Initial commit

server.py

@@ -0,0 +1,51 @@
+from argparse import ArgumentParser
+from pathlib import Path
+import urllib.error
+import urllib.request
+
+from flask import Flask, send_file
+
+
+def main():
+    parser = ArgumentParser()
+    parser.add_argument('--debug', action='store_true', help='Run in debug mode (auto-reload on change)')
+    arguments = parser.parse_args()
+
+    debug_mode: bool = arguments.debug
+    del arguments
+
+    app = Flask('map_server', static_folder='public', static_url_path='/')
+    osm_timeout = 3
+    http_code_ok = 200
+
+    @app.route('/')
+    def _index():
+        return app.send_static_file('index.html')
+
+    @app.route('/<int:zoom>/<int:x>/<int:y>.png')
+    def _tile(zoom: int, x: int, y: int):
+        tile_path = Path('data', str(zoom), str(x), f'{y}.png')
+        if tile_path.exists():
+            return send_file(tile_path)
+        if not tile_path.parent.exists():
+            tile_path.parent.mkdir(parents=True, exist_ok=True)
+        request = urllib.request.Request(f'https://tile.openstreetmap.org/{zoom}/{x}/{y}.png')
+        request.add_header('User-Agent', 'Mozilla/5.0 (X11; Linux x86_64; rv:138.0) Gecko/20100101 Firefox/138.0')
+        request.add_header('Accept', 'image/avif,image/webp,image/png,image/svg+xml,image/*;q=0.8,*/*;q=0.5')
+        request.add_header('Accept-Language', 'en-US,en;q=0.5')
+        request.add_header('Accept-Encoding', 'gzip, deflate, br, zstd')
+        try:
+            with urllib.request.urlopen(request, timeout=osm_timeout) as response:
+                if response.status != http_code_ok:
+                    return (f'tile.openstreetmap.org answer is not OK (status: {response.status}) : {response.read()}',
+                            501)
+                tile_path.write_bytes(response.read())
+                return send_file(tile_path)
+        except urllib.error.URLError as error:
+            return f'Cannot retrieve tile: {error}', 501
+
+    app.run(host='0.0.0.0', port=8000, debug=debug_mode)
+
+
+if __name__ == '__main__':
+    main()