Added flexibility to parse date formats using an arbitrary number of strings. Added automagic conversion between local and remote time zones. By defaults assumes that the remote system is retuning dates in UTC format.

Code/RKModelMapper.m

@@ -9,11 +9,12 @@
 #import <objc/message.h>
 
 #import "RKModelMapper.h"
+#import "NSDictionary+RKRequestSerialization.h"
 #import "RKMappingFormatJSONParser.h"
 
-// TODO: Factor me out...
-#define kRailsToXMLDateTimeFormatterString @"yyyy-MM-dd'T'HH:mm:ss'Z'" // 2009-08-08T17:23:59Z
-#define kRailsToXMLDateFormatterString @"MM/dd/yyyy"
+// Default format string for date and time objects from Rails
+static const NSString* kRKModelMapperRailsDateTimeFormatString = @"yyyy-MM-dd'T'HH:mm:ss'Z'"; // 2009-08-08T17:23:59Z
+static const NSString* kRKModelMapperRailsDateFormatString = @"MM/dd/yyyy";
 
 @interface RKModelMapper (Private)
 
@@ -30,12 +31,8 @@
 - (void)setRelationshipsOfModel:(id)object fromElements:(NSDictionary*)elements;
 - (void)updateModel:(id)model fromElements:(NSDictionary*)elements;
 
-@end
-
-// TODO: Defined in external file but was creating symbol errors... figure out
-@interface NSMutableDictionary (External)
-
-- (id)keyForObject:(id)object;
+- (NSDate*)parseDateFromString:(NSString*)string;
+- (NSDate*)dateInLocalTime:(NSDate*)date;
 
 @end
 
@@ -43,6 +40,9 @@
 
 @synthesize format = _format;
 @synthesize parser = _parser;
+@synthesize dateFormats = _dateFormats;
+@synthesize remoteTimeZone = _remoteTimeZone;
+@synthesize localTimeZone = _localTimeZone;
 
 ///////////////////////////////////////////////////////////////////////////////
 // public
@@ -50,8 +50,11 @@
 - (id)init {
 	if (self = [super init]) {
 		_elementToClassMappings = [[NSMutableDictionary alloc] init];
-		_format = RKMappingFormatXML;
+		_format = RKMappingFormatJSON;
 		_inspector = [[RKObjectPropertyInspector alloc] init];
+		self.dateFormats = [NSArray arrayWithObjects:kRKModelMapperRailsDateTimeFormatString, kRKModelMapperRailsDateFormatString, nil];
+		self.remoteTimeZone = [NSTimeZone timeZoneForSecondsFromGMT:0];
+		self.localTimeZone = [NSTimeZone localTimeZone];
 	}
 	return self;
 }
@@ -60,6 +63,7 @@
 	[_elementToClassMappings release];
 	[_parser release];
 	[_inspector release];
+	[_dateFormats release];
 	[super dealloc];
 }
 
@@ -224,8 +228,7 @@
 - (void)setPropertiesOfModel:(id)model fromElements:(NSDictionary*)elements {
 	NSDictionary* elementToPropertyMappings = [self elementToPropertyMappingsForModel:model];
 	for (NSString* elementKeyPath in elementToPropertyMappings) {
-		NSString* propertyName = [elementToPropertyMappings objectForKey:elementKeyPath];
-		Class class = [self typeClassForProperty:propertyName ofClass:[model class]];
+		NSString* propertyName = [elementToPropertyMappings objectForKey:elementKeyPath];		
 		id elementValue = nil;		
 		
 		@try {
@@ -237,20 +240,11 @@
 		}
 		
 		id propertyValue = elementValue;
+		Class class = [self typeClassForProperty:propertyName ofClass:[model class]];
 		if (elementValue != (id)kCFNull) {
 			if ([class isEqual:[NSDate class]]) {
-				// TODO: This date parsing needs to be factored out...
-				NSDateFormatter* formatter = [[NSDateFormatter alloc] init];
-				// Times coming back are in utc. we should convert them to the local timezone
-				// TODO: Note that this currently only handles times and not stand-alone date's! needs to be cleaned up!
-				[formatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
-				[formatter setDateFormat:kRailsToXMLDateTimeFormatterString];
-				propertyValue = [formatter dateFromString:propertyValue];
-				if (nil == propertyValue) {
-					[formatter setDateFormat:kRailsToXMLDateFormatterString];
-					propertyValue = [formatter dateFromString:propertyValue];
-				}
-				[formatter release];
+				NSDate* date = [self parseDateFromString:(propertyValue)];
+				propertyValue = [self dateInLocalTime:date];
 			}
 		}
 		
@@ -288,4 +282,34 @@
 	[self setRelationshipsOfModel:model fromElements:elements];
 }
 
+///////////////////////////////////////////////////////////////////////////////
+// Date & Time Helpers
+
+- (NSDate*)parseDateFromString:(NSString*)string {
+	NSDate* date = nil;
+	NSDateFormatter* formatter = [[NSDateFormatter alloc] init];	
+	[formatter setTimeZone:self.remoteTimeZone];
+	for (NSString* formatString in self.dateFormats) {
+		[formatter setDateFormat:formatString];
+		date = [formatter dateFromString:string];
+		if (date) {
+			break;
+		}
+	}
+	
+	[formatter release];
+	return date;
+}
+
+- (NSDate*)dateInLocalTime:(NSDate*)date {
+	NSDate* destinationDate = nil;
+	if (date) {
+		NSInteger remoteGMTOffset = [self.remoteTimeZone secondsFromGMTForDate:date];
+		NSInteger localGMTOffset = [self.localTimeZone secondsFromGMTForDate:date];
+		NSTimeInterval interval = localGMTOffset - remoteGMTOffset;		
+		destinationDate = [[[NSDate alloc] initWithTimeInterval:interval sinceDate:date] autorelease];
+	}	
+	return destinationDate;
+}
+
 @end

Code/RestKit/RKModelMapper.h

@@ -31,6 +31,9 @@
 	RKMappingFormat _format;
 	NSObject<RKMappingFormatParser>* _parser;
 	RKObjectPropertyInspector* _inspector;
+	NSArray* _dateFormats;
+	NSTimeZone* _remoteTimeZone;
+	NSTimeZone* _localTimeZone;
 }
 
 /**
@@ -44,6 +47,17 @@
  */
 @property(nonatomic, retain) NSObject<RKMappingFormatParser>* parser;
 
+/**
+ * An array of date format strings to attempt to parse mapped date properties with
+ *
+ * Initialized with a default pair of timestamp and date strings suitable for
+ * parseing time and date objects returned from Rails applications
+ */
+@property(nonatomic, retain) NSArray* dateFormats;
+
+@property(nonatomic, retain) NSTimeZone* remoteTimeZone;
+@property(nonatomic, retain) NSTimeZone* localTimeZone;
+
 /**
  * Register a mapping for a given class for an XML element with the given tag name
  * will blow up if the class does not respond to elementToPropertyMappings and elementToRelationshipMappings