Replace abstract handlers, customer handlers, type annotations, refactoring.

.github/workflows/test.yml

@@ -11,28 +11,28 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10']
+        python-version: ["3.7", "3.8", "3.9", "3.10"]
     steps:
-    - uses: actions/checkout@v2
-    - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v2
-      with:
-        python-version: ${{ matrix.python-version }}
-    - uses: actions/cache@v2
-      name: Configure pip caching
-      with:
-        path: ~/.cache/pip
-        key: ${{ runner.os }}-pip-${{ hashFiles('**/setup.py') }}
-        restore-keys: |
-          ${{ runner.os }}-pip-
-    - name: Install dependencies
-      run: |
-        pip install -U -r requirements.txt
-    - name: Run tests
-      run: |
-        scripts/test
-    - name: Run linters
-      run: |
-        scripts/lint
-    - name: Run codecov
-      run: codecov
+      - uses: actions/checkout@v2
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+      - uses: actions/cache@v2
+        name: Configure pip caching
+        with:
+          path: ~/.cache/pip
+          key: ${{ runner.os }}-pip-${{ hashFiles('**/setup.py') }}
+          restore-keys: |
+            ${{ runner.os }}-pip-
+      - name: Install dependencies
+        run: |
+          pip install -U -r requirements.txt
+      - name: Run tests
+        run: |
+          scripts/test
+      - name: Run linters
+        run: |
+          scripts/lint
+      - name: Run codecov
+        run: codecov

README.md

@@ -8,13 +8,13 @@
 </a>
 <img alt="PyPI - Python Version" src="https://img.shields.io/pypi/pyversions/mangum.svg?style=flat-square">
 
-Mangum is an adapter for using [ASGI](https://asgi.readthedocs.io/en/latest/) applications with AWS Lambda & API Gateway. It is intended to provide an easy-to-use, configurable wrapper for any ASGI application deployed in an AWS Lambda function to handle API Gateway requests and responses.
+Mangum is an adapter for running [ASGI](https://asgi.readthedocs.io/en/latest/) applications in AWS Lambda to handle API Gateway, ALB, and Lambda@Edge events.
 
 ***Documentation***: https://mangum.io/
 
 ## Features
 
-- API Gateway support for [HTTP](https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api.html) and [REST](https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-rest-api.html) APIs.
+- Event handlers for API Gateway [HTTP](https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api.html) and [REST](https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-rest-api.html) APIs, [Application Load Balancer](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/lambda-functions.html), and [CloudFront Lambda@Edge](https://docs.aws.amazon.com/lambda/latest/dg/lambda-edge.html).
 
 - Compatibility with ASGI application frameworks, such as [Starlette](https://www.starlette.io/), [FastAPI](https://fastapi.tiangolo.com/), and [Quart](https://pgjones.gitlab.io/quart/). 
 
@@ -26,7 +26,7 @@ Mangum is an adapter for using [ASGI](https://asgi.readthedocs.io/en/latest/) ap
 
 ## Requirements
 
-Python 3.6+
+Python 3.7+
 
 ## Installation
 
@@ -53,7 +53,7 @@ async def app(scope, receive, send):
 handler = Mangum(app)
 ```
 
-Or using a framework.
+Or using a framework:
 
 ```python
 from fastapi import FastAPI

docs/asgi-frameworks.md

@@ -30,7 +30,7 @@ None of the framework details are important here. The routing decorator, request
 
 ```python
 class Application(Protocol):
-    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
+    async def __call__(self, scope: Scope, receive: ASGIReceive, send: ASGISend) -> None:
         ...
 ```
 

docs/index.md

@@ -8,13 +8,13 @@
 </a>
 <img alt="PyPI - Python Version" src="https://img.shields.io/pypi/pyversions/mangum.svg?style=flat-square">
 
-Mangum is an adapter for using [ASGI](https://asgi.readthedocs.io/en/latest/) applications with AWS Lambda & API Gateway. It is intended to provide an easy-to-use, configurable wrapper for any ASGI application deployed in an AWS Lambda function to handle API Gateway requests and responses.
+Mangum is an adapter for running [ASGI](https://asgi.readthedocs.io/en/latest/) applications in AWS Lambda to handle API Gateway, ALB, and Lambda@Edge events.
 
 ***Documentation***: https://mangum.io/
 
 ## Features
 
-- API Gateway support for [HTTP](https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api.html) and [REST](https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-rest-api.html) APIs.
+- Event handlers for API Gateway [HTTP](https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api.html) and [REST](https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-rest-api.html) APIs, [Application Load Balancer](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/lambda-functions.html), and [CloudFront Lambda@Edge](https://docs.aws.amazon.com/lambda/latest/dg/lambda-edge.html).
 
 - Compatibility with ASGI application frameworks, such as [Starlette](https://www.starlette.io/), [FastAPI](https://fastapi.tiangolo.com/), and [Quart](https://pgjones.gitlab.io/quart/). 
 
@@ -26,7 +26,7 @@ Mangum is an adapter for using [ASGI](https://asgi.readthedocs.io/en/latest/) ap
 
 ## Requirements
 
-Python 3.6+
+Python 3.7+
 
 ## Installation
 
@@ -53,7 +53,7 @@ async def app(scope, receive, send):
 handler = Mangum(app)
 ```
 
-Or using a framework.
+Or using a framework:
 
 ```python
 from fastapi import FastAPI

mangum/__init__.py

@@ -1,4 +1,3 @@
-from .types import Request, Response
-from .adapter import Mangum  # noqa: F401
+from mangum.adapter import Mangum
 
-__all__ = ["Mangum", "Request", "Response"]
+__all__ = ["Mangum"]

mangum/adapter.py

@@ -1,66 +1,92 @@
+from itertools import chain
 import logging
 from contextlib import ExitStack
+from typing import List, Optional, Type
+import warnings
 
-
-from mangum.exceptions import ConfigurationError
-from mangum.handlers.abstract_handler import AbstractHandler
 from mangum.protocols import HTTPCycle, LifespanCycle
-from mangum.types import ASGIApp, LambdaEvent, LambdaContext
+from mangum.handlers import ALB, HTTPGateway, APIGateway, LambdaAtEdge
+from mangum.exceptions import ConfigurationError
+from mangum.types import (
+    ASGIApp,
+    LifespanMode,
+    LambdaConfig,
+    LambdaEvent,
+    LambdaContext,
+    LambdaHandler,
+)
 
 
-DEFAULT_TEXT_MIME_TYPES = [
-    "text/",
-    "application/json",
-    "application/javascript",
-    "application/xml",
-    "application/vnd.api+json",
-]
+logger = logging.getLogger("mangum")
 
 
-logger = logging.getLogger("mangum")
+HANDLERS: List[Type[LambdaHandler]] = [
+    ALB,
+    HTTPGateway,
+    APIGateway,
+    LambdaAtEdge,
+]
 
 
 class Mangum:
-    """
-    Creates an adapter instance.
-
-    * **app** - An asynchronous callable that conforms to version 3.0 of the ASGI
-    specification. This will usually be an ASGI framework application instance.
-    * **lifespan** - A string to configure lifespan support. Choices are `auto`, `on`,
-    and `off`. Default is `auto`.
-    * **text_mime_types** - A list of MIME types to include with the defaults that
-    should not return a binary response in API Gateway.
-    * **api_gateway_base_path** - A string specifying the part of the url path after
-    which the server routing begins.
-    """
-
     def __init__(
         self,
         app: ASGIApp,
-        lifespan: str = "auto",
+        lifespan: LifespanMode = "auto",
         api_gateway_base_path: str = "/",
+        custom_handlers: Optional[List[Type[LambdaHandler]]] = None,
     ) -> None:
+        if lifespan not in ("auto", "on", "off"):
+            raise ConfigurationError(
+                "Invalid argument supplied for `lifespan`. Choices are: auto|on|off"
+            )
+
         self.app = app
         self.lifespan = lifespan
-        self.api_gateway_base_path = api_gateway_base_path
+        self.api_gateway_base_path = api_gateway_base_path or "/"
+        self.config = LambdaConfig(api_gateway_base_path=self.api_gateway_base_path)
 
-        if self.lifespan not in ("auto", "on", "off"):
-            raise ConfigurationError(
-                "Invalid argument supplied for `lifespan`. Choices are: auto|on|off"
+        if custom_handlers is not None:
+            warnings.warn(  # pragma: no cover
+                "Support for custom event handlers is currently provisional and may "
+                "drastically change (or be removed entirely) in the future.",
+                FutureWarning,
             )
 
-    def __call__(self, event: LambdaEvent, context: LambdaContext) -> dict:
-        logger.debug("Event received.")
+        self.custom_handlers = custom_handlers or []
+
+    def infer(self, event: LambdaEvent, context: LambdaContext) -> LambdaHandler:
+        for handler_cls in chain(
+            self.custom_handlers,
+            HANDLERS,
+        ):
+            handler = handler_cls.infer(
+                event,
+                context,
+                self.config,
+            )
+            if handler:
+                break
+        else:
+            raise RuntimeError(  # pragma: no cover
+                "The adapter was unable to infer a handler to use for the event. This "
+                "is likely related to how the Lambda function was invoked. (Are you "
+                "testing locally? Make sure the request payload is valid for a "
+                "supported handler.)"
+            )
+
+        return handler
 
+    def __call__(self, event: LambdaEvent, context: LambdaContext) -> dict:
+        handler = self.infer(event, context)
         with ExitStack() as stack:
-            if self.lifespan != "off":
+            if self.lifespan in ("auto", "on"):
                 lifespan_cycle = LifespanCycle(self.app, self.lifespan)
                 stack.enter_context(lifespan_cycle)
 
-        handler = AbstractHandler.from_trigger(
-            event, context, self.api_gateway_base_path
-        )
-        http_cycle = HTTPCycle(handler.request)
-        response = http_cycle(self.app, handler.body)
+            http_cycle = HTTPCycle(handler.scope, handler.body)
+            http_response = http_cycle(self.app)
+
+            return handler(http_response)
 
-        return handler.transform_response(response)
+        assert False, "unreachable"  # pragma: no cover

mangum/handlers/__init__.py

@@ -0,0 +1,6 @@
+from mangum.handlers.api_gateway import APIGateway, HTTPGateway
+from mangum.handlers.alb import ALB
+from mangum.handlers.lambda_at_edge import LambdaAtEdge
+
+
+__all__ = ["APIGateway", "HTTPGateway", "ALB", "LambdaAtEdge"]