Automator: Decode Decode64 selection and display output in a new TextEdit window

Question

I would like to display a service in a context menu for a selected text which is a base64 string. The service has to decode it to string with a base64 via terminal script and display an output in a new TextEdit window.

I have a service in an Automator app which has a script shell with input as arguments and command:

"$@" | base64 --decode

There is a connected "New TextEdit document action" to the shell script.

This display empty window

If I change the command to pbpaste | base64 --decode and I will copy a base64 string to clipboard then the service works correctly.

How to pipeline the input argument, which is a base64 selected string, to 'base64 --decode' command?

Answer 1

I know the question is about TextEdit, but for anyone who would rather do this in BBEdit, you can create a TextFilter to process the selected text.

#!/usr/bin/python

import sys
  
def decode64(myString):
    return myString.decode('base64')

input = sys.stdin.read()
print decode64(input)

If you want to use python3, it's even easier:

#!/usr/local/bin/python3

import sys, base64

input = sys.stdin.read()
print base64.b64decode(input)

Save this to: ~/Library/Application Support/BBEdit/Text Filters, then you can access it from the Text Filters menu.

Answer 2

if your Automator Service/Quick Action is set to e.g. Service receives selected text in any application / Workflow receives text in any application, then in the Run Shell Script action with Pass input: as arguments set, then the following line of code will return the decrypted text to an e.g. New TextEdit Document action:

^{Note: The use of terms separated with a / is to denote the difference between Automator prior to macOS Mojave and from it onwards.}

base64 --decode <<< "$@"

As an alternative to using the Run Shell Script action and the New TextEdit Document action, by just using a Run AppleScript action to accomplish the task:

on run {input, parameters}
    
    set encodedString to input as string
    
    set decodedString to ¬
        (do shell script "base64 --decode <<<" & encodedString's quoted form)
    
    tell application "TextEdit" to ¬
        make new document with properties {text:decodedString}
    
end run

Answer 3

In Automator, you can set up a workflow as follows:

Pass in base64 data to stdin, as shown, and this will decode the data and write it into the front TextEdit window (opening the app and window, if required). This will overwrite the contents of that window; you can set it to append instead, or add an extra step to open a fresh window first.