Function to detect the NSStringEncoding from NSURL

问题:

I just wanted to know if there is any existing category or any sort of function that will return me NSStringEncoding constant out of NSURLResponse object .

The issue I am facing at the moment is as I have hardcoded the encoding to NSUTF8StringEncoding when I convert the web service response data to String then it actually causes an issue , as my web service sometimes returns the response encoded in UTF8 and sometimes encoded in ASCII ( well I am not too sure about all the encodings though but yes there are sometimes other languages characters in the response like Japanese , Chinese etc )

So My idea is to have a category on NSURLResponse that detects the encoding and returns eg .

 NSURLResponse * response = // NSURLResponse object ( web service response headers )
 NSData * responseData = // NSData object ( web service response data )
 NSStringEncoding encoding = [response stringEncodingUsed];
 NSString * responseText = [[NSString alloc]initWithData:responseData encoding:encoding];

回答1:

There is a better way.

You can get the encoding name from URLResponse as a string, then search for the appropriate NSStringEncoding.

NSString *encodingName = [aURLResponse textEncodingName];
NSStringEncoding encodingType = CFStringConvertEncodingToNSStringEncoding(CFStringConvertIANACharSetNameToEncoding((CFStringRef)encodingName));

Also encodingName might be nil and if there is no appropriate result for the provided encodingName the result value for the encodingType variable will not be valid.