Implement missing utils.decode_json_header

Signed-off-by: Joffrey F <joffrey@docker.com>

2 files changed, 8 insertions, 1 deletions

diff --git a/docker/utils/__init__.py b/docker/utils/__init__.py
index fd0ef5c..92e03e9 100644
--- a/docker/utils/__init__.py
+++ b/docker/utils/__init__.py
@@ -3,7 +3,7 @@ from .utils import (
     mkbuildcontext, tar, exclude_paths, parse_repository_tag, parse_host,
     kwargs_from_env, convert_filters, create_host_config,
     create_container_config, parse_bytes, ping_registry, parse_env_file,
-    version_lt, version_gte
+    version_lt, version_gte, decode_json_header
 ) # flake8: noqa
 
 from .types import Ulimit, LogConfig # flake8: noqa
diff --git a/docker/utils/utils.py b/docker/utils/utils.py
index d9b156b..43eaa6d 100644
--- a/docker/utils/utils.py
+++ b/docker/utils/utils.py
@@ -67,6 +67,13 @@ def mkbuildcontext(dockerfile):
     return f
 
 
+def decode_json_header(header):
+    data = base64.b64decode(header)
+    if six.PY3:
+        data = data.decode('utf-8')
+    return json.loads(data)
+
+
 def tar(path, exclude=None, dockerfile=None):
     f = tempfile.NamedTemporaryFile()
     t = tarfile.open(mode='w', fileobj=f)