[QUESTION] Understand file retrieving long duration

[Tom3652]

Expect

I need the filePath of the AssetEntity to be able to upload it.
So i have tested :

• assetEntity.file
• assetEntity.originFile
• assetEntity.loadFile()

I am also trying to display very quickly a preview of the file (thanks to its path) in a VideoPlayer Widget.
However, my beta test users told me that videos were not playing locally for a very long time and after it's always working.

So i have set a PMProgressHandler to listen to the progress as written in the docs, and it's working.
However i am surprised to see the progress like this :

flutter: Event : PMRequestState.prepare, progress : 0.0 & time : 47
flutter: Event : PMRequestState.loading, progress : 0.01 & time : 49
flutter: Event : PMRequestState.loading, progress : 0.02 & time : 49
flutter: Event : PMRequestState.loading, progress : 0.03 & time : 50
flutter: Event : PMRequestState.loading, progress : 0.04 & time : 50
flutter: Event : PMRequestState.loading, progress : 0.05 & time : 51
flutter: Event : PMRequestState.loading, progress : 0.06 & time : 51
flutter: Event : PMRequestState.loading, progress : 0.07 & time : 52
flutter: Event : PMRequestState.loading, progress : 0.08 & time : 52
flutter: Event : PMRequestState.loading, progress : 0.09 & time : 52
flutter: Event : PMRequestState.loading, progress : 0.1 & time : 53
flutter: Event : PMRequestState.loading, progress : 0.11 & time : 53
flutter: Event : PMRequestState.loading, progress : 0.12 & time : 54
flutter: Event : PMRequestState.loading, progress : 0.13 & time : 54
flutter: Event : PMRequestState.loading, progress : 0.14 & time : 55
flutter: Event : PMRequestState.loading, progress : 0.15 & time : 55
flutter: Event : PMRequestState.loading, progress : 0.16 & time : 55
flutter: Event : PMRequestState.loading, progress : 0.17 & time : 56
flutter: Event : PMRequestState.loading, progress : 0.18 & time : 56
flutter: Event : PMRequestState.loading, progress : 0.19 & time : 57
flutter: Event : PMRequestState.loading, progress : 0.2 & time : 57
flutter: Event : PMRequestState.loading, progress : 0.21 & time : 58
flutter: Event : PMRequestState.loading, progress : 0.22 & time : 58
flutter: Event : PMRequestState.loading, progress : 0.23 & time : 59
flutter: Event : PMRequestState.loading, progress : 0.24 & time : 59
flutter: buffer video false
flutter: Event : PMRequestState.loading, progress : 0.25 & time : 0
flutter: Event : PMRequestState.loading, progress : 0.26 & time : 1
flutter: Event : PMRequestState.loading, progress : 0.27 & time : 1
flutter: Event : PMRequestState.loading, progress : 0.28 & time : 1
flutter: Event : PMRequestState.loading, progress : 0.3 & time : 2
flutter: Event : PMRequestState.loading, progress : 0.31 & time : 3
flutter: buffer video false
flutter: Event : PMRequestState.loading, progress : 0.32 & time : 4
flutter: Event : PMRequestState.loading, progress : 0.33 & time : 4
flutter: Event : PMRequestState.loading, progress : 0.34 & time : 5
flutter: Event : PMRequestState.loading, progress : 0.35 & time : 5
flutter: Event : PMRequestState.loading, progress : 0.36 & time : 6
flutter: Event : PMRequestState.loading, progress : 0.37 & time : 7
flutter: Event : PMRequestState.loading, progress : 0.38 & time : 8
flutter: Event : PMRequestState.loading, progress : 0.39 & time : 8
flutter: Event : PMRequestState.loading, progress : 0.4 & time : 9
flutter: Event : PMRequestState.loading, progress : 0.41 & time : 9
flutter: buffer video false
flutter: Event : PMRequestState.loading, progress : 0.42 & time : 10
flutter: buffer video false
flutter: Event : PMRequestState.loading, progress : 0.43 & time : 10
flutter: Event : PMRequestState.loading, progress : 0.44 & time : 11
flutter: buffer video false
flutter: Event : PMRequestState.loading, progress : 0.45 & time : 11
flutter: Event : PMRequestState.loading, progress : 0.46 & time : 12
flutter: Event : PMRequestState.loading, progress : 0.47 & time : 12
flutter: Event : PMRequestState.loading, progress : 0.48 & time : 13
flutter: Event : PMRequestState.loading, progress : 0.49 & time : 13
flutter: Event : PMRequestState.loading, progress : 0.5 & time : 14
flutter: Event : PMRequestState.loading, progress : 0.51 & time : 14
flutter: Event : PMRequestState.loading, progress : 0.52 & time : 15
flutter: Event : PMRequestState.loading, progress : 0.53 & time : 16
flutter: Event : PMRequestState.loading, progress : 0.54 & time : 16
flutter: Event : PMRequestState.loading, progress : 0.55 & time : 17
flutter: Event : PMRequestState.loading, progress : 0.56 & time : 17
flutter: Event : PMRequestState.loading, progress : 0.57 & time : 18
flutter: Event : PMRequestState.loading, progress : 0.59 & time : 19
flutter: Event : PMRequestState.loading, progress : 0.6 & time : 19
flutter: Event : PMRequestState.loading, progress : 0.61 & time : 20
flutter: Event : PMRequestState.loading, progress : 0.62 & time : 21
flutter: Event : PMRequestState.loading, progress : 0.63 & time : 21
flutter: Event : PMRequestState.loading, progress : 0.64 & time : 22
flutter: Event : PMRequestState.loading, progress : 0.65 & time : 22
flutter: Event : PMRequestState.loading, progress : 0.66 & time : 23
flutter: Event : PMRequestState.loading, progress : 0.68 & time : 23
flutter: Event : PMRequestState.loading, progress : 0.69 & time : 23
flutter: Event : PMRequestState.loading, progress : 0.7 & time : 24
flutter: Event : PMRequestState.loading, progress : 0.72 & time : 24
flutter: Event : PMRequestState.loading, progress : 0.73 & time : 24
flutter: Event : PMRequestState.loading, progress : 0.74 & time : 25
flutter: Event : PMRequestState.loading, progress : 0.75 & time : 25
flutter: Event : PMRequestState.loading, progress : 0.76 & time : 25
flutter: Event : PMRequestState.loading, progress : 0.78 & time : 25
flutter: Event : PMRequestState.loading, progress : 0.79 & time : 26
flutter: Event : PMRequestState.loading, progress : 0.8 & time : 26
flutter: Event : PMRequestState.loading, progress : 0.81 & time : 26
flutter: Event : PMRequestState.loading, progress : 0.82 & time : 27
flutter: Event : PMRequestState.loading, progress : 0.84 & time : 27
flutter: Event : PMRequestState.loading, progress : 0.85 & time : 27
flutter: Event : PMRequestState.loading, progress : 0.86 & time : 28
flutter: Event : PMRequestState.loading, progress : 0.87 & time : 28
flutter: Event : PMRequestState.loading, progress : 0.88 & time : 28
flutter: Event : PMRequestState.loading, progress : 0.9 & time : 29
flutter: Event : PMRequestState.loading, progress : 0.91 & time : 29
flutter: Event : PMRequestState.loading, progress : 0.92 & time : 30
flutter: Event : PMRequestState.loading, progress : 0.93 & time : 30
flutter: Event : PMRequestState.loading, progress : 0.94 & time : 30
flutter: Event : PMRequestState.loading, progress : 0.95 & time : 31
flutter: Event : PMRequestState.loading, progress : 0.96 & time : 31
flutter: Event : PMRequestState.loading, progress : 0.97 & time : 32
flutter: Event : PMRequestState.loading, progress : 0.98 & time : 32
flutter: Event : PMRequestState.loading, progress : 0.99 & time : 33
flutter: Event : PMRequestState.success, progress : 1.0 & time : 33
flutter: Displayed loaded file is : File: '/private/var/mobile/Containers/Data/Application/C92417AB-642F-4FA2-825B-1F380C2E59C7/tmp/.video/IMG_8696.MOV'

Where time is in seconds. The above logs are given by the below code :

 PMProgressHandler handler = PMProgressHandler();
 handler.stream.listen((event) {
      print("Event : ${event.state}, progress : ${event.progress} & time : ${DateTime.now().second}");
 });
 File? displayedFile = await assetEntity.loadFile(isOrigin: true, progressHandler: handler);

So as you can see, it tooks 33 + (60-47) = 46 seconds to load a 19sec video file.
I would like to understand why is it so long to retrieve a path ? This is almost x5 times the time it takes to actually upload the video :/

The only explanation i have came up with is that the path actually doesn't exist and you save the origin file to a temp file path and that takes a huge amount of time even for a powerful device... Which is also weird because i am also saving temp files in my app (1min videos that are edited) and it usually takes maximum 5seconds for the biggest video.

I need this filePath to "exists" as fast as possible, is there any way to do that ?

Thanks a lot in advance for any guidance !

[Tom3652]

This is actually more a bug than a question because i can't upload files because of this reason, even on very performant smartphones it takes too long to retrieve...

Is there any way to make it available instantly like getting a File in Flutter ?

[AlexV525]

If await entity.isLocallyAvailable equals false, which typically means:

• Your entity is only saved on iCloud storage rather than your device. Then the speed of retrieving the file depends on the speed of download.
• The resource you're requesting is not cached into the sandbox of the app. This is required by the iOS and cannot be avoid, which makes the first I/O fetching become few seconds.

All of these conditions are by design and must be implemented accordingly. If you want to know more about how to implement this, we've implemented a more user-friendly interaction at here: https://github.com/fluttercandies/flutter_wechat_assets_picker/blob/973fdcbb469cb2b2c7fc9750f0adf199f69a64d5/lib/src/widget/builder/locally_available_builder.dart

Is there any way to make it available instantly like getting a File in Flutter ?

The answer is NO in most of the time on iOS. This system has a Sandbox mechanism, which will copy newly retrieving files into the sandbox that the app is holding.

[Tom3652]

Thanks for the detailed answer !

[Tom3652]

So it is possible that the asset comes from even if we have not enable iCloud (i have never put photos / videos in iCloud and i have this loading on some files), i had no idea about it.

How can the thumbnail be retrieved instantly with entity.thumbDataWithOption() and when calling entity.file on the same entity it downloads it ?
In other words, how can we get a thumbnail from a file that is not locallyAvailable ? Unless all thumbnails are stored on the device and can be retrieved without the original file.

I would guess that Apple make them available for any apps to avoid using too much disk space per app for caching always the same assets but i don't know...

[AlexV525]

So it is possible that the asset comes from even if we have not enable iCloud (i have never put photos / videos in iCloud and i have this loading on some files), i had no idea about it.

Is it a real question? As you can think this again, it's impossible for us to retrieve any files that are not available locally.

How can the thumbnail be retrieved instantly with entity.thumbDataWithOption() and when calling entity.file on the same entity it downloads it ? In other words, how can we get a thumbnail from a file that is not locallyAvailable ? Unless all thumbnails are stored on the device and can be retrieved without the original file.

Yes, thumbnails can be retrieved locally, since the OS may have a cache manager holding all thumbnails.

I would guess that Apple make them available for any apps to avoid using too much disk space per app for caching always the same assets but i don't know...

That's not related to a photo manage plugin.