Add nodeinfo helper

utils/nodeinfo.py

@@ -0,0 +1,77 @@
+from enum import Enum
+from enum import unique
+from functools import lru_cache
+from typing import Optional
+
+import little_boxes.activitypub as ap
+import requests
+
+
+@unique
+class SoftwareName(Enum):
+    UNKNOWN = "unknown"
+    MASTODON = "mastodon"
+    MICROBLOGPUB = "microblogpub"
+
+
+def _get_nodeinfo_url(server: str) -> Optional[str]:
+    backend = ap.get_backend()
+    for scheme in {"https", "http"}:
+        try:
+            resp = requests.get(
+                f"{scheme}://{server}/.well-known/nodeinfo",
+                timeout=10,
+                allow_redirects=True,
+                headers={"User-Agent": backend.user_agent()},
+            )
+            resp.raise_for_status()
+            data = resp.json()
+            for link in data.get("links", []):
+                return link["href"]
+        except requests.HTTPError:
+            return None
+        except requests.RequestException:
+            continue
+
+    return None
+
+
+def _try_mastodon_api(server: str) -> bool:
+    for scheme in {"https", "http"}:
+        try:
+            resp = requests.get(f"{scheme}://{server}/api/v1/instance")
+            resp.raise_for_status()
+            if resp.json():
+                return True
+        except requests.HTTPError:
+            return False
+        except requests.RequestException:
+            continue
+
+    return False
+
+
+@lru_cache(2048)
+def get_software_name(server: str) -> str:
+    backend = ap.get_backend()
+    nodeinfo_endpoint = _get_nodeinfo_url(server)
+    if nodeinfo_endpoint:
+        try:
+            resp = requests.get(
+                nodeinfo_endpoint,
+                timeout=10,
+                headers={"User-Agent": backend.user_agent()},
+            )
+            resp.raise_for_status()
+            software_name = resp.json().get("software", {}).get("name")
+            if software_name:
+                return software_name
+
+            return SoftwareName.UNKNOWN.value
+        except requests.RequestException:
+            pass
+
+    if _try_mastodon_api(server):
+        return SoftwareName.MASTODON.value
+
+    return SoftwareName.UNKNOWN.value