Accept more types of input for headers/meta

Previously, we only accepted iterables of strings like 'Header: Value'.
Now, we'll also accept lists of tuples like ('Header', 'Value') as well
as dictionaries like {'Header': 'Value'}.

This should be more intuitive for application developers, who are
already used to being able to pass dicts or lists of tuples to libraries
like requests.

Change-Id: I93ed2f1e8305f0168b7a4bd90c205b04730da836

3 files changed, 37 insertions, 12 deletions

diff --git a/swiftclient/service.py b/swiftclient/service.py
index de30d50..8c6880a 100644
--- a/swiftclient/service.py
+++ b/swiftclient/service.py
@@ -29,11 +29,10 @@ from posixpath import join as urljoin
 from random import shuffle
 from time import time
 from threading import Thread
-from six import StringIO, text_type
+from six import Iterator, StringIO, string_types, text_type
 from six.moves.queue import Queue
 from six.moves.queue import Empty as QueueEmpty
 from six.moves.urllib.parse import quote
-from six import Iterator, string_types
 
 import json
 
@@ -274,7 +273,10 @@ def split_headers(options, prefix=''):
     """
     Splits 'Key: Value' strings and returns them as a dictionary.
 
-    :param options: An array of 'Key: Value' strings
+    :param options: Must be one of:
+        * an iterable of 'Key: Value' strings
+        * an iterable of ('Key', 'Value') pairs
+        * a dict of {'Key': 'Value'} pairs
     :param prefix: String to prepend to all of the keys in the dictionary.
         reporting.
     """
diff --git a/swiftclient/utils.py b/swiftclient/utils.py
index e14602d..aa8b28a 100644
--- a/swiftclient/utils.py
+++ b/swiftclient/utils.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """Miscellaneous utility functions for use with Swift."""
+import collections
 import gzip
 import hashlib
 import hmac
@@ -148,15 +149,24 @@ def parse_api_response(headers, body):
 
 def split_request_headers(options, prefix=''):
     headers = {}
+    if isinstance(options, collections.Mapping):
+        options = options.items()
     for item in options:
-        split_item = item.split(':', 1)
-        if len(split_item) == 2:
-            headers[(prefix + split_item[0]).title()] = split_item[1].strip()
-        else:
+        if isinstance(item, six.string_types):
+            if ':' not in item:
+                raise ValueError(
+                    "Metadata parameter %s must contain a ':'.\n"
+                    "Example: 'Color:Blue' or 'Size:Large'"
+                    % item
+                )
+            item = item.split(':', 1)
+        if len(item) != 2:
             raise ValueError(
-                "Metadata parameter %s must contain a ':'.\n%s"
-                % (item, "Example: 'Color:Blue' or 'Size:Large'")
+                "Metadata parameter %r must have exactly two items.\n"
+                "Example: ('Color', 'Blue') or ['Size', 'Large']"
+                % (item, )
             )
+        headers[(prefix + item[0]).title()] = item[1].strip()
     return headers
 
 
diff --git a/tests/unit/test_service.py b/tests/unit/test_service.py
index e8385b7..2fc827c 100644
--- a/tests/unit/test_service.py
+++ b/tests/unit/test_service.py
@@ -592,11 +592,24 @@ class TestServiceUtils(unittest.TestCase):
         actual = swiftclient.service.split_headers(mock_headers, 'prefix-')
         self.assertEqual(expected, actual)
 
-    def test_split_headers_error(self):
-        mock_headers = ['notvalid']
+    def test_split_headers_list_of_tuples(self):
+        mock_headers = [('color', 'blue'), ('size', 'large')]
+        expected = {'Prefix-Color': 'blue', 'Prefix-Size': 'large'}
+
+        actual = swiftclient.service.split_headers(mock_headers, 'prefix-')
+        self.assertEqual(expected, actual)
 
+    def test_split_headers_dict(self):
+        expected = {'Color': 'blue', 'Size': 'large'}
+
+        actual = swiftclient.service.split_headers(expected)
+        self.assertEqual(expected, actual)
+
+    def test_split_headers_error(self):
+        self.assertRaises(SwiftError, swiftclient.service.split_headers,
+                          ['notvalid'])
         self.assertRaises(SwiftError, swiftclient.service.split_headers,
-                          mock_headers)
+                          [('also', 'not', 'valid')])
 
 
 class TestSwiftUploadObject(unittest.TestCase):