How do you URL-encode the @ symbol in the iPhone SDK?

Question

Using stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding to URL-encode an NSString isn't encoding the @ symbol. What's the proper way to resolve this? Thanks.

Answer 1

Add this after the line of code you already have (and change the receiver, etc. to your own variables):

[escaped replaceOccurrencesOfString:@"@" withString:@"%40" options:NSCaseInsensitiveSearch range:wholeString];

If you want to make sure that everything is encoded, here is the best way:

NSMutableString *escaped = [actionString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];       
[escaped replaceOccurrencesOfString:@"&" withString:@"%26" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@"+" withString:@"%2B" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@"," withString:@"%2C" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@"/" withString:@"%2F" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@":" withString:@"%3A" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@";" withString:@"%3B" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@"=" withString:@"%3D" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@"?" withString:@"%3F" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@"@" withString:@"%40" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@" " withString:@"%20" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@"\t" withString:@"%09" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@"#" withString:@"%23" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@"<" withString:@"%3C" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@">" withString:@"%3E" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@"\"" withString:@"%22" options:NSCaseInsensitiveSearch range:wholeString];
[escaped replaceOccurrencesOfString:@"\n" withString:@"%0A" options:NSCaseInsensitiveSearch range:wholeString];

(from Roger @ http://stackoverflow.com/questions/705448/iphone-sdk-problem-with-ampersand-in-the-url-string)

Answer 2

The best way to URL encode is with this, from my blog post http://simonwoodside.com/weblog/2009/4/22/how_to_really_url_encode/ :

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