Refactoring

.gitignore

@@ -23,4 +23,6 @@ doc/api/
 # Further artifacts
 *.exe
 *.zip
-bootstrap
+bootstrap
+
+.idea

example/lib/main.dart

@@ -2,16 +2,15 @@ import 'package:aws_lambda_dart_runtime/aws_lambda_dart_runtime.dart';
 
 void main() async {
   /// This demo's handling an API Gateway request.
-  final Handler<AwsApiGatewayEvent> helloApiGateway = (context, event) async {
-    final response = {"message": "hello ${context.requestId}"};
+  final helloApiGateway = (context, event) async {
+    final response = {'message': 'hello ${context.requestId}'};
 
-    /// it returns an encoded response to the gateway
-    return InvocationResult(
-        context.requestId, AwsApiGatewayResponse.fromJson(response));
+    /// it returns an response to the gateway
+    return AwsApiGatewayResponse.fromJson(response);
   };
 
   /// The Runtime is a singleton. You can define the handlers as you wish.
   Runtime()
-    ..registerHandler<AwsApiGatewayEvent>("hello.apigateway", helloApiGateway)
+    ..registerHandler<AwsApiGatewayEvent>('hello.apigateway', helloApiGateway)
     ..invoke();
 }

lib/client/client.dart

@@ -2,6 +2,9 @@ import 'dart:io';
 import 'dart:async';
 import 'dart:convert';
 
+import 'package:meta/meta.dart';
+import 'package:http/http.dart' as http;
+
 /// Next invocation data wraps the data from the
 /// invocation endpoint of the Lambda Runtime Interface.
 class NextInvocation {
@@ -35,28 +38,26 @@ class NextInvocation {
   final String cognitoIdentity;
 
   /// Digesting a [HttpClientResponse] into a [NextInvocation].
-  static Future<NextInvocation> fromResponse(
-      HttpClientResponse response) async {
-    return NextInvocation(
-        response: json
-            .decode((await response.transform(Utf8Decoder()).toList()).first),
-        requestId: response.headers.value(runtimeRequestId),
-        deadlineMs: response.headers.value(runtimeDeadlineMs),
-        invokedFunctionArn: response.headers.value(runtimeInvokedFunctionArn),
-        traceId: response.headers.value(runtimeTraceId),
-        clientContext: response.headers.value(runtimeClientContext),
-        cognitoIdentity: response.headers.value(runtimeCognitoIdentity));
-  }
-
-  const NextInvocation(
-      {this.requestId,
-      this.deadlineMs,
-      this.traceId,
-      this.clientContext,
-      this.cognitoIdentity,
-      this.invokedFunctionArn,
-      this.response})
-      : assert(requestId != null);
+  static Future<NextInvocation> fromResponse(http.Response response) async =>
+      NextInvocation(
+          response: (json.decode(utf8.decode(response.bodyBytes)) as Map)
+              .cast<String, dynamic>(),
+          requestId: response.headers[runtimeRequestId],
+          deadlineMs: response.headers[runtimeDeadlineMs],
+          invokedFunctionArn: response.headers[runtimeInvokedFunctionArn],
+          traceId: response.headers[runtimeTraceId],
+          clientContext: response.headers[runtimeClientContext],
+          cognitoIdentity: response.headers[runtimeCognitoIdentity]);
+
+  const NextInvocation({
+    @required this.requestId,
+    this.deadlineMs,
+    this.traceId,
+    this.clientContext,
+    this.cognitoIdentity,
+    this.invokedFunctionArn,
+    this.response,
+  }) : assert(requestId != null);
 }
 
 /// Invocation result is the result that the invoked handler
@@ -92,8 +93,7 @@ class InvocationError {
   /// representation for the Runtime Interface.
   Map<String, dynamic> toJson() => {
         'errorMessage': error.toString(),
-        'errorType': "InvocationError",
-        'stackTrace': this.stackTrace.toString()
+        'errorType': 'InvocationError',
       };
 
   const InvocationError(this.error, this.stackTrace);
@@ -103,7 +103,7 @@ class InvocationError {
 /// It is implemented as a singleton whereby [Client.instance]
 /// always returns the already instantiated client.
 class Client {
-  HttpClient _client;
+  http.Client _client;
 
   static final Client _singleton = Client._internal();
 
@@ -112,53 +112,45 @@ class Client {
   }
 
   Client._internal() {
-    _client = HttpClient();
+    _client = http.Client();
   }
 
   static const runtimeApiVersion = '2018-06-01';
-  static final runtimeApi = Platform.environment["AWS_LAMBDA_RUNTIME_API"];
 
-  /// Get the next inovation from the AWS Lambda Runtime Interface (see https://docs.aws.amazon.com/lambda/latest/dg/runtimes-api.html).
+  static String get runtimeApi =>
+      Platform.environment['AWS_LAMBDA_RUNTIME_API'];
+
+  static String get handlerName => Platform.environment['_HANDLER'];
+
+  /// Get the next invocation from the AWS Lambda Runtime Interface (see https://docs.aws.amazon.com/lambda/latest/dg/runtimes-api.html).
   Future<NextInvocation> getNextInvocation() async {
-    final request = await _client.getUrl(Uri.parse(
+    final response = await _client.get(Uri.parse(
         'http://${runtimeApi}/${runtimeApiVersion}/runtime/invocation/next'));
-    final response = await request.close();
     return NextInvocation.fromResponse(response);
   }
 
   /// Post the invocation response to the AWS Lambda Runtime Interface.
-  Future<HttpClientResponse> postInvocationResponse(
-      InvocationResult result) async {
-    final request = await _client.postUrl(
+  Future<http.Response> postInvocationResponse(
+      String requestId, dynamic payload) async {
+    return await _client.post(
       Uri.parse(
-        'http://${runtimeApi}/${runtimeApiVersion}/runtime/invocation/${result.requestId}/response',
+        'http://${runtimeApi}/${runtimeApiVersion}/runtime/invocation/$requestId/response',
       ),
+      body: jsonEncode(payload),
     );
-    request.add(
-      utf8.encode(
-        json.encode(result.body),
-      ),
-    );
-
-    return await request.close();
   }
 
   /// Post an invocation error to the AWS Lambda Runtime Interface.
   /// It takes in an [InvocationError] and the [requestId]. The [requestId]
   /// is used to map the error to the execution.
-  Future<HttpClientResponse> postInvocationError(
+  Future<http.Response> postInvocationError(
       String requestId, InvocationError err) async {
-    final request = await _client.postUrl(
+    return await _client.post(
       Uri.parse(
         'http://${runtimeApi}/${runtimeApiVersion}/runtime/invocation/$requestId/error',
       ),
+      body: jsonEncode(err),
+      headers: {'Content-type': 'application/json'},
     );
-    request.add(
-        utf8.encode(
-            json.encode(err)
-        )
-    );
-
-    return await request.close();
   }
 }

lib/events/alb_event.dart

@@ -1,13 +1,14 @@
 import 'dart:io';
 
+import 'package:aws_lambda_dart_runtime/runtime/event.dart';
 import 'package:json_annotation/json_annotation.dart';
 
 part 'alb_event.g.dart';
 
 /// Event send by an Application Load Balancer to the
 /// invocation to the Lambda.
 @JsonSerializable()
-class AwsALBEvent {
+class AwsALBEvent extends Event {
   /// Request context in which this request is executed.
   /// For the ELB this is the ARN of the target group.
   @JsonKey()
@@ -43,14 +44,15 @@ class AwsALBEvent {
 
   Map<String, dynamic> toJson() => _$AwsALBEventToJson(this);
 
-  const AwsALBEvent(
-      {this.context,
-      this.httpMethod,
-      this.path,
-      this.headers,
-      this.queryStringParameters,
-      this.body,
-      this.isBase64Encoded});
+  const AwsALBEvent({
+    this.context,
+    this.httpMethod,
+    this.path,
+    this.headers,
+    this.queryStringParameters,
+    this.body,
+    this.isBase64Encoded,
+  });
 }
 
 /// Response for a request from an Application Load Balancer.
@@ -100,13 +102,18 @@ class AwsALBResponse {
 
   /// The Response that should be returned to the Application Load Balancer.
   /// It is constructed with some default values for the optional parameters.
-  AwsALBResponse(
-      {body, headers, isBase64Encoded, statusCode, statusDescription}) {
+  AwsALBResponse({
+    String body,
+    Map<String, String> headers,
+    bool isBase64Encoded,
+    int statusCode,
+    String statusDescription,
+  }) {
     this.body = body ?? '';
     this.isBase64Encoded = isBase64Encoded ?? false;
-    this.headers = headers ?? {"Content-Type": "text/html; charset=utf-8"};
+    this.headers = headers ?? {'Content-Type': 'text/html; charset=utf-8'};
     this.statusCode = statusCode ?? HttpStatus.ok;
-    this.statusDescription = statusDescription ?? "200 OK";
+    this.statusDescription = statusDescription ?? '200 OK';
   }
 }
 

lib/events/alexa_event.dart

@@ -1,3 +1,4 @@
+import 'package:aws_lambda_dart_runtime/runtime/event.dart';
 import 'package:json_annotation/json_annotation.dart';
 
 part 'alexa_event.g.dart';
@@ -28,7 +29,7 @@ class AwsAlexaEventHeader {
 /// Event send by an Application Load Balancer to the
 /// invocation to the Lambda.
 @JsonSerializable()
-class AwsAlexaEvent {
+class AwsAlexaEvent extends Event {
   /// Meta information about the event.
   @JsonKey()
   final AwsAlexaEventHeader header;