fix: network-share readers, model unload off the loop, bad save requests (#620)

Every read-only SQLite open now uses one URI helper, so a library on a Windows
network share works in backups, restores, moves and history reads. Unloading a
model no longer blocks the server. A malformed /save body gets a 400, not a 500.

database/health.py

@@ -16,18 +16,17 @@ check, and none of them carries a server path.
 
 import datetime
 import logging
-import ntpath
 import os
 import sqlite3
-from pathlib import PurePosixPath, PureWindowsPath
-from urllib.parse import quote
 
 try:
     from ..utils.hashing import register_prompt_functions
     from .models import normalize_image_path
+    from .sqlite_uri import readonly_uri
 except ImportError:
     from utils.hashing import register_prompt_functions
     from database.models import normalize_image_path
+    from database.sqlite_uri import readonly_uri
 
 logger = logging.getLogger("prompt_manager.database.health")
 
@@ -89,25 +88,6 @@ def _counted(lines):
     return _result(count, detail)
 
 
-def readonly_uri(db_path, *, windows=None):
-    """The ``mode=ro`` SQLite URI of *db_path*, on this platform or the given one.
-
-    pathlib spells a UNC path ``\\\\server\\share\\x.db`` as
-    ``file://server/share/x.db``, a remote authority SQLite refuses to open.
-    With an empty authority (``file:////server/share/x.db``) SQLite hands
-    Windows the ``//server/share`` path, which it opens as the UNC path.
-    """
-    if windows is None:
-        windows = os.name == "nt"
-        db_path = os.path.abspath(db_path)
-    if not windows:
-        return PurePosixPath(db_path).as_uri() + "?mode=ro"
-    path = PureWindowsPath(db_path)
-    if ntpath.splitdrive(str(path))[0].startswith("\\\\"):
-        return "file:" + quote("//" + path.as_posix()) + "?mode=ro"
-    return path.as_uri() + "?mode=ro"
-
-
 def _integrity(conn, _roots):
     rows = [
         row[0] for row in conn.execute(f"PRAGMA integrity_check({INTEGRITY_LIMIT})")

database/library_move.py

@@ -47,11 +47,11 @@ import sqlite3
 import time
 import types
 import uuid
-from pathlib import Path
 from dataclasses import dataclass, field
 from typing import Callable, Dict, List, Optional, Tuple
 
 from .models import BUSY_TIMEOUT_SECONDS, PromptModel
+from .sqlite_uri import readonly_uri
 
 try:
     from ..utils import library_location as ll
@@ -322,7 +322,7 @@ def _verify_copy(temp: str, counts, documents) -> None:
             "verify-failed",
             f"{MESSAGES['verify-failed']} {detail}" if detail else None,
         )
-    uri = Path(os.path.abspath(temp)).as_uri() + "?mode=ro"
+    uri = readonly_uri(temp)
     try:
         with contextlib.closing(sqlite3.connect(uri, uri=True)) as conn:
             copied = _describe(conn)

database/models.py

@@ -14,6 +14,7 @@ from contextlib import closing
 from pathlib import Path
 from typing import Optional, Set, Tuple
 
+from .sqlite_uri import readonly_uri
 from .managed_connection import (
     ManagedConnection,
     await_closed,
@@ -1199,7 +1200,7 @@ class PromptModel:
         if header != SQLITE_HEADER:
             return False, "Not a SQLite database file"
 
-        uri = Path(os.path.abspath(path)).as_uri() + "?mode=ro"
+        uri = readonly_uri(path)
         try:
             conn = sqlite3.connect(uri, uri=True)
         except sqlite3.Error as e:
@@ -1306,9 +1307,7 @@ class PromptModel:
         replacement (for example, incompatible page sizes in WAL mode),
         propagate the error rather than copy files under other open owners.
         """
-        source = sqlite3.connect(
-            Path(src_path).resolve().as_uri() + "?mode=ro", uri=True
-        )
+        source = sqlite3.connect(readonly_uri(Path(src_path).resolve()), uri=True)
         try:
             target = self.get_connection()
             # The target is written under backup's step too: mark it in use

database/restore_stage.py

@@ -42,6 +42,7 @@ from typing import Dict, Optional
 from . import workflow_documents as wd
 from .execution_history_schema import rotate_history_epoch
 from .safety_backup import take_safety_backup
+from .sqlite_uri import readonly_uri
 
 logger = logging.getLogger("prompt_manager.database.restore_stage")
 
@@ -114,7 +115,7 @@ def file_digest(path: str) -> str:
 
 
 def _readonly(path: str) -> sqlite3.Connection:
-    return sqlite3.connect(Path(path).resolve().as_uri() + "?mode=ro", uri=True)
+    return sqlite3.connect(readonly_uri(Path(path).resolve()), uri=True)
 
 
 def _schema(path: str) -> list:

database/sqlite_uri.py

@@ -0,0 +1,25 @@
+"""The read-only SQLite URI of a path, safe for Windows network shares."""
+
+import ntpath
+import os
+from pathlib import PurePosixPath, PureWindowsPath
+from urllib.parse import quote
+
+
+def readonly_uri(db_path, *, windows=None):
+    """The ``mode=ro`` SQLite URI of *db_path*, on this platform or the given one.
+
+    pathlib spells a UNC path ``\\\\server\\share\\x.db`` as
+    ``file://server/share/x.db``, a remote authority SQLite refuses to open.
+    With an empty authority (``file:////server/share/x.db``) SQLite hands
+    Windows the ``//server/share`` path, which it opens as the UNC path.
+    """
+    if windows is None:
+        windows = os.name == "nt"
+        db_path = os.path.abspath(db_path)
+    if not windows:
+        return PurePosixPath(db_path).as_uri() + "?mode=ro"
+    path = PureWindowsPath(db_path)
+    if ntpath.splitdrive(str(path))[0].startswith("\\\\"):
+        return "file:" + quote("//" + path.as_posix()) + "?mode=ro"
+    return path.as_uri() + "?mode=ro"