fix(aws-apigateway): add integrationHttpMethod prop to AwsIntegration

Allows a custom http method to be used for an AWS integration, using POST as default.

Fixes #2105

packages/@aws-cdk/aws-apigateway/lib/integrations/aws.ts

@@ -49,6 +49,13 @@ export interface AwsIntegrationProps {
    */
   readonly actionParameters?: { [key: string]: string };
 
+  /**
+   * The integration's HTTP method type.
+   *
+   * @default POST
+   */
+  readonly integrationHttpMethod?: string;
+
   /**
    * Integration options, such as content handling, request/response mapping, etc.
    */
@@ -70,7 +77,7 @@ export class AwsIntegration extends Integration {
     const { apiType, apiValue } = parseAwsApiCall(props.path, props.action, props.actionParameters);
     super({
       type,
-      integrationHttpMethod: 'POST',
+      integrationHttpMethod: props.integrationHttpMethod || 'POST',
       uri: new cdk.Token(() => {
         if (!this.scope) { throw new Error('AwsIntegration must be used in API'); }
         return this.scope.node.stack.formatArn({

packages/@aws-cdk/aws-apigateway/test/test.method.ts

@@ -87,6 +87,28 @@ export = {
     test.done();
   },
 
+  'integration with a custom http method can be set via a property'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const api = new apigateway.RestApi(stack, 'test-api', { cloudWatchRole: false, deploy: false });
+
+    // WHEN
+    new apigateway.Method(stack, 'my-method', {
+      httpMethod: 'POST',
+      resource: api.root,
+      integration: new apigateway.AwsIntegration({ service: 's3', path: 'bucket/key', integrationHttpMethod: 'GET' })
+    });
+
+    // THEN
+    expect(stack).to(haveResourceLike('AWS::ApiGateway::Method', {
+      Integration: {
+        IntegrationHttpMethod: "GET"
+      }
+    }));
+
+    test.done();
+  },
+
   'use default integration from api'(test: Test) {
     // GIVEN
     const stack = new cdk.Stack();