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angular
Service worker doesn't support seeking in videos
I'm submitting a...
[x] Bug report
[x] Feature request (not sure, maybe this is more a feature request?)
Current behavior
If you ng run app:build:production and your pwa comes with a <video> element where you also utilize seeking (setting currentTime depending on your app logic and/or user input) it will not work or only very inconsistently. Most videos will simply run from start and not at the setted currentTime position. This is only the case when videos are delivered/fetched by the service worker. So it works in development mode.
Expected behavior
Videos should start at the setted currentTime.
Minimal reproduction of the problem with instructions
// on template
<video id="myVideo"><source id="myVideoSrc" src="video.mp4" type="video/mp4"></video>
// in page.ts
let videoObject = document.getElementById("myVideo");
videoObject.currentTime = 100;
videoObject.play();
// now build for production
// @angular/pwa has to be installed
> ng run app:build:production
Environment
Angular version: 6.1.2
Browser: Chrome (desktop) version 69
Others:
This seems to be a known problem since service workers don't know Range requests. However it also looks like very easily fixable if I understand this thread comment correctly: https://bugs.chromium.org/p/chromium/issues/detail?id=575357#c10
A workaround would be a convenient way to completely exclude requests from service worker (not just set strategies for them). But obviously it would be better if we also could cache some videos. For exclusion also this issue may be relevant : https://github.com/angular/angular/issues/21191
EDIT(gkalpak): Issue summary in https://github.com/angular/angular/issues/25865#issuecomment-634048868.
Fixing #21191 would indeed provide a workaround for this usecase (but this could be properly fixable on its own as well).
Does anyone want to take a stub at incorporating this fix into @angular/service-worker.
We hit this issue, because requests to video needed to be withCredentials and SW failed over without applying cookies to headers. A workaround was to skip handling request via SW. We used patch-package to maintain this patch. Here is the patch
diff --git a/node_modules/@angular/service-worker/ngsw-worker.js b/node_modules/@angular/service-worker/ngsw-worker.js
index 51c431b..1216506 100755
--- a/node_modules/@angular/service-worker/ngsw-worker.js
+++ b/node_modules/@angular/service-worker/ngsw-worker.js
@@ -1896,6 +1896,10 @@ ${msgIdle}`, { headers: this.adapter.newHeaders({ 'Content-Type': 'text/plain' }
*/
onFetch(event) {
const req = event.request;
+ //PATCH to prevent caching certain kinds of requests
+ // - PUT requests which breaks files upload
+ // - requests with 'Range' header which breaks credentialed video irequests
+ if (req.method==="PUT" || !!req.headers.get('range')) return;
// The only thing that is served unconditionally is the debug page.
if (this.adapter.parseUrl(req.url, this.scope.registration.scope).path === '/ngsw/state') {
// Allow the debugger to handle the request, but don't affect SW state in any
@mordka Thank you for your suggested fix.
I was having a slightly different issue where range requests were breaking audio in Safari due to the SW failing to apply the Content-Range header. I applied the range header patch using patch-package and it fixed the issue.
Turns out this is actually fixed now by appending ngsw-ignore to your querystring or as a header. https://github.com/angular/angular/blob/master/aio/content/guide/service-worker-devops.md
Turns out this is actually fixed now by appending ngsw-ignore to your querystring or as a header. https://github.com/angular/angular/blob/master/aio/content/guide/service-worker-devops.md
That is just another workaround to ignore videos (though it is one of the best workarounds in that regard so far). But you still cannot include videos in your service worker's caching strategy when you need seeking. So no, I wouldn't say this is fixed.
As mentioned in https://github.com/angular/angular/issues/25865#issuecomment-421925411, if someone wants to take a stub at incorporating range handling into the SW, I'd be happy to help/review. How do other implementations (e.g. workbox) handle this?
Hopefully, this issue gets solved soon. We are using a nasty hack, after building, in the build script we're adding a line to ignore the video:
sed -i $'/^ const req = event.request;.*/a if (req.headers.get(\'range\')) return;' ./dist/ngsw-worker.js
This way we're avoiding a new fork from the main repo.
I have also been facing an issue with this. I have been using audio and doing seeking with currentTime. I obtained the audio in my component using ViewChild and not by it's ID. I was able to get my application working when I cleared the cache every time I opened it and trying to seek audio work successfully only in that edge case. In the end, I just removed the PWA aka the serviceWorker to fix the problem
EDIT:
I added in ?ngsw-bypass=true into the params and that fixed it I believe
One way to do this is to create a patched ngsw-worker.js with Phil Nash's @philnash code to handle range request here: https://github.com/philnash/philna.sh/blob/ba798a2d5d8364fc7c1dae1819cbd8ef103c8b67/sw.js#L50-L94 (from https://philna.sh/blog/2018/10/23/service-workers-beware-safaris-range-request/)
First copy a ngsw-worker.js file from dist and create ngsw-worker-patched.js. Then prepend the following codes to the onFetch function in ngsw-worker.js
onFetch(event) {
if (event.request.headers.get("range")) {
// You need to grab the cache name. On my version of ngsw-worker.js:
const cacheName = `${this.adapter.cacheNamePrefix}:${this.latestHash}:assets:app:cache`;
// note: adjust assets:app with where you put the videos (could be assets:assets group).
// do respondWith with the promise returned from returnRangeRequest()
event.respondWith(returnRangeRequest(event.request, cacheName));
// @philnash code:
function returnRangeRequest(request, cacheName) {
return caches
.open(cacheName)
.then(function (cache) {
return cache.match(request.url);
})
.then(function (res) {
if (!res) {
return fetch(request)
.then((res) => {
const clonedRes = res.clone();
return caches
.open(cacheName)
.then((cache) => cache.put(request, clonedRes))
.then(() => res);
})
.then((res) => {
return res.arrayBuffer();
});
}
return res.arrayBuffer();
})
.then(function (arrayBuffer) {
const bytes = /^bytes\=(\d+)\-(\d+)?$/g.exec(
request.headers.get("range")
);
if (bytes) {
const start = Number(bytes[1]);
const end = Number(bytes[2]) || arrayBuffer.byteLength - 1;
return new Response(arrayBuffer.slice(start, end + 1), {
status: 206,
statusText: "Partial Content",
headers: [
[
"Content-Range",
`bytes ${start}-${end}/${arrayBuffer.byteLength}`,
],
],
});
} else {
return new Response(null, {
status: 416,
statusText: "Range Not Satisfiable",
headers: [["Content-Range", `*/${arrayBuffer.byteLength}`]],
});
}
});
}
return;
}
... // rest of codes onFetch codes
Then on your npm postbuild script you can just cp the file back to your dist folder:
"scripts": {
"build": "ng build --prod",
"postbuild": "cp ngsw-worker-patched.js ./dist/ngsw-worker.js",
If your videos are small and you want to avoid doing manual patch of ngsw-worker.js, you can convert the videos into base 64 and use data uri on the video src. Or append ?ngsw-bypass to your video links: src="video.mp4?ngsw-bypass" to bypass the service worker.
Hello, I actually had to update that SW code recently (turned out the caches API didn't like storing 206 responses), so I'd check the latest from here: https://github.com/philnash/philna.sh/blob/master/sw.js#L49-L100.
To sum up (for future reference):
- The problem is caused by the ServiceWorker's not handling range requests (i.e. requests with a
Rangeheader) correctly. See this blog post for more details. - An easy work around is to make the SW ignore affected requests by adding an ngsw-bypass header or query param. This has the downside that it breaks caching of such resources by the SW and so they won't be available offline.
- A more involved work around is to manually augment the SW to handle range requests correctly, e.g. using something similar to this code by @philnash.
BTW, Workbox has a module to handle range requests: Workbox Range Requests (source code)
If anyone is interested in trying to incorporate the fix into the SW and submit a pull request, I would be happy to help/review.
@gkalpak what king of a fix are we looking into should we add another property in SW-config file. Which if made true add code which handles it
No, we don't need a config option. We just need to teach the SW how to handle range requests (by incorporating code similar to this and potentially making other necessary adjustments).
It seems that we have a lot of workarounds in order to fix the video issues in Safari iOS, but I wonder why the fix is not yet implemented ?
As mentioned in https://github.com/angular/angular/issues/25865#issuecomment-421925411 (and other comments), implementing the fix is up for grabs if anyone is interested. I would be happy to help out.
Otherwise, I will hopefully get to it at some point, but this is not high in priority, so no timeline and no promises :grin:
No timeline, no promise, not high in priority. However this issue is open since June 2018
Of course there is a lot of people interested to see a fix in order to have video working with Safari without having to extand manually the ngsw. I'm one of them :)
My issue was that the videos of my PWA (Angular + NGSW) simply wouldn´t play on iOS using Safari. I finally found the solution in this answer: https://stackoverflow.com/a/58966397/8581106.
The solution for me was to bypass the Angular Service Worker with ?ngsw-bypass=true after the video url. This might not be related to everyones issue in here, however, this issue was linked as a reference to people sharing the same problem as me.
Example:
<video muted preload="metadata" controls playsinline>
<source src="assets/vid/tutorial_invoice.mp4?ngsw-bypass=true" type="video/mp4">
</video>
Hm, what is needed here to get this to work properly?
In our case, we load many PDFs, each must be cached for offline usage, which works, but range requests do not. Weirdly, it only does not work for giant PDFs, above 6Â MB.
Same issue here with range requests and the service worker. We're using @philnash's patch, but we shouldn't have to. Any updates on this?
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I would like this issue to be resolved, which is why I have posted a $60 reward. I would like to contribute but I don't have time to solve it and that's why I thought that a monetary contribution could help attract people who want to help (especially seeing that it is an issue that has been open for quite some time)
