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starkdmi / download_manager

Isolated download manager with progress, cancellation, pause and resume
https://pub.dev/packages/isolated_download_manager
BSD 3-Clause "New" or "Revised" License
15 stars 2 forks source link

are you using IsolateGroup for performance? #2

Closed shahmirzali49 closed 1 year ago

shahmirzali49 commented 1 year ago

can I download lots of files/URLs at once? for example like this :

DownloadManager.instance.init(isolates:200)

starkdmi commented 1 year ago

No, I'm not using IsolateGroup, is there a code example available? The documentation is poor and it kinda require vm_service package.

Isolates are spawned here and there is no internall limitation of running 100-200 instances at once.

Also there is not much data sent between the Isolates - it's not the JSON parsing which sends megabytes back and forward, downloaded bytes are writen to the files directly.

shahmirzali49 commented 1 year ago

yeah, the doc about the isolate group is poor. I just find this resource: https://github.com/dart-lang/sdk/issues/36097

what does mean "Also there is not much data sent between the Isolates"? what is the limit for fileSize? the limit is just for a single isolate or for all isolates? I use can I wanna download 180/200 mp3 files. but one file size is a maximum of 1 MB approximately. I wonder if my file sizes be 10MB what is gonna happen? I can't do that?

starkdmi commented 1 year ago

According to your link the Isolate Group is internal class and used by default.

You can download as many files as you want, there are no limits in MB, and each downloading proceeds separately.

The filesize property is not required, it used to specify bytes end for a range header and actually has no limit too.

starkdmi commented 1 year ago

DownloadManager.instance.init(isolates:200)

download 180/200 mp3 files

Most likely, 100 parallel requests will overload the network too much and will be slower than a queue of 5-10 parallel requests.

shahmirzali49 commented 1 year ago

Okay, probably I will do what you said: 5-10 requests and then others. thanks for your answers. I really appreciate it.

starkdmi commented 1 year ago

5-10 requests and then others

// Init 5 isolates which runs in background and wait for requests
final manager = DownloadManager.instance;
await manager.init(isolates: 5)

// Run 100+ downloads, they will be queued automatically
manager.download(url1, path: destination1);
manager.download(url2, path: destination2);
// ...
manager.download(url100, path: destination100);