add support for git credential helpers

- add misc url-matching functions

Extracted from https://github.com/jelmer/dulwich/pull/976

dulwich/credentials.py

@@ -0,0 +1,89 @@
+# credentials.py -- support for git credential helpers
+
+# Copyright (C) 2022 Daniele Trifirò <daniele@iterative.ai>
+#
+# Dulwich is dual-licensed under the Apache License, Version 2.0 and the GNU
+# General Public License as public by the Free Software Foundation; version 2.0
+# or (at your option) any later version. You can redistribute it and/or
+# modify it under the terms of either of these two licenses.
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# You should have received a copy of the licenses; if not, see
+# <http://www.gnu.org/licenses/> for a copy of the GNU General Public License
+# and <http://www.apache.org/licenses/LICENSE-2.0> for a copy of the Apache
+# License, Version 2.0.
+#
+
+"""Support for git credential helpers
+
+https://git-scm.com/book/en/v2/Git-Tools-Credential-Storage
+
+"""
+import sys
+from typing import Iterator, Optional
+from urllib.parse import ParseResult, urlparse
+
+from dulwich.config import ConfigDict, SectionLike
+
+
+def match_urls(url: ParseResult, url_prefix: ParseResult) -> bool:
+    base_match = (
+        url.scheme == url_prefix.scheme
+        and url.hostname == url_prefix.hostname
+        and url.port == url_prefix.port
+    )
+    user_match = url.username == url_prefix.username if url_prefix.username else True
+    path_match = url.path.rstrip("/").startswith(url_prefix.path.rstrip())
+    return base_match and user_match and path_match
+
+
+def match_partial_url(valid_url: ParseResult, partial_url: str) -> bool:
+    """matches a parsed url with a partial url (no scheme/netloc)"""
+    if "://" not in partial_url:
+        parsed = urlparse("scheme://" + partial_url)
+    else:
+        parsed = urlparse(partial_url)
+        if valid_url.scheme != parsed.scheme:
+            return False
+
+    if any(
+        (
+            (parsed.hostname and valid_url.hostname != parsed.hostname),
+            (parsed.username and valid_url.username != parsed.username),
+            (parsed.port and valid_url.port != parsed.port),
+            (parsed.path and parsed.path.rstrip("/") != valid_url.path.rstrip("/")),
+        ),
+    ):
+        return False
+
+    return True
+
+
+def urlmatch_credential_sections(
+    config: ConfigDict, url: Optional[str]
+) -> Iterator[SectionLike]:
+    """Returns credential sections from the config which match the given URL"""
+    encoding = config.encoding or sys.getdefaultencoding()
+    parsed_url = urlparse(url or "")
+    for config_section in config.sections():
+        if config_section[0] != b"credential":
+            continue
+
+        if len(config_section) < 2:
+            yield config_section
+            continue
+
+        config_url = config_section[1].decode(encoding)
+        parsed_config_url = urlparse(config_url)
+        if parsed_config_url.scheme and parsed_config_url.netloc:
+            is_match = match_urls(parsed_url, parsed_config_url)
+        else:
+            is_match = match_partial_url(parsed_url, config_url)
+
+        if is_match:
+            yield config_section

dulwich/tests/__init__.py

@@ -117,6 +117,7 @@ def self_test_suite():
         "bundle",
         "client",
         "config",
+        "credentials",
         "diff_tree",
         "fastexport",
         "file",

dulwich/tests/test_credentials.py

@@ -0,0 +1,75 @@
+# test_credentials.py -- tests for credentials.py
+
+# Copyright (C) 2022 Daniele Trifirò <daniele@iterative.ai>
+#
+# Dulwich is dual-licensed under the Apache License, Version 2.0 and the GNU
+# General Public License as public by the Free Software Foundation; version 2.0
+# or (at your option) any later version. You can redistribute it and/or
+# modify it under the terms of either of these two licenses.
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# You should have received a copy of the licenses; if not, see
+# <http://www.gnu.org/licenses/> for a copy of the GNU General Public License
+# and <http://www.apache.org/licenses/LICENSE-2.0> for a copy of the Apache
+# License, Version 2.0.
+#
+
+from urllib.parse import urlparse
+
+from dulwich.config import ConfigDict
+from dulwich.credentials import (
+    match_partial_url,
+    match_urls,
+    urlmatch_credential_sections,
+)
+from dulwich.tests import TestCase
+
+
+class TestCredentialHelpersUtils(TestCase):
+
+    def test_match_urls(self):
+        url = urlparse("https://github.com/jelmer/dulwich/")
+        url_1 = urlparse("https://github.com/jelmer/dulwich")
+        url_2 = urlparse("https://github.com/jelmer")
+        url_3 = urlparse("https://github.com")
+        self.assertTrue(match_urls(url, url_1))
+        self.assertTrue(match_urls(url, url_2))
+        self.assertTrue(match_urls(url, url_3))
+
+        non_matching = urlparse("https://git.sr.ht/")
+        self.assertFalse(match_urls(url, non_matching))
+
+    def test_match_partial_url(self):
+        url = urlparse("https://github.com/jelmer/dulwich/")
+        self.assertTrue(match_partial_url(url, "github.com"))
+        self.assertFalse(match_partial_url(url, "github.com/jelmer/"))
+        self.assertTrue(match_partial_url(url, "github.com/jelmer/dulwich"))
+        self.assertFalse(match_partial_url(url, "github.com/jel"))
+        self.assertFalse(match_partial_url(url, "github.com/jel/"))
+
+    def test_urlmatch_credential_sections(self):
+        config = ConfigDict()
+        config.set((b"credential", "https://github.com"), b"helper", "foo")
+        config.set((b"credential", "git.sr.ht"), b"helper", "foo")
+        config.set(b"credential", b"helper", "bar")
+
+        self.assertEqual(
+            list(urlmatch_credential_sections(config, "https://github.com")), [
+                (b"credential", b"https://github.com"),
+                (b"credential",),
+            ])
+
+        self.assertEqual(
+            list(urlmatch_credential_sections(config, "https://git.sr.ht")), [
+                (b"credential", b"git.sr.ht"),
+                (b"credential",),
+            ])
+
+        self.assertEqual(
+            list(urlmatch_credential_sections(config, "missing_url")), [
+                (b"credential",)])