Parse NSURL path and query on iOS

Question

Are there any standard objects or functions to parse an NSURL's components? Clearly I could write one, but why re-invent the wheel?

[NSURL path] will return an NSString like "argX=x&argY=y&argZ=z" What I would rather get back is a dictionary populated with {@"argX" => @"x", @"argY" => @"y", @"argZ" = @"z"}

For the path, which returns a string like "/partA/partB/partC", I would rather get an array with the structure {[0] => @"partA", [1] => @"partB", [2] => @"partC"}

I realize this is a pretty specific ask, but it seems like something a lot of people would want.

This is for iOS! Apparently NSURL has different functions on macOS.

Answer 1

Alright, I got antsy and wrote a solution for extending NSString through Categories. I haven't tested this yet, but if you want to use it, go for it.

@interface NSString (ParseCategory)
- (NSMutableDictionary *)explodeToDictionaryInnerGlue:(NSString *)innerGlue outterGlue:(NSString *)outterGlue;
@end

@implementation NSString (ParseCategory)

- (NSMutableDictionary *)explodeToDictionaryInnerGlue:(NSString *)innerGlue outterGlue:(NSString *)outterGlue {
    // Explode based on outter glue
    NSArray *firstExplode = [self componentsSeparatedByString:outterGlue];
    NSArray *secondExplode;

    // Explode based on inner glue
    NSInteger count = [firstExplode count];
    NSMutableDictionary *returnDictionary = [NSMutableDictionary dictionaryWithCapacity:count];
    for (NSInteger i = 0; i < count; i++) {
        secondExplode = [(NSString *)[firstExplode objectAtIndex:i] componentsSeparatedByString:innerGlue];
        if ([secondExplode count] == 2) {
            [returnDictionary setObject:[secondExplode objectAtIndex:1] forKey:[secondExplode objectAtIndex:0]];
        }
    }

    return returnDictionary;
}

@end

It's called like this:

NSMutableDictionary *parsedQuery = [[myNSURL query] explodeToDictionaryInnerGlue:@"=" outterGlue=@"&"]

For parsing the path portion of the NSURL (ie @"/partA/partB/partC"), just call this:

NSArray *parsedPath = [[nyNSURL path] componentsSeperatedByString:@"/"];

Be aware that parsedPath[0] will be an empty string because of the leading /!

EDIT - Here is a Category extension to NSURL for your usage pleasure. It strips the initial "/" so you don't have an empty 0 index.

@implementation NSURL (ParseCategory)

- (NSArray *)pathArray {
    // Create a character set for the slash character
    NSRange slashRange;
    slashRange.location = (unsigned int)'/';
    slashRange.length = 1;
    NSCharacterSet *slashSet = [NSCharacterSet characterSetWithRange:slashRange];

    // Get path with leading (and trailing) slashes removed
    NSString *path = [[self path] stringByTrimmingCharactersInSet:slashSet];

    return [path componentsSeparatedByCharactersInSet:slashSet];
}

- (NSDictionary *)queryDictionary {
    NSDictionary *returnDictionary = [[[[self query] explodeToDictionaryInnerGlue:@"=" outterGlue:@"&"] copy] autorelease];
    return returnDictionary;
}

@end

Answer 2

Sam Soffes created a well maintained Category for NSURL / NSDictionary. It can be found here: https://github.com/samsoffes/sstoolkit/

Answer 3

You might want to look at pathComponents which returns an array of the components of the URL. Get more information here.

Answer 4

Heres what i use to parse the query string

// Parse the individual parameters
// parameters = @"hello=world&foo=bar";
NSMutableDictionary *dictParameters = [[NSMutableDictionary alloc] init];
NSArray *arrParameters = [parameters componentsSeparatedByString:@"&"];
for (int i = 0; i < [arrParameters count]; i++) {
    NSArray *arrKeyValue = [[arrParameters objectAtIndex:i] componentsSeparatedByString:@"="];
    if ([arrKeyValue count] >= 2) {
        NSMutableString *strKey = [NSMutableString stringWithCapacity:0];
        [strKey setString:[[[arrKeyValue objectAtIndex:0] lowercaseString] stringByReplacingPercentEscapesUsingEncoding: NSUTF8StringEncoding]];
        NSMutableString *strValue   = [NSMutableString stringWithCapacity:0];
        [strValue setString:[[[arrKeyValue objectAtIndex:1]  stringByReplacingOccurrencesOfString:@"+" withString:@" "] stringByReplacingPercentEscapesUsingEncoding: NSUTF8StringEncoding]];
        if (strKey.length > 0) [dictParameters setObject:strValue forKey:strKey];
    }
}
NSLog(@"Parameters: %@", dictParameters);

Answer 5

If you do decide to write one (I'm not sure there are existing methods of getting the components you want), you might want to use NSString's componentsSeparatedByString.