Parse NSURL query property - iphone

Question

I have a URL like myApp://action/1?parameter=2&secondparameter=3
With the property query I get following part of my URL
parameter=2&secondparameter=3
Is there any way easy to put this in a NSDictionary or an Array?
Thx a lot

Answer 1

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.
Swift
let url = "http://example.com?param1=value1&param2=param2"
let queryItems = URLComponents(string: url)?.queryItems
let param1 = queryItems?.filter({$0.name == "param1"}).first
print(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 = "http://example.com?param1=value1&param2=param2"
print(url.queryParameters["param1"])

Answer 2

I had reason to write some extensions for this behavior that might come in handy. First the header:
#import <Foundation/Foundation.h>
#interface NSString (XQueryComponents)
- (NSString *)stringByDecodingURLFormat;
- (NSString *)stringByEncodingURLFormat;
- (NSMutableDictionary *)dictionaryFromQueryComponents;
#end
#interface NSURL (XQueryComponents)
- (NSMutableDictionary *)queryComponents;
#end
#interface NSDictionary (XQueryComponents)
- (NSString *)stringFromQueryComponents;
#end
These methods extend NSString, NSURL, and NSDictionary, to allow you to convert to and from query components strings and dictionary objects containing the results.
Now the related .m code:
#import "XQueryComponents.h"
#implementation NSString (XQueryComponents)
- (NSString *)stringByDecodingURLFormat
{
NSString *result = [self stringByReplacingOccurrencesOfString:#"+" withString:#" "];
result = [result stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
return result;
}
- (NSString *)stringByEncodingURLFormat
{
NSString *result = [self stringByReplacingOccurrencesOfString:#" " withString:#"+"];
result = [result stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
return result;
}
- (NSMutableDictionary *)dictionaryFromQueryComponents
{
NSMutableDictionary *queryComponents = [NSMutableDictionary dictionary];
for(NSString *keyValuePairString in [self componentsSeparatedByString:#"&"])
{
NSArray *keyValuePairArray = [keyValuePairString componentsSeparatedByString:#"="];
if ([keyValuePairArray count] < 2) continue; // Verify that there is at least one key, and at least one value. Ignore extra = signs
NSString *key = [[keyValuePairArray objectAtIndex:0] stringByDecodingURLFormat];
NSString *value = [[keyValuePairArray objectAtIndex:1] stringByDecodingURLFormat];
NSMutableArray *results = [queryComponents objectForKey:key]; // URL spec says that multiple values are allowed per key
if(!results) // First object
{
results = [NSMutableArray arrayWithCapacity:1];
[queryComponents setObject:results forKey:key];
}
[results addObject:value];
}
return queryComponents;
}
#end
#implementation NSURL (XQueryComponents)
- (NSMutableDictionary *)queryComponents
{
return [[self query] dictionaryFromQueryComponents];
}
#end
#implementation NSDictionary (XQueryComponents)
- (NSString *)stringFromQueryComponents
{
NSString *result = nil;
for(__strong NSString *key in [self allKeys])
{
key = [key stringByEncodingURLFormat];
NSArray *allValues = [self objectForKey:key];
if([allValues isKindOfClass:[NSArray class]])
for(__strong NSString *value in allValues)
{
value = [[value description] stringByEncodingURLFormat];
if(!result)
result = [NSString stringWithFormat:#"%#=%#",key,value];
else
result = [result stringByAppendingFormat:#"&%#=%#",key,value];
}
else {
NSString *value = [[allValues description] stringByEncodingURLFormat];
if(!result)
result = [NSString stringWithFormat:#"%#=%#",key,value];
else
result = [result stringByAppendingFormat:#"&%#=%#",key,value];
}
}
return result;
}
#end

Answer 3

Something like that:
NSMutableDictionary *params = [[NSMutableDictionary alloc] init];
for (NSString *param in [url componentsSeparatedByString:#"&"]) {
NSArray *elts = [param componentsSeparatedByString:#"="];
if([elts count] < 2) continue;
[params setObject:[elts lastObject] forKey:[elts firstObject]];
}
Note : This is sample code. All error cases are not managed.

Answer 4

Try this ;)!
NSString *query = #"parameter=2&secondparameter=3"; // replace this with [url query];
NSArray *components = [query componentsSeparatedByString:#"&"];
NSMutableDictionary *parameters = [[NSMutableDictionary alloc] init];
for (NSString *component in components) {
NSArray *subcomponents = [component componentsSeparatedByString:#"="];
[parameters setObject:[[subcomponents objectAtIndex:1] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]
forKey:[[subcomponents objectAtIndex:0] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
}

Answer 5

All previous posts do not do the url encoding properly. I would suggest the following methods:
+(NSString*)concatenateQuery:(NSDictionary*)parameters {
if([parameters count]==0) return nil;
NSMutableString* query = [NSMutableString string];
for(NSString* parameter in [parameters allKeys])
[query appendFormat:#"&%#=%#",[parameter stringByAddingPercentEncodingWithAllowedCharacters:NSCharacterSet.URLQueryAllowedCharacterSet],[[parameters objectForKey:parameter] stringByAddingPercentEncodingWithAllowedCharacters:NSCharacterSet.URLQueryAllowedCharacterSet]];
return [[query substringFromIndex:1] copy];
}
+(NSDictionary*)splitQuery:(NSString*)query {
if([query length]==0) return nil;
NSMutableDictionary* parameters = [NSMutableDictionary dictionary];
for(NSString* parameter in [query componentsSeparatedByString:#"&"]) {
NSRange range = [parameter rangeOfString:#"="];
if(range.location!=NSNotFound)
[parameters setObject:[[parameter substringFromIndex:range.location+range.length] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding] forKey:[[parameter substringToIndex:range.location] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
else [parameters setObject:[[NSString alloc] init] forKey:[parameter stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
}
return [parameters copy];
}

Answer 6

According to the already very clean answer of Onato I wrote an extension for NSURL in Swift where you can get a query param like this:
e.g. the URL contains the pair param=some_value
let queryItem = url.queryItemForKey("param")
let value = queryItem.value // would get String "someValue"
The extension looks like:
extension NSURL {
var allQueryItems: [NSURLQueryItem] {
get {
let components = NSURLComponents(URL: self, resolvingAgainstBaseURL: false)!
let allQueryItems = components.queryItems!
return allQueryItems as [NSURLQueryItem]
}
}
func queryItemForKey(key: String) -> NSURLQueryItem? {
let predicate = NSPredicate(format: "name=%#", key)!
return (allQueryItems as NSArray).filteredArrayUsingPredicate(predicate).first as? NSURLQueryItem
}
}

Answer 7

Here is the extension in swift:
extension NSURL{
func queryParams() -> [String:AnyObject] {
var info : [String:AnyObject] = [String:AnyObject]()
if let queryString = self.query{
for parameter in queryString.componentsSeparatedByString("&"){
let parts = parameter.componentsSeparatedByString("=")
if parts.count > 1{
let key = (parts[0] as String).stringByReplacingPercentEscapesUsingEncoding(NSUTF8StringEncoding)
let value = (parts[1] as String).stringByReplacingPercentEscapesUsingEncoding(NSUTF8StringEncoding)
if key != nil && value != nil{
info[key!] = value
}
}
}
}
return info
}
}

Answer 8

The preferred way to deal with URLs is now NSURLComponents. In particular the queryItems property which returns an NSArray of params.
If you want the params in a NSDictionary, here's a method:
+(NSDictionary<NSString *, NSString *>*)queryParamsFromURL:(NSURL*)url
{
NSURLComponents* urlComponents = [NSURLComponents componentsWithURL:url resolvingAgainstBaseURL:NO];
NSMutableDictionary<NSString *, NSString *>* queryParams = [NSMutableDictionary<NSString *, NSString *> new];
for (NSURLQueryItem* queryItem in [urlComponents queryItems])
{
if (queryItem.value == nil)
{
continue;
}
[queryParams setObject:queryItem.value forKey:queryItem.name];
}
return queryParams;
}
Caveat: URLs can have repeated params, but the dictionary will only contain the last value of any duplicated param. If that is undesirable, use the queryItems array directly.

Answer 9

For those using Bolts Framework you can use:
NSDictionary *parameters = [BFURL URLWithURL:yourURL].inputQueryParameters;
Remember to import:
#import <Bolts/BFURL.h>
If you happen to have Facebook SDK in your project, you also have Bolts. Facebook is using this framework as a dependency.

Answer 10

Swift 2.1
Oneliner:
"p1=v1&p2=v2".componentsSeparatedByString("&").map {
$0.componentsSeparatedByString("=")
}.reduce([:]) {
(var dict: [String:String], p) in
dict[p[0]] = p[1]
return dict
}
// ["p1": "v1", "p2": "v2"]
Used as an extension on NSURL:
extension NSURL {
/**
* URL query string as dictionary. Empty dictionary if query string is nil.
*/
public var queryValues : [String:String] {
get {
if let q = self.query {
return q.componentsSeparatedByString("&").map {
$0.componentsSeparatedByString("=")
}.reduce([:]) {
(var dict: [String:String], p) in
dict[p[0]] = p[1]
return dict
}
} else {
return [:]
}
}
}
}
Example:
let url = NSURL(string: "http://example.com?p1=v1&p2=v2")!
let queryDict = url.queryValues
// ["p1": "v1", "p2": "v2"]
Please note, if using OS X 10.10 or iOS 8 (or later), it's probably better to use NSURLComponents and the queryItems property and create the dictionary from the NSURLQueryItems directly.
Here's a NSURLComponents based NSURL extension solution:
extension NSURL {
/// URL query string as a dictionary. Empty dictionary if query string is nil.
public var queryValues : [String:String] {
get {
guard let components = NSURLComponents(URL: self, resolvingAgainstBaseURL: false) else {
return [:]
}
guard let queryItems = components.queryItems else {
return [:]
}
var result:[String:String] = [:]
for q in queryItems {
result[q.name] = q.value
}
return result
}
}
}
A footnote to the NSURL extension is that it's actually possible in Swift to give the property the same name as the existing string property—query. I didn't know until I tried it, but the polymorphism in Swift lets you differ only on the return type. So if the extended NSURL property is public var query: [String:String] it works. I didn't use this in the example as I find it a little bit crazy, but it does work ...

Answer 11

I published a simple class doing the job under MIT:
https://github.com/anegmawad/URLQueryToCocoa
With it you can have arrays and objects in the query, which are collected and glued together
For Example
users[0][firstName]=Amin&users[0][lastName]=Negm&name=Devs&users[1][lastName]=Kienle&users[1][firstName]=Christian
will become:
#{
name : #"Devs",
users :
#[
#{
firstName = #"Amin",
lastName = #"Negm"
},
#{
firstName = #"Christian",
lastName = #"Kienle"
}
]
}
You can think of it as a URL query counterpart of NSJSONSerializer.

Answer 12

It looks that you are using it to process incoming data from another iOS application. If so, this is what I use for the same purpose.
Initial call (e.g. in external application):
UIApplication *application = [UIApplication sharedApplication];
NSURL *url = [NSURL URLWithString:#"myApp://action/1?parameter=2&secondparameter=3"];
if ([application canOpenURL:url]) {
[application openURL:url];
NSLog(#"myApp is installed");
} else {
NSLog(#"myApp is not installed");
}
Method to extract QueryString data from NSURL and save as NSDictionary:
-(NSDictionary *) getNSDictionaryFromQueryString:(NSURL *)url {
NSMutableDictionary *result = [[NSMutableDictionary alloc] init];
NSRange needle = [url.absoluteString rangeOfString:#"?" options:NSCaseInsensitiveSearch];
NSString *data = nil;
if(needle.location != NSNotFound) {
NSUInteger start = needle.location + 1;
NSUInteger end = [url.absoluteString length] - start;
data = [url.absoluteString substringWithRange:NSMakeRange(start, end)];
}
for (NSString *param in [data componentsSeparatedByString:#"&"]) {
NSArray *keyvalue = [param componentsSeparatedByString:#"="];
if([keyvalue count] == 2){
[result setObject:[keyvalue objectAtIndex:1] forKey:[keyvalue objectAtIndex:0]];
}
}
return result;
}
Usage:
NSDictionary *result = [self getNSDictionaryFromQueryString:url];

Answer 13

This class is a nice solution for url parsing.
.h file
#interface URLParser : NSObject {
NSArray *variables;
}
#property (nonatomic, retain) NSArray *variables;
- (id)initWithURLString:(NSString *)url;
- (NSString *)valueForVariable:(NSString *)varName;
#end
.m file
#import "URLParser.h"
#implementation URLParser
#synthesize variables;
- (id) initWithURLString:(NSString *)url{
self = [super init];
if (self != nil) {
NSString *string = url;
NSScanner *scanner = [NSScanner scannerWithString:string];
[scanner setCharactersToBeSkipped:[NSCharacterSet characterSetWithCharactersInString:#"&?"]];
NSString *tempString;
NSMutableArray *vars = [NSMutableArray new];
[scanner scanUpToString:#"?" intoString:nil]; //ignore the beginning of the string and skip to the vars
while ([scanner scanUpToString:#"&" intoString:&tempString]) {
[vars addObject:[tempString copy]];
}
self.variables = vars;
}
return self;
}
- (NSString *)valueForVariable:(NSString *)varName {
for (NSString *var in self.variables) {
if ([var length] > [varName length]+1 && [[var substringWithRange:NSMakeRange(0, [varName length]+1)] isEqualToString:[varName stringByAppendingString:#"="]]) {
NSString *varValue = [var substringFromIndex:[varName length]+1];
return varValue;
}
}
return nil;
}
#end

Answer 14

Hendrik wrote a nice example for extension in this question, however I had to re-write it to not use any objective-c library methods. Using NSArray in swift is not the correct approach.
This is the result, all swift and a bit more safe. The usage example will be less lines of code with Swift 1.2.
public extension NSURL {
/*
Set an array with all the query items
*/
var allQueryItems: [NSURLQueryItem] {
get {
let components = NSURLComponents(URL: self, resolvingAgainstBaseURL: false)!
if let allQueryItems = components.queryItems {
return allQueryItems as [NSURLQueryItem]
} else {
return []
}
}
}
/**
Get a query item form the URL query
:param: key The parameter to fetch from the URL query
:returns: `NSURLQueryItem` the query item
*/
public func queryItemForKey(key: String) -> NSURLQueryItem? {
let filteredArray = filter(allQueryItems) { $0.name == key }
if filteredArray.count > 0 {
return filteredArray.first
} else {
return nil
}
}
}
Usage:
let queryItem = url.queryItemForKey("myItem")
Or, more detailed usage:
if let url = NSURL(string: "http://www.domain.com/?myItem=something") {
if let queryItem = url.queryItemForKey("myItem") {
if let value = queryItem.value {
println("The value of 'myItem' is: \(value)")
}
}
}

Answer 15

try this:
-(NSDictionary *)getUrlParameters:(NSString *)url{
NSArray *justParamsArr = [url componentsSeparatedByString:#"?"];
url = [justParamsArr lastObject];
NSMutableDictionary *params = [[NSMutableDictionary alloc] init];
for (NSString *param in [url componentsSeparatedByString:#"&"]) {
NSArray *elts = [param componentsSeparatedByString:#"="];
if([elts count] < 2) continue;
[params setObject:[elts lastObject] forKey:[elts firstObject]];
}
return params;
}

Answer 16

Fairly compact approach:
func stringParamsToDict(query: String) -> [String: String] {
let params = query.components(separatedBy: "&").map {
$0.components(separatedBy: "=")
}.reduce(into: [String: String]()) { dict, pair in
if pair.count == 2 {
dict[pair[0]] = pair[1]
}
}
return params
}

Answer 17

Most robust solution if you are using a URL to pass data from the web app to the phone and you want to pass arrays, numbers, strings, ...
JSON encode your object in PHP
header("Location: myAppAction://".urlencode(json_encode($YOUROBJECT)));
And JSON decode the result in iOS
NSData *data = [[[request URL] host] dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *packed = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];