1 files changed, 57 insertions, 0 deletions
diff --git a/sphinx/ext/githubpages.py b/sphinx/ext/githubpages.py
new file mode 100644
index 0000000..c9be928
--- /dev/null
+++ b/sphinx/ext/githubpages.py
@@ -0,0 +1,57 @@
+"""To publish HTML docs at GitHub Pages, create .nojekyll file."""
+
+from __future__ import annotations
+
+import contextlib
+import os
+import urllib.parse
+from typing import TYPE_CHECKING, Any
+
+import sphinx
+
+if TYPE_CHECKING:
+    from sphinx.application import Sphinx
+    from sphinx.environment import BuildEnvironment
+
+
+def _get_domain_from_url(url: str) -> str:
+    """Get the domain from a URL."""
+    return url and urllib.parse.urlparse(url).hostname or ''
+
+
+def create_nojekyll_and_cname(app: Sphinx, env: BuildEnvironment) -> None:
+    """Manage the ``.nojekyll`` and ``CNAME`` files for GitHub Pages.
+
+    For HTML-format builders (e.g. 'html', 'dirhtml') we unconditionally create
+    the ``.nojekyll`` file to signal that GitHub Pages should not run Jekyll
+    processing.
+
+    If the :confval:`html_baseurl` option is set, we also create a CNAME file
+    with the domain from ``html_baseurl``, so long as it is not a ``github.io``
+    domain.
+
+    If this extension is loaded and the domain in ``html_baseurl`` no longer
+    requires a CNAME file, we remove any existing ``CNAME`` files from the
+    output directory.
+    """
+    if app.builder.format != 'html':
+        return
+
+    app.builder.outdir.joinpath('.nojekyll').touch()
+    cname_path = os.path.join(app.builder.outdir, 'CNAME')
+
+    domain = _get_domain_from_url(app.config.html_baseurl)
+    # Filter out GitHub Pages domains, as they do not require CNAME files.
+    if domain and not domain.endswith(".github.io"):
+        with open(cname_path, 'w', encoding="utf-8") as f:
+            # NOTE: don't write a trailing newline. The `CNAME` file that's
+            # auto-generated by the GitHub UI doesn't have one.
+            f.write(domain)
+    else:
+        with contextlib.suppress(FileNotFoundError):
+            os.unlink(cname_path)
+
+
+def setup(app: Sphinx) -> dict[str, Any]:
+    app.connect('env-updated', create_nojekyll_and_cname)
+    return {'version': sphinx.__display_version__, 'parallel_read_safe': True}