如何在 Swift 中将字符串编码为 Base64？

Question

我想将字符串转换为 Base64。我在几个地方找到了答案，但它在 Swift 中不再起作用。我正在使用 Xcode 6.2。我相信答案可能适用于以前的 Xcode 版本，而不是 Xcode 6.2。

有人可以指导我在 Xcode 6.2 中执行此操作吗？

我找到的答案是这样的，但它在我的 Xcode 版本中不起作用：

var str = "iOS Developer Tips encoded in Base64"
println("Original: \(str)")

// UTF 8 str from original
// NSData! type returned (optional)
let utf8str = str.dataUsingEncoding(NSUTF8StringEncoding)

// Base64 encode UTF 8 string
// fromRaw(0) is equivalent to objc 'base64EncodedStringWithOptions:0'
// Notice the unwrapping given the NSData! optional
// NSString! returned (optional)
let base64Encoded = utf8str.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.fromRaw(0)!)
println("Encoded:  \(base64Encoded)")

// Base64 Decode (go back the other way)
// Notice the unwrapping given the NSString! optional
// NSData returned
let data = NSData(base64EncodedString: base64Encoded, options:   NSDataBase64DecodingOptions.fromRaw(0)!)

// Convert back to a string
let base64Decoded = NSString(data: data, encoding: NSUTF8StringEncoding)
println("Decoded:  \(base64Decoded)")

参考：http://iosdevelopertips.com/swift-code/base64-encode-decode-swift.html

Answer 1

斯威夫特

import Foundation

extension String {

    func fromBase64() -> String? {
        guard let data = Data(base64Encoded: self) else {
            return nil
        }

        return String(data: data, encoding: .utf8)
    }

    func toBase64() -> String {
        return Data(self.utf8).base64EncodedString()
    }

}

Answer 2

我没有安装 6.2，但我认为 6.3 在这方面没有什么不同：

dataUsingEncoding 返回一个可选的，所以你需要解开它。

NSDataBase64EncodingOptions.fromRaw 已替换为 NSDataBase64EncodingOptions(rawValue:)。有点令人惊讶的是，这不是一个可失败的初始化程序，因此您不需要解包它。

但是由于NSData(base64EncodedString:) 是一个可失败的初始化器，你需要解开它。

顺便说一句，所有这些更改都是由 Xcode 迁移器建议的（单击装订线中的错误消息，它有一个“修复它”的建议）。

为避免强制解包而重写的最终代码如下所示：

import Foundation

let str = "iOS Developer Tips encoded in Base64"
println("Original: \(str)")

let utf8str = str.dataUsingEncoding(NSUTF8StringEncoding)

if let base64Encoded = utf8str?.base64EncodedStringWithOptions(NSDataBase64EncodingOptions(rawValue: 0)) 
{

    println("Encoded:  \(base64Encoded)")

    if let base64Decoded = NSData(base64EncodedString: base64Encoded, options:   NSDataBase64DecodingOptions(rawValue: 0))
                          .map({ NSString(data: $0, encoding: NSUTF8StringEncoding) })
    {
        // Convert back to a string
        println("Decoded:  \(base64Decoded)")
    }
}

（如果使用 Swift 1.2，你可以使用多个 if-let 而不是 map）

Swift 5 更新：

import Foundation

let str = "iOS Developer Tips encoded in Base64"
print("Original: \(str)")

let utf8str = str.data(using: .utf8)

if let base64Encoded = utf8str?.base64EncodedString(options: Data.Base64EncodingOptions(rawValue: 0)) {
    print("Encoded: \(base64Encoded)")

    if let base64Decoded = Data(base64Encoded: base64Encoded, options: Data.Base64DecodingOptions(rawValue: 0))
    .map({ String(data: $0, encoding: .utf8) }) {
        // Convert back to a string
        print("Decoded: \(base64Decoded ?? "")")
    }
}

Answer 3

斯威夫特 4.2

"abcd1234".data(using: .utf8)?.base64EncodedString()

Answer 4

你可以做一个简单的扩展，比如：

import UIKit

// MARK: - Mixed string utils and helpers
extension String {


    /**
    Encode a String to Base64

    :returns: 
    */
    func toBase64()->String{

        let data = self.dataUsingEncoding(NSUTF8StringEncoding)

        return data!.base64EncodedStringWithOptions(NSDataBase64EncodingOptions(rawValue: 0))

    }

}

iOS 7 及更高版本

Answer 5

Swift 4.0.3

import UIKit

extension String {

func fromBase64() -> String? {
    guard let data = Data(base64Encoded: self, options: Data.Base64DecodingOptions(rawValue: 0)) else {
        return nil
    }

    return String(data: data as Data, encoding: String.Encoding.utf8)
}

func toBase64() -> String? {
    guard let data = self.data(using: String.Encoding.utf8) else {
        return nil
    }

    return data.base64EncodedString(options: Data.Base64EncodingOptions(rawValue: 0))
    }
}

Answer 6

Xcode 11.4 • Swift 5.2 或更高版本

extension StringProtocol {
    var data: Data { Data(utf8) }
    var base64Encoded: Data { data.base64EncodedData() }
    var base64Decoded: Data? { Data(base64Encoded: string) }
}

---

extension LosslessStringConvertible {
    var string: String { .init(self) }
}

---

extension Sequence where Element == UInt8 {
    var data: Data { .init(self) }
    var base64Decoded: Data? { Data(base64Encoded: data) }
    var string: String? { String(bytes: self, encoding: .utf8) }
}

---

let original = "iOS Developer Tips encoded in Base64"

let utf8Data = original.data                             // 36 bytes
let base64EncodedString = utf8Data.base64EncodedString() //  aU9TIERldmVsb3BlciBUaXBzIGVuY29kZWQgaW4gQmFzZTY0\n"
let base64EncodedData = utf8Data.base64EncodedData()     //  48 bytes"

print("base64EncodedData:", original.base64Encoded)      //  48 bytes
print("base64EncodedString:", original.base64Encoded.string ?? "") // "aU9TIERldmVsb3BlciBUaXBzIGVuY29kZWQgaW4gQmFzZTY0"
print("base64DecodedData:", original.base64Encoded.string?.base64Decoded  ?? "") // 36 bytes
print("base64DecodedString:", original.base64Encoded.base64Decoded?.string ?? "") // iOS Developer Tips encoded in Base64

Answer 7

经过深入研究，我找到了解决方案

编码

    let plainData = (plainString as NSString).dataUsingEncoding(NSUTF8StringEncoding)
    let base64String =plainData.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.fromRaw(0)!)
    println(base64String) // bXkgcGxhbmkgdGV4dA==

解码

    let decodedData = NSData(base64EncodedString: base64String, options:NSDataBase64DecodingOptions.fromRaw(0)!)
    let decodedString = NSString(data: decodedData, encoding: NSUTF8StringEncoding)    
    println(decodedString) // my plain data

更多关于http://creativecoefficient.net/swift/encoding-and-decoding-base64/

Answer 8

Swift 3 或 4

let base64Encoded = Data("original string".utf8).base64EncodedString()

Answer 9

Swift 5.1、Xcode 11：

public extension String {

    /// Assuming the current string is base64 encoded, this property returns a String
    /// initialized by converting the current string into Unicode characters, encoded to
    /// utf8. If the current string is not base64 encoded, nil is returned instead.
    var base64Decoded: String? {
        guard let base64 = Data(base64Encoded: self) else { return nil }
        let utf8 = String(data: base64, encoding: .utf8)
        return utf8
    }

    /// Returns a base64 representation of the current string, or nil if the
    /// operation fails.
    var base64Encoded: String? {
        let utf8 = self.data(using: .utf8)
        let base64 = utf8?.base64EncodedString()
        return base64
    }

}

Answer 10

Swift 3 / 4 / 5.1

这是一个简单的String 扩展，允许在解码时发生错误时保留选项。

extension String {
    /// Encode a String to Base64
    func toBase64() -> String {
        return Data(self.utf8).base64EncodedString()
    }

    /// Decode a String from Base64. Returns nil if unsuccessful.
    func fromBase64() -> String? {
        guard let data = Data(base64Encoded: self) else { return nil }
        return String(data: data, encoding: .utf8)
    }
}

例子：

let testString = "A test string."

let encoded = testString.toBase64() // "QSB0ZXN0IHN0cmluZy4="

guard let decoded = encoded.fromBase64() // "A test string."
    else { return } 

Answer 11

经过所有的努力，我还是这样做了。

func conversion(str:NSString)
{

    if let decodedData = NSData(base64EncodedString: str as String, options:NSDataBase64DecodingOptions(rawValue: 0)),
        let decodedString = NSString(data: decodedData, encoding: NSUTF8StringEncoding) {

        print(decodedString)//Here we are getting decoded string

在我调用另一个将解码字符串转换为字典的函数之后

        self .convertStringToDictionary(decodedString as String)
    }


}//function close

//字符串转字典

func convertStringToDictionary(text: String) -> [String:AnyObject]? {
    if let data = text.dataUsingEncoding(NSUTF8StringEncoding) {
        do {
            let json = try NSJSONSerialization.JSONObjectWithData(data, options: []) as? [String:AnyObject]

            print(json)
            if let stack = json!["cid"]  //getting key value here
            {
                customerID = stack as! String
                print(customerID)
            }

        } catch let error as NSError {
            print(error)
        }
    }
    return nil
}

Answer 12

适用于 SWIFT 3.0

let str = "iOS Developer Tips encoded in Base64"
print("Original: \(str)")

let utf8str = str.data(using: String.Encoding.utf8)

if let base64Encoded = utf8str?.base64EncodedString(options: NSData.Base64EncodingOptions(rawValue: 0))
{

  print("Encoded:  \(base64Encoded)")

  if let base64Decoded = NSData(base64Encoded: base64Encoded, options:   NSData.Base64DecodingOptions(rawValue: 0))
    .map({ NSString(data: $0 as Data, encoding: String.Encoding.utf8.rawValue) })
  {
    // Convert back to a string
    print("Decoded:  \(base64Decoded)!")
  }
}

Answer 13

斯威夫特 4.2

var base64String = "my fancy string".data(using: .utf8, allowLossyConversion: false)?.base64EncodedString()

要解码，请参阅（来自https://gist.github.com/stinger/a8a0381a57b4ac530dd029458273f31a）

//: # Swift 3: Base64 encoding and decoding
import Foundation

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) {
            return String(data: data, encoding: .utf8)
        }
        return nil
    }
}
var str = "Hello, playground"
print("Original string: \"\(str)\"")

if let base64Str = str.base64Encoded() {
    print("Base64 encoded string: \"\(base64Str)\"")
    if let trs = base64Str.base64Decoded() {
        print("Base64 decoded string: \"\(trs)\"")
        print("Check if base64 decoded string equals the original string: \(str == trs)")
    }
}

Answer 14

SwiftyBase64（完全公开：我写的）是原生 Swift Base64 编码（没有解码库。有了它，你可以编码标准 Base64：

let bytesToEncode : [UInt8] = [1,2,3]
let base64EncodedString = SwiftyBase64.EncodeString(bytesToEncode)

或 URL 和文件名 Safe Base64：

let bytesToEncode : [UInt8] = [1,2,3]
let base64EncodedString = SwiftyBase64.EncodeString(bytesToEncode, alphabet:.URLAndFilenameSafe)

Answer 15

@Airspeed Velocity 在 Swift 2.0 中的回答：

let str = "iOS Developer Tips encoded in Base64"
print("Original: \(str)")
let base64Encoded = str.dataUsingEncoding(NSUTF8StringEncoding)!.base64EncodedStringWithOptions([])
print("Encoded: \(base64Encoded)")
let base64DecodedData = NSData(base64EncodedString: base64Encoded, options: [])!
var base64DecodedString = String(data: base64DecodedData, encoding: NSUTF8StringEncoding)!
print("Decoded: \(base64DecodedString)")