Only prefix a slash on the api_gateway_base_path if needed (#138)

* Only prefix a slash on the api_gateway_base_path if needed

* Improve readability and compatibility with black python linter

Co-authored-by: DJ Spatoulas <djs@knowbe4.com>

Author: dspatoulas

.gitignore

@@ -102,3 +102,6 @@ venv.bak/
 
 # mypy
 .mypy_cache/
+
+# IDE Settings
+.idea/

mangum/adapter.py

@@ -84,7 +84,11 @@ def __post_init__(self, enable_lifespan: bool) -> None:
                 "Invalid argument supplied for `log_level`. "
                 "Choices are: critical|error|warning|info|debug"
             )
-        if self.api_gateway_base_path:
+        should_prefix_base_path = (
+            self.api_gateway_base_path
+            and not self.api_gateway_base_path.startswith("/")
+        )
+        if should_prefix_base_path:
             self.api_gateway_base_path = f"/{self.api_gateway_base_path}"
         if self.text_mime_types:
             self.text_mime_types = self.text_mime_types + DEFAULT_TEXT_MIME_TYPES

requirements.txt

@@ -5,7 +5,6 @@ pytest-cov
 black
 starlette
 quart; python_version == '3.7'
-dataclasses; python_version < '3.7'
 moto
 mypy