fix(event-handler): Set Content-Encoding header for compress

Author: Michael Brewer

aws_lambda_powertools/event_handler/api_gateway.py

@@ -75,10 +75,11 @@ def resolve(self, event: Dict, context: LambdaContext) -> Dict:
             headers["Cache-Control"] = route.cache_control if status_code == 200 else "no-cache"
 
         if route.compress and "gzip" in (self.current_event.get_header_value("accept-encoding") or ""):
+            headers["Content-Encoding"] = "gzip"
             if isinstance(body, str):
                 body = bytes(body, "utf-8")
-            gzip_compress = zlib.compressobj(9, zlib.DEFLATED, zlib.MAX_WBITS | 16)
-            body = gzip_compress.compress(body) + gzip_compress.flush()
+            gzip = zlib.compressobj(9, zlib.DEFLATED, zlib.MAX_WBITS | 16)
+            body = gzip.compress(body) + gzip.flush()
 
         base64_encoded = False
         if isinstance(body, bytes):

tests/functional/event_handler/test_api_gateway.py

@@ -158,6 +158,8 @@ def handler(event, context):
     assert isinstance(body, str)
     decompress = zlib.decompress(base64.b64decode(body), wbits=zlib.MAX_WBITS | 16).decode("UTF-8")
     assert decompress == expected_value
+    headers = result["headers"]
+    assert headers["Content-Encoding"] == "gzip"
 
 
 def test_base64_encode():
@@ -173,6 +175,22 @@ def read_image():
     assert result["isBase64Encoded"] is True
     body = result["body"]
     assert isinstance(body, str)
+    headers = result["headers"]
+    assert headers["Content-Encoding"] == "gzip"
+
+
+def test_compress_no_accept_encoding():
+    app = ApiGatewayResolver()
+    expected_value = "Foo"
+
+    @app.get("/my/path", compress=True)
+    def return_text():
+        return 200, "text/plain", expected_value
+
+    result = app({"path": "/my/path", "httpMethod": "GET", "headers": {}}, None)
+
+    assert result["isBase64Encoded"] is False
+    assert result["body"] == expected_value
 
 
 def test_cache_control_200():