Avoid multiple parallel network requests for the same URL

[Kazachenko1998]

I am developing an application where there can be many identical pictures on one screen (SVG from the server). When I open the application for the first time, I see multiple parallel requests behind the same picture.

I think it's worth adding a pool of downloads, and if this URL is already being processed, do not make this request again, but wait for the first one to complete and use its result.

override fun onCreate(savedInstanceState: Bundle?) {
        CODE
        Coil.setImageLoader(
            ImageLoader
                .Builder(this)
                .components { add(SvgDecoder.Factory()) }
                .crossfade(true)
                .build()
        )
        CODE
}

AsyncImage(
    placeholder = rememberAsyncImagePainter(R.drawable.ic_plchldr),
    error = rememberAsyncImagePainter(R.drawable.ic_plchldr),
    model = URL,
    contentDescription = URL,
    contentScale = ContentScale.Crop,
    modifier = Modifier.fillMaxSize()
)

[colinrtwhite]

I agree this would be nice to have. Ideally, HttpUriFetcher should reference count the number of responses waiting for its network request. We probably can't merge requests that only share the same URL - we'll need request headers to match as well (at least by default).

Additionally - we can only do this for requests that are going to be written to the disk cache. If they're not being written to the disk cache then we can only read the response body once. There's a few other edge cases that means this would have to be opt-in at least for a while.

[colinrtwhite]

Thinking about this more we should also provide a configurable "keep alive" duration for network requests. That way the user can configure how long to wait before cancelling a network request if there's no more consumer for the result.

This would be useful for RecyclerViews and other cases where a request can be restarted multiple times in quick succession.

[gargVader]

What is the status on this?