utils: Add format_user_agent helper

mopidy/utils/http.py

@@ -1,5 +1,11 @@
 from __future__ import unicode_literals
 
+import platform
+
+import mopidy
+
+"Helpers for configuring HTTP clients used in Mopidy extensions."
+
 
 def format_proxy(proxy_config):
     """Convert a Mopidy proxy config to the commonly used proxy string format.
@@ -23,3 +29,17 @@ def format_proxy(proxy_config):
                            username=proxy_config.get('username'),
                            password=proxy_config.get('password'),
                            hostname=proxy_config['hostname'], port=port)
+
+
+def format_user_agent(name=None):
+    """Construct a User-Agent suitable for use in client code.
+
+    This will identify use by the provided name (which should be
+    ``dist_name/version``), Mopidy version and Python version.
+    """
+    parts = ['Mopidy/%s' % (mopidy.__version__),
+             '%s/%s' % (platform.python_implementation(),
+                        platform.python_version())]
+    if name:
+        parts.insert(0, name)
+    return ' '.join(parts)

tests/utils/test_http.py

@@ -1,5 +1,7 @@
 from __future__ import unicode_literals
 
+import re
+
 import pytest
 
 from mopidy.utils import http
@@ -18,3 +20,12 @@ from mopidy.utils import http
 ])
 def test_format_proxy(config, expected):
     assert http.format_proxy(config) == expected
+
+
+@pytest.mark.parametrize("name,expected", [
+    (None, r'^Mopidy/[^ ]+ CPython|/[^ ]+$'),
+    ('Foo', r'^Foo Mopidy/[^ ]+ CPython|/[^ ]+$'),
+    ('Foo/1.2.3', r'^Foo/1.2.3 Mopidy/[^ ]+ CPython|/[^ ]+$'),
+])
+def test_format_user_agent(name, expected):
+    assert re.match(expected, http.format_user_agent(name))