Open Radar

Engineering has provided the following feedback regarding this issue:

There are currently no plans to add an additional character set for your purposes.

However, it’s very simple to do it yourself.

NSMutableCharacterSet *myURLQueryParameterAllowedCharacterSet = [[NSCharacterSet URLQueryAllowedCharacterSet] mutableCopy];
[myURLQueryParameterAllowedCharacterSet removeCharactersInString:@“?&=“];

We consider this issue closed.

Thanks for your detailed answer and your suggestion to use NSURLComponents instead. I was expecting to be able to achieve the same using -stringByAddingPercentEncodingWithAllowedCharacters: and an appropriate character set. Alas, such a character seems to not exist yet. So I suggest adding a URLQueryParameterAllowedCharacterSet that excludes the "?", "&" and "=" in addition to URLQueryAllowedCharacterSet.

Thanks for your detailed answer and your suggestion to use NSURLComponents instead. I expected to be able to achieve the same using -stringByAddingPercentEncodingWithAllowedCharacters and an appropriate character set. Alas, such a character seems to not exist yet. So I suggest adding a URLQueryParameterAllowedCharacterSet that excludes the "?", "&" and "=" in addition to the characters in URLQueryAllowedCharacterSet.

Engineering has determined that this issue behaves as intended based on the following information:

The "&" character is in the sub-delims characters which are all allowed in a host in the reg-name form.

Entire URL strings cannot be percent-encoded unless you know what will be done with the encoded string.

If you’re trying to set the entire query component to a URL, you can use stringByAddingPercentEncodingWithAllowedCharacters with the URLQueryAllowedCharacterSet.

If you are trying to set the value of query name-value pair, you should just do this:

// base URL
NSURLComponents *components =[NSURLComponents componentsWithString:@"http://www.example.com/"];
// create a couple of query items with URLs as the values.
NSURLQueryItem *item1 = [NSURLQueryItem queryItemWithName:@"url1" value:@"scheme://user:pass@host:80/path?query&name=value#fragment"];
NSURLQueryItem *item2 = [NSURLQueryItem queryItemWithName:@"url2" value:@"http://www.foo.bar/"];
// set the query to the query items
components.queryItems = [NSArray arrayWithObjects:item1, item2, nil];
// show me the URL
NSURL *url = components.URL;
NSLog(@"%@", url);

output:

http://www.example.com/?url1=scheme://user:pass@host:80/path?query%26name%3Dvalue%23fragment&url2=http://www.foo.bar/

The reverse is:

NSURLComponents *components =[NSURLComponents componentsWithURL:url resolvingAgainstBaseURL:YES];
NSLog(@"%@", components.queryItems);

output:

(
    "<NSURLQueryItem 0x1012005b0> {name = url1, value = scheme://user:pass@host:80/path?query&name=value#fragment}",
    "<NSURLQueryItem 0x101200c00> {name = url2, value = http://www.foo.bar/}"
)