Huge cache size

[MattesGroeger]

We are using AwesomeCache and it's great.

Now I implemented it for some bigger images and suddenly noticed a crazy amount of disk usage.

A picture with 414kb takes up almost 5MB on disk (Caches/com.aschuch.cache/images/xxx.cache). Is this something expected?

Help would be much appreciated!

[aschuch]

Hm, this indeed sounds a bit strange. I've not experienced this.
AwesomeCache uses NSCoding and NSKeyedArchiver to persist objects under the hood.

Could you try and persist the picture using NSKeyedArchiver to try and see if the persisted object is of similar size?

[MattesGroeger]

I'll try that tomorrow.

When I inspected the cached binary I saw NSKeyedArchiver annotations already. Maybe this problem is also specific to JPEG files. Will investigate further tomorrow.

[mbuchetics]

NSKeyedArchiver will persist the uncompressed UIImage and that's why you see the difference in size compared to the JPEG file. You would need to cache the data returned by UIImageJPEGRepresentation.

[MattesGroeger]

@mbuchetics Good point! Thanks a lot, that makes sense and I just changed our implementation accordingly:

Use NSData as cached type:

struct Images {
    static let cache = Cache<NSData>(name: "images")
}

Writing to cache:

if let data = UIImageJPEGRepresentation(processedImage, 0.6) {
    Images.cache.setObject(data,
        forKey: imageId,
        expires: cacheExpiry)
}

Reading from cache:

if let imageData = Images.cache[imageId] {
    return UIImage(data: imageData)
}

Now file sizes are under 1MB. Issue can be closed then. Keep up the good work!

[aschuch]

@mbuchetics Thanks for the clarification.

@MattesGroeger Awesome, if you have further questions feel free to reopen. 🎇