Initial commit for new v2

app/lookup.py

@@ -0,0 +1,40 @@
+import mf2py  # type: ignore
+from sqlalchemy.orm import Session
+
+from app import activitypub as ap
+from app import webfinger
+from app.actor import Actor
+from app.actor import fetch_actor
+from app.ap_object import RemoteObject
+
+
+def lookup(db: Session, query: str) -> Actor | RemoteObject:
+    if query.startswith("@"):
+        query = webfinger.get_actor_url(query)  # type: ignore  # None check below
+
+        if not query:
+            raise ap.NotAnObjectError(query)
+
+    try:
+        ap_obj = ap.fetch(query)
+    except ap.NotAnObjectError as not_an_object_error:
+        resp = not_an_object_error.resp
+        if not resp:
+            raise ap.NotAnObjectError(query)
+
+        alternate_obj = None
+        if resp.headers.get("content-type", "").startswith("text/html"):
+            for alternate in mf2py.parse(doc=resp.text).get("alternates", []):
+                if alternate.get("type") == "application/activity+json":
+                    alternate_obj = ap.fetch(alternate["url"])
+
+        if alternate_obj:
+            ap_obj = alternate_obj
+        else:
+            raise
+
+    if ap_obj["type"] in ap.ACTOR_TYPES:
+        actor = fetch_actor(db, ap_obj["id"])
+        return actor
+    else:
+        return RemoteObject(ap_obj)