Question

In order to obtain URL, I usually follow this way.

    NSString *userText = urlText.text;
    NSURL *url = [NSURL URLWithString:userText];

Of coursely, urlText is linked with UITextField.

However, Recently, I saw this code in audioStreaming program.
(This is the program.)

NSString *escapedValue =
    [(NSString *)CFURLCreateStringByAddingPercentEscapes(nil, (CFStringRef)downloadSourceField.text, NULL, NULL, 
                                                         kCFStringEncodingUTF8) autorelease];
NSURL *url = [NSURL URLWithString:escapedValue];

downloadSourceField is linked with UITextField.

What is diffence between these two methodes?
When I replaced the second method (escapedValue = ~~~ ) with (escapedValue = downloadSourceField.text;), the program worked well.
Could you let me know what is difference?
And What is the best method to obtain URL for streaming?

Answer 1

The second method will percent-escape some characters which are typically not allowed in URLs. As an example, the space character is not allowed and will be encoded as %20. NSURL does not support passing a string containing a non-allowed character which has not been escaped to +URLWithString:, therefore passing the string through CFURLCreateStringByAddingPercentEscapes first will let you support such URLs.