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Decoding HTML Entities in Swift 4
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| // Swift 4 | |
| // Check out the history for contributions and acknowledgements. | |
| extension String { | |
| /// Returns a new string made by replacing all HTML character entity references with the corresponding character. | |
| /// | |
| /// - Returns: decoded string | |
| func decodingHTMLEntities() -> String { | |
| var result = String() | |
| var position = startIndex | |
| // Get the range to the next '&' | |
| while let ampRange = range(of: "&", range: position ..< endIndex) { | |
| result += self[position ..< ampRange.lowerBound] | |
| position = ampRange.lowerBound | |
| // Get the range to the next ';' | |
| if let semiRange = range(of: ";", range: position ..< endIndex ) { | |
| if let nextAmpRange = range(of: "&", range: index(position, offsetBy: 1) ..< endIndex ), | |
| nextAmpRange.upperBound < semiRange.upperBound { | |
| // We have an other "&" before the next ";", let's add it and step over. | |
| result += "&" | |
| position = index(ampRange.lowerBound, offsetBy: 1) | |
| } else { | |
| let entity = String(self[position ..< semiRange.upperBound]) | |
| if let decoded = decode(entity: entity) { | |
| // Add the decoded character. | |
| result.append(decoded) | |
| } else { | |
| // Character wasn't decoded, append the entry. | |
| result += entity | |
| } | |
| position = semiRange.upperBound | |
| } | |
| } else { | |
| // No remaining ';'. | |
| break | |
| } | |
| } | |
| // Add remaining characters. | |
| result += self[position ..< endIndex] | |
| return result | |
| } | |
| } | |
| private extension String { | |
| /// Convert the numeric value to the corresponding Unicode character | |
| /// e.g. | |
| /// decodeNumeric("64", 10) -> "@" | |
| /// decodeNumeric("20ac", 16) -> "€" | |
| /// | |
| /// - Parameters: | |
| /// - string: the string to decode | |
| /// - base: base value of the integer | |
| /// - Returns: the resulting character | |
| func decodeNumeric(string: String, base: Int32) -> Character? { | |
| let code = UInt32(strtoul(string, nil, base)) | |
| if let unicodeScalar = UnicodeScalar(code) { | |
| return Character(unicodeScalar) | |
| } | |
| return nil | |
| } | |
| /// Decode the HTML character entity to the corresponding | |
| /// Unicode character, return `nil` for invalid input. | |
| /// decode("@") -> "@" | |
| /// decode("€") -> "€" | |
| /// decode("<") -> "<" | |
| /// decode("&foo;") -> nil | |
| /// | |
| /// - Parameter entity: The entity reference | |
| /// - Returns: the resulting character | |
| func decode(entity: String) -> Character? { | |
| if let character = String.characterEntities[entity] { | |
| return character | |
| } else if entity.hasPrefix("&#x") || entity.hasPrefix("&#X") { | |
| let number = String(entity[entity.index(entity.startIndex, offsetBy: 3)...].dropLast()) | |
| return decodeNumeric(string: number, base: 16) | |
| } else if entity.hasPrefix("&#") { | |
| let number = String(entity[entity.index(entity.startIndex, offsetBy: 2)...].dropLast()) | |
| return decodeNumeric(string: number, base: 10) | |
| } else { | |
| return nil | |
| } | |
| } | |
| // Mapping from XML/HTML character entity reference to character | |
| static let characterEntities: [String: Character] = [ | |
| // Taken from http://en.wikipedia.org/wiki/List_of_XML_and_HTML_character_entity_references | |
| // Complete refrence here https://www.w3.org/TR/xml-entity-names/ | |
| """: "\u{0022}", | |
| "&": "\u{0026}", | |
| "'": "\u{0027}", | |
| "<": "\u{003C}", | |
| ">": "\u{003E}", | |
| " ": "\u{00A0}", | |
| "¡": "\u{00A1}", | |
| "¢": "\u{00A2}", | |
| "£": "\u{00A3}", | |
| "¤": "\u{00A4}", | |
| "¥": "\u{00A5}", | |
| "¦": "\u{00A6}", | |
| "§": "\u{00A7}", | |
| "¨": "\u{00A8}", | |
| "©": "\u{00A9}", | |
| "ª": "\u{00AA}", | |
| "«": "\u{00AB}", | |
| "¬": "\u{00AC}", | |
| "­": "\u{00AD}", | |
| "®": "\u{00AE}", | |
| "¯": "\u{00AF}", | |
| "°": "\u{00B0}", | |
| "±": "\u{00B1}", | |
| "²": "\u{00B2}", | |
| "³": "\u{00B3}", | |
| "´": "\u{00B4}", | |
| "µ": "\u{00B5}", | |
| "¶": "\u{00B6}", | |
| "·": "\u{00B7}", | |
| "¸": "\u{00B8}", | |
| "¹": "\u{00B9}", | |
| "º": "\u{00BA}", | |
| "»": "\u{00BB}", | |
| "¼": "\u{00BC}", | |
| "½": "\u{00BD}", | |
| "¾": "\u{00BE}", | |
| "¿": "\u{00BF}", | |
| "À": "\u{00C0}", | |
| "Á": "\u{00C1}", | |
| "Â": "\u{00C2}", | |
| "Ã": "\u{00C3}", | |
| "Ä": "\u{00C4}", | |
| "Å": "\u{00C5}", | |
| "Æ": "\u{00C6}", | |
| "Ç": "\u{00C7}", | |
| "È": "\u{00C8}", | |
| "É": "\u{00C9}", | |
| "Ê": "\u{00CA}", | |
| "Ë": "\u{00CB}", | |
| "Ì": "\u{00CC}", | |
| "Í": "\u{00CD}", | |
| "Î": "\u{00CE}", | |
| "Ï": "\u{00CF}", | |
| "Ð": "\u{00D0}", | |
| "Ñ": "\u{00D1}", | |
| "Ò": "\u{00D2}", | |
| "Ó": "\u{00D3}", | |
| "Ô": "\u{00D4}", | |
| "Õ": "\u{00D5}", | |
| "Ö": "\u{00D6}", | |
| "×": "\u{00D7}", | |
| "Ø": "\u{00D8}", | |
| "Ù": "\u{00D9}", | |
| "Ú": "\u{00DA}", | |
| "Û": "\u{00DB}", | |
| "Ü": "\u{00DC}", | |
| "Ý": "\u{00DD}", | |
| "Þ": "\u{00DE}", | |
| "ß": "\u{00DF}", | |
| "à": "\u{00E0}", | |
| "á": "\u{00E1}", | |
| "â": "\u{00E2}", | |
| "ã": "\u{00E3}", | |
| "ä": "\u{00E4}", | |
| "å": "\u{00E5}", | |
| "æ": "\u{00E6}", | |
| "ç": "\u{00E7}", | |
| "è": "\u{00E8}", | |
| "é": "\u{00E9}", | |
| "ê": "\u{00EA}", | |
| "ë": "\u{00EB}", | |
| "ì": "\u{00EC}", | |
| "í": "\u{00ED}", | |
| "î": "\u{00EE}", | |
| "ï": "\u{00EF}", | |
| "ð": "\u{00F0}", | |
| "ñ": "\u{00F1}", | |
| "ò": "\u{00F2}", | |
| "ó": "\u{00F3}", | |
| "ô": "\u{00F4}", | |
| "õ": "\u{00F5}", | |
| "ö": "\u{00F6}", | |
| "÷": "\u{00F7}", | |
| "ø": "\u{00F8}", | |
| "ù": "\u{00F9}", | |
| "ú": "\u{00FA}", | |
| "û": "\u{00FB}", | |
| "ü": "\u{00FC}", | |
| "ý": "\u{00FD}", | |
| "þ": "\u{00FE}", | |
| "ÿ": "\u{00FF}", | |
| "Œ": "\u{0152}", | |
| "œ": "\u{0153}", | |
| "Š": "\u{0160}", | |
| "š": "\u{0161}", | |
| "Ÿ": "\u{0178}", | |
| "ƒ": "\u{0192}", | |
| "ˆ": "\u{02C6}", | |
| "˜": "\u{02DC}", | |
| "Α": "\u{0391}", | |
| "Β": "\u{0392}", | |
| "Γ": "\u{0393}", | |
| "Δ": "\u{0394}", | |
| "Ε": "\u{0395}", | |
| "Ζ": "\u{0396}", | |
| "Η": "\u{0397}", | |
| "Θ": "\u{0398}", | |
| "Ι": "\u{0399}", | |
| "Κ": "\u{039A}", | |
| "Λ": "\u{039B}", | |
| "Μ": "\u{039C}", | |
| "Ν": "\u{039D}", | |
| "Ξ": "\u{039E}", | |
| "Ο": "\u{039F}", | |
| "Π": "\u{03A0}", | |
| "Ρ": "\u{03A1}", | |
| "Σ": "\u{03A3}", | |
| "Τ": "\u{03A4}", | |
| "Υ": "\u{03A5}", | |
| "Φ": "\u{03A6}", | |
| "Χ": "\u{03A7}", | |
| "Ψ": "\u{03A8}", | |
| "Ω": "\u{03A9}", | |
| "α": "\u{03B1}", | |
| "β": "\u{03B2}", | |
| "γ": "\u{03B3}", | |
| "δ": "\u{03B4}", | |
| "ε": "\u{03B5}", | |
| "ζ": "\u{03B6}", | |
| "η": "\u{03B7}", | |
| "θ": "\u{03B8}", | |
| "ι": "\u{03B9}", | |
| "κ": "\u{03BA}", | |
| "λ": "\u{03BB}", | |
| "μ": "\u{03BC}", | |
| "ν": "\u{03BD}", | |
| "ξ": "\u{03BE}", | |
| "ο": "\u{03BF}", | |
| "π": "\u{03C0}", | |
| "ρ": "\u{03C1}", | |
| "ς": "\u{03C2}", | |
| "σ": "\u{03C3}", | |
| "τ": "\u{03C4}", | |
| "υ": "\u{03C5}", | |
| "φ": "\u{03C6}", | |
| "χ": "\u{03C7}", | |
| "ψ": "\u{03C8}", | |
| "ω": "\u{03C9}", | |
| "ϑ": "\u{03D1}", | |
| "ϒ": "\u{03D2}", | |
| "ϖ": "\u{03D6}", | |
| " ": "\u{2002}", | |
| " ": "\u{2003}", | |
| " ": "\u{2009}", | |
| "‌": "\u{200C}", | |
| "‍": "\u{200D}", | |
| "‎": "\u{200E}", | |
| "‏": "\u{200F}", | |
| "–": "\u{2013}", | |
| "—": "\u{2014}", | |
| "‘": "\u{2018}", | |
| "’": "\u{2019}", | |
| "‚": "\u{201A}", | |
| "“": "\u{201C}", | |
| "”": "\u{201D}", | |
| "„": "\u{201E}", | |
| "†": "\u{2020}", | |
| "‡": "\u{2021}", | |
| "•": "\u{2022}", | |
| "…": "\u{2026}", | |
| "‰": "\u{2030}", | |
| "′": "\u{2032}", | |
| "″": "\u{2033}", | |
| "‹": "\u{2039}", | |
| "›": "\u{203A}", | |
| "‾": "\u{203E}", | |
| "⁄": "\u{2044}", | |
| "€": "\u{20AC}", | |
| "ℑ": "\u{2111}", | |
| "℘": "\u{2118}", | |
| "ℜ": "\u{211C}", | |
| "™": "\u{2122}", | |
| "ℵ": "\u{2135}", | |
| "←": "\u{2190}", | |
| "↑": "\u{2191}", | |
| "→": "\u{2192}", | |
| "↓": "\u{2193}", | |
| "↔": "\u{2194}", | |
| "↵": "\u{21B5}", | |
| "⇐": "\u{21D0}", | |
| "⇑": "\u{21D1}", | |
| "⇒": "\u{21D2}", | |
| "⇓": "\u{21D3}", | |
| "⇔": "\u{21D4}", | |
| "∀": "\u{2200}", | |
| "∂": "\u{2202}", | |
| "∃": "\u{2203}", | |
| "∅": "\u{2205}", | |
| "∇": "\u{2207}", | |
| "∈": "\u{2208}", | |
| "∉": "\u{2209}", | |
| "∋": "\u{220B}", | |
| "∏": "\u{220F}", | |
| "∑": "\u{2211}", | |
| "−": "\u{2212}", | |
| "∗": "\u{2217}", | |
| "√": "\u{221A}", | |
| "∝": "\u{221D}", | |
| "∞": "\u{221E}", | |
| "∠": "\u{2220}", | |
| "∧": "\u{2227}", | |
| "∨": "\u{2228}", | |
| "∩": "\u{2229}", | |
| "∪": "\u{222A}", | |
| "∫": "\u{222B}", | |
| "∴": "\u{2234}", | |
| "∼": "\u{223C}", | |
| "≅": "\u{2245}", | |
| "≈": "\u{2248}", | |
| "≠": "\u{2260}", | |
| "≡": "\u{2261}", | |
| "≤": "\u{2264}", | |
| "≥": "\u{2265}", | |
| "⊂": "\u{2282}", | |
| "⊃": "\u{2283}", | |
| "⊄": "\u{2284}", | |
| "⊆": "\u{2286}", | |
| "⊇": "\u{2287}", | |
| "⊕": "\u{2295}", | |
| "⊗": "\u{2297}", | |
| "⊥": "\u{22A5}", | |
| "⋅": "\u{22C5}", | |
| "⌈": "\u{2308}", | |
| "⌉": "\u{2309}", | |
| "⌊": "\u{230A}", | |
| "⌋": "\u{230B}", | |
| "⟨": "\u{2329}", | |
| "⟩": "\u{232A}", | |
| "◊": "\u{25CA}", | |
| "♠": "\u{2660}", | |
| "♣": "\u{2663}", | |
| "♥": "\u{2665}", | |
| "♦": "\u{2666}", | |
| // Special cases from Windows-1252. https://en.wikipedia.org/wiki/Windows-1252 | |
| "€": "\u{20AC}", | |
| "‚": "\u{201A}", | |
| "ƒ": "\u{0192}", | |
| "„": "\u{201E}", | |
| "…": "\u{2026}", | |
| "†": "\u{2020}", | |
| "‡": "\u{2021}", | |
| "ˆ": "\u{02C6}", | |
| "Š": "\u{0160}", | |
| "‹": "\u{2039}", | |
| "Œ": "\u{0152}", | |
| "Ž": "\u{017D}", | |
| "‘": "\u{2018}", | |
| "’": "\u{2019}", | |
| "“": "\u{201C}", | |
| "”": "\u{201D}", | |
| "•": "\u{2022}", | |
| "–": "\u{2013}", | |
| "—": "\u{2014}", | |
| "˜": "\u{02DC}", | |
| "™": "\u{2122}", | |
| "š": "\u{0161}", | |
| "›": "\u{203A}", | |
| "œ": "\u{0153}", | |
| "ž": "\u{017E}", | |
| "Ÿ": "\u{0178}" | |
| ] | |
| } |
Great work, thanks!
Good one... thanks a lot for the Swift 4 version. Was literally scratching my head for hours.
Thanks a lot!!!
In Swift 4+ you can avoid the use of strtoul(), which is a C function, by changing decodeNumeric(string:base) to the following:
func decodeNumeric(string: String, base: Int) -> Character? {
if let code = UInt32(string, radix: base), let unicodeScalar = UnicodeScalar(code) {
return Character(unicodeScalar)
}
return nil
}
Hello guys,
I have a problem with "
". Everything works with "&#x" but not "
".
Please help me.
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Many changes and updates to the original approach. Swift 4 compatible.