An auto-mapper for inflating custom data objects from a given NSDictionary. This is a highly dangerous / unsafe category on NSObject, mainly done just as a fun exercise to see if it could be done. Can't say I recommend you use it.

NSObject+AutoMapping.m

@implementation NSObject (DataMapping)

- (instancetype)initByAutoMappingFromDictionary:(NSDictionary *)dictionary
{
  Class thisClass = [self class];
  self = [thisClass init];
  if (self)
  {
    [self mapDictionaryValues:dictionary];
  }
  return self;
}

- (void)mapDictionaryValues:(NSDictionary *)dictionary
{
  NSArray *dictKeys = [dictionary allKeys];
  for (NSString *key in dictKeys)
  {
    [self attemptToSetPropertyWithObject:dictionary[key] forKey:key];
  }
}

#pragma - mark private / helper methods

- (void)attemptToSetPropertyWithObject:(NSObject *)object forKey:(NSString *)key
{
  SEL selectorFromString = [self setterSelectorFromKeyString:key];
  if ([self respondsToSelector:selectorFromString])
  {
    [self performSelector:selectorFromString withObject:object];
  }
}

- (SEL)setterSelectorFromKeyString:(NSString *)inputString
{
  NSString *capitalizedString = [inputString capitalizedString];
  NSString *selectorString = [NSString stringWithFormat:@"set%@:", capitalizedString];
  return NSSelectorFromString(selectorString);
}

@end

This also works if you get rid of the init and expose the mapDictionaryValues method instead. Then you just use it as an instance method on an already initialized object.

Shouldn't you call self = [super init] in your initializer? In fact, you don't want to call +alloc again because your object is already allocated.

I see you're stripping out spaces. What is the goal of your method? Isn't the onus on the caller to provide valid inputs? There's a whole host of invalid characters (including the +[NSCharacterSet whitespaceCharacterSet]) the caller could provide. Are you sure accounting for these rules is something you want to take the burden of?

Shouldn't you call self = [super init] in your initializer? In fact, you don't want to call +alloc again because your object is already allocated.

Very good point.

I see you're stripping out spaces. What is the goal of your method? Isn't the onus on the caller to provide valid inputs? There's a whole host of invalid characters (including the +[NSCharacterSet whitespaceCharacterSet]) the caller could provide. Are you sure accounting for these rules is something you want to take the burden of?

Also a great point.