Merge pull request steipete#21 from arturgrigor/master

Allow SDURLCache to be subclassed instead of hijacking SDURLCache's methods

Author: steipete

SDURLCache.h

@@ -10,14 +10,18 @@
 
 #import <Foundation/Foundation.h>
 
-@interface SDURLCache : NSURLCache {
+/* Define SDURLCACHE_DEBUG=1 if you want to get some more info about the cached requests. */
+
+@interface SDURLCache : NSURLCache
+{
     @private
-    BOOL _diskCacheInfoDirty;
-    BOOL _ignoreMemoryOnlyStoragePolicy;
-    BOOL _timerPaused;
-    NSUInteger _diskCacheUsage;
-    NSTimeInterval _minCacheInterval;
-    dispatch_source_t _maintenanceTimer;
+        BOOL _diskCacheInfoDirty;
+        BOOL _ignoreMemoryOnlyStoragePolicy;
+        BOOL _timerPaused;
+        BOOL _shouldRespectCacheControlHeaders;
+        NSUInteger _diskCacheUsage;
+        NSTimeInterval _minCacheInterval;
+        dispatch_source_t _maintenanceTimer;
 }
 
 /*
@@ -38,7 +42,6 @@
  */
 @property (nonatomic, assign) BOOL ignoreMemoryOnlyStoragePolicy;
 
-
 /*
  * Allow caching responses for a request with a cache policy that ignores the local cache.
  * Usually, these responses don't need to be cached, because a request that ignores the cache
@@ -48,6 +51,13 @@
  */
 @property (nonatomic, assign) BOOL allowCachingResponsesToNonCachedRequests;
 
+/*
+ * If the server sends cache-control / pragma: no-cache headers, then the requests will not be cached.
+ *
+ * The default value is YES.
+ */
+@property (nonatomic, assign) BOOL shouldRespectCacheControlHeaders;
+
 /*
  * Returns a default cache director path to be used at cache initialization. The generated path directory
  * will be located in the application's cache directory and thus won't be synced by iTunes.
@@ -66,3 +76,15 @@
 - (void)removeAllCachedResponsesInMemory;
 
 @end
+
+#pragma mark - For subclasses only
+
+@interface SDURLCache (PrivateMethods)
+
+/*
+ * This is the perfect place to strip some query parameters in case you are sending
+ * OAuth information via query string instead of the Authorization request header.
+ */
++ (NSURLRequest *)canonicalRequestForRequest:(NSURLRequest *)request;
+
+@end

SDURLCache.m

@@ -35,6 +35,7 @@
 static NSString *const kAFURLCacheInfoFileName = @"cacheInfo.plist";
 static NSString *const kAFURLCacheInfoAccessesKey = @"accesses";
 static NSString *const kAFURLCacheInfoSizesKey = @"sizes";
+static NSString *const kAFURLCacheInfoURLsKey = @"URLs";
 static float const kAFURLCacheLastModFraction = 0.1f; // 10% since Last-Modified suggested by RFC2616 section 13.2.4
 static float const kAFURLCacheDefault = 3600.0f; // Default cache expiration delay if none defined (1 hour)
 
@@ -419,7 +420,7 @@ + (NSDate *)expirationDateFromHeaders:(NSDictionary *)headers withStatusCode:(NS
     // Define "now" based on the request
     NSString *date = [headers objectForKey:@"Date"];
     // If no Date: header, define now from local clock
-    NSDate *now = date ? [SDURLCache dateFromHttpDateString:date] : [NSDate date];
+    NSDate *now = date ? [[self class] dateFromHttpDateString:date] : [NSDate date];
 
     // Look at info from the Cache-Control: max-age=n header
     NSString *cacheControl = [[headers objectForKey:@"Cache-Control"] lowercaseString];
@@ -447,7 +448,7 @@ + (NSDate *)expirationDateFromHeaders:(NSDictionary *)headers withStatusCode:(NS
     NSString *expires = [headers objectForKey:@"Expires"];
     if (expires) {
         NSTimeInterval expirationInterval = 0;
-        NSDate *expirationDate = [SDURLCache dateFromHttpDateString:expires];
+        NSDate *expirationDate = [[self class] dateFromHttpDateString:expires];
         if (expirationDate) {
             expirationInterval = [expirationDate timeIntervalSinceDate:now];
         }
@@ -470,7 +471,7 @@ + (NSDate *)expirationDateFromHeaders:(NSDictionary *)headers withStatusCode:(NS
     NSString *lastModified = [headers objectForKey:@"Last-Modified"];
     if (lastModified) {
         NSTimeInterval age = 0;
-        NSDate *lastModifiedDate = [SDURLCache dateFromHttpDateString:lastModified];
+        NSDate *lastModifiedDate = [[self class] dateFromHttpDateString:lastModified];
         if (lastModifiedDate) {
             // Define the age of the document by comparing the Date header with the Last-Modified header
             age = [now timeIntervalSinceDate:lastModifiedDate];
@@ -491,6 +492,9 @@ - (NSMutableDictionary *)diskCacheInfo {
                     _diskCacheInfo = [[NSMutableDictionary alloc] initWithObjectsAndKeys:
                                       [NSMutableDictionary dictionary], kAFURLCacheInfoAccessesKey,
                                       [NSMutableDictionary dictionary], kAFURLCacheInfoSizesKey,
+#if SDURLCACHE_DEBUG
+                                      [NSMutableDictionary dictionary], kAFURLCacheInfoURLsKey,
+#endif
                                       nil];
                 }
                 _diskCacheInfoDirty = NO;
@@ -541,12 +545,18 @@ - (void)removeCachedResponseForCachedKeys:(NSArray *)cacheKeys {
 
             NSMutableDictionary *accesses = [self.diskCacheInfo objectForKey:kAFURLCacheInfoAccessesKey];
             NSMutableDictionary *sizes = [self.diskCacheInfo objectForKey:kAFURLCacheInfoSizesKey];
+#if SDURLCACHE_DEBUG
+            NSMutableDictionary *urls = [self.diskCacheInfo objectForKey:kAFURLCacheInfoURLsKey];
+#endif
             NSFileManager *fileManager = [[NSFileManager alloc] init];
 
             while ((cacheKey = [enumerator nextObject])) {
                 NSUInteger cacheItemSize = [[sizes objectForKey:cacheKey] unsignedIntegerValue];
                 [accesses removeObjectForKey:cacheKey];
                 [sizes removeObjectForKey:cacheKey];
+#if SDURLCACHE_DEBUG
+                [urls removeObjectForKey:cacheKey];
+#endif
                 [fileManager removeItemAtPath:[_diskCachePath stringByAppendingPathComponent:cacheKey] error:NULL];
 
                 _diskCacheUsage -= cacheItemSize;
@@ -583,7 +593,7 @@ - (void)balanceDiskUsage {
 
 
 - (void)storeRequestToDisk:(NSURLRequest *)request response:(NSCachedURLResponse *)cachedResponse {
-    NSString *cacheKey = [SDURLCache cacheKeyForURL:request.URL];
+    NSString *cacheKey = [[self class] cacheKeyForURL:request.URL];
     NSString *cacheFilePath = [_diskCachePath stringByAppendingPathComponent:cacheKey];
 
     [self createDiskCachePath];
@@ -606,6 +616,9 @@ - (void)storeRequestToDisk:(NSURLRequest *)request response:(NSCachedURLResponse
         // Update cache info for the stored item
         [(NSMutableDictionary *)[self.diskCacheInfo objectForKey:kAFURLCacheInfoAccessesKey] setObject:[NSDate date] forKey:cacheKey];
         [(NSMutableDictionary *)[self.diskCacheInfo objectForKey:kAFURLCacheInfoSizesKey] setObject:cacheItemSize forKey:cacheKey];
+#if SDURLCACHE_DEBUG
+        [(NSMutableDictionary *)[self.diskCacheInfo objectForKey:kAFURLCacheInfoURLsKey] setObject:request.URL.absoluteString forKey:cacheKey];
+#endif
 
         [self saveCacheInfo];
 
@@ -643,6 +656,7 @@ + (NSString *)defaultCachePath {
 - (id)initWithMemoryCapacity:(NSUInteger)memoryCapacity diskCapacity:(NSUInteger)diskCapacity diskPath:(NSString *)path {
     if ((self = [super initWithMemoryCapacity:memoryCapacity diskCapacity:diskCapacity diskPath:path])) {
         self.minCacheInterval = kAFURLCacheInfoDefaultMinCacheInterval;
+        self.shouldRespectCacheControlHeaders = YES;
         self.diskCachePath = path;
         self.ignoreMemoryOnlyStoragePolicy = NO;
 	}
@@ -651,7 +665,7 @@ - (id)initWithMemoryCapacity:(NSUInteger)memoryCapacity diskCapacity:(NSUInteger
 }
 
 - (void)storeCachedResponse:(NSCachedURLResponse *)cachedResponse forRequest:(NSURLRequest *)request {
-    request = [SDURLCache canonicalRequestForRequest:request];
+    request = [[self class] canonicalRequestForRequest:request];
 
     if (!_allowCachingResponsesToNonCachedRequests &&
         (request.cachePolicy == NSURLRequestReloadIgnoringLocalCacheData
@@ -668,15 +682,19 @@ - (void)storeCachedResponse:(NSCachedURLResponse *)cachedResponse forRequest:(NS
     NSURLCacheStoragePolicy storagePolicy = cachedResponse.storagePolicy;
     if ((storagePolicy == NSURLCacheStorageAllowed || (storagePolicy == NSURLCacheStorageAllowedInMemoryOnly && _ignoreMemoryOnlyStoragePolicy))
         && [cachedResponse.response isKindOfClass:[NSHTTPURLResponse self]]
-        && cachedResponse.data.length < self.diskCapacity) {
-        NSDictionary *headers = [(NSHTTPURLResponse *)cachedResponse.response allHeaderFields];
-        // RFC 2616 section 13.3.4 says clients MUST use Etag in any cache-conditional request if provided by server
-        if (![headers objectForKey:@"Etag"]) {
-            NSDate *expirationDate = [SDURLCache expirationDateFromHeaders:headers
-                                                            withStatusCode:((NSHTTPURLResponse *)cachedResponse.response).statusCode];
-            if (!expirationDate || [expirationDate timeIntervalSinceNow] - _minCacheInterval <= 0) {
-                // This response is not cacheable, headers said
-                return;
+        && cachedResponse.data.length < self.diskCapacity)
+    {
+        if (self.shouldRespectCacheControlHeaders)
+        {
+            NSDictionary *headers = [(NSHTTPURLResponse *)cachedResponse.response allHeaderFields];
+            // RFC 2616 section 13.3.4 says clients MUST use Etag in any cache-conditional request if provided by server
+            if (![headers objectForKey:@"Etag"]) {
+                NSDate *expirationDate = [[self class] expirationDateFromHeaders:headers
+                                                                withStatusCode:((NSHTTPURLResponse *)cachedResponse.response).statusCode];
+                if (!expirationDate || [expirationDate timeIntervalSinceNow] - _minCacheInterval <= 0) {
+                    // This response is not cacheable, headers said
+                    return;
+                }
             }
         }
 
@@ -687,14 +705,14 @@ - (void)storeCachedResponse:(NSCachedURLResponse *)cachedResponse forRequest:(NS
 }
 
 - (NSCachedURLResponse *)cachedResponseForRequest:(NSURLRequest *)request {
-    request = [SDURLCache canonicalRequestForRequest:request];
+    request = [[self class] canonicalRequestForRequest:request];
 
     NSCachedURLResponse *memoryResponse = [super cachedResponseForRequest:request];
     if (memoryResponse) {
         return memoryResponse;
     }
 
-    NSString *cacheKey = [SDURLCache cacheKeyForURL:request.URL];
+    NSString *cacheKey = [[self class] cacheKeyForURL:request.URL];
 
     // NOTE: We don't handle expiration here as even staled cache data is necessary for NSURLConnection to handle cache revalidation.
     //       Staled cache data is also needed for cachePolicies which force the use of the cache.
@@ -739,10 +757,10 @@ - (NSUInteger)currentDiskUsage {
 }
 
 - (void)removeCachedResponseForRequest:(NSURLRequest *)request {
-    request = [SDURLCache canonicalRequestForRequest:request];
+    request = [[self class] canonicalRequestForRequest:request];
 
     [super removeCachedResponseForRequest:request];
-    [self removeCachedResponseForCachedKeys:[NSArray arrayWithObject:[SDURLCache cacheKeyForURL:request.URL]]];
+    [self removeCachedResponseForCachedKeys:[NSArray arrayWithObject:[[self class] cacheKeyForURL:request.URL]]];
     [self saveCacheInfo];
 }
 
@@ -761,12 +779,12 @@ - (void)removeAllCachedResponsesInMemory {
 
 - (BOOL)isCached:(NSURL *)url {
     NSURLRequest *request = [NSURLRequest requestWithURL:url];
-    request = [SDURLCache canonicalRequestForRequest:request];
+    request = [[self class] canonicalRequestForRequest:request];
 
     if ([super cachedResponseForRequest:request]) {
         return YES;
     }
-    NSString *cacheKey = [SDURLCache cacheKeyForURL:url];
+    NSString *cacheKey = [[self class] cacheKeyForURL:url];
     NSString *cacheFile = [_diskCachePath stringByAppendingPathComponent:cacheKey];
 
     BOOL isCached = [[[NSFileManager alloc] init] fileExistsAtPath:cacheFile];
@@ -787,6 +805,7 @@ - (void)dealloc {
 @synthesize minCacheInterval = _minCacheInterval;
 @synthesize ignoreMemoryOnlyStoragePolicy = _ignoreMemoryOnlyStoragePolicy;
 @synthesize allowCachingResponsesToNonCachedRequests = _allowCachingResponsesToNonCachedRequests;
+@synthesize shouldRespectCacheControlHeaders = _shouldRespectCacheControlHeaders;
 @synthesize diskCachePath = _diskCachePath;
 @synthesize diskCacheInfo = _diskCacheInfo;
 

SDURLCache.xcodeproj/project.pbxproj

@@ -3,7 +3,7 @@
 	archiveVersion = 1;
 	classes = {
 	};
-	objectVersion = 45;
+	objectVersion = 46;
 	objects = {
 
 /* Begin PBXBuildFile section */
@@ -163,8 +163,11 @@
 /* Begin PBXProject section */
 		0867D690FE84028FC02AAC07 /* Project object */ = {
 			isa = PBXProject;
+			attributes = {
+				LastUpgradeCheck = 0460;
+			};
 			buildConfigurationList = 1DEB922208733DC00010E9CD /* Build configuration list for PBXProject "SDURLCache" */;
-			compatibilityVersion = "Xcode 3.1";
+			compatibilityVersion = "Xcode 3.2";
 			developmentRegion = English;
 			hasScannedForEncodings = 1;
 			knownRegions = (
@@ -246,7 +249,6 @@
 				COPY_PHASE_STRIP = NO;
 				DSTROOT = /tmp/SDURLCache.dst;
 				GCC_DYNAMIC_NO_PIC = NO;
-				GCC_ENABLE_FIX_AND_CONTINUE = YES;
 				GCC_MODEL_TUNING = G5;
 				GCC_OPTIMIZATION_LEVEL = 0;
 				GCC_PRECOMPILE_PREFIX_HEADER = YES;
@@ -348,7 +350,6 @@
 					"\"$(DEVELOPER_LIBRARY_DIR)/Frameworks\"",
 				);
 				GCC_DYNAMIC_NO_PIC = NO;
-				GCC_ENABLE_FIX_AND_CONTINUE = NO;
 				GCC_ENABLE_OBJC_EXCEPTIONS = YES;
 				GCC_OPTIMIZATION_LEVEL = 0;
 				OTHER_LDFLAGS = (
@@ -359,7 +360,6 @@
 					"-framework",
 					UIKit,
 				);
-				PREBINDING = NO;
 				PRODUCT_NAME = SDURLCacheTestBundle;
 				SDKROOT = iphoneos;
 				WRAPPER_EXTENSION = octest;
@@ -377,7 +377,6 @@
 					"\"$(SDKROOT)/Developer/Library/Frameworks\"",
 					"\"$(DEVELOPER_LIBRARY_DIR)/Frameworks\"",
 				);
-				GCC_ENABLE_FIX_AND_CONTINUE = NO;
 				GCC_ENABLE_OBJC_EXCEPTIONS = YES;
 				INFOPLIST_FILE = "SDURLCacheTestBundle-Info.plist";
 				OTHER_LDFLAGS = (
@@ -388,7 +387,6 @@
 					"-framework",
 					UIKit,
 				);
-				PREBINDING = NO;
 				PRODUCT_NAME = SDURLCacheTestBundle;
 				SDKROOT = iphoneos;
 				WRAPPER_EXTENSION = octest;