Allow providing a custom cache key which overrides the url in pin_setImage(from: URL?)

[MilesV64]

My server sends lots of signed URLs which means the PIN cache downloads new images every time since the signed URL is slightly different. I'd like to use a custom key that I pass in, and then the library would only use the URL for downloading the image, not for use as the cache key.

It could look like this:

// The latest signed url from my server
let myURL = self.imageURL 

// A string uniquing the image; if this changes then it means the image changed. 
// Otherwise it's the same image but could be a different URL due to signed URLs.
let id = self.imageID

// CacheKey would be optional so current library behavior is unchanged
// The library would then use the given id as the cache key, only using `myURL` if it needs to be downloaded
self.imageView.pin_setImage(from: myURL, cacheKey: id) 

Would this be possible? Is there any other way to get around handling lots of signed URLs without redownloading every time?

[garrettmoon]

Can you override imageFromCacheWithCacheKey? https://github.com/pinterest/PINRemoteImage/blob/18637e4414d77fbc95cd7d499179a9880e9a78d8/Source/Classes/include/PINRemoteImageManager.h#L596-L605

[MilesV64]

Thank you for the reply, I think that should be enough to go on! I like the idea of setting the key at the same time as setting the URL because this override method requires additional state management/parsing of the URL (unless I'm missing a better way), but thank you for the suggestion.

To use this properly I would subclass PINRemoteImageManager correct? How would I then ensure that is being used instead of .shared() when calling pin_setImage() on a UIImageView?

[garrettmoon]

Yes, you'll need to override the class and then call setSharedImageManagerWithConfiguration: on the overridden class (since that method calls [self class] when instantiating the shared image manager, it'll correctly return your subclass when other places call PINRemoteImageManager.shared(). https://github.com/pinterest/PINRemoteImage/blob/18637e4414d77fbc95cd7d499179a9880e9a78d8/Source/Classes/include/PINRemoteImageManager.h#L219-L225

It's certainly not the most elegant solution and annoyingly has to be called before any parts of your code call the .shared() method, but it should work!

[MilesV64]

Really appreciate the quick responses, thank you! I think this is enough for me to go on, I do think something like what I mentioned in the issue would be pretty slick in the future but this should work!