Add cache key filter support to SDWebManager in order to allow custom cache key generation

README.md

@@ -170,6 +170,28 @@ By default, the image will be stored in memory cache as well as on disk cache (a
 you want only the memory cache, use the alternative method storeImage:forKey:toDisk: with a negative
 third argument.
 
+### Using cache key filter
+
+Sometime, you may not want to use the image URL as cache key because part of the URL is dynamic
+(i.e.: for access control purpose). SDWebImageManager provides a way to set a cache key filter that
+takes the NSURL as input, and output a cache key NSString.
+
+The following example sets a filter in the application delegate that will remove any query-string from
+the URL before to use it as a cache key:
+
+    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
+    {
+        [[SDWebImageManager sharedManager] setCacheKeyFilter:^(NSURL *url)
+        {
+            url = [[[NSURL alloc] initWithScheme:url.scheme host:url.host path:url.path] autorelease];
+            return [url absoluteString];
+        }];
+
+        // Your app init code...
+        return YES;
+    }
+
+
 Common Problems
 ---------------
 
@@ -203,10 +225,10 @@ The following instructions are adapted from the excellent "Using Open Source Sta
 
 ### Add the SDWebImage project to your workspace
 
-Make sure your project is in a workspace. If it's not, click File -> Save As Workspace first. 
+Make sure your project is in a workspace. If it's not, click File -> Save As Workspace first.
 
 Right-click on the project navigator and select "Add Files to "Your Project" and select SDWebImage.xcodeproj.
-You may want to include the SDWebImage directory in your workspace repository before adding it to your project. 
+You may want to include the SDWebImage directory in your workspace repository before adding it to your project.
 
 ![Add SDWebImage](http://blog.carbonfive.com/wp-content/uploads/2011/04/adding_an_existing_project.png?w=300)
 
@@ -214,7 +236,7 @@ You should end up with your project and SDWebimage project at the same level in
 
 ### Build libSDWebImage.a File
 
-Set your build target to iOS Device, then click Build. Make sure the libSDWebImage.a file inside SDWebImage -> Products is not red. 
+Set your build target to iOS Device, then click Build. Make sure the libSDWebImage.a file inside SDWebImage -> Products is not red.
 
 ### Add build target dependency
 
@@ -222,11 +244,11 @@ Select your project's build target and add the 'libSDWebImage.a' library to the
 
 ![Add target dependency](http://blog.carbonfive.com/wp-content/uploads/2011/04/linkable_libraries.png?w=214)
 
-You may also need to add MapKit.framework here too as 'MKAnnotationView_WebCache.h' depends on it. 
+You may also need to add MapKit.framework here too as 'MKAnnotationView_WebCache.h' depends on it.
 
 ### Add headers
 
-Open the "Build Settingsæ tab and locate the "User Header Search Paths" setting. Set this to 
+Open the "Build Settingsæ tab and locate the "User Header Search Paths" setting. Set this to
 "$(BUILT_PRODUCTS_DIR)/../../Headers" and check the "Recursive" check box.
 
 ![Header Search Paths](http://blog.carbonfive.com/wp-content/uploads/2011/04/header_search_path_value.png?w=300)
@@ -234,7 +256,7 @@ Open the "Build Settingsæ tab and locate the "User Header Search Paths" setting
 Add the "-ObjC" flag to the "Other Linker Flags" build setting.
 
 ### Build Project
-At this point your workspace should build without error. If you are having problem, post to the Issue and the community can help you solve it. 
+At this point your workspace should build without error. If you are having problem, post to the Issue and the community can help you solve it.
 
 ### Fixing indexing
 

SDWebImageManager.h

@@ -28,6 +28,12 @@ typedef enum
     NSMutableArray *failedURLs;
 }
 
+#if NS_BLOCKS_AVAILABLE
+typedef NSString *(^CacheKeyFilter)(NSURL *url);
+@property (strong) CacheKeyFilter cacheKeyFilter;
+#endif
+
+
 + (id)sharedManager;
 - (UIImage *)imageWithURL:(NSURL *)url;
 - (void)downloadWithURL:(NSURL *)url delegate:(id<SDWebImageManagerDelegate>)delegate;

SDWebImageManager.m

@@ -20,6 +20,10 @@ static SDWebImageManager *instance;
 
 @implementation SDWebImageManager
 
+#if NS_BLOCKS_AVAILABLE
+@synthesize cacheKeyFilter;
+#endif
+
 - (id)init
 {
     if ((self = [super init]))
@@ -56,12 +60,28 @@ static SDWebImageManager *instance;
     return instance;
 }
 
+- (NSString *)cacheKeyForURL:(NSURL *)url
+{
+#if NS_BLOCKS_AVAILABLE
+    if (self.cacheKeyFilter)
+    {
+        return self.cacheKeyFilter(url);
+    }
+    else
+    {
+        return [url absoluteString];
+    }
+#else
+    return [url absoluteString];
+#endif
+}
+
 /**
  * @deprecated
  */
 - (UIImage *)imageWithURL:(NSURL *)url
 {
-    return [[SDImageCache sharedImageCache] imageFromKey:[url absoluteString]];
+    return [[SDImageCache sharedImageCache] imageFromKey:[self cacheKeyForURL:url]];
 }
 
 /**
@@ -106,7 +126,7 @@ static SDWebImageManager *instance;
     [cacheDelegates addObject:delegate];
     [cacheURLs addObject:url];
     NSDictionary *info = [NSDictionary dictionaryWithObjectsAndKeys:delegate, @"delegate", url, @"url", [NSNumber numberWithInt:options], @"options", nil];
-    [[SDImageCache sharedImageCache] queryDiskCacheForKey:[url absoluteString] delegate:self userInfo:info];
+    [[SDImageCache sharedImageCache] queryDiskCacheForKey:[self cacheKeyForURL:url] delegate:self userInfo:info];
 }
 
 #if NS_BLOCKS_AVAILABLE
@@ -134,7 +154,7 @@ static SDWebImageManager *instance;
     NSDictionary *info = [NSDictionary dictionaryWithObjectsAndKeys:delegate, @"delegate", url, @"url", [NSNumber numberWithInt:options], @"options", successCopy, @"success", failureCopy, @"failure", nil];
     SDWIRelease(successCopy);
     SDWIRelease(failureCopy);
-    [[SDImageCache sharedImageCache] queryDiskCacheForKey:[url absoluteString] delegate:self userInfo:info];
+    [[SDImageCache sharedImageCache] queryDiskCacheForKey:[self cacheKeyForURL:url] delegate:self userInfo:info];
 }
 #endif
 
@@ -313,7 +333,7 @@ static SDWebImageManager *instance;
         // Store the image in the cache
         [[SDImageCache sharedImageCache] storeImage:image
                                           imageData:downloader.imageData
-                                             forKey:[downloader.url absoluteString]
+                                             forKey:[self cacheKeyForURL:downloader.url]
                                              toDisk:!(options & SDWebImageCacheMemoryOnly)];
     }
     else if (!(options & SDWebImageRetryFailed))