Parse workaround for "isPrefixOf" query

gistfile1.m

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
    [Parse setApplicationId:kDevParseAppId clientKey:kDevParseClientKey];


#ifdef CREATE_TESTDATA
    NSArray * data = @[
    @"12345",     //A
    @"12346",     //B
    @"1234",      //C
    @"2345",      //D
    @"23451"      //E
    ];


    NSMutableArray *testObjects = [@[] mutableCopy];

    for (NSString *testObject in data) {
        PFObject *object = [PFObject objectWithClassName:@"TestClass"];
        [object setObject:testObject forKey:@"TestKey"];

        [testObjects addObject:object];
    }

    [PFObject saveAll:testObjects];
#endif
    
    NSArray * search = @[   // Expected Results
    @"12345",   // [A,C]
    @"123456",  //[A,C]
    @"234",      // []
    @"2345222", // [D]
    @"2345111", // [D, E]
    ];

    for (NSString *searchString in search)
    {
        PFQuery *prefixOf = [self key:@"TestKey" isPrefixOf:searchString inClassName:@"TestClass"];
        PFQuery *prefixOfUsingRegex = [self key:@"TestKey" isPrefixOfUsingRegex:searchString inClassName:@"TestClass"];

        PFQuery *hasPrefix = [PFQuery queryWithClassName:@"TestClass"];
        [hasPrefix whereKey:@"TestKey" hasPrefix:searchString];

        NSLog(@"PrefixOf %@ results: %@", searchString, prefixOf.findObjects);
        NSLog(@"PrefixOfUsingRegex %@ results: %@", searchString, prefixOfUsingRegex.findObjects);

        NSLog(@"HasPrefix %@ results: %@", searchString, hasPrefix.findObjects);
    }

    

}


// hasPrefix - returns objects where values of key being with searchString:  key = <searchString>*

// Return objects where values of key are prefixes of searchString: key* = searchString
- (PFQuery *)key:(NSString *)key isPrefixOf:(NSString *)searchString inClassName:(NSString *)className
{
    NSMutableArray *queries = [@[] mutableCopy];

    for (int i=1; i<=searchString.length; i++)
    {
        NSString *match = [searchString substringWithRange:NSMakeRange(0, i)];
        PFQuery *query = [PFQuery queryWithClassName:className];
        [query whereKey:key equalTo:match];

        [queries addObject:query];
    }

    return [PFQuery orQueryWithSubqueries:queries];
}

// Return objects where values of key are prefixes of searchString: key* = searchString
- (PFQuery *)key:(NSString *)key isPrefixOfUsingRegex:(NSString *)searchString inClassName:(NSString *)className
{
    NSString *regex = nil;
    for (int i=1; i<=searchString.length; i++)
    {
        NSString *match = [searchString substringWithRange:NSMakeRange(0, i)];

        if (regex == nil) regex = match;
        else regex = [NSString stringWithFormat:@"%@|%@", regex, match];
    }

    regex = [NSString stringWithFormat:@"^(%@)$", regex];

    PFQuery *query = [PFQuery queryWithClassName:className];
    [query whereKey:key matchesRegex:regex];

    NSLog(@"Regex to match prefix of %@ is %@", searchString, regex);

    return query;
}

2012-09-04 20:03:35.714 parseScaffold[22384:c07] Regex to match prefix of 12345 is ^(1|12|123|1234|12345)$
2012-09-04 20:03:40.515 parseScaffold[22384:c07] PrefixOf 12345 results: (
"TestClass:WFjd8Uz883 {\n TestKey = 1234;\n}",
"TestClass:jKUQyyPFI2 {\n TestKey = 12345;\n}"
)
2012-09-04 20:03:41.435 parseScaffold[22384:c07] PrefixOfUsingRegex 12345 results: (
"TestClass:WFjd8Uz883 {\n TestKey = 1234;\n}",
"TestClass:jKUQyyPFI2 {\n TestKey = 12345;\n}"
)
2012-09-04 20:03:42.664 parseScaffold[22384:c07] HasPrefix 12345 results: (
"TestClass:jKUQyyPFI2 {\n TestKey = 12345;\n}"
)
2012-09-04 20:03:42.664 parseScaffold[22384:c07] Regex to match prefix of 123456 is ^(1|12|123|1234|12345|123456)$
2012-09-04 20:03:43.893 parseScaffold[22384:c07] PrefixOf 123456 results: (
"TestClass:WFjd8Uz883 {\n TestKey = 1234;\n}",
"TestClass:jKUQyyPFI2 {\n TestKey = 12345;\n}"
)
2012-09-04 20:03:44.814 parseScaffold[22384:c07] PrefixOfUsingRegex 123456 results: (
"TestClass:WFjd8Uz883 {\n TestKey = 1234;\n}",
"TestClass:jKUQyyPFI2 {\n TestKey = 12345;\n}"
)
2012-09-04 20:03:45.736 parseScaffold[22384:c07] HasPrefix 123456 results: (
)
2012-09-04 20:03:45.736 parseScaffold[22384:c07] Regex to match prefix of 234 is ^(2|23|234)$
2012-09-04 20:03:46.657 parseScaffold[22384:c07] PrefixOf 234 results: (
)
2012-09-04 20:03:47.579 parseScaffold[22384:c07] PrefixOfUsingRegex 234 results: (
)
2012-09-04 20:03:48.501 parseScaffold[22384:c07] HasPrefix 234 results: (
"TestClass:aTdP84wPxb {\n TestKey = 2345;\n}",
"TestClass:UGVlIAyj6e {\n TestKey = 23451;\n}"
)
2012-09-04 20:03:48.501 parseScaffold[22384:c07] Regex to match prefix of 2345222 is ^(2|23|234|2345|23452|234522|2345222)$
2012-09-04 20:03:49.501 parseScaffold[22384:c07] PrefixOf 2345222 results: (
"TestClass:aTdP84wPxb {\n TestKey = 2345;\n}"
)
2012-09-04 20:03:50.652 parseScaffold[22384:c07] PrefixOfUsingRegex 2345222 results: (
"TestClass:aTdP84wPxb {\n TestKey = 2345;\n}"
)
2012-09-04 20:03:51.880 parseScaffold[22384:c07] HasPrefix 2345222 results: (
)
2012-09-04 20:03:51.880 parseScaffold[22384:c07] Regex to match prefix of 2345111 is ^(2|23|234|2345|23451|234511|2345111)$
2012-09-04 20:03:52.800 parseScaffold[22384:c07] PrefixOf 2345111 results: (
"TestClass:UGVlIAyj6e {\n TestKey = 23451;\n}",
"TestClass:aTdP84wPxb {\n TestKey = 2345;\n}"
)
2012-09-04 20:03:53.186 parseScaffold[22384:c07] PrefixOfUsingRegex 2345111 results: (
"TestClass:aTdP84wPxb {\n TestKey = 2345;\n}",
"TestClass:UGVlIAyj6e {\n TestKey = 23451;\n}"
)
2012-09-04 20:03:53.721 parseScaffold[22384:c07] HasPrefix 2345111 results: (
)