From d9fc311433c7a2bb1afa12c6ca31c3acca6b163f Mon Sep 17 00:00:00 2001
From: Daniel Hammond <daniel@twotoasters.com>
Date: Thu, 16 Jun 2011 21:17:14 -0400
Subject: [PATCH] Remove objects persisted to Core Dataduring postObject: when
 there is an error (Fix Issue #125)

---
 Code/CoreData/RKManagedObjectLoader.m     |  7 +++++
 Code/ObjectMapping/RKObjectLoader.h       |  4 +++
 Code/ObjectMapping/RKObjectLoader.m       | 36 ++++++++++++-----------
 Specs/ObjectMapping/RKObjectManagerSpec.m | 16 ++++++++++
 Specs/Server/server.rb                    |  6 ++++
 5 files changed, 52 insertions(+), 17 deletions(-)

diff --git a/Code/CoreData/RKManagedObjectLoader.m b/Code/CoreData/RKManagedObjectLoader.m
index 0959d348..01d7d835 100644
--- a/Code/CoreData/RKManagedObjectLoader.m
+++ b/Code/CoreData/RKManagedObjectLoader.m
@@ -116,4 +116,11 @@
     return nil;    
 }
 
+// Overloaded to handle deleting an object orphaned by a failed postObject:
+- (void)handleResponseError {
+    [super handleResponseError];
+    [[self.objectStore managedObjectContext] deleteObject:[self.objectStore objectWithID:_targetObjectID]];
+    [self.objectStore save];
+}
+
 @end
diff --git a/Code/ObjectMapping/RKObjectLoader.h b/Code/ObjectMapping/RKObjectLoader.h
index 674aae62..530b887e 100644
--- a/Code/ObjectMapping/RKObjectLoader.h
+++ b/Code/ObjectMapping/RKObjectLoader.h
@@ -117,5 +117,9 @@
  * Initialize a new object loader with an object mapper, a request, and a delegate
  */
 - (id)initWithResourcePath:(NSString*)resourcePath objectManager:(RKObjectManager*)objectManager delegate:(id<RKObjectLoaderDelegate>)delegate;				
+/**
+ * Handle an error in the response preventing it from being mapped, called from -isResponseMappable
+ */
+- (void)handleResponseError;
 
 @end
diff --git a/Code/ObjectMapping/RKObjectLoader.m b/Code/ObjectMapping/RKObjectLoader.m
index d18f8349..e9b12c1f 100644
--- a/Code/ObjectMapping/RKObjectLoader.m
+++ b/Code/ObjectMapping/RKObjectLoader.m
@@ -198,23 +198,7 @@
         
 		return NO;
 	} else if ([self.response isError]) {
-        
-        if ([self.response isServiceUnavailable]) {
-            [[NSNotificationCenter defaultCenter] postNotificationName:RKServiceDidBecomeUnavailableNotification object:self];
-        }
-        
-        // Since we are mapping what we know to be an error response, we don't want to map the result back onto our
-        // target object
-        NSError* error = nil;
-        RKObjectMappingResult* result = [self mapResponseWithMappingProvider:self.objectManager.mappingProvider toObject:nil error:&error];
-        if (result) {
-            error = [result asError];
-        } else {
-            RKLogError(@"Encountered an error while attempting to map server side errors from payload: %@", [error localizedDescription]);
-        }
-        
-        [(NSObject<RKObjectLoaderDelegate>*)_delegate objectLoader:self didFailWithError:error];
-        
+        [self handleResponseError];
 		return NO;
 	} else if ([self.response isSuccessful] && NO == [self canParseMIMEType:[self.response MIMEType]]) {
         RKLogWarning(@"Encountered unexpected response code: %d (MIME Type: %@)", self.response.statusCode, self.response.MIMEType);
@@ -233,6 +217,24 @@
 	return YES;
 }
 
+- (void)handleResponseError {
+    if ([self.response isServiceUnavailable]) {
+        [[NSNotificationCenter defaultCenter] postNotificationName:RKServiceDidBecomeUnavailableNotification object:self];
+    }
+    
+    // Since we are mapping what we know to be an error response, we don't want to map the result back onto our
+    // target object
+    NSError* error = nil;
+    RKObjectMappingResult* result = [self mapResponseWithMappingProvider:self.objectManager.mappingProvider toObject:nil error:&error];
+    if (result) {
+        error = [result asError];
+    } else {
+        RKLogError(@"Encountered an error while attempting to map server side errors from payload: %@", [error localizedDescription]);
+    }
+    
+    [(NSObject<RKObjectLoaderDelegate>*)_delegate objectLoader:self didFailWithError:error];
+}
+
 #pragma mark - RKRequest & RKRequestDelegate methods
 
 // Invoked just before request hits the network
diff --git a/Specs/ObjectMapping/RKObjectManagerSpec.m b/Specs/ObjectMapping/RKObjectManagerSpec.m
index 69128073..437cba1e 100644
--- a/Specs/ObjectMapping/RKObjectManagerSpec.m
+++ b/Specs/ObjectMapping/RKObjectManagerSpec.m
@@ -91,6 +91,22 @@
     assertThat(human.railsID, is(equalToInt(1)));
 }
 
+- (void)itShouldDeleteACoreDataBackedTargetObjectOnError {
+    RKHuman* temporaryHuman = [[RKHuman alloc] initWithEntity:[NSEntityDescription entityForName:@"RKHuman" inManagedObjectContext:_objectManager.objectStore.managedObjectContext] insertIntoManagedObjectContext:_objectManager.objectStore.managedObjectContext];
+    temporaryHuman.name = @"My Name";    
+    [_objectManager.objectStore save];
+    
+    RKSpecResponseLoader* loader = [RKSpecResponseLoader responseLoader];    
+    NSString* resourcePath = @"/humans/fail";
+    RKObjectLoader* objectLoader = [_objectManager objectLoaderWithResourcePath:resourcePath delegate:loader];
+    objectLoader.method = RKRequestMethodPOST;
+    objectLoader.targetObject = temporaryHuman;
+	[objectLoader send];
+    [loader waitForResponse];
+
+    assertThat(temporaryHuman.managedObjectContext, is(equalTo(nil)));
+}
+
 // TODO: Move to Core Data specific spec file...
 - (void)itShouldLoadAHuman {
     RKSpecResponseLoader* loader = [RKSpecResponseLoader responseLoader];
diff --git a/Specs/Server/server.rb b/Specs/Server/server.rb
index 686fb87b..7f5253e4 100644
--- a/Specs/Server/server.rb
+++ b/Specs/Server/server.rb
@@ -46,6 +46,12 @@ class RestKit::SpecServer < Sinatra::Base
     {:human => {:name => "My Name", :id => 1, :website => "http://restkit.org/"}}.to_json
   end
   
+  post '/humans/fail' do
+    status 500
+    content_type 'application/json'
+    send_file 'Specs/Server/../Fixtures/JSON/errors.json'
+  end
+  
   get '/humans/1' do
     status 200
     content_type 'application/json'