json - 如何在 Swift 中解码 HTML 实体？

Question

我正在从网站中提取一个 JSON 文件，收到的字符串之一是:

The Weeknd ‘King Of The Fall’ [Video Premiere] | @TheWeeknd | #SoPhi

如何将 ‘ 之类的内容转换为正确的字符？

我制作了一个 Xcode Playground 来演示它:

import UIKit

var error: NSError?
let blogUrl: NSURL = NSURL.URLWithString("http://sophisticatedignorance.net/api/get_recent_summary/")
let jsonData = NSData(contentsOfURL: blogUrl)

let dataDictionary = NSJSONSerialization.JSONObjectWithData(jsonData, options: nil, error: &error) as NSDictionary

var a = dataDictionary["posts"] as NSArray

println(a[0]["title"])

Answer 1

此答案最后针对 Swift 5.2 和 iOS 13.4 SDK 进行了修订。

---

没有直接的方法可以做到这一点，但您可以使用 NSAttributedString 魔法使这个过程尽可能轻松(请注意，此方法也会去除所有 HTML 标记)。

记住仅从主线程初始化NSAttributedString。它使用 WebKit 来解析底层的 HTML，因此需要。

// This is a[0]["title"] in your case
let htmlEncodedString = "The Weeknd <em>&#8216;King Of The Fall&#8217;</em>"

guard let data = htmlEncodedString.data(using: .utf8) else {
    return
}

let options: [NSAttributedString.DocumentReadingOptionKey: Any] = [
    .documentType: NSAttributedString.DocumentType.html,
    .characterEncoding: String.Encoding.utf8.rawValue
]

guard let attributedString = try? NSAttributedString(data: data, options: options, documentAttributes: nil) else {
    return
}

// The Weeknd ‘King Of The Fall’
let decodedString = attributedString.string

extension String {

    init?(htmlEncodedString: String) {

        guard let data = htmlEncodedString.data(using: .utf8) else {
            return nil
        }

        let options: [NSAttributedString.DocumentReadingOptionKey: Any] = [
            .documentType: NSAttributedString.DocumentType.html,
            .characterEncoding: String.Encoding.utf8.rawValue
        ]

        guard let attributedString = try? NSAttributedString(data: data, options: options, documentAttributes: nil) else {
            return nil
        }

        self.init(attributedString.string)

    }

}

let encodedString = "The Weeknd <em>&#8216;King Of The Fall&#8217;</em>"
let decodedString = String(htmlEncodedString: encodedString)