Simon Says : How to really URL encode an NSString in Objective-C, iPhone, etc.

How to really URL encode an NSString in Objective-C, iPhone, etc.

Posted by Simon on April 22, 2009 at 02:52 AM

Categories: code, mac, iphone, objectivec

Trying to encode URL parameters on Mac or iPhone? Frustrated because NSString stringByAddingPercentEscapesUsingEncoding encodes non-URL characters but leaves the reserved characters (like slash / and ampersand &) alone? "Apparently" this is a "bug" apple is aware of, but they haven't done anything about it yet, and so, here is a solution that actually works.

Try this:

  NSString * encodedString = (NSString *)CFURLCreateStringByAddingPercentEscapes(
    NULL,
    (CFStringRef)unencodedString,
    NULL,
    (CFStringRef)@"!*'();:@&=+$,/?%#[]",
    kCFStringEncodingUTF8 );

As an example, @"'Decoded data!'/foo.bar:baz" will become "%27Decoded%20data%21%27%2Ffoo.bar%3Abaz".

Obviously you would use this, not on the full URL, but just on the parameters.

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Comments

There are 13 comments on this post. Post yours →

Rich

posted on May 02, 2009 at 09:30 PM

Ah, thanks for that! It's a shame you have to fall back on CF, but hopefully it'll get fixed in NSString at some point...

Danny

posted on May 08, 2009 at 07:35 PM

This is awesome, thanks.

Jmini

posted on May 12, 2009 at 09:43 AM

According to http://www.blooberry.com/indexdot/html/topics/urlencoding.htm and some other sources, I added some caracters in your list :

NSString * encodedString = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
                                                                               (CFStringRef)unencodedString,
                                                                               NULL,
                                                                               (CFStringRef)@"!*'\"();:@&=+$,/?%#[]% ",
                                                                               kCFStringEncodingUTF8 );

Jmini

posted on May 12, 2009 at 10:57 AM

I want to add that most of the server still work with the "Percent Escapes" Table of Latin1

PHP urlencode function still works so

For example : é -> %E9 (with PHP urlencode)

é -> %C3%A9 (with kCFStringEncodingUTF8 as last parameter) é -> %E9 (with kCFStringEncodingISOLatin1 as last parameter)

So I modify the given function, with this parameter

JLM

posted on May 28, 2009 at 02:25 PM

Simon. You RULE. Thanks for taking the time to give your insights.

Bye!

MagicYang

posted on June 11, 2009 at 11:30 PM

thx, but I test it with your example string @"'Decoded data!'/foo.bar:baz", the result is 471684ecoded 0ata2270.000000foo.bar-0X1.FE638A05E9CCP+0baz, is it right ?