mtdb

README.md

@@ -45,6 +45,14 @@ Example:
 
 Prefer cbor+gzip for big imports. lzma is much slower than gzip but produces slightly smaller files. cbor is much smaller than json.
 
+## Library
+
+`mtdb.py` is a Python3 library for interacting with MineTest db.
+
+	import mtdb
+	db = mtdb.init_pgsql("host=127.0.0.1 port=5432 user=minetest password=PASSWORD dbname=minetest-world")
+	mtdb.get_chunk(db, (0,0,0)) # Chunk position, not node position (1 chunk = cube of 16*16*16 nodes)
+
 ## License
 
 GNU AGPL 3.0

mtdb.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python3
+
+DB_PGSQL = 1
+DB_SQLITE = 2
+
+class Db:
+	def __init__(self, obj, dbtype):
+		self.obj = obj
+		self.dbtype = dbtype
+
+# Init PostgreSQL database
+def init_pgsql(connect: str):
+	global psycopg2
+	import psycopg2
+	return Db(psycopg2.connect(connect), DB_PGSQL)
+
+# Init SQLite database
+def init_sqlite(dbname: str):
+	global sqlite3
+	import sqlite3
+	return Db(sqlite3.connect(dbname), DB_SQLITE)
+
+def to_signed(x, bits=11):
+	return x if x >= 0 else (1<<bits)-x
+
+def from_signed(x, bits=11):
+	b = 1<<bits
+	return x if x < b else (b^x)-b
+
+def chunk_to_int(pos: (int, int, int)):
+	return to_signed(pos[2])<<24 | to_signed(pos[1])<<12 | to_signed(pos[0])
+
+def int_to_chunk(pos: int):
+	return (from_signed(pos>>24), from_signed(pos>>12&0xfff), from_signed(pos&0xfff))
+
+# Read chunk from db
+def get_chunk(db: Db, pos: (int, int, int)):
+	if db.dbtype == DB_PGSQL:
+		c = db.obj.cursor()
+		c.execute("SELECT data FROM blocks WHERE posx={} AND posy={} AND posz={} LIMIT 1".format(*pos))
+		res = c.fetchone()
+		if res:
+			res = res[0].tobytes()
+		return res
+	else:
+		c = db.obj.cursor()
+		c.execute("SELECT data FROM blocks WHERE pos={} LIMIT 1".format(chunk_to_int(pos)))
+		res = c.fetchone()
+		if res:
+			res = res[0]
+		return res
+
+# Write chunk to db
+def set_chunk(db: Db, pos: (int, int, int), data: bytes):
+	if db.dbtype == DB_PGSQL:
+		c = db.obj.cursor()
+		c.execute("SELECT 1 FROM blocks WHERE posx={} AND posy={} AND posz={} LIMIT 1".format(*pos))
+		if c.fetchone():
+			c.execute("UPDATE blocks SET data={} WHERE posx={} AND posy={} AND posz={} LIMIT 1".format(data, *pos))
+		else:
+			c.execute("INSERT INTO blocks (posx, posy, posz, data) VALUES ({}, {}, {}, {})".format(*pos, data))
+	else:
+		chunk_id = chunk_to_int(pos)
+		c.execute("SELECT 1 FROM blocks WHERE pos={} LIMIT 1".format(chunk_id))
+		if c.fetchone():
+			c.execute("UPDATE blocks SET data={} WHERE pos={} LIMIT 1".format(data, chunk_id))
+		else:
+			c.execute("INSERT INTO blocks (pos, data) VALUES ({}, {})".format(chunk_id, data))