How to properly encode UTF-8 in iOS using NSMutableURLRequest? - ios

Question

I am trying to send information to a login web service but certain characters are giving me trouble.
For example, if the password is something like h+4hfP, the web service rejects it because the plus sign ('+') is not properly encoded to %2B.
The web service uses UTF-8 encoding so I have been building an NSData object with this NSString method, - (NSData *)dataUsingEncoding:(NSStringEncoding)encoding; choosing NSUTF8StringEncoding as the encoding.
This doesn't seem to be enough though.
The problem could also be with how I'm building an NSMutableURLRequest:
NSData *postData = [#"h+4hfP" dataUsingEncoding:NSUTF8StringEncoding];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:url]];
[request setHTTPMethod:#"POST"];
[request setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Content-Type"];
[request setValue:#"application/json" forHTTPHeaderField:#"Accept"];
[request setValue:contentLength forHTTPHeaderField:#"Content-Length"];
[request setHTTPBody:postData];
How can I ensure the encoding is done properly?

Answer 1

Use
[theRequest setValue:#"application/json; charset=UTF-8" forHTTPHeaderField:#"Content-Type"];

Answer 2

You could percent encode the string before representing it as NSData:
NSString *password = [#"h+4hfP" stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet alphanumericCharacterSet]];
NSData *postData = [password dataUsingEncoding:NSUTF8StringEncoding];
...

Answer 3

This can be a solution:
I was facing this problem. After some hours and search, I discovered this:
http://madebymany.com/blog/url-encoding-an-nsstring-on-ios
Solution:
1st: You must create a method or class with content:
-(NSString *)urlEncodeUsingEncoding:(NSStringEncoding)encoding withString:(NSString *) str{
return (NSString *)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(NULL,
(CFStringRef)str,
NULL,
(CFStringRef)#"!*'\"();:#&=+$,/?%#[]% ",
CFStringConvertNSStringEncodingToEncoding(encoding)));
}
2nd: Use:
NSString *stringToSend = [self urlEncodeUsingEncoding:NSUTF8StringEncoding withString:stringToBeVerifyed];
Then
NSData *postData = [stringToSend dataUsingEncoding:NSUTF8StringEncoding];
[...]