Add IndieAuth support

app/utils/indieauth.py

@@ -0,0 +1,59 @@
+from dataclasses import dataclass
+from typing import Any
+
+import httpx
+import mf2py  # type: ignore
+from loguru import logger
+
+from app import config
+from app.utils.url import make_abs
+
+
+@dataclass
+class IndieAuthClient:
+    logo: str | None
+    name: str
+    url: str
+
+
+def _get_prop(props: dict[str, Any], name: str, default=None) -> Any:
+    if name in props:
+        items = props.get(name)
+        if isinstance(items, list):
+            return items[0]
+        return items
+    return default
+
+
+async def get_client_id_data(url: str) -> IndieAuthClient | None:
+    async with httpx.AsyncClient() as client:
+        try:
+            resp = await client.get(
+                url,
+                headers={
+                    "User-Agent": config.USER_AGENT,
+                },
+                follow_redirects=True,
+            )
+            resp.raise_for_status()
+        except (httpx.HTTPError, httpx.HTTPStatusError):
+            logger.exception(f"Failed to discover webmention endpoint for {url}")
+            return None
+
+    data = mf2py.parse(doc=resp.text)
+    for item in data["items"]:
+        if "h-x-app" in item["type"] or "h-app" in item["type"]:
+            props = item.get("properties", {})
+            print(props)
+            logo = _get_prop(props, "logo")
+            return IndieAuthClient(
+                logo=make_abs(logo, url) if logo else None,
+                name=_get_prop(props, "name"),
+                url=_get_prop(props, "url", url),
+            )
+
+    return IndieAuthClient(
+        logo=None,
+        name=url,
+        url=url,
+    )