Base64 Decoding in iOS 7+
Swift 3+
let plainString = "foo"
Encoding
let plainData = plainString.data(using: .utf8)
let base64String = plainData?.base64EncodedString()
print(base64String!) // Zm9v
Decoding
if let decodedData = Data(base64Encoded: base64String!),
let decodedString = String(data: decodedData, encoding: .utf8) {
print(decodedString) // foo
}
Swift < 3
let plainString = "foo"
Encoding
let plainData = plainString.dataUsingEncoding(NSUTF8StringEncoding)
let base64String = plainData?.base64EncodedStringWithOptions(NSDataBase64EncodingOptions(rawValue: 0))
print(base64String!) // Zm9v
Decoding
let decodedData = NSData(base64EncodedString: base64String!, options: NSDataBase64DecodingOptions(rawValue: 0))
let decodedString = NSString(data: decodedData, encoding: NSUTF8StringEncoding)
print(decodedString) // foo
Objective-C
NSString *plainString = @"foo";
Encoding
NSData *plainData = [plainString dataUsingEncoding:NSUTF8StringEncoding];
NSString *base64String = [plainData base64EncodedStringWithOptions:0];
NSLog(@"%@", base64String); // Zm9v
Decoding
NSData *decodedData = [[NSData alloc] initWithBase64EncodedString:base64String options:0];
NSString *decodedString = [[NSString alloc] initWithData:decodedData encoding:NSUTF8StringEncoding];
NSLog(@"%@", decodedString); // foo
how to decode base64 string to NSString in ios?
I hope it will helpful to you
NSString *decodeString = @"Raja";
Encode String
NSData *encodeData = [decodeString dataUsingEncoding:NSUTF8StringEncoding];
NSString *base64String = [encodeData base64EncodedStringWithOptions:0];
NSLog(@"Encode String Value: %@", base64String);
Decode String
NSData *decodedData = [[NSData alloc] initWithBase64EncodedString:base64String options:0];
NSString *decodedString = [[NSString alloc] initWithData:decodedData encoding:NSUTF8StringEncoding];
NSLog(@"Decode String Value: %@", decodedString);
How to Base64 encoding on the iPhone
You can see an example here.
This is for iOS7+.
I copy the code here, just in case:
// Create NSData object
NSData *nsdata = [@"iOS Developer Tips encoded in Base64"
dataUsingEncoding:NSUTF8StringEncoding];
// Get NSString from NSData object in Base64
NSString *base64Encoded = [nsdata base64EncodedStringWithOptions:0];
// Print the Base64 encoded string
NSLog(@"Encoded: %@", base64Encoded);
// Let's go the other way...
// NSData from the Base64 encoded str
NSData *nsdataFromBase64String = [[NSData alloc]
initWithBase64EncodedString:base64Encoded options:0];
// Decoded NSString from the NSData
NSString *base64Decoded = [[NSString alloc]
initWithData:nsdataFromBase64String encoding:NSUTF8StringEncoding];
NSLog(@"Decoded: %@", base64Decoded);
Decoding Base64 String Returns nil
Your string contains underscore character ('_' U+005F LOW LINE), which is invalid as Base-64.
There are some variations of Base-64, so you need to find which one your Gmail something is using. (Wikipedia Base-64.)
Assuming it uses base64url URL- and filename-safe, you may need to write something like this:
extension String {
func urlSafeBase64Decoded() -> String? {
var st = self
.replacingOccurrences(of: "_", with: "/")
.replacingOccurrences(of: "-", with: "+")
let remainder = self.count % 4
if remainder > 0 {
st = self.padding(toLength: self.count + 4 - remainder,
withPad: "=",
startingAt: 0)
}
guard let d = Data(base64Encoded: st, options: .ignoreUnknownCharacters) else{
return nil
}
return String(data: d, encoding: .utf8)
}
}
Example:
let base64 = "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_RW1haWw9c2lkcmFpYnJhaGltMDM0OUBnbWFpbC5jb20mY29udGludWU9aHR0cHM6Ly9teWFjY291bnQuZ29vZ2xlLmNvbS9hbGVydC9udC8xNTY3ODQ3ODEyMDAwP3JmbiUzRDEyNyUyNnJmbmMlM0QxJTI2ZWlkJTNELTE1NzQzMDEyNjk4Mjg2MTM3OTQlMjZldCUzRDElMjZhbmV4cCUzRGdpdmFiLWZhLS1tZHYyLWZhPg0KWW91IHJlY2VpdmVkIHRoaXMgZW1haWwgdG8gbGV0IHlvdSBrbm93IGFib3V0IGltcG9ydGFudCBjaGFuZ2VzIHRvIHlvdXINCkdvb2dsZSBBY2NvdW50IGFuZCBzZXJ2aWNlcy4NCsKpIDIwMTkgR29vZ2xlIExMQywgMTYwMCBBbXBoaXRoZWF0cmUgUGFya3dheSwgTW91bnRhaW4gVmlldywgQ0EgOTQwNDMsIFVTQQ0K"
print(base64.urlSafeBase64Decoded() ?? "* decoding failed*")
Output:
You received this email to let you know about important changes to your
Google Account and services.
© 2019 Google LLC, 1600 Amphitheatre Parkway, Mountain View, CA 94043, USA
How can I encode a string to Base64 in Swift?
I don’t have 6.2 installed but I don’t think 6.3 is any different in this regard:
dataUsingEncoding
returns an optional, so you need to unwrap that.
NSDataBase64EncodingOptions.fromRaw
has been replaced with NSDataBase64EncodingOptions(rawValue:)
. Slightly surprisingly, this is not a failable initializer so you don’t need to unwrap it.
But since NSData(base64EncodedString:)
is a failable initializer, you need to unwrap that.
Btw, all these changes were suggested by Xcode migrator (click the error message in the gutter and it has a “fix-it” suggestion).
Final code, rewritten to avoid force-unwraps, looks like this:
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)")
}
}
(if using Swift 1.2 you could use multiple if-lets instead of the map)
Swift 5 Update:
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 ?? "")")
}
}
Base64Encoding is deprecated : first deprecated in iOS 7.0
Started from iOS 7 SDK , NSData class now has methods that help encode/decode base 64 data and string objects with the following:
- (instancetype)initWithBase64EncodedData:(NSData *)base64Data
options:(NSDataBase64DecodingOptions)options
- (instancetype)initWithBase64EncodedString:(NSString *)base64String
options:(NSDataBase64DecodingOptions)options
Once you got your NSData instances initialize a UIImage object with: + (UIImage *)imageWithData:(NSData *)data
types of encoding:
- NSDataBase64Encoding64CharacterLineLength
NSDataBase64Encoding76CharacterLineLength
NSDataBase64EncodingEndLineWithCarriageReturn
NSDataBase64EncodingEndLineWithLineFeed
types of decoding:
- NSDataBase64DecodingIgnoreUnknownCharacters
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