feat: add search relevance review lab

backend/search/reviews.py

@@ -0,0 +1,82 @@
+"""Persistence and signed snapshots for search relevance reviews."""
+
+from __future__ import annotations
+
+import base64
+import hashlib
+import hmac
+import json
+import secrets
+import sqlite3
+import threading
+import time
+from pathlib import Path
+
+
+MAX_COMMENT = 4000
+MAX_REVIEWER = 120
+
+
+class ReviewStore:
+    def __init__(self, path: Path | str = ":memory:"):
+        if path != ":memory:":
+            Path(path).parent.mkdir(parents=True, exist_ok=True)
+        self.connection = sqlite3.connect(path, check_same_thread=False)
+        self.connection.row_factory = sqlite3.Row
+        # ponytail: one SQLite lock; split connections only if review throughput matters.
+        self._lock = threading.Lock()
+        self.connection.execute("""
+            CREATE TABLE IF NOT EXISTS search_reviews (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                created_at TEXT NOT NULL,
+                reviewer TEXT NOT NULL,
+                query TEXT NOT NULL,
+                language TEXT NOT NULL,
+                index_name TEXT NOT NULL,
+                top_result_code TEXT,
+                results_json TEXT NOT NULL,
+                overall_comment TEXT NOT NULL
+            )
+        """)
+        self.connection.commit()
+
+    def save(self, review: dict) -> int:
+        with self._lock:
+            cursor = self.connection.execute(
+                "INSERT INTO search_reviews(created_at, reviewer, query, language, index_name, top_result_code, results_json, overall_comment) VALUES(?, ?, ?, ?, ?, ?, ?, ?)",
+                (review["created_at"], review["reviewer"], review["query"], review["language"], review["index_name"], review["top_result_code"], json.dumps(review["results"], ensure_ascii=False), review["overall_comment"]),
+            )
+            self.connection.commit()
+            return int(cursor.lastrowid)
+
+    def export(self) -> list[dict]:
+        with self._lock:
+            return [
+                {**dict(row), "results": json.loads(row["results_json"])}
+                for row in self.connection.execute("SELECT * FROM search_reviews ORDER BY id")
+            ]
+
+
+class ReviewSnapshots:
+    def __init__(self, secret: bytes | None = None, ttl: int = 3600):
+        self.secret = secret or secrets.token_bytes(32)
+        self.ttl = ttl
+
+    def create(self, query: str, language: str, index: str, results: list[dict]) -> str:
+        payload = {"query": query, "language": language, "index_name": index, "results": results, "expires_at": int(time.time()) + self.ttl}
+        encoded = base64.urlsafe_b64encode(json.dumps(payload, ensure_ascii=False, separators=(",", ":")).encode()).decode().rstrip("=")
+        signature = hmac.new(self.secret, encoded.encode(), hashlib.sha256).hexdigest()
+        return f"{encoded}.{signature}"
+
+    def verify(self, token: str) -> dict:
+        try:
+            encoded, signature = token.split(".", 1)
+            expected = hmac.new(self.secret, encoded.encode(), hashlib.sha256).hexdigest()
+            if not hmac.compare_digest(signature, expected):
+                raise ValueError
+            payload = json.loads(base64.urlsafe_b64decode(encoded + "=" * (-len(encoded) % 4)))
+            if payload["expires_at"] < int(time.time()):
+                raise ValueError
+            return payload
+        except (ValueError, KeyError, TypeError, json.JSONDecodeError, UnicodeError) as error:
+            raise ValueError("invalid or expired search snapshot") from error