base64 filter: Added ability to specify encoding (ansible#39714)

* base64 filter: Added ability to specify encoding

* Added unicode chars for further testing

* Removed errors to keep previous behaviour in place

* Removed surrogate pairs due to issues loading YAML in CI

changelogs/fragments/base64_filter_encoding.yaml

@@ -0,0 +1,3 @@
+minor_changes:
+- Added an ``encoding`` option to the ``b64encode`` and ``b64decode`` filters
+  to specify the encoding of the string that is base64 encoded.

docs/docsite/rst/user_guide/playbooks_filters.rst

@@ -935,6 +935,13 @@ To work with Base64 encoded strings::
     {{ encoded | b64decode }}
     {{ decoded | b64encode }}
 
+As of version 2.6, you can define the type of encoding to use, the default is ``utf-8``::
+
+    {{ encoded | b64decode(encoding='utf-16-le') }}
+    {{ decoded | b64encode(encoding='utf-16-le') }}
+
+.. versionadded:: 2.6
+
 To create a UUID from a string (new in version 1.9)::
 
     {{ hostname | to_uuid }}

lib/ansible/plugins/filter/core.py

@@ -459,12 +459,12 @@ def do_groupby(environment, value, attribute):
     return [tuple(t) for t in _do_groupby(environment, value, attribute)]
 
 
-def b64encode(string):
-    return to_text(base64.b64encode(to_bytes(string, errors='surrogate_or_strict')))
+def b64encode(string, encoding='utf-8'):
+    return to_text(base64.b64encode(to_bytes(string, encoding=encoding, errors='surrogate_or_strict')))
 
 
-def b64decode(string):
-    return to_text(base64.b64decode(to_bytes(string, errors='surrogate_or_strict')))
+def b64decode(string, encoding='utf-8'):
+    return to_text(base64.b64decode(to_bytes(string, errors='surrogate_or_strict')), encoding=encoding)
 
 
 def flatten(mylist, levels=None):

test/integration/targets/filters/tasks/main.yml

@@ -185,3 +185,11 @@
           - flat_two == [1, 2, 3, 4, [5], 6, 7]
   vars:
     orig_list: [1, 2, [3, [4, [5]], 6], 7]
+
+- name: Test base64 filter
+  assert:
+    that:
+    - "'Ansible - くらとみ\n' | b64encode == 'QW5zaWJsZSAtIOOBj+OCieOBqOOBvwo='"
+    - "'QW5zaWJsZSAtIOOBj+OCieOBqOOBvwo=' | b64decode == 'Ansible - くらとみ\n'"
+    - "'Ansible - くらとみ\n' | b64encode(encoding='utf-16-le') == 'QQBuAHMAaQBiAGwAZQAgAC0AIABPMIkwaDB/MAoA'"
+    - "'QQBuAHMAaQBiAGwAZQAgAC0AIABPMIkwaDB/MAoA' | b64decode(encoding='utf-16-le') == 'Ansible - くらとみ\n'"