Files
PMTiles/serverless/aws/lambda_function.py

62 lines
1.5 KiB
Python

import base64
import collections
from functools import lru_cache
import gzip
import json
import os
import re
import boto3
import pmtiles
Zxy = collections.namedtuple("Zxy", ["z", "x", "y"])
s3 = boto3.client("s3")
@lru_cache
def get_object_bytes(key, offset, length):
end = offset + length - 1
return (
s3.get_object(
Bucket=os.environ["BUCKET"],
Key=key,
Range=f"bytes={offset}-{end}",
)
.get("Body")
.read()
)
def parse_tile_uri(str):
m = re.match("^(?:/([0-9a-zA-Z/!\-_\.\*'\(\)]+))?/(\d+)/(\d+)/(\d+).pbf$", str)
if not m:
return None, None
return (m.group(1), Zxy(int(m.group(2)), int(m.group(3)), int(m.group(4))))
def lambda_handler(event, context):
start = datetime.now()
uri = event["rawPath"] # API Gateway and Lambda Function URLs
tileset, tile = parse_tile_uri(uri)
if not tile:
return {"statusCode": 400, "body": "Invalid Tile URL"}
def get_bytes(offset, length):
return get_object_bytes(tileset + ".pmtiles", offset, length)
reader = pmtiles.Reader(get_bytes)
tile_data = reader.get(tile.z, tile.x, tile.y)
if not tile_data:
return {"statusCode": 404, "body": "Tile not found"}
if reader.header().metadata.get("compression") == "gzip":
tile_data = gzip.decompress(tile_data)
return {
"statusCode": 200,
"body": base64.b64encode(tile_data),
"isBase64Encoded": True,
"headers": {"Content-Type": "application/protobuf"},
}