Serve TMS tiles from an SQLite3, MBTiles spec database. Also provide a timestamp suitable for HTTP headers based on file timestamp.

mbtiles.py

import sqlite3
import os.path
from email import utils

class MBTilesTMS:
    def __init__(self, filename):
        if os.path.isfile(filename):
            self.filename = filename
            self.dbconn = sqlite3.connect(filename)
        else:
            raise ValueError("Value must be a valid file name")
    
    def get_format(self):
        #TODO: Tilemill is not using the current version of mbtiles spec
        #      which means the following does not work
        c = self.dbconn.cursor()
        c.execute('SELECT format FROM metadata')
        row = c.fetchone()
        return row[0]
    
    def get_image_bytes(self, z, x, y):
        c = self.dbconn.cursor()
        c.execute('''SELECT tile_data FROM tiles
                     WHERE zoom_level = {}
                     AND tile_column = {}
                     AND tile_row = {}'''.format(z, x, y)
        )
        row = c.fetchone()
        if not row:
            return None
        return bytes(row[0])
    def get_date_modified(self):
        filetimestamp = os.path.getmtime(self.filename)
        return utils.formatdate(filetimestamp)