Convert NSAttributedString into Data for storage

Question

I have a UITextView with attributed text and allowsEditingTextAttributes set to true.

I'm trying to convert the attributed string into a Data object, using the following code:

let text = self.textView.attributedText
let data = try text.data(from: NSMakeRange(0, text.length), documentAttributes: [:])

However, this is throwing the following error:

Error Domain=NSCocoaErrorDomain Code=66062 "(null)"

Any ideas what this error means or what could cause this? I'm on the latest Xcode and iOS. Thanks.

Leo Dabus · Accepted Answer

You need to specify what kind of document data you would like to convert your attributed string to:

.txt    // Plain Text Document Type (Simple Text)
.html   // HTML  Text Document Type (Hypertext Markup Language) 
.rtf    // RTF   Text Document Type (Rich text format document)
.rtfd   // RTFD  Text Document Type (Rich text format document with attachment)

update Xcode 10.2 • Swift 5 or later

let textView = UITextView()
textView.attributedText = .init(string: "abc",
                                attributes: [.font: UIFont(name: "Helvetica", size: 16)!])
if let attributedText = textView.attributedText {
    do {
        let htmlData = try attributedText.data(from: .init(location: 0, length: attributedText.length),
                                               documentAttributes: [.documentType: NSAttributedString.DocumentType.html])
        let htmlString = String(data: htmlData, encoding: .utf8) ?? ""
        print(htmlString)
    } catch {
        print(error)
    }
}

Expanding on that:

extension NSAttributedString {

    convenience init(data: Data, documentType: DocumentType, encoding: String.Encoding = .utf8) throws {
        try self.init(attributedString: .init(data: data, options: [.documentType: documentType, .characterEncoding: encoding.rawValue], documentAttributes: nil))
    }

    func data(_ documentType: DocumentType) -> Data {
        // Discussion
        // Raises an rangeException if any part of range lies beyond the end of the receiver’s characters.
        // Therefore passing a valid range allow us to force unwrap the result
        try! data(from: .init(location: 0, length: length),
                  documentAttributes: [.documentType: documentType])
    }

    var text: Data { data(.plain) }
    var html: Data { data(.html)  }
    var rtf:  Data { data(.rtf)   }
    var rtfd: Data { data(.rtfd)  }
}

Usage:

let textView = UITextView()
textView.attributedText = .init(string: "abc", attributes: [.font: UIFont(name: "Helvetica", size: 16)!])
if let textData = textView.attributedText?.text {
    let text = String(data: textData, encoding: .utf8) ?? ""
    print(text)  // abc
}
if let htmlData = textView.attributedText?.html {
    let html = String(data: htmlData, encoding: .utf8) ?? ""
    print(html)  // /* <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" ...
}

This will print

abc
/* <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta http-equiv="Content-Style-Type" content="text/css">
<title></title>
<meta name="Generator" content="Cocoa HTML Writer">
<style type="text/css">
p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 16.0px Helvetica}
span.s1 {font-family: 'Helvetica'; font-weight: normal; font-style: normal; font-size: 16.00pt}
</style>
</head>
<body>
<p class="p1"><span class="s1">abc</span></p>
</body>
</html>
*/

Vikas Rajput · Answer

Please check it once this work for me. You can update font style and family also by using below functions.

 var htmlStr = "<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01//EN\" \"http://www.w3.org/TR/html4/strict.dtd\">
<html>
<head>
<meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\">
<meta http-equiv=\"Content-Style-Type\" content=\"text/css\">
<title></title>
<meta name=\"Generator\" content=\"Cocoa HTML Writer\">
<style type=\"text/css\">
p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; line-height: 22.0px; font: 17.0px \'Times New Roman\'; color: #000000; -webkit-text-stroke: #000000}
span.s1 {font-family: \'TimesNewRomanPS-BoldMT\'; font-weight: bold; font-style: normal; font-size: 17.00px; font-kerning: none}
span.s2 {font-family: \'Times New Roman\'; font-weight: normal; font-style: normal; font-size: 17.00px; text-decoration: underline ; font-kerning: none}
span.s3 {font-family: \'Times New Roman\'; font-weight: normal; font-style: normal; font-size: 17.00px; font-kerning: none}
</style>
</head>
<body>
<p class=\"p1\"><span class=\"s1\">This </span><span class=\"s2\">is</span><span class=\"s1\"> pikes</span><span class=\"s3\"> AsD this </span><span class=\"s1\">is</span><span class=\"s3\"> finding </span><span class=\"s2\">error</span></p>
</body>
</html>
"
    htmlStr = htmlStr.replacingOccurrences(of: "
", with: "")
    htmlStr = htmlStr.replacingOccurrences(of: "\", with: "")

//Send htmlStr to server and when you will get back it from
// then convert html string to attributed string by below line

    let str = Self.htmlToAttributedString(html: htmlStr,fontSize :17, fontName:"Times New Roman")
    self.tfEmail.attributedText = str


//Function for attributed string from html string
func htmlToAttributedString(html:String,fontSize:CGFloat = 15.0, fontName : String = "NunitoSans-Regular",ignorFontBold: Bool = false) -> NSAttributedString {
    let attr = (try? NSAttributedString(htmlString: html, font: UIFont(name: fontName, size: fontSize),ignorFontBold: ignorFontBold)) ?? NSAttributedString()
    return attr
}

//Extension for NSAttribute string
extension NSAttributedString {

convenience init(htmlString html: String, font: UIFont? = nil, useDocumentFontSize: Bool = false, ignorFontBold: Bool = false) throws {
    let options: [NSAttributedString.DocumentReadingOptionKey : Any] = [
        .documentType: NSAttributedString.DocumentType.html,
        .characterEncoding: String.Encoding.utf8.rawValue
    ]

    let data = html.data(using: .utf8, allowLossyConversion: true)
    guard (data != nil), let fontFamily = font?.familyName, let attr = try? NSMutableAttributedString(data: data!, options: options, documentAttributes: nil) else {
        try self.init(data: data ?? Data(html.utf8), options: options, documentAttributes: nil)
        return
    }

    let fontSize: CGFloat? = useDocumentFontSize ? nil : font!.pointSize
    let range = NSRange(location: 0, length: attr.length)
    attr.enumerateAttribute(.font, in: range, options: .longestEffectiveRangeNotRequired) { attrib, range, _ in
        if let htmlFont = attrib as? UIFont {
            let traits = htmlFont.fontDescriptor.symbolicTraits
            var descrip = htmlFont.fontDescriptor.withFamily(fontFamily)
            if ignorFontBold == false{
            if (traits.rawValue & UIFontDescriptor.SymbolicTraits.traitBold.rawValue) != 0 {
                descrip = descrip.withSymbolicTraits(.traitBold)!
            }

            if (traits.rawValue & UIFontDescriptor.SymbolicTraits.traitItalic.rawValue) != 0 {
                descrip = descrip.withSymbolicTraits(.traitItalic) ?? descrip
            }
            }
            attr.addAttribute(.font, value: UIFont(descriptor: descrip, size: fontSize ?? htmlFont.pointSize), range: range)
        }
    }

    self.init(attributedString: attr)
}

}

Convert NSAttributedString into Data for storage

Tags:

ios

swift

nsdata

nsattributedstring

Ruben Martinez Jr.

2 Answers

Leo Dabus

Vikas Rajput

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Convert NSAttributedString into Data for storage

Tags:

ios

swift

nsdata

nsattributedstring

Ruben Martinez Jr.

2 Answers

Leo Dabus

Vikas Rajput

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