Base64 encode and decode strings
In this post, we’ll discuss how to Base64 encode and decode strings in Swift. We’ll also create a couple of extensions to make this easier to use and more readable.
The basics
Base64-encoding strings in Swift is very easy. You just have to convert the string to data, then encode that data with base64EncodedString():
let string = "Let's encode this string"
let encoded = string.data(using: .utf8)?.base64EncodedString()
To decode a Base64 encoded string, you just have to convert it to data, then create a string from the decoded data:
guard let data = Data(base64Encoded: self) else { return nil }
return String(data: data, encoding: .utf8)
Note that both encoding and decoding can fail, which means that they return optional strings.
Extending String
Although the above operations are very easy and straightforward, I prefer to use more convenient and readable extensions, to avoid having to write the same code over and over.
To Base64 encode and devode strings, I just wrap the logic in a String extension:
extension String {
func base64Encoded() -> String? {
data(using: .utf8)?.base64EncodedString()
}
func base64Decoded() -> String? {
guard let data = Data(base64Encoded: self) else { return nil }
return String(data: data, encoding: .utf8)
}
}
We can now encode and decode strings like this:
let string = "Let's encode this string"
let encoded = string.base64Encoded()
let decoded = encoded?.base64Decoded()
I think that this is a lot cleaner. Since the decode logic requires a guard, you also save one line each time and avoid having to use control flow where you may not want it.
Source code
I have added these extensions to my SwiftKit library. You can find the source code here. Feel free to try it out and let me know what you think!