SlopTonio SlopTonio - 2 months ago 15
iOS Question

Decode base64 to uiimage iOS Swift

decodedData is nil but My base64String contains an extremely long string

Encode

var imgProfile:NSData = UIImagePNGRepresentation(imgUI)
let base64String = imgProfile.base64EncodedStringWithOptions(.allZeros)


Decode

let base64String = prefs.valueForKey("imgDefault") as? String
let decodedData = NSData(base64EncodedString: base64String!, options: NSDataBase64DecodingOptions(rawValue: 0) )
var decodedimage = UIImage(data: decodedData!)


enter image description here





enter image description here

I"m having trouble outputting my image from base64

base64 string ENCODE before inserting into db:

"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

base64 string DECODE when pulling down from db:

Optional("iVBORw0KGgoAAAANSUhEUgAAAgAAAAIACAMAAADDpiTIAAAADFBMVEXFxcX////p6enW1tbAmiBwAAAAHGlET1QAAAACAAAAAAAAAQAAAAAoAAABAAAAAQAAAAYAppse6QAABcxJREFUeAHs3et22jAQReEQ3v di8sikDaxZeGLdPTxpzS202jP9pwRkNWPDw8EEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQQAABBBBAAAEEEEAAAQQQiCVwvV4/p8fl9fH3K7cjsau2sBuBqfKvVf/x ecnDQJtKSn9qw83DQIpDLqktcV/iECCAGFuXf9Rz6o/5UHPEtTe t9V0Qj6dGCb6t9d4EBvDrzb b/3gOlvsqAjB97M/f rf/ KjUEfDuxU/nsb6APBwD/llsn/UycwDTQt1443/9MGSdCqA4eUXxK0Wv6P917xed7hJc8 m6Uw7A922O1/90MOtGXaweWXA8OXnwINKXAtSe1dzvGWcQManND9nzIZBU434MjZ/1n45zP7gVMVOPX2v1ugCZxowHnp/2wBl4tJ4CwFzm7/DwvEwCkGNND vwzQBI5XoI32/1CAAUcb0Er7fxggBg41oKH2/2WAJnCcAg3Wf/rU4HEABv Xmqw/Aw6zsq3x7xEB0596wBEStFt/Boxefwbsb0Br27/XBJie2w7u60Dr9WfA6PVnwJ4GtDz/PbPAXmAvB/qov0lw9PozYB8Dern/pyyQAts70Ojrv8/of33mfYHNB

Rob Rob
Answer

There are two different problems:

  1. It would appear that the + characters have been replaced with spaces. That will happen if you submit an application/x-www-form-urlencoded request without percent escaping the + characters. This probably happened when you first sent the base64 string to be stored in the database.

    See http://stackoverflow.com/a/24888789/1271826 for a discussion of some percent encoding patterns. The key point here is to not rely upon stringByAddingPercentEscapesUsingEncoding, because that will allow + characters to go unescaped.

  2. The string is also missing the trailing = characters. (The string's length should be a multiple of four, and in this case, it's two characters short, so there should be == at the end of the rendition with the + characters in it (the "before" string). While that is sometimes a mistake made by poorly designed base64-encoders, this is not a problem that base64EncodedStringWithOptions suffers from.

    In this case, it looks like a much longer base64 string must have been truncated somehow. (Your strings are suspiciously close to 1024 characters. lol.) This truncation could happen if you put the parameters in the URL rather than the body of the request. But nothing in this code sample would account for this behavior, so the problem rests elsewhere.

    But look at the length of the original NSData. The base64 string should be 1/3 larger than that (plus rounded up to the nearest four characters, once you include the trailing = characters).

    And, once you decode the string that you've provided and look at the actual contents, you can also see that the base64 string was truncated. (According to the portion provided, there should be 1484 bytes of IDAT data, and there's not, plus there's no IEND chunk ... don't worry about those details, but rest assured that it's basically saying that the PNG data stream is incomplete.)

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