Better features separation

[datasette-connectors.git] / datasette_connectors / monkey.py

diff --git a/datasette_connectors/monkey.py b/datasette_connectors/monkey.py
new file mode 100644 (file)
index 0000000..e18175f
--- /dev/null
+++ b/datasette_connectors/monkey.py
@@ -0,0 +1,87 @@
+import asyncio
+import datasette
+from datasette.app import connections
+from datasette.inspect import inspect_hash
+from datasette.utils import Results
+from pathlib import Path
+import sqlite3
+
+from . import connectors
+
+
+def patch_datasette():
+    """
+    Monkey patching for original Datasette
+    """
+
+    def inspect(self):
+        " Inspect the database and return a dictionary of table metadata "
+        if self._inspect:
+            return self._inspect
+
+        _inspect = {}
+        files = self.files
+
+        for filename in files:
+            self.files = (filename,)
+            path = Path(filename)
+            name = path.stem
+            if name in _inspect:
+                raise Exception("Multiple files with the same stem %s" % name)
+            try:
+                _inspect[name] = self.original_inspect()[name]
+            except sqlite3.DatabaseError:
+                tables, views, dbtype = connectors.inspect(path)
+                _inspect[name] = {
+                    "hash": inspect_hash(path),
+                    "file": str(path),
+                    "dbtype": dbtype,
+                    "tables": tables,
+                    "views": views,
+                }
+
+        self.files = files
+        self._inspect = _inspect
+        return self._inspect
+
+    datasette.app.Datasette.original_inspect = datasette.app.Datasette.inspect
+    datasette.app.Datasette.inspect = inspect
+
+
+    async def execute(self, db_name, sql, params=None, truncate=False, custom_time_limit=None, page_size=None):
+        """Executes sql against db_name in a thread"""
+        page_size = page_size or self.page_size
+
+        def is_sqlite3_conn():
+            conn = getattr(connections, db_name, None)
+            if not conn:
+                info = self.inspect()[db_name]
+                return info.get('dbtype', 'sqlite3') == 'sqlite3'
+            else:
+                return isinstance(conn, sqlite3.Connection)
+
+        def sql_operation_in_thread():
+            conn = getattr(connections, db_name, None)
+            if not conn:
+                info = self.inspect()[db_name]
+                conn = connectors.connect(info['file'], info['dbtype'])
+                setattr(connections, db_name, conn)
+
+            rows, truncated, description = conn.execute(
+                sql,
+                params or {},
+                truncate=truncate,
+                page_size=page_size,
+                max_returned_rows=self.max_returned_rows,
+            )
+            return Results(rows, truncated, description)
+
+        if is_sqlite3_conn():
+            return await self.original_execute(db_name, sql, params=params, truncate=truncate, custom_time_limit=custom_time_limit, page_size=page_size)
+        else:
+            return await asyncio.get_event_loop().run_in_executor(
+                self.executor, sql_operation_in_thread
+            )
+
+    datasette.app.Datasette.original_execute = datasette.app.Datasette.execute
+    datasette.app.Datasette.execute = execute