Swift NSAttributedString Trim

I want to get ride of the white spaces in front and at the end of my NSAttributedString(Trimming it). I can't simply convert it to string and do trimming because there are images(attachments) in it. How can i do it?

Create extension of NSAttributedString as below.

extension NSAttributedString {
     public func attributedStringByTrimmingCharacterSet(charSet: CharacterSet) -> NSAttributedString {
         let modifiedString = NSMutableAttributedString(attributedString: self)
        modifiedString.trimCharactersInSet(charSet: charSet)
         return NSAttributedString(attributedString: modifiedString)
     }
}

extension NSMutableAttributedString {
     public func trimCharactersInSet(charSet: CharacterSet) {
        var range = (string as NSString).rangeOfCharacter(from: charSet as CharacterSet)

         // Trim leading characters from character set.
         while range.length != 0 && range.location == 0 {
            replaceCharacters(in: range, with: "")
            range = (string as NSString).rangeOfCharacter(from: charSet)
         }

         // Trim trailing characters from character set.
        range = (string as NSString).rangeOfCharacter(from: charSet, options: .backwards)
         while range.length != 0 && NSMaxRange(range) == length {
            replaceCharacters(in: range, with: "")
            range = (string as NSString).rangeOfCharacter(from: charSet, options: .backwards)
         }
     }
}

and use in viewController where you want to use. like this

let attstring = NSAttributedString(string: "this is test message. Please wait.                   ")
let result = attstring.attributedStringByTrimmingCharacterSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())