Add dot as a valid s3 metadata key (#3958)

moto/s3/utils.py

@@ -73,7 +73,7 @@ def parse_region_from_url(url):
 
 def metadata_from_headers(headers):
     metadata = CaseInsensitiveDict()
-    meta_regex = re.compile(r"^x-amz-meta-([a-zA-Z0-9\-_]+)$", flags=re.IGNORECASE)
+    meta_regex = re.compile(r"^x-amz-meta-([a-zA-Z0-9\-_.]+)$", flags=re.IGNORECASE)
     for header, value in headers.items():
         if isinstance(header, six.string_types):
             result = meta_regex.match(header)

tests/test_s3/test_s3.py

@@ -65,13 +65,16 @@ def reduced_min_part_size(f):
 
 
 class MyModel(object):
-    def __init__(self, name, value):
+    def __init__(self, name, value, metadata={}):
         self.name = name
         self.value = value
+        self.metadata = metadata
 
     def save(self):
         s3 = boto3.client("s3", region_name=DEFAULT_REGION_NAME)
-        s3.put_object(Bucket="mybucket", Key=self.name, Body=self.value)
+        s3.put_object(
+            Bucket="mybucket", Key=self.name, Body=self.value, Metadata=self.metadata
+        )
 
 
 @mock_s3
@@ -133,6 +136,24 @@ def test_my_model_save():
     assert body == "is awesome"
 
 
+@mock_s3
+def test_object_metadata():
+    """Metadata keys can contain certain special characters like dash and dot"""
+    # Create Bucket so that test can run
+    conn = boto3.resource("s3", region_name=DEFAULT_REGION_NAME)
+    conn.create_bucket(Bucket="mybucket")
+    ####################################
+
+    metadata = {"meta": "simple", "my-meta": "dash", "meta.data": "namespaced"}
+
+    model_instance = MyModel("steve", "is awesome", metadata=metadata)
+    model_instance.save()
+
+    meta = conn.Object("mybucket", "steve").get()["Metadata"]
+
+    assert meta == metadata
+
+
 @mock_s3
 def test_key_etag():
     conn = boto3.resource("s3", region_name=DEFAULT_REGION_NAME)