Description

• JSCache is a simple and fast thread-safe key-value cache class to easily archive objects and cache images to disk.
• It is built on top of EGOCache
• It can be easily turned off for debugging just by setting

#define JSCACHE_ENABLED 0

• The default cache durations are these (but can be easily changed)

#define kJSCacheImageCacheDurationInSeconds 1296000 // 15 days
#define kJSCacheDataCacheDurationInSeconds 604800 // 7 days

Usage

• You can get a shared instance by calling:

+ (JSCache *)sharedCache;

Data caching

• To cache objects you simply call -cacheObject:forKey: passing an object which can be serialized (conforms to the NSCoding protocol)

- (void)cacheObject:(id<NSObject, NSCoding>)object forKey:(NSString *)key;

• This method will archive the object in a background queue for avoiding unnecessarily blocking the UI and then pass the NSData to EGOCache to save it to disk.
• You can later on access that object by calling -cachedObjectForKey: and passing the same key.

Image caching

• To cache an image object you call -cacheImage:forKey: with an UIImage object or -cacheImageData:forKey: with an NSData representing the image. Usually you will want the URL from where you got the image to be the key.

- (void)cacheImage:(UIImage *)image forKey:(NSString *)key;
- (void)cacheImageData:(NSData *)data forKey:(NSString *)key;

• And then to retrieve a cached image you just call -cachedImageForKey: or -cachedImageDataForKey:.

Invalidation of cached objects

• You can call -invalidateAllCachedObjects to purge the whole cache, or you can call -invalidateCachedObjectForKey: to invalidate a certain cached object.

- (void)invalidateCachedObjectForKey:(NSString *)key;
- (void)invalidateAllCachedObjects;