[firebase storage] uploadTask.events.listen() fires weird events

[logemann]

Describe the bug
I am implementing an upload progress bar (definite) with the help of uploadTask.events.listen().

In the callback i computing percents of upload completion like this:

callback: (StorageTaskEvent event) {
    // this is form 0.0 to 1.0
   double percent = event.snapshot.bytesTransferred / event.snapshot.totalByteCount;
}

Imagine i have a print() statement right in the callback. The log looks like this:

13:28:37.163347 - Bytes 85 von 219131 --) 0.03878958248718803 %
13:28:40.099999 - Bytes 16469 of 219131 --) 7.5155956938999955 %
13:28:40.101480 - Bytes 32853 of 219131 --) 14.992401805312806 %
13:28:40.102404 - Bytes 49237 of 219131 --) 22.469207916725612 %
13:28:40.103234 - Bytes 65620 of 219131 --) 29.945557680109157 %
13:28:40.984518 - Bytes 82004 of 219131 --) 37.42236379152197 %
13:28:40.987146 - Bytes 98388 of 219131 --) 44.89916990293478 %
13:28:40.988821 - Bytes 98389 of 219131 --) 44.89962625096403 %
13:28:40.990674 - Bytes 114773 of 219131 --) 52.376432362376846 %
13:28:40.992537 - Bytes 131157 of 219131 --) 59.85323847378965 %
13:28:40.993965 - Bytes 147541 of 219131 --) 67.33004458520246 %
13:28:40.995440 - Bytes 163925 of 219131 --) 74.80685069661527 %
13:28:40.996644 - Bytes 180309 of 219131 --) 82.28365680802807 %
13:28:40.997861 - Bytes 196693 of 219131 --) 89.76046291944088 %
13:28:40.998986 - Bytes 213077 of 219131 --) 97.2372690308537 %
13:28:41.000252 - Bytes 219131 of 219131 --) 100.0 %
13:28:52.824658 - Bytes 219131 of 219131 --) 100.0 %
13:28:52.826356 - Bytes 219131 of 219131 --) 100.0 %

Pay attention to the first 100% output and the following two 100%. There is a gap of 11 seconds and this is most likely the upload itself of 219kb The uploadTask.onComplete Future is completed after the last 100% line.

As you can see, its impossible to make a proper upload progress bar with these numbers. The only thing i do is to throttle the Network speed via iOS -> Settings -> Developer -> Network Link Conditioner and set it to Edge to test larger upload durations. Dont know if its related.

To Reproduce
Just implement a callback yourself on an Cloud Storage Upload as described above.

Expected behavior
Only one Event fired when 100% and the one event should be right before the Future completes.

[iapicca]

Hi @logemann
can you please provide your updated flutter doctor -v
and your flutter run --verbose ?
Also, to better address the issue, would be helpful
if you could post a self contained app on github
or the steps to reproduce it.
Thank you

[logemann]

i can provide flutter doctor but self contained app is impossible cause it would involve a Cloud Storage account to upload something....

[✓] Flutter (Channel dev, v1.10.14, on Mac OS X 10.15 19A602, locale de-DE)
• Flutter version 1.10.14 at /Users/ml/development/flutter
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[✓] Connected device (1 available)
• iPhone Xʀ • C3565AFC-01CB-47DA-8EB8-62FFBBCD9B84 • ios •
com.apple.CoreSimulator.SimRuntime.iOS-12-2 (simulator)

[logemann]

If someone is really willing to test it with their Firebase Account. I could at least provide a small test app.

[Salakar]

Closing in favour of trying the latest Storage plugin which has since been refactored and a lot of underlying issues fixed. Thanks.