Implement Timeout Based Caches

Code/Network/RKRequest.h

@@ -45,8 +45,11 @@ typedef enum {
     
     // Load from the cache if we have data stored
     RKRequestCachePolicyEnabled = 1 << 3,
+    
+    // Load from the cache if we are within the timeout window
+    RKRequestCachePolicyTimeout = 1 << 4,
 
-    RKRequestCachePolicyDefault = RKRequestCachePolicyEtag
+    RKRequestCachePolicyDefault = RKRequestCachePolicyEtag | RKRequestCachePolicyTimeout
 } RKRequestCachePolicy;
 
 /**
@@ -86,6 +89,7 @@ typedef enum RKRequestBackgroundPolicy {
     BOOL _sentSynchronously;
     BOOL _forceBasicAuthentication;
     RKRequestCache* _cache;
+    NSTimeInterval _cacheTimeoutInterval;
     
     #if TARGET_OS_IPHONE
     RKRequestBackgroundPolicy _backgroundPolicy;
@@ -181,6 +185,13 @@ typedef enum RKRequestBackgroundPolicy {
  */
 @property (nonatomic, retain) NSString* HTTPBodyString;
 
+/**
+ * The timeout interval within which the request should not be sent
+ * and the cached response should be used. Used if the cache policy
+ * includes RKRequestCachePolicyTimeout
+ */
+@property (nonatomic, assign) NSTimeInterval cacheTimeoutInterval;
+
 ////////////////////////////////////////////////////////////////////////////////
 ////////////////////////////////////////////////////////////////////////////////
 

Code/Network/RKRequest.m

@@ -27,7 +27,8 @@
 
 @synthesize URL = _URL, URLRequest = _URLRequest, delegate = _delegate, additionalHTTPHeaders = _additionalHTTPHeaders,
             params = _params, userData = _userData, username = _username, password = _password, method = _method,
-            forceBasicAuthentication = _forceBasicAuthentication, cachePolicy = _cachePolicy, cache = _cache;
+            forceBasicAuthentication = _forceBasicAuthentication, cachePolicy = _cachePolicy, cache = _cache,
+            cacheTimeoutInterval = _cacheTimeoutInterval;
 
 #if TARGET_OS_IPHONE
 @synthesize backgroundPolicy = _backgroundPolicy, backgroundTaskIdentifier = _backgroundTaskIdentifier;
@@ -44,6 +45,7 @@
         [self reset];
         _forceBasicAuthentication = NO;
 		_cachePolicy = RKRequestCachePolicyDefault;
+        _cacheTimeoutInterval = 0;
 	}
 	return self;
 }
@@ -268,23 +270,37 @@
     [[NSNotificationCenter defaultCenter] postNotificationName:RKRequestSentNotification object:self userInfo:nil];
 }
 
-- (BOOL)shouldDispatchRequest {    
+- (BOOL)shouldLoadFromCache {
+    // if RKRequestCachePolicyEnabled or if RKRequestCachePolicyTimeout and we are in the timeout
+    if ([self.cache hasResponseForRequest:self]) {
+        if (self.cachePolicy & RKRequestCachePolicyEnabled) {
+            return YES;
+        } else if (self.cachePolicy & RKRequestCachePolicyTimeout) {
+            NSDate* date = [self.cache cacheDateForRequest:self];
+            NSTimeInterval interval = [[NSDate date] timeIntervalSinceDate:date];
+            return interval <= self.cacheTimeoutInterval;
+        }
+    }
+    return NO;
+}
+
+- (RKResponse*)loadResponseFromCache {
+    RKLogDebug(@"Found cached content, loading...");
+    return [self.cache responseForRequest:self];
+}
+
+- (BOOL)shouldDispatchRequest {
     return [RKClient sharedClient] == nil || [[RKClient sharedClient] isNetworkAvailable];
 }
 
 - (void)sendAsynchronously {
     NSAssert(NO == _isLoading || NO == _isLoaded, @"Cannot send a request that is loading or loaded without resetting it first.");
-    _sentSynchronously = NO;
-    if (self.cachePolicy & RKRequestCachePolicyEnabled) {
-        if ([self.cache hasResponseForRequest:self]) {
-            RKLogDebug(@"Found cached content, loading...");
-            _isLoading = YES;
-            [self didFinishLoad:[self.cache responseForRequest:self]];
-            return;
-        }
-    }
-    
-	if ([self shouldDispatchRequest]) {        
+    _sentSynchronously = NO;    
+	  if ([self shouldLoadFromCache]) {
+        RKResponse* response = [self loadResponseFromCache];
+        _isLoading = YES;
+        [self didFinishLoad:response];
+    } else if ([self shouldDispatchRequest]) {
 #if TARGET_OS_IPHONE
         // Background Request Policy support
         UIApplication* app = [UIApplication sharedApplication];
@@ -327,7 +343,7 @@
 			[self.cache hasResponseForRequest:self]) {
 
 			_isLoading = YES;
-			[self didFinishLoad:[self.cache responseForRequest:self]];
+			[self didFinishLoad:[self loadResponseFromCache]];
 
 		} else {
             RKLogCritical(@"SharedClient = %@ and network availability = %d", [RKClient sharedClient], [[RKClient sharedClient] isNetworkAvailable]);
@@ -349,12 +365,16 @@
 	RKResponse* response = nil;
     _sentSynchronously = YES;
 
-	if ([self shouldDispatchRequest]) {
-        RKLogDebug(@"Sending synchronous %@ request to URL %@.", [self HTTPMethod], [[self URL] absoluteString]);
-		if (![self prepareURLRequest]) {
-            // TODO: Logging
-            return nil;
-        }
+	if ([self shouldLoadFromCache]) {
+        response = [self loadResponseFromCache];
+        _isLoading = YES;
+        [self didFinishLoad:response];
+    } else if ([self shouldDispatchRequest]) {
+      RKLogDebug(@"Sending synchronous %@ request to URL %@.", [self HTTPMethod], [[self URL] absoluteString]);
+		  if (![self prepareURLRequest]) {
+      // TODO: Logging
+        return nil;
+      }
 
 		[[NSNotificationCenter defaultCenter] postNotificationName:RKRequestSentNotification object:self userInfo:nil];
 
@@ -378,7 +398,7 @@
 		if (_cachePolicy & RKRequestCachePolicyLoadIfOffline &&
 			[self.cache hasResponseForRequest:self]) {
 
-			response = [self.cache responseForRequest:self];
+			response = [self loadResponseFromCache];
 
 		} else {
 			NSString* errorMessage = [NSString stringWithFormat:@"The client is unable to contact the resource at %@", [[self URL] absoluteString]];
@@ -404,7 +424,7 @@
 	if (_cachePolicy & RKRequestCachePolicyLoadOnError &&
 		[self.cache hasResponseForRequest:self]) {
 
-		[self didFinishLoad:[self.cache responseForRequest:self]];
+		[self didFinishLoad:[self loadResponseFromCache]];
 	} else {
 		_isLoading = NO;
 
@@ -429,7 +449,7 @@
 	RKResponse* finalResponse = response;
 
 	if ((_cachePolicy & RKRequestCachePolicyEtag) && [response isNotModified]) {
-		finalResponse = [self.cache responseForRequest:self];
+		finalResponse = [self loadResponseFromCache];
 	}
 
 	if (![response wasLoadedFromCache] && [response isSuccessful] && (_cachePolicy != RKRequestCachePolicyNone)) {

Code/Network/RKRequestCache.h

@@ -48,6 +48,8 @@ typedef enum {
 
 - (NSString*)etagForRequest:(RKRequest*)request;
 
+- (NSDate*)cacheDateForRequest:(RKRequest*)request;
+
 - (void)invalidateRequest:(RKRequest*)request;
 
 - (void)invalidateWithStoragePolicy:(RKRequestCacheStoragePolicy)storagePolicy;

Code/Network/RKRequestCache.m

@@ -245,6 +245,27 @@ static NSDateFormatter* __rfc1123DateFormatter;
 	return etag;
 }
 
+- (NSDate*)cacheDateForRequest:(RKRequest*)request {
+	NSDate* date;
+    NSString* dateString;
+    
+    NSDictionary* responseHeaders = [self headersForRequest:request];
+    
+    [_cacheLock lock];
+    if (responseHeaders) {
+        for (NSString* responseHeader in responseHeaders) {
+            if ([[responseHeader uppercaseString] isEqualToString:[cacheDateHeaderKey uppercaseString]]) {
+                dateString = [responseHeaders objectForKey:responseHeader];
+            }
+        }
+    }
+	[_cacheLock unlock];
+    date = [[RKRequestCache rfc1123DateFormatter] dateFromString:dateString];
+    
+    RKLogDebug(@"Found cached date '%@' for '%@'", date, request);
+	return date;
+}
+
 - (void)invalidateRequest:(RKRequest*)request {
 	[_cacheLock lock];
     RKLogDebug(@"Invalidating cache entry for '%@'", request);

Specs/Network/RKRequestSpec.m

@@ -324,6 +324,72 @@
     }
 }
 
+- (void)itShouldLoadFromTheCacheIfWeAreWithinTheTimeout {
+    RKLogConfigureByName("RestKit/Network", RKLogLevelTrace);
+    
+    NSString* baseURL = RKSpecGetBaseURL();
+    NSString* cacheDirForClient = [NSString stringWithFormat:@"RKClientRequestCache-%@",
+								   [[NSURL URLWithString:baseURL] host]];
+	NSString* cachePath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0]
+						   stringByAppendingPathComponent:cacheDirForClient];
+    RKRequestCache* cache = [[RKRequestCache alloc] initWithCachePath:cachePath
+                                                        storagePolicy:RKRequestCacheStoragePolicyPermanently];
+    [cache invalidateWithStoragePolicy:RKRequestCacheStoragePolicyPermanently];
+    
+    NSString* url = [NSString stringWithFormat:@"%@/disk/cached", RKSpecGetBaseURL()];
+    NSURL* URL = [NSURL URLWithString:url];
+    {
+        RKSpecResponseLoader* loader = [RKSpecResponseLoader responseLoader];
+        RKRequest* request = [[RKRequest alloc] initWithURL:URL];
+        request.cachePolicy = RKRequestCachePolicyTimeout;
+        request.cacheTimeoutInterval = 5;
+        request.cache = cache;
+        request.delegate = loader;
+        [request sendAsynchronously];
+        [loader waitForResponse];
+        [expectThat([loader success]) should:be(YES)];
+        [expectThat([loader.response bodyAsString]) should:be(@"This Should Get Cached For 5 Seconds")];
+        [expectThat([loader.response wasLoadedFromCache]) should:be(NO)];
+    }
+    {
+        RKSpecResponseLoader* loader = [RKSpecResponseLoader responseLoader];
+        RKRequest* request = [[RKRequest alloc] initWithURL:URL];
+        request.cachePolicy = RKRequestCachePolicyTimeout;
+        request.cacheTimeoutInterval = 5;
+        request.cache = cache;
+        request.delegate = loader;
+        [request sendAsynchronously];
+        // Don't wait for a response as this actually returns synchronously.
+        [expectThat([loader.response bodyAsString]) should:be(@"This Should Get Cached For 5 Seconds")];
+        [expectThat([loader.response wasLoadedFromCache]) should:be(YES)];
+    }
+    {
+        RKSpecResponseLoader* loader = [RKSpecResponseLoader responseLoader];
+        RKRequest* request = [[RKRequest alloc] initWithURL:URL];
+        request.cachePolicy = RKRequestCachePolicyTimeout;
+        request.cacheTimeoutInterval = 5;
+        request.cache = cache;
+        request.delegate = loader;
+        [request sendSynchronously];
+        // Don't wait for a response as this actually returns synchronously.
+        [expectThat([loader.response bodyAsString]) should:be(@"This Should Get Cached For 5 Seconds")];
+        [expectThat([loader.response wasLoadedFromCache]) should:be(YES)];
+    }
+    {
+        RKSpecResponseLoader* loader = [RKSpecResponseLoader responseLoader];
+        RKRequest* request = [[RKRequest alloc] initWithURL:URL];
+        request.cachePolicy = RKRequestCachePolicyTimeout;
+        request.cacheTimeoutInterval = 0;
+        request.cache = cache;
+        request.delegate = loader;
+        [request sendAsynchronously];
+        [loader waitForResponse];
+        [expectThat([loader success]) should:be(YES)];
+        [expectThat([loader.response bodyAsString]) should:be(@"This Should Get Cached For 5 Seconds")];
+        [expectThat([loader.response wasLoadedFromCache]) should:be(NO)];
+    }
+}
+
 - (void)itShouldLoadFromTheCacheIfWeAreOffline {
     NSString* baseURL = RKSpecGetBaseURL();
     NSString* cacheDirForClient = [NSString stringWithFormat:@"RKClientRequestCache-%@",

Specs/Server/server.rb

@@ -11,11 +11,13 @@ Debugger.start
 $: << File.join(File.expand_path(File.dirname(__FILE__)), 'lib')
 require 'restkit/network/authentication'
 require 'restkit/network/etags'
+require 'restkit/network/timeout'
 
 class RestKit::SpecServer < Sinatra::Base
   self.app_file = __FILE__
   use RestKit::Network::Authentication
   use RestKit::Network::ETags
+  use RestKit::Network::Timeout
   
   configure do
     set :logging, true