feat(discovery): ListenBrainz similarity source

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-12 00:17:58 +02:00
parent 0338d8e119
commit 6f504a7c04
2 changed files with 92 additions and 0 deletions
@@ -0,0 +1,49 @@
+import requests
+
+from lyra_worker.similarity.base import SimilarArtist
+
+_DEFAULT_URL = "https://labs.api.listenbrainz.org"
+# ListenBrainz Labs similar-artists dataset requires an algorithm parameter.
+# NOTE: confirm this string + response field names against the live API during
+# manual verification; parsing below is defensive if the shape shifts.
+_DEFAULT_ALGORITHM = (
+    "session_based_days_7500_session_300_contribution_5_threshold_15_limit_50_filter_True_skip_30"
+)
+
+
+class ListenBrainzSource:
+    """SimilaritySource backed by the (unauthenticated) ListenBrainz Labs API."""
+
+    name = "listenbrainz"
+
+    def __init__(self, base_url: str = _DEFAULT_URL, algorithm: str = _DEFAULT_ALGORITHM,
+                 timeout: float = 15.0):
+        self._base = (base_url or _DEFAULT_URL).rstrip("/")
+        self._algorithm = algorithm
+        self._timeout = timeout
+
+    def health(self) -> bool:
+        try:
+            res = requests.get(self._base + "/", timeout=self._timeout)
+            return res.status_code < 500
+        except requests.RequestException:
+            return False
+
+    def similar_artists(self, mbid: str) -> list[SimilarArtist]:
+        res = requests.get(
+            self._base + "/similar-artists/json",
+            params={"artist_mbids": mbid, "algorithm": self._algorithm},
+            timeout=self._timeout,
+        )
+        res.raise_for_status()
+        out: list[SimilarArtist] = []
+        for row in res.json() or []:
+            ambid = row.get("artist_mbid")
+            if not ambid or ambid == mbid:
+                continue
+            out.append(SimilarArtist(
+                mbid=ambid,
+                name=row.get("name") or row.get("comment") or "",
+                score=float(row.get("score") or 0),
+            ))
+        return out