these will be recreated as assert failures in the caller


I see. Can you elaborate a bit on this comment so that it's easier to understand why this has the effect it has, and what the vision for the future is?

infrastructure/channels/serialize_child.html

resources/channel.sub.js

foolip · 2021-12-03T11:42:21Z

resources/channel.sub.js

+                        typeof self[item.value.type] === "function") {
+                        result = new self[item.value.type](item.value.message);
+                    } else {
+                        result = new Error(item.value.message);


If item.value.type is "Error", the above case should be taken. Can you add a comment that this isn't about deserializing Error objects, but non-Error values?

resources/channel.sub.js

foolip

OK, I've reviewed the Python parts (tools/ and websockets/) too now.

tools/wptrunner/requirements.txt

websockets/handlers/msg_channel_wsh.py

resources/channel.sub.js

foolip

All that is left is some minor things.

Thanks for getting through this, it must have taken much longer to write than to review :D

resources/channel.sub.js

websockets/handlers/msg_channel_wsh.py

This allows stash-owned queues that can then be accessed across multiple servers etc. In particular it can be used as the backend for a shared message queue in which multiple browsing contexts can send messages using the stash.

This allows creating message channels that can cross multiple browsing contexts or script execution environments. A simple channel pair can be created using the channel function e.g. let [recvChan, sendChan] = await channel(); This generates a channel pair such that messages sent on sendChan will arrive on recvChan. Channels are multiple producer, single consumer, so there can only be a single ReadChannel for each network, but multiple SendChannels. On top of this underlying abstraction there's a higher level API which provides known message structures. There is currently a command message type where each command has an id, a method, a set of params, and a respChannel which is a channel to use to reply to the command. Currently two commands are provided: call, which runs a function in a remote context, and postMessage, which sends a message to a remote context. Messages and script parameters are serialized using a WebDriver BiDi like remote value serialization algorithm which allows passing complex objects over the wire. To work with multiple contexts, one takes the following actions: * In the context that will recieve messages, use: let recvChannel = await start_global_channel(); This starts listening for messages on a channel defined by the testdriver context id (typically in the URL; maybe this should just be always in the URL which could also remove the testdriver.js dependency). If only executeScript is being used nothing more needs to be done. For postMessage, one can register message handlers using `recvChannel.addMessageHandler("message", fn)`. * In the context that will send messages, use the uuid of the remote context to create a RemoteGlobal object. This will allow sending messages to the remote. let remote = RemoteGlobal(uuid); let result = remote.call(selector => document.querySelector(selector).textContent, "body") remote.postMessage("done"); Message channels are backed with websockets, which use the stash as the data storage layer. For use cases where it's important to close all websockets (e.g. testing bfcache), the closeAllChannelSockets helper is provided.

This makes them easier to diagnose.

These aren't tests, so it can be assumed we're using it carefully.

The current setup assumed that we had one Stash instance per process and so if the lock property on the class was initialised then we must also have initialised the manager. The way that websockets handlers are loaded breaks this assumption, so we need to ensure that the lifecycle of the lock and of the manager object are identical. Sharing the manager state between instances makes sense since we're already sharing the proxy we get from the stash.

jgraham · 2021-12-09T15:57:52Z

Thanks for all the reviews @foolip!

jgraham mentioned this pull request Jul 27, 2021

RFC 86: fetch_tests_from_prefixed_local_storage web-platform-tests/rfcs#86

Closed

hiroshige-g mentioned this pull request Aug 9, 2021

RFC 88: [testdriver] Extend the mechanisms for giving browsing contexts ids. web-platform-tests/rfcs#88

Closed

jgraham force-pushed the testdriver_cross_group branch 2 times, most recently from c31ae78 to e2ffed0 Compare September 7, 2021 10:40

jgraham mentioned this pull request Sep 7, 2021

RFC 90: [testdriver] Primitives for cross-context messaging web-platform-tests/rfcs#90

Closed

hiroshige-g reviewed Sep 13, 2021

View reviewed changes

jgraham force-pushed the testdriver_cross_group branch from e2ffed0 to 53032f1 Compare September 21, 2021 11:20

jgraham force-pushed the testdriver_cross_group branch from 53032f1 to 8cf5ab4 Compare October 4, 2021 16:54

hiroshige-g mentioned this pull request Oct 5, 2021

RFC 98: Remote channels for cross-browsing-group communication web-platform-tests/rfcs#98

Merged

jgraham force-pushed the testdriver_cross_group branch from 8cf5ab4 to 9354388 Compare October 11, 2021 12:49

jgraham force-pushed the testdriver_cross_group branch from 9354388 to 742bde1 Compare October 27, 2021 10:23

jgraham force-pushed the testdriver_cross_group branch from 742bde1 to 6084028 Compare November 24, 2021 13:02

jgraham marked this pull request as ready for review November 24, 2021 13:03

wpt-pr-bot added html infra testharness.js websockets wg-s_htmlwg wptrunner The automated test runner, commonly called through ./wpt run wptserve labels Nov 24, 2021

wpt-pr-bot assigned hiroshige-g Nov 24, 2021

wpt-pr-bot requested review from annevk, arturjanc, domenic, foolip, hemeryar, jdm, jugglinmike and mikewest November 24, 2021 13:03

jgraham force-pushed the testdriver_cross_group branch from 6084028 to 64bb7c1 Compare November 24, 2021 14:20

foolip reviewed Nov 25, 2021

View reviewed changes

jgraham force-pushed the testdriver_cross_group branch 3 times, most recently from 44fd479 to bfaf63c Compare November 25, 2021 16:18

jgraham requested a review from foolip November 30, 2021 11:45

foolip reviewed Dec 3, 2021

View reviewed changes

jgraham force-pushed the testdriver_cross_group branch from bfaf63c to 786d1ff Compare December 6, 2021 20:31

wpt-pr-bot added the docs label Dec 6, 2021

wpt-pr-bot requested a review from sideshowbarker December 6, 2021 20:31

jgraham requested a review from foolip December 6, 2021 20:34

sideshowbarker removed their request for review December 7, 2021 02:15

foolip reviewed Dec 7, 2021

View reviewed changes

resources/channel.sub.js Show resolved Hide resolved

resources/channel.sub.js Outdated Show resolved Hide resolved

resources/channel.sub.js Show resolved Hide resolved

resources/channel.sub.js Outdated Show resolved Hide resolved

foolip approved these changes Dec 7, 2021

View reviewed changes

jgraham added 3 commits December 9, 2021 14:54

Add support for shared queues in the stash

b2406fc

This allows stash-owned queues that can then be accessed across multiple servers etc. In particular it can be used as the backend for a shared message queue in which multiple browsing contexts can send messages using the stash.

Try to set the stack property on the status for cleanup errors

64c6991

This makes them easier to diagnose.

jgraham force-pushed the testdriver_cross_group branch from 786d1ff to 6359481 Compare December 9, 2021 14:54

wpt-pr-bot requested a review from DanielRyanSmith December 9, 2021 14:55

jgraham added 3 commits December 9, 2021 15:25

Allow all resources to use setTimeout

c2026f8

These aren't tests, so it can be assumed we're using it carefully.

Add documentation for the channels support

8b194c9

jgraham force-pushed the testdriver_cross_group branch from 6359481 to 8b194c9 Compare December 9, 2021 15:26

jgraham merged commit 896ec65 into master Dec 9, 2021

jgraham deleted the testdriver_cross_group branch December 9, 2021 15:57

moz-wptsync-bot added mozilla:gecko-blocked and removed mozilla:gecko-blocked labels Dec 9, 2021

asutherland mentioned this pull request Jan 5, 2022

Proposal: beforePutToBFcache and afterRestoreFromBFcache events for DedicatedWorkerGlobalScope whatwg/html#7216

Open

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Add support for messaging between different browsing contexts #29803

Add support for messaging between different browsing contexts #29803

jgraham commented Jul 27, 2021

hiroshige-g Sep 13, 2021

hiroshige-g Sep 13, 2021

foolip left a comment

foolip left a comment

foolip Dec 3, 2021

foolip Dec 3, 2021

foolip left a comment

foolip left a comment

jgraham commented Dec 9, 2021


		let lastData;

		// Hack: these will be recreated as assert failures in the caller

Add support for messaging between different browsing contexts #29803

Add support for messaging between different browsing contexts #29803

Conversation

jgraham commented Jul 27, 2021

hiroshige-g Sep 13, 2021

Choose a reason for hiding this comment

hiroshige-g Sep 13, 2021

Choose a reason for hiding this comment

foolip left a comment

Choose a reason for hiding this comment

foolip left a comment

Choose a reason for hiding this comment

foolip Dec 3, 2021

Choose a reason for hiding this comment

foolip Dec 3, 2021

Choose a reason for hiding this comment

foolip left a comment

Choose a reason for hiding this comment

foolip left a comment

Choose a reason for hiding this comment

jgraham commented Dec 9, 2021