ImageRequest userInfo dictionary `Any` type for value allows unsupported types for imageIdKey

[sean-escendant]

My project is using signed URLs for images and Nuke 12.4. I followed the documentation to use a custom image id key. Initially I had passed a URL, with query parameters stripped, as the custom key but testing showed that the cache wasn't working as expected. Only when I changed the key to a String, as in the documentation example, it started working as expected.

It seems some trade offs were made in the API design from Nuke 9 to 10 which introduced this, hopefully you can find a way to keep the API strongly typed otherwise a clear notice in the documentation as to what are the supported types for imageIdKey.

[kean]

Hey, @sean-escendant. Thanks for raising this. I think it's a valid concern, and this change also had other implications: a slight impact on performance and potentially higher memory use if one of the user info keys is used.

How would you suggest approaching it?

[kean]

I'm planning to work on version 13.0 soon, and it would be a good time to introduce any breaking changes if needed.

[kean]

Starting with Nuke 13.0, these are now available as dedicated type-safe properties directly on ImageRequest:

var request = ImageRequest(url: url)
request.imageID = "http://example.com/image.jpeg"  // override cache key
request.scale = 2.0
request.thumbnail = ImageRequest.ThumbnailOptions(maxPixelSize: 320)

It more ergonomic and results in better performance.

For the imageID use case specifically - if you're stripping an auth token from the URL to get a stable cache key - there's now also an alternative: keep the base URL in the request and inject the token dynamically in ImagePipeline.Delegate.willLoadData:

func willLoadData(
    for request: ImageRequest,
    urlRequest: URLRequest,
    pipeline: ImagePipeline
) async throws -> URLRequest {
    var urlRequest = urlRequest
    urlRequest.setValue("Bearer \(try await TokenStore.shared.validToken())", forHTTPHeaderField: "Authorization")
    return urlRequest
}

This way the cache key stays stable automatically — no need to set imageID on every request.