add Lambda python implementation

serverless/aws/lambda_function.py

@@ -0,0 +1,79 @@
+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)