Convierte una cadena atribuida a html etiquetado "simple"

Question

May 17, 2017, 04:26 PM

Convierte una cadena atribuida a html etiquetado "simple"

Quiero convertir un NSAttributedString, a html como este:

This is a <i>string</i> with some <b>simple</b> <i><b>html</b></i> tags in it.

Lamentablemente, si utiliza el sistema integrado de Apple, genera html detallado basado en CSS. (Ejemplo a continuación como referencia).

Entonces, ¿cómo generar html etiquetado simple a partir de una NSAttributedString?

Escribí un llamado muy detallado y frágil para hacerlo, lo cual es una mala solución.

func simpleTagStyle(fromNSAttributedString att: NSAttributedString)->String {

    // verbose, fragile solution

    // essentially, iterate all the attribute ranges in the attString
    // make a note of what style they are, bold italic etc
    // (totally ignore any not of interest to us)
    // then basically get the plain string, and munge it for those ranges.
    // be careful with the annoying "multiple attribute" case
    // (an alternative would be to repeatedly munge out attributed ranges
    // one by one until there are none left.)

    let rangeAll = NSRange(location: 0, length: att.length)

    // make a note of all of the ranges of bold/italic
    // (use a tuple to remember which is which)
    var allBlocks: [(NSRange, String)] = []

    att.enumerateAttribute(
        NSFontAttributeName,
        in: rangeAll,
        options: .longestEffectiveRangeNotRequired
        )
            { value, range, stop in

            handler: if let font = value as? UIFont {

                let b = font.fontDescriptor.symbolicTraits.contains(.traitBold)
                let i = font.fontDescriptor.symbolicTraits.contains(.traitItalic)

                if b && i {
                    allBlocks.append( (range, "bolditalic") )
                    break handler   // take care not to duplicate
                }

                if b {
                    allBlocks.append( (range, "bold") )
                    break handler
                }

                if i {
                    allBlocks.append( (range, "italic") )
                    break handler
                }
            }

        }

    // traverse those backwards and munge away

    var plainString = att.string

    for oneBlock in allBlocks.reversed() {

        let r = oneBlock.0.range(for: plainString)!

        let w = plainString.substring(with: r)

        if oneBlock.1 == "bolditalic" {
            plainString.replaceSubrange(r, with: "<b><i>" + w + "</i></b>")
        }

        if oneBlock.1 == "bold" {
            plainString.replaceSubrange(r, with: "<b>" + w + "</b>")
        }

        if oneBlock.1 == "italic" {
            plainString.replaceSubrange(r, with: "<i>" + w + "</i>")
        }

    }

    return plainString
}

Así que aquí está cómo usar el sistema integrado de Apple, que desafortunadamente genera CSS completo, etc.

x = ... your NSAttributedText
var resultHtmlText = ""
do {

    let r = NSRange(location: 0, length: x.length)
    let att = [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType]

    let d = try x.data(from: r, documentAttributes: att)

    if let h = String(data: d, encoding: .utf8) {
        resultHtmlText = h
    }
}
catch {
    print("utterly failed to convert to html!!! \n>\(x)<\n")
}
print(resultHtmlText)

Salida de ejemplo ...

<!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: 14.0px 'Some Font'}
span.s1 {font-family: 'SomeFont-ItalicOrWhatever'; font-weight: normal; font-style: normal; font-size: 14.00pt}
span.s2 {font-family: 'SomeFont-SemiboldItalic'; font-weight: bold; font-style: italic; font-size: 14.00pt}
</style>
</head>
<body>
<p class="p1"><span class="s1">So, </span><span class="s2">here is</span><span class="s1"> some</span> stuff</p>
</body>
</html>