Add lambda extractors (#2038)

rust-runtime/aws-smithy-http-server/src/request/lambda.rs

@@ -0,0 +1,52 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+//! The [`lambda_http`] types included in [`http::Request`]s when [`LambdaHandler`](crate::routing::LambdaHandler) is
+//! used. Each are given a [`FromParts`] implementation for easy use within handlers.
+
+use lambda_http::request::RequestContext;
+#[doc(inline)]
+pub use lambda_http::{
+    aws_lambda_events::apigw::{ApiGatewayProxyRequestContext, ApiGatewayV2httpRequestContext},
+    Context,
+};
+
+use super::{extension::MissingExtension, FromParts};
+use crate::Extension;
+
+impl<P> FromParts<P> for Context {
+    type Rejection = MissingExtension;
+
+    fn from_parts(parts: &mut http::request::Parts) -> Result<Self, Self::Rejection> {
+        let Extension(context) = <Extension<Self> as FromParts<P>>::from_parts(parts)?;
+        Ok(context)
+    }
+}
+
+impl<P> FromParts<P> for ApiGatewayProxyRequestContext {
+    type Rejection = MissingExtension;
+
+    fn from_parts(parts: &mut http::request::Parts) -> Result<Self, Self::Rejection> {
+        let Extension(context) = <Extension<RequestContext> as FromParts<P>>::from_parts(parts)?;
+        if let RequestContext::ApiGatewayV1(context) = context {
+            Ok(context)
+        } else {
+            Err(MissingExtension)
+        }
+    }
+}
+
+impl<P> FromParts<P> for ApiGatewayV2httpRequestContext {
+    type Rejection = MissingExtension;
+
+    fn from_parts(parts: &mut http::request::Parts) -> Result<Self, Self::Rejection> {
+        let Extension(context) = <Extension<RequestContext> as FromParts<P>>::from_parts(parts)?;
+        if let RequestContext::ApiGatewayV2(context) = context {
+            Ok(context)
+        } else {
+            Err(MissingExtension)
+        }
+    }
+}

rust-runtime/aws-smithy-http-server/src/request/mod.rs

@@ -52,6 +52,9 @@ use crate::{rejection::any_rejections, response::IntoResponse};
 
 pub mod connect_info;
 pub mod extension;
+#[cfg(feature = "aws-lambda")]
+#[cfg_attr(docsrs, doc(cfg(feature = "aws-lambda")))]
+pub mod lambda;
 
 #[doc(hidden)]
 #[derive(Debug)]