Everything but attributes in the light dom is manually compared during
DOM traversal, for example child nodes or scroll offset.
This way we get a bullet-proof solution that works with input values,
scroll offsets, shadow dom and anything else web comes up with.
We also restore scroll only on the document scrolling element, for
performance reasons. We should figure out the story around scrolling.
Changes stationary snapshots from ~0.5ms to ~2.5ms due to DOM traversal.
- Intercept CSSOM modifications and recalculate overridden css text.
- When css text does not change, use "backwards reference" similar
to node references.
- Set 'Cache-Control: no-cache' for resources that could be overridden.
This introduces an http server that serves our frontend and our snapshots. There is more work to untangle the big server into a few modules.
This change allows us:
- Maybe eventually serve the trace viewer as a web page.
- Rely on browser caches for fast snapshot rendering. This PR also adds "snapshot on hover" feature, subject to change.
feat(trace viewer): Extending existing NetworkTab view
Currently the network tab contains a limited amount of information on the resources that were loaded in the browser. This change proposes extending the details displayed for each resource, to include:
- HTTP method,
- Full url,
- Easily visible response content type,
- Request headers,
- Request & response bodies.
Such level of information could help quickly understand what happened in the application, when it was communicating with backend services. This can help debug tests quicker to figure out why they are failing.
This implementation still needs some clean up & tests improvement, but I wanted to propose such changes and gather your feedback before going too far.
- Instead of capturing snapshots on demand, we now stream them
from each frame every 100ms.
- Certain actions can also force snapshots at particular moment using
"checkpoints".
- Trace viewer is able to show the page snapshot at a particular
timestamp, or using a "checkpoint" snapshot.
- Small optimization to not process stylesheets if CSSOM was not used.
There still is a lot of room for improvement.
- This leaves just `recordVideos` and `videoSize` options on the context.
- Videos are saved to `artifactsPath`. We also save their ids to trace.
- `context.close()` waits for the processed videos.
api(trace): introduce artifacts options
This introduces launch({ artifactsPath }) and newContext({ relativeArtifactsPath, recordTrace }) options.
- artifactsPath option controls the directory where all artifacts go. If not passed, artifacts are not collected.
- relativeArtifactsPath can be used to put context-specific artifacts into a subfolder. If not passed, shared artifactsPath is used.
- recordTrace controls trace recording.
We also expose trace types under playwright/types/trace.d.ts.
In the follow up:
- videos will be put into artifactsPath;
- downloads will be put into artifactsPath, or keep using existing downloadsPath when artifactsPath is not specified.
Sometimes, we are unable to take a frame snapshot. The most common
example would be "frame is stuck during the navigation in Chromium",
where we cannot evaluate until the frame is done navigating.
In this case, use all other frames and just stub the failing ones
with "Snapshot is not available". Chances are, noone will even see
this frame because it's an invisible tracking iframe.
- Fill and click actions pass metadata to Progress.
- Progress reports success/failure through instrumentation.
- Tracer consumes ActionResult and ActionMetadata and records them.
Currently, only click and fill actions pass metadata to
contain the size of the change. Everything else should follow.
