iOS 7+ 中的 Base64 解码

Question

我使用 iOS7 中添加的 NSData 类新 API 对文本（NSString）进行了编码。

使用这个

- (NSData *)dataUsingEncoding:(NSStringEncoding)encoding;  

这是我的代码

NSString *base64EncodedString = [[myText dataUsingEncoding:NSUTF8StringEncoding] base64EncodedStringWithOptions:0];

NSLog(@"%@", base64EncodedString);

我正在寻找解码它

Answer 1

斯威夫特 3+

let plainString = "foo"

编码

let plainData = plainString.data(using: .utf8)
let base64String = plainData?.base64EncodedString()
print(base64String!) // Zm9v

解码

if let decodedData = Data(base64Encoded: base64String!),
   let decodedString = String(data: decodedData, encoding: .utf8) {
  print(decodedString) // foo
}

---

斯威夫特

let plainString = "foo"

编码

let plainData = plainString.dataUsingEncoding(NSUTF8StringEncoding)
let base64String = plainData?.base64EncodedStringWithOptions(NSDataBase64EncodingOptions(rawValue: 0))
print(base64String!) // Zm9v

解码

let decodedData = NSData(base64EncodedString: base64String!, options: NSDataBase64DecodingOptions(rawValue: 0))
let decodedString = NSString(data: decodedData, encoding: NSUTF8StringEncoding)
print(decodedString) // foo

---

目标-C

NSString *plainString = @"foo";

编码

NSData *plainData = [plainString dataUsingEncoding:NSUTF8StringEncoding];
NSString *base64String = [plainData base64EncodedStringWithOptions:0];
NSLog(@"%@", base64String); // Zm9v

解码

NSData *decodedData = [[NSData alloc] initWithBase64EncodedString:base64String options:0];
NSString *decodedString = [[NSString alloc] initWithData:decodedData encoding:NSUTF8StringEncoding];
NSLog(@"%@", decodedString); // foo 

---

Answer 2

如果您想编写后备代码，则从一开始就在 iOS 中提供 base64 解码，这是 NSURL 的警告：

NSURL *URL = [NSURL URLWithString:
      [NSString stringWithFormat:@"data:application/octet-stream;base64,%@",
           base64String]];

return [NSData dataWithContentsOfURL:URL];