Files
RestKit/Code/RKObjectMapper.m

364 lines
14 KiB
Objective-C

//
// RKObjectMapper.m
// RestKit
//
// Created by Blake Watters on 3/4/10.
// Copyright 2010 Two Toasters. All rights reserved.
//
#import <objc/message.h>
#import "RKObjectMapper.h"
#import "NSDictionary+RKRequestSerialization.h"
#import "RKMappingFormatJSONParser.h"
// Default format string for date and time objects from Rails
// TODO: Rails specifics should probably move elsewhere...
static const NSString* kRKModelMapperRailsDateTimeFormatString = @"yyyy-MM-dd'T'HH:mm:ss'Z'"; // 2009-08-08T17:23:59Z
static const NSString* kRKModelMapperRailsDateFormatString = @"MM/dd/yyyy";
static const NSString* kRKModelMapperMappingFormatParserKey = @"RKMappingFormatParser";
@interface RKObjectMapper (Private)
- (void)updateModel:(id)model fromElements:(NSDictionary*)elements;
- (Class)typeClassForProperty:(NSString*)property ofClass:(Class)class;
- (NSDictionary*)elementToPropertyMappingsForModel:(id)model;
- (id)findOrCreateInstanceOfModelClass:(Class)class fromElements:(NSDictionary*)elements;
- (id)createOrUpdateInstanceOfModelClass:(Class)class fromElements:(NSDictionary*)elements;
- (void)updateModel:(id)model ifNewPropertyValue:(id)propertyValue forPropertyNamed:(NSString*)propertyName; // Rename!
- (void)setPropertiesOfModel:(id)model fromElements:(NSDictionary*)elements;
- (void)setRelationshipsOfModel:(id)object fromElements:(NSDictionary*)elements;
- (void)updateModel:(id)model fromElements:(NSDictionary*)elements;
- (NSDate*)parseDateFromString:(NSString*)string;
- (NSDate*)dateInLocalTime:(NSDate*)date;
@end
@implementation RKObjectMapper
@synthesize format = _format;
@synthesize dateFormats = _dateFormats;
@synthesize remoteTimeZone = _remoteTimeZone;
@synthesize localTimeZone = _localTimeZone;
///////////////////////////////////////////////////////////////////////////////
// public
- (id)init {
if (self = [super init]) {
_elementToClassMappings = [[NSMutableDictionary alloc] init];
_format = RKMappingFormatJSON;
_inspector = [[RKObjectPropertyInspector alloc] init];
self.dateFormats = [NSArray arrayWithObjects:kRKModelMapperRailsDateTimeFormatString, kRKModelMapperRailsDateFormatString, nil];
self.remoteTimeZone = [NSTimeZone timeZoneForSecondsFromGMT:0];
self.localTimeZone = [NSTimeZone localTimeZone];
}
return self;
}
- (void)dealloc {
[_elementToClassMappings release];
[_inspector release];
[_dateFormats release];
[super dealloc];
}
- (void)registerClass:(Class<RKObjectMappable>)aClass forElementNamed:(NSString*)elementName {
[_elementToClassMappings setObject:aClass forKey:elementName];
}
- (void)setFormat:(RKMappingFormat)format {
if (format == RKMappingFormatXML) {
[NSException raise:@"No XML parser is available" format:@"RestKit does not currently have XML support. Use JSON."];
}
_format = format;
}
///////////////////////////////////////////////////////////////////////////////
// Mapping from a string
- (id)parseString:(NSString*)string {
NSMutableDictionary* threadDictionary = [[NSThread currentThread] threadDictionary];
NSObject<RKMappingFormatParser>* parser = [threadDictionary objectForKey:kRKModelMapperMappingFormatParserKey];
if (!parser) {
if (_format == RKMappingFormatJSON) {
parser = [[RKMappingFormatJSONParser alloc] init];
[threadDictionary setObject:parser forKey:kRKModelMapperMappingFormatParserKey];
[parser release];
}
}
return [parser objectFromString:string];
}
- (id)mapFromString:(NSString*)string {
id object = [self parseString:string];
if ([object isKindOfClass:[NSDictionary class]]) {
return [self mapObjectFromDictionary:(NSDictionary*)object];
} else if ([object isKindOfClass:[NSArray class]]) {
return [self mapObjectsFromArrayOfDictionaries:(NSArray*)object];
} else if (nil == object) {
NSLog(@"[RestKit] RKModelMapper: mapObject:fromString: attempted to map from a nil payload. Skipping...");
return nil;
} else {
[NSException raise:@"Unable to map from requested string"
format:@"The object was deserialized into a %@. A dictionary or array of dictionaries was expected.", [object class]];
return nil;
}
}
- (void)mapObject:(id)model fromString:(NSString*)string {
id object = [self parseString:string];
if ([object isKindOfClass:[NSDictionary class]]) {
[self mapObject:model fromDictionary:object];
} else if (nil == object) {
NSLog(@"[RestKit] RKModelMapper: mapObject:fromString: attempted to map from a nil payload. Skipping...");
return;
} else {
[NSException raise:@"Unable to map from requested string"
format:@"The object was serialized into a %@. A dictionary of elements was expected.", [object class]];
}
}
///////////////////////////////////////////////////////////////////////////////
// Mapping from objects
- (void)mapObject:(id)model fromDictionary:(NSDictionary*)dictionary {
Class class = [model class];
NSString* elementName = [_elementToClassMappings keyForObject:class];
if (elementName) {
NSDictionary* elements = [dictionary objectForKey:elementName];
[self updateModel:model fromElements:elements];
} else {
[NSException raise:@"Unable to map from requested dictionary"
format:@"There was no mappable element found for objects of type %@", class];
}
}
- (id)mapObjectFromDictionary:(NSDictionary*)dictionary {
NSString* elementName = [[dictionary allKeys] objectAtIndex:0];
Class class = [_elementToClassMappings objectForKey:elementName];
NSDictionary* elements = [dictionary objectForKey:elementName];
id model = [self findOrCreateInstanceOfModelClass:class fromElements:elements];
[self updateModel:model fromElements:elements];
return model;
}
- (NSArray*)mapObjectsFromArrayOfDictionaries:(NSArray*)array {
NSMutableArray* objects = [NSMutableArray array];
for (NSDictionary* dictionary in array) {
if (![dictionary isKindOfClass:[NSNull class]]) {
NSString* elementName = [[dictionary allKeys] objectAtIndex:0];
Class class = [_elementToClassMappings objectForKey:elementName];
NSDictionary* elements = [dictionary objectForKey:elementName];
id object = [self createOrUpdateInstanceOfModelClass:class fromElements:elements];
[objects addObject:object];
}
}
return (NSArray*)objects;
}
// TODO: This form of mapping may need to be factored out... simple mapper / element mapper?
- (NSArray*)mapObjectsFromArrayOfDictionaries:(NSArray*)array toClass:(Class)class {
NSMutableArray* objects = [NSMutableArray array];
for (NSDictionary* dictionary in array) {
if (![dictionary isKindOfClass:[NSNull class]]) {
id object = [self createOrUpdateInstanceOfModelClass:class fromElements:dictionary];
[objects addObject:object];
}
}
return (NSArray*)objects;
}
///////////////////////////////////////////////////////////////////////////////
// Utility Methods
- (Class)typeClassForProperty:(NSString*)property ofClass:(Class)class {
return [[_inspector propertyNamesAndTypesForClass:class] objectForKey:property];
}
- (NSDictionary*)elementToPropertyMappingsForModel:(id)model {
return [[model class] elementToPropertyMappings];
}
///////////////////////////////////////////////////////////////////////////////
// Persistent Instance Finders
// TODO: This responsibility probaby belongs elsewhere...
- (id)findOrCreateInstanceOfModelClass:(Class)class fromElements:(NSDictionary*)elements {
id object = nil;
// TODO: Maybe add back to RKObjectMappable protocol. better selectors?
if ([class respondsToSelector:@selector(findByPrimaryKey:)]) {
NSString* primaryKeyElement = [class performSelector:@selector(primaryKeyElement)];
NSNumber* primaryKey = [elements objectForKey:primaryKeyElement];
object = [class performSelector:@selector(findByPrimaryKey:) withObject:primaryKey];
}
// instantiate if object is nil
if (object == nil) {
if ([class respondsToSelector:@selector(newObject)]) {
object = [class newObject];
} else {
object = [[[class alloc] init] autorelease];
}
}
return object;
}
- (id)createOrUpdateInstanceOfModelClass:(Class)class fromElements:(NSDictionary*)elements {
id model = [self findOrCreateInstanceOfModelClass:class fromElements:elements];
[self updateModel:model fromElements:elements];
return model;
}
///////////////////////////////////////////////////////////////////////////////
// Property & Relationship Manipulation
- (void)updateModel:(id)model ifNewPropertyValue:(id)propertyValue forPropertyNamed:(NSString*)propertyName {
id currentValue = [model valueForKey:propertyName];
if (nil == currentValue && nil == propertyValue) {
// Don't set the property, both are nil
} else if (nil == propertyValue || [propertyValue isKindOfClass:[NSNull class]]) {
// Clear out the value to reset it
[model setValue:nil forKey:propertyName];
} else if (currentValue == nil || [currentValue isKindOfClass:[NSNull class]]) {
// Existing value was nil, just set the property and be happy
[model setValue:propertyValue forKey:propertyName];
} else {
SEL comparisonSelector;
if ([propertyValue isKindOfClass:[NSString class]]) {
comparisonSelector = @selector(isEqualToString:);
} else if ([propertyValue isKindOfClass:[NSNumber class]]) {
comparisonSelector = @selector(isEqualToNumber:);
} else if ([propertyValue isKindOfClass:[NSDate class]]) {
comparisonSelector = @selector(isEqualToDate:);
} else if ([propertyValue isKindOfClass:[NSArray class]]) {
comparisonSelector = @selector(isEqualToArray:);
} else if ([propertyValue isKindOfClass:[NSDictionary class]]) {
comparisonSelector = @selector(isEqualToDictionary:);
} else {
[NSException raise:@"NoComparisonSelectorFound" format:@"You need a comparison selector for %@ (%@)", propertyName, [propertyValue class]];
}
// Comparison magic using function pointers. See this page for details: http://www.red-sweater.com/blog/320/abusing-objective-c-with-class
// Original code courtesy of Greg Parker
// This is necessary because isEqualToNumber will return negative integer values that aren't coercable directly to BOOL's without help [sbw]
BOOL (*ComparisonSender)(id, SEL, id) = (BOOL (*)(id, SEL, id)) objc_msgSend;
BOOL areEqual = ComparisonSender(currentValue, comparisonSelector, propertyValue);
if (NO == areEqual) {
[model setValue:propertyValue forKey:propertyName];
}
}
}
- (void)setPropertiesOfModel:(id)model fromElements:(NSDictionary*)elements {
NSDictionary* elementToPropertyMappings = [self elementToPropertyMappingsForModel:model];
for (NSString* elementKeyPath in elementToPropertyMappings) {
id elementValue = nil;
BOOL setValue = YES;
@try {
elementValue = [elements valueForKeyPath:elementKeyPath];
}
@catch (NSException * e) {
NSLog(@"[RestKit] RKModelMapper: Unable to find element at keyPath %@ in elements dictionary for %@. Skipping...", elementKeyPath, [model class]);
setValue = NO;
}
if (setValue) {
id propertyValue = elementValue;
NSString* propertyName = [elementToPropertyMappings objectForKey:elementKeyPath];
Class class = [self typeClassForProperty:propertyName ofClass:[model class]];
if (elementValue != (id)kCFNull && nil != elementValue) {
if ([class isEqual:[NSDate class]]) {
NSDate* date = [self parseDateFromString:(propertyValue)];
propertyValue = [self dateInLocalTime:date];
}
}
[self updateModel:model ifNewPropertyValue:propertyValue forPropertyNamed:propertyName];
}
}
}
- (void)setRelationshipsOfModel:(id)object fromElements:(NSDictionary*)elements {
NSDictionary* elementToRelationshipMappings = [[object class] elementToRelationshipMappings];
for (NSString* elementKeyPath in elementToRelationshipMappings) {
NSString* propertyName = [elementToRelationshipMappings objectForKey:elementKeyPath];
id relationshipElements = nil;
@try {
relationshipElements = [elements valueForKeyPath:elementKeyPath];
}
@catch (NSException* e) {
NSLog(@"Caught exception:%@ when trying valueForKeyPath with path:%@ for elements:%@", e, elementKeyPath, elements);
}
if ([relationshipElements isKindOfClass:[NSArray class]] || [relationshipElements isKindOfClass:[NSSet class]]) {
// NOTE: The last part of the keyPath contains the elementName for the mapped destination class of our children
NSArray* componentsOfKeyPath = [elementKeyPath componentsSeparatedByString:@"."];
Class class = [_elementToClassMappings objectForKey:[componentsOfKeyPath objectAtIndex:[componentsOfKeyPath count] - 1]];
NSMutableSet* children = [NSMutableSet setWithCapacity:[relationshipElements count]];
for (NSDictionary* childElements in relationshipElements) {
id child = [self createOrUpdateInstanceOfModelClass:class fromElements:childElements];
if (child) {
[children addObject:child];
}
}
[object setValue:children forKey:propertyName];
} else if ([relationshipElements isKindOfClass:[NSDictionary class]]) {
NSArray* componentsOfKeyPath = [elementKeyPath componentsSeparatedByString:@"."];
Class class = [_elementToClassMappings objectForKey:[componentsOfKeyPath objectAtIndex:[componentsOfKeyPath count] - 1]];
id child = [self createOrUpdateInstanceOfModelClass:class fromElements:relationshipElements];
[object setValue:child forKey:propertyName];
}
}
}
- (void)updateModel:(id)model fromElements:(NSDictionary*)elements {
[self setPropertiesOfModel:model fromElements:elements];
[self setRelationshipsOfModel:model fromElements:elements];
}
///////////////////////////////////////////////////////////////////////////////
// Date & Time Helpers
- (NSDate*)parseDateFromString:(NSString*)string {
NSDate* date = nil;
NSDateFormatter* formatter = [[NSDateFormatter alloc] init];
// TODO: I changed this to local time and it fixes my date issues. wtf?
[formatter setTimeZone:self.localTimeZone];
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