Related
I have an NSURL:
serverCall?x=a&y=b&z=c
What is the quickest and most efficient way to get the value of y?
Thanks
UPDATE:
Since 2010 when this was written, it seems Apple has released a set of tools for that purpose. Please see the answers below for those.
Old-School Solution:
Well I know you said "the quickest way" but after I started doing a test with NSScanner I just couldn't stop. And while it is not the shortest way, it is sure handy if you are planning to use that feature a lot. I created a URLParser class that gets these vars using an NSScanner. The use is a simple as:
URLParser *parser = [[[URLParser alloc] initWithURLString:#"http://blahblahblah.com/serverCall?x=a&y=b&z=c&flash=yes"] autorelease];
NSString *y = [parser valueForVariable:#"y"];
NSLog(#"%#", y); //b
NSString *a = [parser valueForVariable:#"a"];
NSLog(#"%#", a); //(null)
NSString *flash = [parser valueForVariable:#"flash"];
NSLog(#"%#", flash); //yes
And the class that does this is the following (*source files at the bottom of the post):
URLParser.h
#interface URLParser : NSObject {
NSArray *variables;
}
#property (nonatomic, retain) NSArray *variables;
- (id)initWithURLString:(NSString *)url;
- (NSString *)valueForVariable:(NSString *)varName;
#end
URLParser.m
#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;
[vars release];
}
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;
}
- (void) dealloc{
self.variables = nil;
[super dealloc];
}
#end
*if you don't like copying and pasting you can just download the source files - I made a quick blog post about this here.
So many custom url parsers here, remember NSURLComponents is your friend!
Here is an example where I pull out a url encoded parameter for "page"
Swift
let myURL = "www.something.com?page=2"
var pageNumber : Int?
if let queryItems = NSURLComponents(string: myURL)?.queryItems {
for item in queryItems {
if item.name == "page" {
if let itemValue = item.value {
pageNumber = Int(itemValue)
}
}
}
}
print("Found page number: \(pageNumber)")
Objective-C
NSString *myURL = #"www.something.com?page=2";
NSURLComponents *components = [NSURLComponents componentsWithString:myURL];
NSNumber *page = nil;
for(NSURLQueryItem *item in components.queryItems)
{
if([item.name isEqualToString:#"page"])
page = [NSNumber numberWithInteger:item.value.integerValue];
}
"Why reinvent the wheel!" - Someone Smart
I'm pretty sure you have to parse it yourself. However, it's not too bad:
NSString * q = [myURL query];
NSArray * pairs = [q componentsSeparatedByString:#"&"];
NSMutableDictionary * kvPairs = [NSMutableDictionary dictionary];
for (NSString * pair in pairs) {
NSArray * bits = [pair componentsSeparatedByString:#"="];
NSString * key = [[bits objectAtIndex:0] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSString * value = [[bits objectAtIndex:1] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
[kvPairs setObject:value forKey:key];
}
NSLog(#"y = %#", [kvPairs objectForKey:#"y"]);
In Swift you can use NSURLComponents to parse the query string of an NSURL into an [AnyObject].
You can then create a dictionary from it (or access the items directly) to get at the key/value pairs. As an example this is what I am using to parse a NSURL variable url:
let urlComponents = NSURLComponents(URL: url, resolvingAgainstBaseURL: false)
let items = urlComponents?.queryItems as [NSURLQueryItem]
var dict = NSMutableDictionary()
for item in items{
dict.setValue(item.value, forKey: item.name)
}
println(dict["x"])
I've been using this Category: https://github.com/carlj/NSURL-Parameters.
It's small and easy to use:
#import "NSURL+Parameters.h"
...
NSURL *url = [NSURL URLWithString:#"http://foo.bar.com?paramA=valueA¶mB=valueB"];
NSString *paramA = url[#"paramA"];
NSString *paramB = url[#"paramB"];
You can use Google Toolbox for Mac.
It adds a function to NSString to convert query string to a dictionary.
http://code.google.com/p/google-toolbox-for-mac/
It works like a charm
NSDictionary * d = [NSDictionary gtm_dictionaryWithHttpArgumentsString:[[request URL] query]];
Here's a Swift 2.0 extension that provides simple access to parameters:
extension NSURL {
var params: [String: String] {
get {
let urlComponents = NSURLComponents(URL: self, resolvingAgainstBaseURL: false)
var items = [String: String]()
for item in urlComponents?.queryItems ?? [] {
items[item.name] = item.value ?? ""
}
return items
}
}
}
Sample usage:
let url = NSURL(string: "http://google.com?test=dolphins")
if let testParam = url.params["test"] {
print("testParam: \(testParam)")
}
I wrote a simple category to extend NSString/NSURL that lets you extract URL query parameters individually or as a dictionary of key/value pairs:
https://github.com/nicklockwood/RequestUtils
I did it using a category method based on #Dimitris solution
#import "NSURL+DictionaryValue.h"
#implementation NSURL (DictionaryValue)
-(NSDictionary *)dictionaryValue
{
NSString *string = [[self.absoluteString stringByReplacingOccurrencesOfString:#"+" withString:#" "]
stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSScanner *scanner = [NSScanner scannerWithString:string];
[scanner setCharactersToBeSkipped:[NSCharacterSet characterSetWithCharactersInString:#"&?"]];
NSString *temp;
NSMutableDictionary *dict = [[[NSMutableDictionary alloc] init] autorelease];
[scanner scanUpToString:#"?" intoString:nil]; //ignore the beginning of the string and skip to the vars
while ([scanner scanUpToString:#"&" intoString:&temp])
{
NSArray *parts = [temp componentsSeparatedByString:#"="];
if([parts count] == 2)
{
[dict setObject:[parts objectAtIndex:1] forKey:[parts objectAtIndex:0]];
}
}
return dict;
}
#end
All of the current answers are version specific or needlessly wasteful. Why create a dictionary if you only want one value?
Here's a simple answer that supports all iOS versions:
- (NSString *)getQueryParam:(NSString *)name fromURL:(NSURL *)url
{
if (url)
{
NSArray *urlComponents = [url.query componentsSeparatedByString:#"&"];
for (NSString *keyValuePair in urlComponents)
{
NSArray *pairComponents = [keyValuePair componentsSeparatedByString:#"="];
NSString *key = [[pairComponents firstObject] stringByRemovingPercentEncoding];
if ([key isEqualToString:name])
{
return [[pairComponents lastObject] stringByRemovingPercentEncoding];
}
}
}
return nil;
}
You can do that easy :
- (NSMutableDictionary *) getUrlParameters:(NSURL *) url
{
NSMutableDictionary *params = [[NSMutableDictionary alloc] init];
NSString *tmpKey = [url query];
for (NSString *param in [[url query] componentsSeparatedByString:#"="])
{
if ([tmpKey rangeOfString:param].location == NSNotFound)
{
[params setValue:param forKey:tmpKey];
tmpKey = nil;
}
tmpKey = param;
}
[tmpKey release];
return params;
}
It return Dictionary like it : Key = value
I edited Dimitris' code slightly for better memory management and efficiency. Also, it works in ARC.
URLParser.h
#interface URLParser : NSObject
- (void)setURLString:(NSString *)url;
- (NSString *)valueForVariable:(NSString *)varName;
#end
URLParser.m
#import "URLParser.h"
#implementation URLParser {
NSMutableDictionary *_variablesDict;
}
- (void)setURLString:(NSString *)url {
[_variablesDict removeAllObjects];
NSString *string = url;
NSScanner *scanner = [NSScanner scannerWithString:string];
[scanner setCharactersToBeSkipped:[NSCharacterSet characterSetWithCharactersInString:#"&?"]];
NSString *tempString;
[scanner scanUpToString:#"?" intoString:nil]; //ignore the beginning of the string and skip to the vars
while ([scanner scanUpToString:#"&" intoString:&tempString]) {
NSString *dataString = [tempString copy];
NSArray *sepStrings = [dataString componentsSeparatedByString:#"="];
if ([sepStrings count] == 2) {
[_variablesDict setValue:sepStrings[1] forKeyPath:sepStrings[0]];
}
}
}
- (id)init
{
self = [super init];
if (self) {
_variablesDict = [[NSMutableDictionary alloc] init];
}
return self;
}
- (NSString *)valueForVariable:(NSString *)varName {
NSString *val = [_variablesDict valueForKeyPath:varName];
return val;
return nil;
}
-(NSString *)description {
return [NSString stringWithFormat:#"Current Variables: %#", _variablesDict];
}
#end
Quickest is:
NSString* x = [url valueForQueryParameterKey:#"x"];
With all the URL-handling objects lying around in the standard Cocoa libraries (NSURL, NSMutableURL, NSMutableURLRequest, etc), I know I must be overlooking an easy way to programmatically compose a GET request.
Currently I'm manually appending "?" followed by name value pairs joined by "&", but all of my name and value pairs need to be manually encoded so NSMutableURLRequest doesn't fail entirely when it tries to connect to the URL.
This feels like something I should be able to use a pre-baked API for.... is there anything out of the box to append an NSDictionary of query parameters to an NSURL? Is there another way I should approach this?
Introduced in iOS8 and OS X 10.10 is NSURLQueryItem, which can be used to build queries. From the docs on NSURLQueryItem:
An NSURLQueryItem object represents a single name/value pair for an item in the query portion of a URL. You use query items with the queryItems property of an NSURLComponents object.
To create one use the designated initializer queryItemWithName:value: and then add them to NSURLComponents to generate an NSURL. For example:
NSURLComponents *components = [NSURLComponents componentsWithString:#"http://stackoverflow.com"];
NSURLQueryItem *search = [NSURLQueryItem queryItemWithName:#"q" value:#"ios"];
NSURLQueryItem *count = [NSURLQueryItem queryItemWithName:#"count" value:#"10"];
components.queryItems = #[ search, count ];
NSURL *url = components.URL; // http://stackoverflow.com?q=ios&count=10
Notice that the question mark and ampersand are automatically handled. Creating an NSURL from a dictionary of parameters is as simple as:
NSDictionary *queryDictionary = #{ #"q": #"ios", #"count": #"10" };
NSMutableArray *queryItems = [NSMutableArray array];
for (NSString *key in queryDictionary) {
[queryItems addObject:[NSURLQueryItem queryItemWithName:key value:queryDictionary[key]]];
}
components.queryItems = queryItems;
I've also written a blog post on how to build URLs with NSURLComponents and NSURLQueryItems.
You can create a category for NSDictionary to do this -- there isn't a standard way in the Cocoa library that I could find either. The code that I use looks like this:
// file "NSDictionary+UrlEncoding.h"
#import <cocoa/cocoa.h>
#interface NSDictionary (UrlEncoding)
-(NSString*) urlEncodedString;
#end
with this implementation:
// file "NSDictionary+UrlEncoding.m"
#import "NSDictionary+UrlEncoding.h"
// helper function: get the string form of any object
static NSString *toString(id object) {
return [NSString stringWithFormat: #"%#", object];
}
// helper function: get the url encoded string form of any object
static NSString *urlEncode(id object) {
NSString *string = toString(object);
return [string stringByAddingPercentEscapesUsingEncoding: NSUTF8StringEncoding];
}
#implementation NSDictionary (UrlEncoding)
-(NSString*) urlEncodedString {
NSMutableArray *parts = [NSMutableArray array];
for (id key in self) {
id value = [self objectForKey: key];
NSString *part = [NSString stringWithFormat: #"%#=%#", urlEncode(key), urlEncode(value)];
[parts addObject: part];
}
return [parts componentsJoinedByString: #"&"];
}
#end
I think the code's pretty straightforward, but I discuss it in some more detail at http://blog.ablepear.com/2008/12/urlencoding-category-for-nsdictionary.html.
I wanted to use Chris's answer, but it wasn't written for Automatic Reference Counting (ARC) so I updated it. I thought I'd paste my solution in case anyone else has this same issue. Note: replace self with the instance or class name where appropriate.
+(NSString*)urlEscapeString:(NSString *)unencodedString
{
CFStringRef originalStringRef = (__bridge_retained CFStringRef)unencodedString;
NSString *s = (__bridge_transfer NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,originalStringRef, NULL, (CFStringRef)#"!*'\"();:#&=+$,/?%#[]% ", kCFStringEncodingUTF8);
CFRelease(originalStringRef);
return s;
}
+(NSString*)addQueryStringToUrlString:(NSString *)urlString withDictionary:(NSDictionary *)dictionary
{
NSMutableString *urlWithQuerystring = [[NSMutableString alloc] initWithString:urlString];
for (id key in dictionary) {
NSString *keyString = [key description];
NSString *valueString = [[dictionary objectForKey:key] description];
if ([urlWithQuerystring rangeOfString:#"?"].location == NSNotFound) {
[urlWithQuerystring appendFormat:#"?%#=%#", [self urlEscapeString:keyString], [self urlEscapeString:valueString]];
} else {
[urlWithQuerystring appendFormat:#"&%#=%#", [self urlEscapeString:keyString], [self urlEscapeString:valueString]];
}
}
return urlWithQuerystring;
}
The other answers work great if the values are strings, however if the values are dictionaries or arrays then this code will handle that.
Its important to note that there is no standard way of passing an array/dictionary via the query string but PHP handles this output just fine
-(NSString *)serializeParams:(NSDictionary *)params {
/*
Convert an NSDictionary to a query string
*/
NSMutableArray* pairs = [NSMutableArray array];
for (NSString* key in [params keyEnumerator]) {
id value = [params objectForKey:key];
if ([value isKindOfClass:[NSDictionary class]]) {
for (NSString *subKey in value) {
NSString* escaped_value = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
(CFStringRef)[value objectForKey:subKey],
NULL,
(CFStringRef)#"!*'();:#&=+$,/?%#[]",
kCFStringEncodingUTF8);
[pairs addObject:[NSString stringWithFormat:#"%#[%#]=%#", key, subKey, escaped_value]];
}
} else if ([value isKindOfClass:[NSArray class]]) {
for (NSString *subValue in value) {
NSString* escaped_value = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
(CFStringRef)subValue,
NULL,
(CFStringRef)#"!*'();:#&=+$,/?%#[]",
kCFStringEncodingUTF8);
[pairs addObject:[NSString stringWithFormat:#"%#[]=%#", key, escaped_value]];
}
} else {
NSString* escaped_value = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
(CFStringRef)[params objectForKey:key],
NULL,
(CFStringRef)#"!*'();:#&=+$,/?%#[]",
kCFStringEncodingUTF8);
[pairs addObject:[NSString stringWithFormat:#"%#=%#", key, escaped_value]];
[escaped_value release];
}
}
return [pairs componentsJoinedByString:#"&"];
}
Examples
[foo] => bar
[translations] =>
{
[one] => uno
[two] => dos
[three] => tres
}
foo=bar&translations[one]=uno&translations[two]=dos&translations[three]=tres
[foo] => bar
[translations] =>
{
uno
dos
tres
}
foo=bar&translations[]=uno&translations[]=dos&translations[]=tres
I refactored and converted to ARC answer by AlBeebe
- (NSString *)serializeParams:(NSDictionary *)params {
NSMutableArray *pairs = NSMutableArray.array;
for (NSString *key in params.keyEnumerator) {
id value = params[key];
if ([value isKindOfClass:[NSDictionary class]])
for (NSString *subKey in value)
[pairs addObject:[NSString stringWithFormat:#"%#[%#]=%#", key, subKey, [self escapeValueForURLParameter:[value objectForKey:subKey]]]];
else if ([value isKindOfClass:[NSArray class]])
for (NSString *subValue in value)
[pairs addObject:[NSString stringWithFormat:#"%#[]=%#", key, [self escapeValueForURLParameter:subValue]]];
else
[pairs addObject:[NSString stringWithFormat:#"%#=%#", key, [self escapeValueForURLParameter:value]]];
}
return [pairs componentsJoinedByString:#"&"];
}
- (NSString *)escapeValueForURLParameter:(NSString *)valueToEscape {
return (__bridge_transfer NSString *) CFURLCreateStringByAddingPercentEscapes(NULL, (__bridge CFStringRef) valueToEscape,
NULL, (CFStringRef) #"!*'();:#&=+$,/?%#[]", kCFStringEncodingUTF8);
}
If you are already using AFNetworking (as was the case with me), you can use it's class AFHTTPRequestSerializer to create the required NSURLRequest.
[[AFHTTPRequestSerializer serializer] requestWithMethod:#"GET" URLString:#"YOUR_URL" parameters:#{PARAMS} error:nil];
In case you only require the URL for your work, use NSURLRequest.URL.
Here is a simple example in Swift (iOS8+):
private let kSNStockInfoFetchRequestPath: String = "http://dev.markitondemand.com/Api/v2/Quote/json"
private func SNStockInfoFetchRequestURL(symbol:String) -> NSURL? {
if let components = NSURLComponents(string:kSNStockInfoFetchRequestPath) {
components.queryItems = [NSURLQueryItem(name:"symbol", value:symbol)]
return components.URL
}
return nil
}
I took Joel's recommendation of using URLQueryItems and turned into a Swift Extension (Swift 3)
extension URL
{
/// Creates an NSURL with url-encoded parameters.
init?(string : String, parameters : [String : String])
{
guard var components = URLComponents(string: string) else { return nil }
components.queryItems = parameters.map { return URLQueryItem(name: $0, value: $1) }
guard let url = components.url else { return nil }
// Kinda redundant, but we need to call init.
self.init(string: url.absoluteString)
}
}
(The self.init method is kinda cheesy, but there was no NSURL init with components)
Can be used as
URL(string: "http://www.google.com/", parameters: ["q" : "search me"])
I've got another solution:
http://splinter.com.au/build-a-url-query-string-in-obj-c-from-a-dict
+(NSString*)urlEscape:(NSString *)unencodedString {
NSString *s = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
(CFStringRef)unencodedString,
NULL,
(CFStringRef)#"!*'\"();:#&=+$,/?%#[]% ",
kCFStringEncodingUTF8);
return [s autorelease]; // Due to the 'create rule' we own the above and must autorelease it
}
// Put a query string onto the end of a url
+(NSString*)addQueryStringToUrl:(NSString *)url params:(NSDictionary *)params {
NSMutableString *urlWithQuerystring = [[[NSMutableString alloc] initWithString:url] autorelease];
// Convert the params into a query string
if (params) {
for(id key in params) {
NSString *sKey = [key description];
NSString *sVal = [[params objectForKey:key] description];
// Do we need to add ?k=v or &k=v ?
if ([urlWithQuerystring rangeOfString:#"?"].location==NSNotFound) {
[urlWithQuerystring appendFormat:#"?%#=%#", [Http urlEscape:sKey], [Http urlEscape:sVal]];
} else {
[urlWithQuerystring appendFormat:#"&%#=%#", [Http urlEscape:sKey], [Http urlEscape:sVal]];
}
}
}
return urlWithQuerystring;
}
You can then use it like so:
NSDictionary *params = #{#"username":#"jim", #"password":#"abc123"};
NSString *urlWithQuerystring = [self addQueryStringToUrl:#"https://myapp.com/login" params:params];
-(NSString*)encodeDictionary:(NSDictionary*)dictionary{
NSMutableString *bodyData = [[NSMutableString alloc]init];
int i = 0;
for (NSString *key in dictionary.allKeys) {
i++;
[bodyData appendFormat:#"%#=",key];
NSString *value = [dictionary valueForKey:key];
NSString *newString = [value stringByReplacingOccurrencesOfString:#" " withString:#"+"];
[bodyData appendString:newString];
if (i < dictionary.allKeys.count) {
[bodyData appendString:#"&"];
}
}
return bodyData;
}
Yet another solution, if you use RestKit there's a function in RKURLEncodedSerialization called RKURLEncodedStringFromDictionaryWithEncoding that does exactly what you want.
Simple way of converting NSDictionary to url query string in Objective-c
Ex: first_name=Steve&middle_name=Gates&last_name=Jobs&address=Palo Alto, California
NSDictionary *sampleDictionary = #{#"first_name" : #"Steve",
#"middle_name" : #"Gates",
#"last_name" : #"Jobs",
#"address" : #"Palo Alto, California"};
NSMutableString *resultString = [NSMutableString string];
for (NSString* key in [sampleDictionary allKeys]){
if ([resultString length]>0)
[resultString appendString:#"&"];
[resultString appendFormat:#"%#=%#", key, [sampleDictionary objectForKey:key]];
}
NSLog(#"QueryString: %#", resultString);
Hope will help :)
If you are already using AFNetwork, you can use their built in serializer to to produce an encoded URL;
NSString *baseURL = #"https://api.app.com/parse";
NSDictionary *mutableParameters = [[NSMutableDictionary alloc] initWithObjectsAndKeys:#"true",#"option1", data, #"option2", token, #"token", #"3.0", #"app", nil];
NSURLRequest *request = [[AFHTTPRequestSerializer serializer] requestWithMethod:#"GET" URLString:baseURL parameters:mutableParameters error:nil];
NSString *urlPath = request.URL.absoluteString;
NSLog(#"%#", urlPath); // https://api.app.com/parse?option1=true&option2=datavalue&token=200%3ATEST%3AENCODE ....
Note; this is an extension to an above answer. The edit queue is full so cannot be added to the existing answer.
Thanks to a lot of help I've received here on SO, I've gotten an algorithm to check a list of around 15,000 8-letter words for any partial anagrams, against a list of around 50,000 total words (so I suppose a total of 108 million iterations). I call this method once for each comparison (so 750 million times). I'm getting the following error, always somewhere in the midst of the 119th iteration through the 1,350 there should be:
AnagramFINAL(2960,0xac8c7a28) malloc: *** mmap(size=2097152) failed (error code=12)
*** error: can't allocate region
*** set a breakpoint in malloc_error_break to debug
I've narrowed the memory issue down to being a huge number of allocated CFStrings (immutable). Any idea what I can do to remedy the issue? I'm using ARC and an #autoreleasepool, not sure what else I could do, it seems something isn't being released when it should be.
AnagramDetector.h
#import <Foundation/Foundation.h>
#interface AnagramDetector : NSObject {
NSDictionary *allEightLetterWords;
NSDictionary *allWords;
NSFileManager *fileManager;
NSArray *paths;
NSString *documentsDirectory;
NSString *filePath;
}
- (BOOL) does: (NSString *) longWord contain: (NSString *) shortWord;
- (NSDictionary *) setupAllWordList;
- (NSDictionary *) setupEightLetterWordList;
- (void) saveDictionary: (NSMutableDictionary *)currentArray;
#end
AnagramDetector.m
#implementation AnagramDetector
- (id) init {
self = [super init];
if (self) {
fileManager = [NSFileManager defaultManager];
paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
documentsDirectory = [paths objectAtIndex:0];
}
return self;
}
- (BOOL) does: (NSString *) longWord contain: (NSString *) shortWord {
#autoreleasepool {
NSMutableString *longerWord = [longWord mutableCopy];
for (int i = 0; i < [shortWord length]; i++) {
NSString *letter = [shortWord substringWithRange: NSMakeRange(i, 1)];
NSRange letterRange = [longerWord rangeOfString: letter];
if (letterRange.location != NSNotFound) {
[longerWord deleteCharactersInRange: letterRange];
} else {
return NO;
}
}
return YES;
}
}
- (NSDictionary *) setupAllWordList {
#autoreleasepool {
NSString *fileWithAllWords = [[NSBundle mainBundle] pathForResource:#"AllDefinedWords" ofType:#"plist"];
allWords = [[NSDictionary alloc] initWithContentsOfFile: fileWithAllWords];
NSLog(#"Total number of words: %d.", [allWords count]);
}
return allWords;
}
- (NSDictionary *) setupEightLetterWordList {
#autoreleasepool {
NSString *fileWithEightWords = [[NSBundle mainBundle] pathForResource:#"AllDefinedEights" ofType:#"plist"];
allEightLetterWords = [[NSDictionary alloc] initWithContentsOfFile: fileWithEightWords];
NSLog(#"Total number of words: %d.", [allEightLetterWords count]);
}
return allEightLetterWords;
}
- (void) saveDictionary: (NSMutableDictionary *)currentArray {
#autoreleasepool {
filePath = [documentsDirectory stringByAppendingPathComponent: #"A.plist"];
[fileManager createFileAtPath:filePath contents: nil attributes: nil];
[currentArray writeToFile: filePath atomically:YES];
[currentArray removeAllObjects];
}
}
#end
Code running on launch (inside AppDelegate for now, since no VC):
#autoreleasepool {
AnagramDetector *detector = [[AnagramDetector alloc] init];
NSDictionary *allWords = [[NSDictionary alloc] initWithDictionary:[detector setupAllWordList]];
NSDictionary *eightWords = [[NSDictionary alloc] initWithDictionary:[detector setupEightLetterWordList]];
int remaining = [eightWords count];
for (NSString *currentEightWord in eightWords) {
if (remaining % 10 == 0) NSLog(#"%d ::: REMAINING :::", remaining);
for (NSString *currentAllWord in allWords) {
if ([detector does: [eightWords objectForKey: currentEightWord] contain: [allWords objectForKey: currentAllWord]]) {
// NSLog(#"%# ::: CONTAINS ::: %#", [eightWords objectForKey: currentEightWord], [allWords objectForKey: currentAllWord]);
}
}
remaining--;
}
}
The problem seems to be that a lot of autoreleased objects fill up the memory waiting to be released. So a solution is to add your own autorelease pool scope to collect autoreleased objects and release them sooner.
I suggest that you do something like this:
for (NSString *currentEightLetterWord in [eightLetterWordsDictionary allKeys]) {
#autoreleasepool {
for (NSString *currentWord in [allWordsDictionary allKeys]) {
}
}
}
Now all autoreleased objects inside #autoreleasepool { .. } will be released for each iteration of the outer loop.
As you see ARC might save you from thinking about most reference counting and memory management issues but objects can still end up in autorelease pools with ARC when using methods that directly or indirectly create autoreleased objects.
An alternative solution that I don't really recommend is to try to avoid using method that will use autorelease. Then does:contain: could awkwardly be rewritten to something like this:
- (BOOL) does: (NSString* ) longWord contain: (NSString *) shortWord {
NSMutableString *haystack = [longWord mutableCopy];
NSMutableString *needle = [shortWord mutableCopy];
while([haystack length] > 0 && [needle length] > 0) {
NSMutableCharacterSet *set = [[NSMutableCharacterSet alloc] init];
[set addCharactersInRange:NSMakeRange([needle characterAtIndex:0], 1)];
if ([haystack rangeOfCharacterFromSet:set].location == NSNotFound) return NO;
haystack = [haystack mutableCopy];
[haystack deleteCharactersInRange:NSMakeRange(0, [haystack rangeOfCharacterFromSet: set].location)];
needle = [needle mutableCopy];
[needle deleteCharactersInRange:NSMakeRange(0, 1)];
}
return YES;
}
I'm still trying to wrap my head around how things should be done in the object-oriented world and I think my problem is that I don't understand how to best utilize encapsulation. Specifically, I have lots of small bits of code that I use in several classes in my project. For example:
+ (NSString *)getFormattedDate;
+ (NSString *)getResultsFilePath;
+ (NSError *)removeFileFromCache:(NSString *)fileName;
These are all 3-5 line methods that I use in more than one class. My standard practice has been to put these snippets into a Utility.inc file and call them when I need them. Is that appropriate in the object-oriented world or should each class be self-contained? And if it's appropriate, would you put the code into a singleton or just a regular class file and [[Utilities alloc] init] in each class where you want to use the methods?
Look into using Categories. For the examples you gave, these are methods related to objects of a particular class that happen to be used in several of your own classes. Categories will allow you to park these often used methods where they can be associated with the common factors.
Create a utitity singelton which will be created only ones and then used by the other classes.
Thanks for the answers. I'm not sure that this the right way to do things, but this is what I've done on the projects I just submitted.
I made two classes, one for Utility methods and one for globals. The methods in the Utilities class are all class methods since they operate on files and constants or globals. Then I made a singleton for global variables. I have all of my global constants in the .pch file. Also in the .pch file I put the following two lines of code so that the utilities and globals are available everywhere.
// File for utilities like file delete, find Documents file
#import "Utilities.h"
#import "Globals.h"
Accessing the methods is straightforward. Here's an example of a call to both methods to generate an HTML header for an email.
NSString *gameNameHeader = [NSString stringWithFormat:#"<p> </p><h1>%# Results</h1><h2>%#%#</h2>",GAME_NAME_TITLE,[Utilities formattedClientName], [Utilities formattedDate]];
In case anyone can use it, here is my current version of the code. (Sorry for the formatting-I can't seem to get the wiki to cooperate.)
#interface Utilities : NSObject {
}
+ (NSString *)formattedDate;
+ (NSString *)formattedClientName;
+ (NSString *)cachedResultsFilePath;
+ (NSString *)cachedResultsFileContents;
+ (NSString *)resultsFileName;
+ (NSError *)removeFileFromCache:(NSString *)fileName;
+ (NSString *)applicationCachesDirectory;
+ (NSString *)applicationDocumentsDirectory;
+ (NSString *)applicationLibraryDirectory;
+ (NSError *)copyCachedResultsToFile;
#end
#import "Utilities.h"
#implementation Utilities {
}
+ (NSString *)formattedDate {
NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy-MM-dd"];
NSString *todaysDate = [dateFormatter stringFromDate:[NSDate date]];
return todaysDate;
}
+ (NSString *)formattedClientName {
NSString *client = [NSString stringWithFormat:#" "];
if( [Globals sharedInstance].currentClient ) client = [NSString stringWithFormat:#" %# ",[Globals sharedInstance].currentClient];
return client;
}
+ (NSString *)cachedResultsFilePath {
NSString *resultsFilePath = [[self applicationCachesDirectory] stringByAppendingPathComponent:#"Results.txt"];
return resultsFilePath;
}
+ (NSString *)cachedResultsFileContents {
NSStringEncoding encoding; NSError* error = nil;
NSString *resultsText = [NSString stringWithContentsOfFile:[self cachedResultsFilePath] usedEncoding:&encoding error:&error];
return resultsText;
}
+ (NSString *)resultsFileName {
return [NSString stringWithFormat:#"%# Results%#%#.html",GAME_NAME_TITLE,[self formattedClientName],[self formattedDate] ];
}
+ (NSError *)removeFileFromCache:(NSString *)fileName {
NSError *error = nil;
NSFileManager *localFileManager=[[NSFileManager alloc] init];
NSString *fullPath = [NSString stringWithFormat:#"%#/%#", [self applicationCachesDirectory],fileName];
[localFileManager removeItemAtPath: fullPath error:&error ];
return error;
}
+ (NSString *)applicationCachesDirectory {
return [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
}
+ (NSString *)applicationDocumentsDirectory {
return [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
}
+ (NSString *)applicationLibraryDirectory {
return [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) lastObject];
}
+ (NSError *)copyCachedResultsToFile {
// Grab the header and footer and put it around the cached data
NSStringEncoding encoding; NSError *error = nil;
NSString *htmlHeaderTextPath = [[NSBundle mainBundle] pathForResource:#"HTML_header" ofType:#"html" ];
NSString *htmlHeaderText = [NSString stringWithContentsOfFile:htmlHeaderTextPath usedEncoding:&encoding error:&error];
NSString *cachedResultsText = [NSString stringWithContentsOfFile:[self cachedResultsFilePath] usedEncoding:&encoding error:&error];
// Write the results to a file if there are any
if (cachedResultsText) {
NSString *htmlFooterTextPath = [[NSBundle mainBundle] pathForResource:#"HTML_footer" ofType:#"html" ];
NSString *htmlFooterText = [NSString stringWithContentsOfFile:htmlFooterTextPath usedEncoding:&encoding error:&error];
NSString *gameNameHeader = [NSString stringWithFormat:#"<h1>%# Results for%#%#</h1>",GAME_NAME_TITLE,[self formattedClientName],[self formattedDate] ];
NSString *tempStringP1 = [htmlHeaderText stringByAppendingString:gameNameHeader];
NSString *tempStringP2 = [tempStringP1 stringByAppendingString:cachedResultsText];
NSString *formattedTextForPrinting = [tempStringP2 stringByAppendingString:htmlFooterText];
NSString *resultsFilePath = [ [Utilities applicationDocumentsDirectory] stringByAppendingPathComponent:[self resultsFileName] ];
if ( !([[NSFileManager defaultManager] fileExistsAtPath:resultsFilePath]) ) {
if (! ([[NSFileManager defaultManager] createFileAtPath:resultsFilePath contents:nil attributes:nil]) ) {
NSLog(#"Error was code: %d - message: %s", errno, strerror(errno));
}
}
NSFileHandle *fileHandler = [NSFileHandle fileHandleForUpdatingAtPath:resultsFilePath];
[fileHandler writeData:[formattedTextForPrinting dataUsingEncoding:NSUTF8StringEncoding]];
[fileHandler closeFile];
}
return error;
}
#end
Globals in a singleton. Probably not thread-safe, but I don't care right now.
#interface Globals : NSObject {
}
#property (nonatomic, strong) NSString *currentClient;
#property (nonatomic, strong) NSString *showmePict;
#property BOOL checkBoxes;
+ (Globals *)sharedInstance;
- (void)resetClient;
#end
#implementation Globals {
}
static Globals *singleton = nil;
#synthesize currentClient = _currentClient;
#synthesize showmePict = _showmePict;
#synthesize checkBoxes = _checkBoxes;
+(Globals *) sharedInstance {
NSLog (#"sharedInstance of Globals called.");
if (nil != singleton) return singleton;
static dispatch_once_t pred; // lock
dispatch_once(&pred, ^{ // this code is at most once
singleton = [[Globals alloc] init];
});
return singleton;
}
- (void)resetClient {
self.currentClient = nil;
}
#end
With all the URL-handling objects lying around in the standard Cocoa libraries (NSURL, NSMutableURL, NSMutableURLRequest, etc), I know I must be overlooking an easy way to programmatically compose a GET request.
Currently I'm manually appending "?" followed by name value pairs joined by "&", but all of my name and value pairs need to be manually encoded so NSMutableURLRequest doesn't fail entirely when it tries to connect to the URL.
This feels like something I should be able to use a pre-baked API for.... is there anything out of the box to append an NSDictionary of query parameters to an NSURL? Is there another way I should approach this?
Introduced in iOS8 and OS X 10.10 is NSURLQueryItem, which can be used to build queries. From the docs on NSURLQueryItem:
An NSURLQueryItem object represents a single name/value pair for an item in the query portion of a URL. You use query items with the queryItems property of an NSURLComponents object.
To create one use the designated initializer queryItemWithName:value: and then add them to NSURLComponents to generate an NSURL. For example:
NSURLComponents *components = [NSURLComponents componentsWithString:#"http://stackoverflow.com"];
NSURLQueryItem *search = [NSURLQueryItem queryItemWithName:#"q" value:#"ios"];
NSURLQueryItem *count = [NSURLQueryItem queryItemWithName:#"count" value:#"10"];
components.queryItems = #[ search, count ];
NSURL *url = components.URL; // http://stackoverflow.com?q=ios&count=10
Notice that the question mark and ampersand are automatically handled. Creating an NSURL from a dictionary of parameters is as simple as:
NSDictionary *queryDictionary = #{ #"q": #"ios", #"count": #"10" };
NSMutableArray *queryItems = [NSMutableArray array];
for (NSString *key in queryDictionary) {
[queryItems addObject:[NSURLQueryItem queryItemWithName:key value:queryDictionary[key]]];
}
components.queryItems = queryItems;
I've also written a blog post on how to build URLs with NSURLComponents and NSURLQueryItems.
You can create a category for NSDictionary to do this -- there isn't a standard way in the Cocoa library that I could find either. The code that I use looks like this:
// file "NSDictionary+UrlEncoding.h"
#import <cocoa/cocoa.h>
#interface NSDictionary (UrlEncoding)
-(NSString*) urlEncodedString;
#end
with this implementation:
// file "NSDictionary+UrlEncoding.m"
#import "NSDictionary+UrlEncoding.h"
// helper function: get the string form of any object
static NSString *toString(id object) {
return [NSString stringWithFormat: #"%#", object];
}
// helper function: get the url encoded string form of any object
static NSString *urlEncode(id object) {
NSString *string = toString(object);
return [string stringByAddingPercentEscapesUsingEncoding: NSUTF8StringEncoding];
}
#implementation NSDictionary (UrlEncoding)
-(NSString*) urlEncodedString {
NSMutableArray *parts = [NSMutableArray array];
for (id key in self) {
id value = [self objectForKey: key];
NSString *part = [NSString stringWithFormat: #"%#=%#", urlEncode(key), urlEncode(value)];
[parts addObject: part];
}
return [parts componentsJoinedByString: #"&"];
}
#end
I think the code's pretty straightforward, but I discuss it in some more detail at http://blog.ablepear.com/2008/12/urlencoding-category-for-nsdictionary.html.
I wanted to use Chris's answer, but it wasn't written for Automatic Reference Counting (ARC) so I updated it. I thought I'd paste my solution in case anyone else has this same issue. Note: replace self with the instance or class name where appropriate.
+(NSString*)urlEscapeString:(NSString *)unencodedString
{
CFStringRef originalStringRef = (__bridge_retained CFStringRef)unencodedString;
NSString *s = (__bridge_transfer NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,originalStringRef, NULL, (CFStringRef)#"!*'\"();:#&=+$,/?%#[]% ", kCFStringEncodingUTF8);
CFRelease(originalStringRef);
return s;
}
+(NSString*)addQueryStringToUrlString:(NSString *)urlString withDictionary:(NSDictionary *)dictionary
{
NSMutableString *urlWithQuerystring = [[NSMutableString alloc] initWithString:urlString];
for (id key in dictionary) {
NSString *keyString = [key description];
NSString *valueString = [[dictionary objectForKey:key] description];
if ([urlWithQuerystring rangeOfString:#"?"].location == NSNotFound) {
[urlWithQuerystring appendFormat:#"?%#=%#", [self urlEscapeString:keyString], [self urlEscapeString:valueString]];
} else {
[urlWithQuerystring appendFormat:#"&%#=%#", [self urlEscapeString:keyString], [self urlEscapeString:valueString]];
}
}
return urlWithQuerystring;
}
The other answers work great if the values are strings, however if the values are dictionaries or arrays then this code will handle that.
Its important to note that there is no standard way of passing an array/dictionary via the query string but PHP handles this output just fine
-(NSString *)serializeParams:(NSDictionary *)params {
/*
Convert an NSDictionary to a query string
*/
NSMutableArray* pairs = [NSMutableArray array];
for (NSString* key in [params keyEnumerator]) {
id value = [params objectForKey:key];
if ([value isKindOfClass:[NSDictionary class]]) {
for (NSString *subKey in value) {
NSString* escaped_value = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
(CFStringRef)[value objectForKey:subKey],
NULL,
(CFStringRef)#"!*'();:#&=+$,/?%#[]",
kCFStringEncodingUTF8);
[pairs addObject:[NSString stringWithFormat:#"%#[%#]=%#", key, subKey, escaped_value]];
}
} else if ([value isKindOfClass:[NSArray class]]) {
for (NSString *subValue in value) {
NSString* escaped_value = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
(CFStringRef)subValue,
NULL,
(CFStringRef)#"!*'();:#&=+$,/?%#[]",
kCFStringEncodingUTF8);
[pairs addObject:[NSString stringWithFormat:#"%#[]=%#", key, escaped_value]];
}
} else {
NSString* escaped_value = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
(CFStringRef)[params objectForKey:key],
NULL,
(CFStringRef)#"!*'();:#&=+$,/?%#[]",
kCFStringEncodingUTF8);
[pairs addObject:[NSString stringWithFormat:#"%#=%#", key, escaped_value]];
[escaped_value release];
}
}
return [pairs componentsJoinedByString:#"&"];
}
Examples
[foo] => bar
[translations] =>
{
[one] => uno
[two] => dos
[three] => tres
}
foo=bar&translations[one]=uno&translations[two]=dos&translations[three]=tres
[foo] => bar
[translations] =>
{
uno
dos
tres
}
foo=bar&translations[]=uno&translations[]=dos&translations[]=tres
I refactored and converted to ARC answer by AlBeebe
- (NSString *)serializeParams:(NSDictionary *)params {
NSMutableArray *pairs = NSMutableArray.array;
for (NSString *key in params.keyEnumerator) {
id value = params[key];
if ([value isKindOfClass:[NSDictionary class]])
for (NSString *subKey in value)
[pairs addObject:[NSString stringWithFormat:#"%#[%#]=%#", key, subKey, [self escapeValueForURLParameter:[value objectForKey:subKey]]]];
else if ([value isKindOfClass:[NSArray class]])
for (NSString *subValue in value)
[pairs addObject:[NSString stringWithFormat:#"%#[]=%#", key, [self escapeValueForURLParameter:subValue]]];
else
[pairs addObject:[NSString stringWithFormat:#"%#=%#", key, [self escapeValueForURLParameter:value]]];
}
return [pairs componentsJoinedByString:#"&"];
}
- (NSString *)escapeValueForURLParameter:(NSString *)valueToEscape {
return (__bridge_transfer NSString *) CFURLCreateStringByAddingPercentEscapes(NULL, (__bridge CFStringRef) valueToEscape,
NULL, (CFStringRef) #"!*'();:#&=+$,/?%#[]", kCFStringEncodingUTF8);
}
If you are already using AFNetworking (as was the case with me), you can use it's class AFHTTPRequestSerializer to create the required NSURLRequest.
[[AFHTTPRequestSerializer serializer] requestWithMethod:#"GET" URLString:#"YOUR_URL" parameters:#{PARAMS} error:nil];
In case you only require the URL for your work, use NSURLRequest.URL.
Here is a simple example in Swift (iOS8+):
private let kSNStockInfoFetchRequestPath: String = "http://dev.markitondemand.com/Api/v2/Quote/json"
private func SNStockInfoFetchRequestURL(symbol:String) -> NSURL? {
if let components = NSURLComponents(string:kSNStockInfoFetchRequestPath) {
components.queryItems = [NSURLQueryItem(name:"symbol", value:symbol)]
return components.URL
}
return nil
}
I took Joel's recommendation of using URLQueryItems and turned into a Swift Extension (Swift 3)
extension URL
{
/// Creates an NSURL with url-encoded parameters.
init?(string : String, parameters : [String : String])
{
guard var components = URLComponents(string: string) else { return nil }
components.queryItems = parameters.map { return URLQueryItem(name: $0, value: $1) }
guard let url = components.url else { return nil }
// Kinda redundant, but we need to call init.
self.init(string: url.absoluteString)
}
}
(The self.init method is kinda cheesy, but there was no NSURL init with components)
Can be used as
URL(string: "http://www.google.com/", parameters: ["q" : "search me"])
I've got another solution:
http://splinter.com.au/build-a-url-query-string-in-obj-c-from-a-dict
+(NSString*)urlEscape:(NSString *)unencodedString {
NSString *s = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
(CFStringRef)unencodedString,
NULL,
(CFStringRef)#"!*'\"();:#&=+$,/?%#[]% ",
kCFStringEncodingUTF8);
return [s autorelease]; // Due to the 'create rule' we own the above and must autorelease it
}
// Put a query string onto the end of a url
+(NSString*)addQueryStringToUrl:(NSString *)url params:(NSDictionary *)params {
NSMutableString *urlWithQuerystring = [[[NSMutableString alloc] initWithString:url] autorelease];
// Convert the params into a query string
if (params) {
for(id key in params) {
NSString *sKey = [key description];
NSString *sVal = [[params objectForKey:key] description];
// Do we need to add ?k=v or &k=v ?
if ([urlWithQuerystring rangeOfString:#"?"].location==NSNotFound) {
[urlWithQuerystring appendFormat:#"?%#=%#", [Http urlEscape:sKey], [Http urlEscape:sVal]];
} else {
[urlWithQuerystring appendFormat:#"&%#=%#", [Http urlEscape:sKey], [Http urlEscape:sVal]];
}
}
}
return urlWithQuerystring;
}
You can then use it like so:
NSDictionary *params = #{#"username":#"jim", #"password":#"abc123"};
NSString *urlWithQuerystring = [self addQueryStringToUrl:#"https://myapp.com/login" params:params];
-(NSString*)encodeDictionary:(NSDictionary*)dictionary{
NSMutableString *bodyData = [[NSMutableString alloc]init];
int i = 0;
for (NSString *key in dictionary.allKeys) {
i++;
[bodyData appendFormat:#"%#=",key];
NSString *value = [dictionary valueForKey:key];
NSString *newString = [value stringByReplacingOccurrencesOfString:#" " withString:#"+"];
[bodyData appendString:newString];
if (i < dictionary.allKeys.count) {
[bodyData appendString:#"&"];
}
}
return bodyData;
}
Yet another solution, if you use RestKit there's a function in RKURLEncodedSerialization called RKURLEncodedStringFromDictionaryWithEncoding that does exactly what you want.
Simple way of converting NSDictionary to url query string in Objective-c
Ex: first_name=Steve&middle_name=Gates&last_name=Jobs&address=Palo Alto, California
NSDictionary *sampleDictionary = #{#"first_name" : #"Steve",
#"middle_name" : #"Gates",
#"last_name" : #"Jobs",
#"address" : #"Palo Alto, California"};
NSMutableString *resultString = [NSMutableString string];
for (NSString* key in [sampleDictionary allKeys]){
if ([resultString length]>0)
[resultString appendString:#"&"];
[resultString appendFormat:#"%#=%#", key, [sampleDictionary objectForKey:key]];
}
NSLog(#"QueryString: %#", resultString);
Hope will help :)
If you are already using AFNetwork, you can use their built in serializer to to produce an encoded URL;
NSString *baseURL = #"https://api.app.com/parse";
NSDictionary *mutableParameters = [[NSMutableDictionary alloc] initWithObjectsAndKeys:#"true",#"option1", data, #"option2", token, #"token", #"3.0", #"app", nil];
NSURLRequest *request = [[AFHTTPRequestSerializer serializer] requestWithMethod:#"GET" URLString:baseURL parameters:mutableParameters error:nil];
NSString *urlPath = request.URL.absoluteString;
NSLog(#"%#", urlPath); // https://api.app.com/parse?option1=true&option2=datavalue&token=200%3ATEST%3AENCODE ....
Note; this is an extension to an above answer. The edit queue is full so cannot be added to the existing answer.