如何将 base64String 转换为 Swift 中的字符串？

Question

我从 NSData 中的网络服务响应中接收到一个 base64String，如何将该 base64String 转换为 swift 中的字符串？

    //Code
    var jsonResult = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &err) as! NSDictionary  // Response JSON from webservice
    var base64String : String = ""
    base64String = jsonResult["Base64String"] as! String  // Retrieve base64String as string from json response
    println("Base64String Alone: \(base64String)")

// Code to decode that base64String
let decodedData = NSData(base64EncodedString: base64String, options: NSDataBase64DecodingOptions(rawValue: 0))
                                    println("Decoded:  \(decodedData)")
                                    let decodedString = NSString(data: decodedData!, encoding: NSUTF8StringEncoding)
                                    println(decodedString) // Prints nil

base64String 的编码和解码适用于仅包含文本的文件，如果文件包含一些 table formats/images，那么编码和解码都会给出无效的 base64String。如何将文件转换为 base64String 编码和解码文件的任何内容？文件格式为doc、docx、pdf、txt

预先感谢您的帮助！

Answer 1

试试这个

let base64Encoded = "YW55IGNhcm5hbCBwbGVhc3VyZS4="

let decodedData = Data(base64Encoded: base64Encoded)!
let decodedString = String(data: decodedData, encoding: .utf8)!

print(decodedString)

println(decodedString)

确保您的 base 64 编码字符串有效

Answer 2

Swift 扩展很方便。

extension String {
    func base64Encoded() -> String? {
        return data(using: .utf8)?.base64EncodedString()
    }

    func base64Decoded() -> String? {
        guard let data = Data(base64Encoded: self) else { return nil }
        return String(data: data, encoding: .utf8)
    }
}

"heroes".base64Encoded() // It will return: aGVyb2Vz
"aGVyb2Vz".base64Decoded() // It will return: heroes

Answer 3

我已经更新了 Ashok Kumar S 的回答以在字符串大小不能被 4 整除时添加填充字符，引发异常并返回 nil

extension String {
func base64Encoded() -> String? {
    return data(using: .utf8)?.base64EncodedString()
}

func base64Decoded() -> String? {
    var st = self;
    if (self.count % 4 <= 2){
        st += String(repeating: "=", count: (self.count % 4))
    }
    guard let data = Data(base64Encoded: st) else { return nil }
    return String(data: data, encoding: .utf8)
}

Answer 4

以上答案是核心，但我有一个错误，如

fatal error, found nil while unwrapping an optional value

解决方法是添加options

extension String {
//: ### Base64 encoding a string
    func base64Encoded() -> String? {
        if let data = self.data(using: .utf8) {
            return data.base64EncodedString()
        }
        return nil
    }

//: ### Base64 decoding a string
    func base64Decoded() -> String? {
        if let data = Data(base64Encoded: self, options: .ignoreUnknownCharacters) {
            return String(data: data, encoding: .utf8)
        }
        return nil
    }
}

并安全使用它

var str = "HelloWorld"
if let base64Str = str.base64Encoded() {
    print("Base64 encoded string: \"\(base64Str)\"")
    if let trs = base64Str.base64Decoded() {
        print("Base64 decoded string: \"\(trs)\"")
    }
}

Answer 5

您可以 encrypt/decrypt 使用此扩展名的 base64 字符串：

public extension String {


    var base64Decoded: String? {
        guard let decodedData = Data(base64Encoded: self) else { return nil }
        return String(data: decodedData, encoding: .utf8)
    }

    var base64Encoded: String? {
        let plainData = data(using: .utf8)
        return plainData?.base64EncodedString()
    }
}

要编码：

"Hello World!".base64Encoded

结果是可选字符串：“SGVsbG8gV29ybGQh”

解码：

"SGVsbG8gV29ybGQh".base64Decoded

结果是可选字符串：“Hello World!”

Source

如何将 base64String 转换为 Swift 中的字符串？

How to convert a base64String to String in Swift?

base64

swift