Custom image cache search paths

This is particularly useful if you are bundling images with your app that have been cached by SDWebImage. (ie. if you are 'seeding' your app with a core-data file that contains a lot of URL's to images and would like to also seed those images without having to copy every one of them over)

For example, you can tell SDImageCache to add '[[NSBundle mainBundle] resourcePath]' as a custom path, so that the main bundle will be queried for cached images.

This prevents the need for you to copy pre-cached images over to the caches/ImageCache folder that SDImageCache normally checks for.

The custom paths are read-only.

Examples/SDWebImage Demo.xcodeproj/project.pbxproj

@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		3E75A9861742DBE700DA412D /* CustomPathImages in Resources */ = {isa = PBXBuildFile; fileRef = 3E75A9851742DBE700DA412D /* CustomPathImages */; };
 		531041C1157EAC8F00BBABC3 /* ImageIO.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 537612E6155ABA44005750A4 /* ImageIO.framework */; };
 		5376129A155AB74D005750A4 /* UIKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 53761299155AB74D005750A4 /* UIKit.framework */; };
 		5376129C155AB74D005750A4 /* Foundation.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 5376129B155AB74D005750A4 /* Foundation.framework */; };
@@ -48,6 +49,7 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
+		3E75A9851742DBE700DA412D /* CustomPathImages */ = {isa = PBXFileReference; lastKnownFileType = folder; path = CustomPathImages; sourceTree = SOURCE_ROOT; };
 		53761295155AB74D005750A4 /* SDWebImage Demo.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = "SDWebImage Demo.app"; sourceTree = BUILT_PRODUCTS_DIR; };
 		53761299155AB74D005750A4 /* UIKit.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = UIKit.framework; path = System/Library/Frameworks/UIKit.framework; sourceTree = SDKROOT; };
 		5376129B155AB74D005750A4 /* Foundation.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Foundation.framework; path = System/Library/Frameworks/Foundation.framework; sourceTree = SDKROOT; };
@@ -120,6 +122,7 @@
 		5376129F155AB74D005750A4 /* SDWebImage Demo */ = {
 			isa = PBXGroup;
 			children = (
+				3E75A9851742DBE700DA412D /* CustomPathImages */,
 				537612A8155AB74D005750A4 /* AppDelegate.h */,
 				537612A9155AB74D005750A4 /* AppDelegate.m */,
 				537612AB155AB74D005750A4 /* MasterViewController.h */,
@@ -235,6 +238,7 @@
 				53A2B50D155B155A00B12423 /* placeholder.png in Resources */,
 				53A2B50E155B155A00B12423 /* placeholder@2x.png in Resources */,
 				53EEC18916484553007601E1 /* Default-568h@2x.png in Resources */,
+				3E75A9861742DBE700DA412D /* CustomPathImages in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

Examples/SDWebImage Demo/AppDelegate.m

@@ -10,6 +10,8 @@
 
 #import "MasterViewController.h"
 
+#import <SDWebImage/SDImageCache.h>
+
 @implementation AppDelegate
 
 @synthesize window = _window;
@@ -17,6 +19,10 @@
 
 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
 {
+    //Add a custom read-only cache path
+    NSString *bundledPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"CustomPathImages"];
+    [[SDImageCache sharedImageCache] addReadOnlyCachePath:bundledPath];
+
     self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
     // Override point for customization after application launch.
 

SDWebImage/SDImageCache.h

@@ -56,6 +56,14 @@ typedef enum SDImageCacheType SDImageCacheType;
  */
 - (id)initWithNamespace:(NSString *)ns;
 
+/**
+ * Add a read-only cache path to search for images pre-cached by SDImageCache
+ * Useful if you want to bundle pre-loaded images with your app
+ *
+ * @param path The path to use for this read-only cache path
+ */
+- (void)addReadOnlyCachePath:(NSString *)path;
+
 /**
  * Store an image into memory and disk cache at the given key.
  *

SDWebImage/SDImageCache.m

@@ -19,6 +19,7 @@ static const NSInteger kDefaultCacheMaxCacheAge = 60 * 60 * 24 * 7; // 1 week
 
 @property (strong, nonatomic) NSCache *memCache;
 @property (strong, nonatomic) NSString *diskCachePath;
+@property (strong, nonatomic) NSMutableArray *customPaths;
 @property (SDDispatchQueueSetterSementics, nonatomic) dispatch_queue_t ioQueue;
 
 @end
@@ -82,9 +83,33 @@ static const NSInteger kDefaultCacheMaxCacheAge = 60 * 60 * 24 * 7; // 1 week
     SDDispatchQueueRelease(_ioQueue);
 }
 
+- (void)addReadOnlyCachePath:(NSString *)path
+{
+    if (!self.customPaths)
+    {
+        self.customPaths = NSMutableArray.new;
+    }
+
+    if (![self.customPaths containsObject:path])
+    {
+        [self.customPaths addObject:path];
+    }
+}
+
 #pragma mark SDImageCache (private)
 
-- (NSString *)cachePathForKey:(NSString *)key
+- (NSString *)cachePathForKey:(NSString *)key inPath:(NSString *)path
+{
+    NSString *filename = [self cachedFileNameForKey:key];
+    return [path stringByAppendingPathComponent:filename];
+}
+
+- (NSString *)defaultCachePathForKey:(NSString *)key
+{
+    return [self cachePathForKey:key inPath:self.diskCachePath];
+}
+
+- (NSString *)cachedFileNameForKey:(NSString *)key
 {
     const char *str = [key UTF8String];
     unsigned char r[CC_MD5_DIGEST_LENGTH];
@@ -92,7 +117,7 @@ static const NSInteger kDefaultCacheMaxCacheAge = 60 * 60 * 24 * 7; // 1 week
     NSString *filename = [NSString stringWithFormat:@"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
                           r[0], r[1], r[2], r[3], r[4], r[5], r[6], r[7], r[8], r[9], r[10], r[11], r[12], r[13], r[14], r[15]];
 
-    return [self.diskCachePath stringByAppendingPathComponent:filename];
+    return filename;
 }
 
 #pragma mark ImageCache
@@ -134,7 +159,7 @@ static const NSInteger kDefaultCacheMaxCacheAge = 60 * 60 * 24 * 7; // 1 week
                     [fileManager createDirectoryAtPath:_diskCachePath withIntermediateDirectories:YES attributes:nil error:NULL];
                 }
 
-                [fileManager createFileAtPath:[self cachePathForKey:key] contents:data attributes:nil];
+                [fileManager createFileAtPath:[self defaultCachePathForKey:key] contents:data attributes:nil];
             }
         });
     }
@@ -175,10 +200,30 @@ static const NSInteger kDefaultCacheMaxCacheAge = 60 * 60 * 24 * 7; // 1 week
     return diskImage;
 }
 
+- (NSData *)diskImageDataBySearchingAllPathsForKey:(NSString *)key
+{
+    NSString *defaultPath = [self defaultCachePathForKey:key];
+    NSData *data = [NSData dataWithContentsOfFile:defaultPath];
+    if (data)
+    {
+        return data;
+    }
+
+    for (NSString *path in self.customPaths)
+    {
+        NSString *filePath = [self cachePathForKey:key inPath:path];
+        NSData *imageData = [NSData dataWithContentsOfFile:filePath];
+        if (imageData) {
+            return imageData;
+        }
+    }
+
+    return nil;
+}
+
 - (UIImage *)diskImageForKey:(NSString *)key
 {
-    NSString *path = [self cachePathForKey:key];
-    NSData *data = [NSData dataWithContentsOfFile:path];
+    NSData *data = [self diskImageDataBySearchingAllPathsForKey:key];
     if (data)
     {
         if ([data sd_isGIF])
@@ -259,7 +304,7 @@ static const NSInteger kDefaultCacheMaxCacheAge = 60 * 60 * 24 * 7; // 1 week
     {
         dispatch_async(self.ioQueue, ^
         {
-            [[NSFileManager defaultManager] removeItemAtPath:[self cachePathForKey:key] error:nil];
+            [[NSFileManager defaultManager] removeItemAtPath:[self defaultCachePathForKey:key] error:nil];
         });
     }
 }