add Lambda python implementation

serverless/aws/.gitignore

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+lambda_function.zip

serverless/aws/config.py

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+BUCKET = "example-bucket-name"
+REGION = "us-east-1"

serverless/aws/create_lambda_function.py

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+import argparse
+import os
+import zipfile
+import sys
+
+parser = argparse.ArgumentParser(
+    description="Create a deployment-ready PMTiles Lambda zip."
+)
+parser.add_argument("region", help="AWS Region of the S3 bucket.")
+parser.add_argument("bucket", help="S3 Bucket Name.")
+args = parser.parse_args()
+
+with zipfile.ZipFile("lambda_function.zip", "w", zipfile.ZIP_DEFLATED) as z:
+    z.write("lambda_function.py")
+    z.write("../../python/pmtiles/reader.py", "pmtiles.py")
+    info = zipfile.ZipInfo("config.py")
+    info.external_attr = 0o777 << 16
+    z.writestr(info, f'REGION="{args.region}"\nBUCKET="{args.bucket}"')
+
+print(f"created lambda_function.zip with REGION {args.region} and BUCKET {args.bucket}")

serverless/aws/lambda_function.py

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+import json
+import pmtiles
+import re
+import boto3
+import base64
+import collections
+from config import BUCKET, REGION
+
+Zxy = collections.namedtuple("Zxy", ["z", "x", "y"])
+
+s3 = boto3.client("s3")
+
+rootCache = {}
+
+
+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 cloudfrontResponse(status_code, body, body_b64=False, headers={}):
+    headers = {key: [{"value": value}] for key, value in headers.items()}
+    resp = {"status": status_code, "body": body, "headers": headers}
+    if body_b64:
+        resp["bodyEncoding"] = "base64"
+    return resp
+
+
+def apiGatewayResponse(status_code, body, body_b64=False, headers={}):
+    resp = {"status": status_code, "body": body, "headers": headers}
+    if body_b64:
+        resp["isBase64Encoded"] = True
+    return resp
+
+
+def lambda_handler(event, context):
+    if "Records" in event:
+        uri = event["Records"][0]["cf"]["request"]["uri"]  # CloudFront Origin Request
+        lambdaResponse = cloudfrontResponse
+    else:
+        uri = event["rawPath"]  # API Gateway and Lambda Function URLs
+        lambdaResponse = apiGatewayResponse
+    tileset, tile = parse_tile_uri(uri)
+
+    if not tile:
+        return lambdaResponse(400, "Invalid tile URL")
+
+    def get_bytes(offset, length):
+        global rootCache
+        if offset == 0 and length == 512000 and tileset in rootCache:
+            return rootCache[tileset]
+
+        end = offset + length - 1
+        result = (
+            s3.get_object(
+                Bucket=BUCKET,
+                Key=tileset + ".pmtiles",
+                Range=f"bytes={offset}-{end}",
+            )
+            .get("Body")
+            .read()
+        )
+        if offset == 0 and length == 512000:
+            rootCache[tileset] = result
+        return result
+
+    reader = pmtiles.Reader(get_bytes)
+    tile_data = reader.get(tile.z, tile.x, tile.y)
+    if not tile_data:
+        return lambdaResponse(404, "Tile not found")
+
+    headers = {
+        "Content-Encoding": "gzip",
+        "Content-Type": "application/protobuf",
+        "Access-Control-Allow-Origin": "*",
+    }
+    return lambdaResponse(200, base64.b64encode(tile_data), True, headers)

serverless/aws/test_lambda_function.py

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+import unittest
+from lambda_function import parse_tile_uri, cloudfrontResponse, apiGatewayResponse
+
+
+class TestLambda(unittest.TestCase):
+    def test_parse_regex(self):
+        tileset, tile = parse_tile_uri("/0/0/0.pbf")
+        self.assertEqual(tileset, None)
+        self.assertEqual(tile.x, 0)
+        self.assertEqual(tile.y, 0)
+        self.assertEqual(tile.z, 0)
+
+        tileset, tile = parse_tile_uri("abcd")
+        self.assertEqual(tile, None)
+
+    def test_cloudfront_response(self):
+        resp = cloudfrontResponse(200, "ok", False, {"a": "b"})
+        self.assertEqual(resp["headers"]["a"], [{"value": "b"}])
+
+    def test_api_gateway_response(self):
+        resp = apiGatewayResponse(200, "ok", False, {"a": "b"})
+        self.assertEqual(resp["headers"]["a"], "b")
+
+
+if __name__ == "__main__":
+    unittest.main()