Best way to parse URL string to get values for keys?

I also answered this at https://stackoverflow.com/a/26406478/215748.

You can use queryItems in URLComponents.

When you get this property’s value, the NSURLComponents class parses the query string and returns an array of NSURLQueryItem objects, each of which represents a single key-value pair, in the order in which they appear in the original query string.

let url = "http://example.com?param1=value1&param2=param2"let queryItems = URLComponents(string: url)?.queryItemslet param1 = queryItems?.filter({$0.name == "param1"}).firstprint(param1?.value)

Alternatively, you can add an extension on URL to make things easier.

extension URL {    var queryParameters: QueryParameters { return QueryParameters(url: self) }}class QueryParameters {    let queryItems: [URLQueryItem]    init(url: URL?) {        queryItems = URLComponents(string: url?.absoluteString ?? "")?.queryItems ?? []        print(queryItems)    }    subscript(name: String) -> String? {        return queryItems.first(where: { $0.name == name })?.value    }}

You can then access the parameter by its name.

let url = URL(string: "http://example.com?param1=value1&param2=param2")!print(url.queryParameters["param1"])

edit (June 2018): this answer is better. Apple added NSURLComponents in iOS 7.

I would create a dictionary, get an array of the key/value pairs with

NSMutableDictionary *queryStringDictionary = [[NSMutableDictionary alloc] init];NSArray *urlComponents = [urlString componentsSeparatedByString:@"&"];

Then populate the dictionary :

for (NSString *keyValuePair in urlComponents){    NSArray *pairComponents = [keyValuePair componentsSeparatedByString:@"="];    NSString *key = [[pairComponents firstObject] stringByRemovingPercentEncoding];    NSString *value = [[pairComponents lastObject] stringByRemovingPercentEncoding];    [queryStringDictionary setObject:value forKey:key];}

You can then query with

[queryStringDictionary objectForKey:@"ad_eurl"];

This is untested, and you should probably do some more error tests.

I'm a bit late, but the answers provided until now didn't work as I needed to. You can use this code snippet:

NSMutableDictionary *queryStrings = [[NSMutableDictionary alloc] init];for (NSString *qs in [url.query componentsSeparatedByString:@"&"]) {    // Get the parameter name    NSString *key = [[qs componentsSeparatedByString:@"="] objectAtIndex:0];    // Get the parameter value    NSString *value = [[qs componentsSeparatedByString:@"="] objectAtIndex:1];    value = [value stringByReplacingOccurrencesOfString:@"+" withString:@" "];    value = [value stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];    queryStrings[key] = value;}

Where url is the URL you want to parse. You have all of the query strings, escaped, in the queryStrings mutable dictionary.

EDIT: Swift version:

var queryStrings = [String: String]()if let query = url.query {    for qs in query.componentsSeparatedByString("&") {        // Get the parameter name        let key = qs.componentsSeparatedByString("=")[0]        // Get the parameter value        var value = qs.componentsSeparatedByString("=")[1]        value = value.stringByReplacingOccurrencesOfString("+", withString: " ")        value = value.stringByReplacingPercentEscapesUsingEncoding(NSUTF8StringEncoding)!        queryStrings[key] = value    }}