Add simple database example

examples/LICENSE

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2018 Tulir Asokan
+Copyright (c) 2022 Tulir Asokan
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of
 this software and associated documentation files (the "Software"), to deal in

examples/README.md

@@ -4,3 +4,4 @@ All examples are published under the [MIT license](LICENSE).
 * [Hello World](helloworld/) - Very basic event handling bot that responds "Hello, World!" to all messages.
 * [Echo bot](https://github.com/maubot/echo) - Basic command handling bot with !echo and !ping commands
 * [Config example](config/) - Simple example of using a config file
+* [Database example](database/) - Simple example of using a database

examples/config/maubot.yaml

@@ -1,5 +1,5 @@
 maubot: 0.1.0
-id: xyz.maubot.databasebot
+id: xyz.maubot.configurablebot
 version: 2.0.0
 license: MIT
 modules:

examples/database/storagebot.py

@@ -0,0 +1,72 @@
+from __future__ import annotations
+
+from mautrix.util.async_db import UpgradeTable, Connection
+from maubot import Plugin, MessageEvent
+from maubot.handlers import command
+
+upgrade_table = UpgradeTable()
+
+
+@upgrade_table.register(description="Initial revision")
+async def upgrade_v1(conn: Connection) -> None:
+    await conn.execute(
+        """CREATE TABLE stored_data (
+            key   TEXT PRIMARY KEY,
+            value TEXT NOT NULL
+        )"""
+    )
+
+
+@upgrade_table.register(description="Remember user who added value")
+async def upgrade_v2(conn: Connection) -> None:
+    await conn.execute("ALTER TABLE stored_data ADD COLUMN creator TEXT")
+
+
+class StorageBot(Plugin):
+    @command.new()
+    async def storage(self, evt: MessageEvent) -> None:
+        pass
+
+    @storage.subcommand(help="Store a value")
+    @command.argument("key")
+    @command.argument("value", pass_raw=True)
+    async def put(self, evt: MessageEvent, key: str, value: str) -> None:
+        q = """
+            INSERT INTO stored_data (key, value, creator) VALUES ($1, $2, $3)
+            ON CONFLICT (key) DO UPDATE SET value=excluded.value, creator=excluded.creator
+        """
+        await self.database.execute(q, key, value, evt.sender)
+        await evt.reply(f"Inserted {key} into the database")
+
+    @storage.subcommand(help="Get a value from the storage")
+    @command.argument("key")
+    async def get(self, evt: MessageEvent, key: str) -> None:
+        q = "SELECT key, value, creator FROM stored_data WHERE LOWER(key)=LOWER($1)"
+        row = await self.database.fetchrow(q, key)
+        if row:
+            key = row["key"]
+            value = row["value"]
+            creator = row["creator"]
+            await evt.reply(f"`{key}` stored by {creator}:\n\n```\n{value}\n```")
+        else:
+            await evt.reply(f"No data stored under `{key}` :(")
+
+    @storage.subcommand(help="List keys in the storage")
+    @command.argument("prefix", required=False)
+    async def list(self, evt: MessageEvent, prefix: str | None) -> None:
+        q = "SELECT key, creator FROM stored_data WHERE key LIKE $1"
+        rows = await self.database.fetch(q, prefix + "%")
+        prefix_reply = f" starting with `{prefix}`" if prefix else ""
+        if len(rows) == 0:
+            await evt.reply(f"Nothing{prefix_reply} stored in database :(")
+        else:
+            formatted_data = "\n".join(
+                f"* `{row['key']}` stored by {row['creator']}" for row in rows
+            )
+            await evt.reply(
+                f"Found {len(rows)} keys{prefix_reply} in database:\n\n{formatted_data}"
+            )
+
+    @classmethod
+    def get_db_upgrade_table(cls) -> UpgradeTable | None:
+        return upgrade_table