Cache - Nothing but Cache.

Hello,

I am using your cache for images. The type-safe one. However it doesnt persisted cached images to object. When I restart the app, the image is not there :( I am using .disk for back cache.

let config = Config(frontKind: .memory, backKind: .disk)
cache = Cache<UIImage>(name: SnapshotManager.CACHE_NAME, config: config)

I forked Cache because I got a Carthage error when building my main project. In the fork, I migrated to newest Swift (e.g., 5) syntax and set iOS 12 and macOS Mojave as OS versions.

In Xcode, everything builds fine, no problems, everything's clean.

When executing a carthage build (carthage build --no-skip-current --platform iOS), I get this error: `*** xcodebuild output can be found in /var/folders/hk/9cl_0hwx1czbgzsb26_tl2lc295kd8/T/carthage-xcodebuild.5LIvOf.log *** Building scheme "Cache-iOS" in Cache.xcodeproj Build Failed Task failed with exit code 65: /usr/bin/xcrun xcodebuild -project /Users/.../Cache/Cache.xcodeproj -scheme Cache-iOS -configuration Release -sdk iphoneos ONLY_ACTIVE_ARCH=NO CODE_SIGNING_REQUIRED=NO CODE_SIGN_IDENTITY= CARTHAGE=YES archive -archivePath /var/folders/hk/9cl_0hwx1czbgzsb26_tl2lc295kd8/T/Cache SKIP_INSTALL=YES GCC_INSTRUMENT_PROGRAM_FLOW_ARCS=NO CLANG_ENABLE_CODE_COVERAGE=NO STRIP_INSTALLED_PRODUCT=NO (launched in /Users/.../Cache)

This usually indicates that project itself failed to compile. Please check the xcodebuild log for more details: /var/folders/hk/9cl_0hwx1czbgzsb26_tl2lc295kd8/T/carthage-xcodebuild.5LIvOf.log`

Ths log does not give a helpful indication for the reason: `error: Bus error: 10

:0: error: unable to execute command: Bus error: 10 :0: error: compile command failed due to signal 10 (use -v to see invocation) ** ARCHIVE FAILED **

The following build commands failed: CompileSwift normal arm64 CompileSwiftSources normal arm64 com.apple.xcode.tools.swift.compiler (2 failures) `

Thanks for the excellent cache library. When using for caching images I noticed that you take the UIImage data as PNG or JPEG then serialize it into a JSON like

{"object":{"image":"\/9j\/4AAQSkZJRgABAQAASABIAAD\/4QBYRXhpZ...

This transformation I'm afraid is expensive, the resulting cache files also are easily double in size from the original binary. Then when we retrieve the data from the cache we have to deserialize it again.

So what happens now:

1. Fetch data from URL
2. Load it into UIImage
3. Send it to Cache: 3.1 Convert back to Data as PNG or JSON, depending on Alpha channel, again 3.2 Wrap it into a Codable 3.3 Serialize into JSON text (larger size) 3.4 Save to cache (disk and memory)

then in reverse when retrieving..

I prefer the way your previous Swift 3 version of the library worked where it would cache the actual data we fetch from a URL.

If you want to store an image (using Imaginary) in the disk storage and use the file’s remote URL as key, saving will fail if the URL is long. This PR tries to fix the issue by using the URL’s MD5 digest as file name instead of the Base64 encoded version of the URL

let diskConfig = DiskConfig(name: "Floppy")
let memoryConfig = MemoryConfig(expiry: .never, countLimit: 10, totalCostLimit: 10)

let storage = try? Storage(
  diskConfig: diskConfig, 
  memoryConfig: memoryConfig, 
  transformer: TransformerFactory.forCodable(ofType: User.self) // Storage<User>
)

Docs indicate to have a separate instance of storage for every type in the new version, why? In the previous version, I used one storage to store all Codable entities, not sure how to migrate it now...

Xcode 8.3 beta will complain about override statement on these methods:

  public override func add(_ key: String, object: T, expiry: Expiry? = nil, completion: (() -> Void)? = nil) {
  public override func object(_ key: String, completion: @escaping (_ object: T?) -> Void) {

Xcode 8.2 is fine with it. Probably a Swift compiler upgrade so it should be helpful to check it soon.

So I've been chasing a weird issue and I think I've gotten to the bottom of it. My app launches in the background periodically and I need to recover user data. After some logging it appeared my users were being logged out way too often/not having user credentials frequently.

So keychain periodically (~5%) of the time fails in the background (longstanding iOS issue), so I store a backup copy in cache to catch it.

Thing is, periodically cache fails too (with a not-found error for a user that definitely exists, and successfully wrote some info to disk)

I discovered that the default directory is Library/Caches, and according to:

https://stackoverflow.com/questions/7155964/will-application-home-library-caches-be-clear-on-app-update

and various other places iOS can periodically clear those files.

This seems counter-intuitive as I would expect most devs to expect a .never expiry to not be at risk of deletion from the OS itself.

All in all it's not a big deal to switch to /Documents (it's nice that this will be backed up by itunes/icloud... library/caches is not!) I am wondering if a change to the default location wouldn't make sense.

Thanks for such a great tool!

Edit: For those who find this later, the correct folder for this is Library/Application Support. I will update this post if moving to this folder solves my issue. I have a build rolling out now that uses the new location so I will see if this fixes my primary issue.

when i'm use cache and RealmSwift，for example:

import Foundation import RealmSwift import ObjectMapper import Cache

class Session: Object, Mappable { dynamic var token = "" dynamic var ttl: Double = 0

required convenience init?(_ map: Map) {
    self.init()
}

override static func primaryKey() -> String? {
    return "token"
}

func mapping(map: Map) {
    token               <- map["token"]
    ttl                 <- map["ttl"]
}

}

extension Session: Cachable {

typealias CacheType = Session

static func decode(data: NSData) -> CacheType? {
    Log.debug("decode")
    var object: CacheType?

    do {
        object = try DefaultCacheConverter<CacheType>().decode(data)
        Log.debug("object: \(object)")
    } catch {}

    return object
}

func encode() -> NSData? {
    var data: NSData?
    Log.debug("encode")
    do {
        data = try DefaultCacheConverter<CacheType>().encode(self)
    } catch {}

    return data
}

}

    let session = Session()
    session.token = "aaa"
    session.ttl = 20
    syncCache.add("tujiaoSession", object: session, expiry: .Date(NSDate().dateByAddingTimeInterval(100000)))

    let s:Session? = syncCache.object("tujiaoSession")
    Log.debug("ssssss: \(s)")

there have some errors for decode method.

I'm using Cache to store JSON coming from the server. This content is updated everyday, so I'm setting it's expiration date to be the day it was downloaded at 11:59 PM. this works just fine and the content is expired and re downloaded the next day.

The problem I'm facing is that, due to business rules, I need to return expired content (so I can have something to show user), identify that this content has expired and download the new version. And then update view with this new content and cache it.

Is there any way to flag Cache to not clear expired data on initialization, and when receiving some notifications?

• Use the homegrown SwiftHash, it contains just 1 file
• I've tested it a lot, even with https://github.com/minimaxir/big-list-of-naughty-strings
• This is not about file size, there's no problem with CryptoSwift, it's just about taste 😈

Hey there!

First, congrats on delivering Cache, it seems to be a very well built and appreciated library. I'm working for SoundCloud, and we are considering using your library in our iOS app. Although, before we get to this point, I would have a couple of questions if you don't mind!

There's a feature we probably would like to see in our caching layer: the ability to notify external observers that something changed. By changed, I mean:

• a key was modified (i.e. edition or removal)
• same goes on a store level: a key is added, edited or removed

Do you think that's something you would like to feature in your library? If so, would you build this yourself? Or would you expect a pull request?

Thanks in advance for you reply!

Cheers, Romain.

When use directory as cache key, disk cache just fail

This key dose not work

/private/var/mobile/Containers/Data/Application/BBFA132393-27C1-4A50-903420-B5742173983BF8A/Documents/14231/2022-11-03_11-30-28.zip

And this works

2022-11-03_11-30-28.zip

This may be a bug?

First, I'm saying "thank you!" for great caching library! It eliminates lots of needs related to caching, especially for expirable entries

Next, I'd like to ask to add convenient extension to the library

• requesting object with checking if it is still alive
• scheduling cache cleanup

extension StorageAware {
    public func aliveObject(forKey key: Key) -> Value? {
        try? !isExpiredObject(forKey: key) ? object(forKey: key) : nil
    }
    
    public func scheduleCleanup(_ interval: TimeInterval) where Self: AnyObject {
        DispatchQueue.global().asyncAfter(deadline: .now() + interval) { [weak self] in
            try? self?.removeExpiredObjects()
            self?.scheduleCleanup(interval)
        }
    }
}

I have the following case:

I'm fetching from API, decoding the response to concrete model. After that the model gets store in Cache (HybridStorage). Everything is fine until I'm trying to retrieve the model from Cache. Because the model is Inherited from other model and I think that is the problem. The ModelCache is declared because I have a list of FootballCountryModel.

 public class RemapableObject: NSObject, Codable {

 }

 public class FootballCountryModel: RemapableObject {
    var id: String;
    var alias: String?;
    var countryCode: String?;
    var assets: CountryAssets?;
    var name: String;

    enum CodingKeys: String, CodingKey {
        case id, alias, assets, name;
        case countryCode = "country_code";
    }
    
    /*
     For a subclass of a class already adopting Codable (e.g. RemapableObject) we need to
     override our superclass's implementation by offering our own.
     There is no way for the compiler to synthesize an implementation here for us.
     */
    
    required init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self);

        self.id = try container.decode(String.self, forKey: .id);
        self.alias = try container.decode(String?.self, forKey: .alias);
        self.countryCode = try container.decode(String?.self, forKey: .countryCode);
        self.assets = try container.decode(CountryAssets?.self, forKey: .assets);
        self.name = try container.decode(String.self, forKey: .name);
        
        try super.init(from: container.superDecoder());
    }
}

class ModelCache<T: Codable>: NSObject, Codable {
    let data: [T];
    
    init (data: [T]) {
        self.data = data;
    }
}

Here is when Im trying to retrieve from Cache:

let diskConfig = DiskConfig(name: "FansUnitedSDK")
let memoryConfig = MemoryConfig(expiry: .never, countLimit: 10, totalCostLimit: 10)
let storage = try! Storage<String, ModelCache<FootballCountryModel>>(
          diskConfig: diskConfig,
          memoryConfig: memoryConfig,
          transformer: TransformerFactory.forCodable(ofType: ModelCache<FootballCountryModel>.self))
let cacheKey = "football_countries";
do {
        let footballCountriesCache = try storage.object(forKey: cacheKey) // Here it returns keyNotFound Error
} catch {
        print(error)
}

The keyNotFound Error is the following one:

keyNotFound(CodingKeys(stringValue: "id", intValue: nil), Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "object", intValue: nil), CodingKeys(stringValue: "data", intValue: nil), _JSONKey(stringValue: "Index 0", intValue: 0)], debugDescription: "No value associated with key CodingKeys(stringValue: \"id\", intValue: nil) (\"id\").", underlyingError: nil))

Any suggestions will be helpful. I'm trying for days to implement some caching in my project (with Core Data and other dependencies) but there always some issues coming up.

let sortedFiles = objects.sorted { if let time1 = $0.resourceValues.contentModificationDate?.timeIntervalSinceReferenceDate, let time2 = $1.resourceValues.contentModificationDate?.timeIntervalSinceReferenceDate { return time1 > time2 } else { return false } } this will remove recent file, generally speaking should remove the file which older not the recent

Try to update cached object:

step 1: delete object using **removeObject** 
step 2: save updated object using **setObject**

Every things goes well but the problem appears when try to get data using async.object it returns old value of object. I have checked value saved on disk it is new data.

I have trace the code and figure out to get data this first check memory : public func entry(forKey key: Key) throws -> Entry<Value> { do { return try memoryStorage.entry(forKey: key) } catch { let entry = try diskStorage.entry(forKey: key) // set back to memoryStorage memoryStorage.setObject(entry.object, forKey: key, expiry: entry.expiry) return entry } }

how can remove object in first step to make sure it is removed from disk & memory?