2018 way to add a querystring to an NSURL in Objective-C

Question

The best way to add a querystring to an NSURL seems to have changed over the years. Here is one from 2009 and here they are from 2014. All of the approaches seem rather heavy for such a seemingly simple task.

The following code is not working for me:

#define kWeatherStemURL [NSURL URLWithString: @"https://api.openweathermap.org/data/2.5/weather?units=imperial&APPID=xxxxxxx"];
NSURL* startingUrl = kWeatherStemURL;
NSString *querystring = @"&lat=35&lon=139";
NSURL *dataUrl = [NSURL URLWithString:[startingUrl.path stringByAppendingString:querystring]];

What is the best way to do it today?

Answer 1

A modern way is NSURLComponents and NSURLQueryItem, it even applies percent encoding if needed.

NSURLComponents *components = [NSURLComponents componentsWithString: @"https://api.openweathermap.org/data/2.5/weather"];
NSArray<NSURLQueryItem *> *queryItems = @[[NSURLQueryItem queryItemWithName:@"units" value:@"imperial"],
                                          [NSURLQueryItem queryItemWithName:@"APPID" value:@"xxxxxxx"],
                                          [NSURLQueryItem queryItemWithName:@"lat" value:@"35"],
                                          [NSURLQueryItem queryItemWithName:@"lon" value:@"139"]];
components.queryItems = queryItems;
NSURL *dataUrl = components.URL;