gitweb: Deal with edge cases

Some instance:
- have summary page which lists metadata_url field with multiple comma separated urls
- lists an incomplete url of the repository so we need to join it with the main page
- have summary page which does not list any git repository urls so try to determine one

Refs. swh/devel/swh-lister#1800

swh/lister/gitweb/lister.py

@@ -6,7 +6,7 @@ from datetime import timezone
 import logging
 import re
 from typing import Any, Dict, Iterator, List, Optional
-from urllib.parse import urljoin, urlparse
+from urllib.parse import parse_qs, urljoin, urlparse
 
 from bs4 import BeautifulSoup
 from dateparser import parse
@@ -86,7 +86,7 @@ class GitwebLister(StatelessLister[Repositories]):
             if not link:
                 continue
 
-            repo_url = link["href"]
+            repo_url = urljoin(self.url, link["href"]).strip("/")
 
             if repo_url.endswith("?o=descr"):
                 continue
@@ -151,15 +151,19 @@ class GitwebLister(StatelessLister[Repositories]):
                     return self._get_origin_from_repository_url(summary_url)
             else:
                 logger.debug("No summary tab found on %s", repository_url)
+        urls = []
+        for row in bs.find_all("tr", {"class": "metadata_url"}):
+            url = row.contents[-1].string.strip()
 
-        urls = [
-            row.contents[-1].string
-            for row in bs.find_all("tr", {"class": "metadata_url"})
-        ]
+            if "," in url:
+                urls_ = [s.strip() for s in url.split(",") if s]
+                urls.extend(urls_)
+            else:
+                urls.append(url)
 
         if not urls:
             logger.debug("No git urls found on %s", repository_url)
-            return None
+            return try_to_determine_git_repository(repository_url)
 
         # look for the http/https url, if any, and use it as origin_url
         for url in urls:
@@ -170,3 +174,21 @@ class GitwebLister(StatelessLister[Repositories]):
             # otherwise, choose the first one
             origin_url = urls[0]
         return origin_url
+
+
+def try_to_determine_git_repository(repository_url: str) -> Optional[str]:
+    """Some cgit instances does not advertise the git urls.
+
+    But the following mostly works.
+
+    """
+    result = None
+    parsed_url = urlparse(repository_url)
+    params = parse_qs(parsed_url.query).get("p")
+    if params:
+        repo = params[0]
+        if repo and repo.endswith(";a=summary"):
+            repo = repo.rstrip(";a=summary")
+
+        result = f"git://{parsed_url.netloc}/{repo}"
+    return result

swh/lister/gitweb/tests/data/https_git.distorted.org.uk/~mdw_doc_ips

@@ -43,8 +43,7 @@ summary | <a href="https://git.distorted.org.uk/~mdw/doc/ips/shortlog">shortlog<
 <tr id="metadata_desc"><td>description</td><td>Introduction to Provable Security slides and notes</td></tr>
 <tr id="metadata_owner"><td>owner</td><td>Mark Wooding</td></tr>
 <tr id="metadata_lchange"><td>last change</td><td><span class="datetime">Wed, 1 Nov 2006 14:32:34 +0000</span> (14:32 +0000)</td></tr>
-<tr class="metadata_url"><td>URL</td><td>https://git.distorted.org.uk/~mdw/doc/ips</td></tr>
-<tr class="metadata_url"><td></td><td>git://git.distorted.org.uk/~mdw/doc/ips</td></tr>
+<tr class="metadata_url"><td>URL</td><td>https://git.distorted.org.uk/~mdw/doc/ips , git://git.distorted.org.uk/~mdw/doc/ips</td></tr>
 </table>
 <div class="header">
 <a class="title" href="https://git.distorted.org.uk/~mdw/doc/ips/shortlog">shortlog</a>

swh/lister/gitweb/tests/test_lister.py

@@ -8,7 +8,7 @@ from typing import List
 import pytest
 
 from swh.lister import __version__
-from swh.lister.gitweb.lister import GitwebLister
+from swh.lister.gitweb.lister import GitwebLister, try_to_determine_git_repository
 from swh.lister.pattern import ListerStats
 
 MAIN_INSTANCE = "git.distorted.org.uk"
@@ -71,6 +71,7 @@ def test_lister_gitweb_run(requests_mock_datadir, swh_scheduler):
         assert listed_origin.visit_type == "git"
         assert listed_origin.url.startswith(url)
         assert listed_origin.last_update is not None
+        assert "," not in listed_origin.url
 
     # test user agent content
     for request in requests_mock_datadir.request_history:
@@ -117,3 +118,21 @@ def test_lister_gitweb_get_origin_from_repo_failing(
     # so they are filtered out, only the 7 we know are thus listed
     expected_nb_origins = 7
     assert stats == ListerStats(pages=1, origins=expected_nb_origins)
+
+
+@pytest.mark.parametrize(
+    "url,expected_repo",
+    [
+        (
+            "https://git.shadowcat.co.uk?p=urisagit/gitosis-admin.git",
+            "git://git.shadowcat.co.uk/urisagit/gitosis-admin.git",
+        ),
+        (
+            "https://git.shadowcat.co.uk?p=File-Slurp.git;a=summary",
+            "git://git.shadowcat.co.uk/File-Slurp.git",
+        ),
+        ("https://domain.org/foobar", None),
+    ],
+)
+def test_try_to_determine_git_repository(url, expected_repo):
+    assert try_to_determine_git_repository(url) == expected_repo