Merge 1eea31c into 728891c

requirements.txt

@@ -1,2 +1,4 @@
+frozendict
+frozenlist2
 PyYAML
 requests

src/cdn_definitions/_impl/__init__.py

@@ -17,16 +17,46 @@
 # annotation even though the actual import still works.
 from requests.packages.urllib3.util.retry import Retry  # pylint: disable=import-error
 
+# It is preferred to return the data as immutable when possible
+try:
+    from frozendict import frozendict
+except ImportError:  # pragma: no cover
+    # If frozendict is not available, fall back to builtin dict
+    frozendict = dict  # pylint: disable=invalid-name
+try:
+    from frozenlist2 import frozenlist
+except ImportError:  # pragma: no cover
+    # If frozenlist is not available, fall back to builtin list
+    frozenlist = list  # pylint: disable=invalid-name
+
+
+def freeze(node):
+    """
+    Converts dict to frozendict and list to frozenlist.
+    """
+    if isinstance(node, list):
+        # Iterating using index instead of enumeration
+        # so we can replace the list items in place
+        for index in range(len(node)):  # pylint: disable=consider-using-enumerate
+            node[index] = freeze(node[index])
+        return frozenlist(node)
+    if isinstance(node, dict):
+        for key, value in node.items():
+            node[key] = freeze(value)
+        return frozendict(node)
+    return node
+
 
 def parsed(data, ext):
     """
     Parses a JSON or YAML string or a requests.Response object.
     """
+    is_response = isinstance(data, requests.Response)
     if ext.lower() == ".json":
-        return data.json() if isinstance(data, requests.Response) else json.loads(data)
-    return yaml.load(
-        data.text if isinstance(data, requests.Response) else data, yaml.SafeLoader
-    )
+        parsed_data = data.json() if is_response else json.loads(data)
+    else:
+        parsed_data = yaml.safe_load(data.text if is_response else data)
+    return freeze(parsed_data)
 
 
 def get_remote_data(url, session=None):

tests/test_load.py

@@ -1,35 +1,40 @@
 import os
 import json
 
+from frozendict import frozendict
+from frozenlist2 import frozenlist
 import pytest
-import requests
 import requests_mock
 
 from cdn_definitions import load_data, load_schema
 
 
 def test_can_load_custom_json_data(monkeypatch, tmpdir):
     json_file = tmpdir.join("myfile.json")
-    json_file.write('{"hello": "json"}')
+    json_file.write('{"hello": ["from", "json"]}')
 
     # If we set an env var pointing at the above JSON file, the library
     # should load it instead of the bundled data
     monkeypatch.setenv("CDN_DEFINITIONS_PATH", str(json_file))
     data = load_data()
 
-    assert data == {"hello": "json"}
+    assert data == {"hello": ["from", "json"]}
+    assert isinstance(data, frozendict)
+    assert isinstance(data["hello"], frozenlist)
 
 
 def test_can_load_custom_yaml_data(monkeypatch, tmpdir):
     yaml_file = tmpdir.join("myfile.yaml")
-    yaml_file.write("hello: yaml")
+    yaml_file.write("hello:\n  - from\n  - yaml")
 
     # If we set an env var pointing at the above YAML file, the library
     # should load it instead of the bundled data
     monkeypatch.setenv("CDN_DEFINITIONS_PATH", str(yaml_file))
     data = load_data()
 
-    assert data == {"hello": "yaml"}
+    assert data == {"hello": ["from", "yaml"]}
+    assert isinstance(data, frozendict)
+    assert isinstance(data["hello"], frozenlist)
 
 
 @pytest.mark.parametrize(