feat(AWS API Gateway): Allow to opt-out from default request templates

(PR #8159)

docs/providers/aws/events/apigateway.md

@@ -994,6 +994,22 @@ functions:
 You can then access the query string `https://example.com/dev/whatever?bar=123` by `event.foo` in the lambda function.
 If you want to spread a string into multiple lines, you can use the `>` or `|` syntax, but the following strings have to be all indented with the same amount, [read more about `>` syntax](http://stackoverflow.com/questions/3790454/in-yaml-how-do-i-break-a-string-over-multiple-lines).
 
+In order to remove one of the default request templates you just need to pass it as null, as follows:
+
+```yml
+functions:
+  create:
+    handler: posts.create
+    events:
+      - http:
+          method: get
+          path: whatever
+          integration: lambda
+          request:
+            template:
+              application/x-www-form-urlencoded: null
+```
+
 #### Pass Through Behavior
 
 [API Gateway](https://serverless.com/amazon-api-gateway/) provides multiple ways to handle requests where the Content-Type header does not match any of the specified mapping templates. When this happens, the request payload will either be passed through the integration request _without transformation_ or rejected with a `415 - Unsupported Media Type`, depending on the configuration.

lib/plugins/aws/package/compile/events/apiGateway/lib/method/index.test.js

@@ -1304,6 +1304,37 @@ describe('#compileMethods()', () => {
       });
     });
 
+    it('should delete the default "application/x-www-form-urlencoded" template if it\'s overriden with null', () => {
+      awsCompileApigEvents.validated.events = [
+        {
+          functionName: 'Second',
+          http: {
+            method: 'get',
+            path: 'users/list',
+            integration: 'AWS',
+            request: {
+              template: {
+                'application/x-www-form-urlencoded': null,
+              },
+            },
+            response: {
+              statusCodes: {
+                200: {
+                  pattern: '',
+                },
+              },
+            },
+          },
+        },
+      ];
+      return awsCompileApigEvents.compileMethods().then(() => {
+        expect(
+          awsCompileApigEvents.serverless.service.provider.compiledCloudFormationTemplate.Resources
+            .ApiGatewayMethodUsersListGet.Properties.Integration.RequestTemplates
+        ).to.not.have.key('application/x-www-form-urlencoded');
+      });
+    });
+
     it('should use defined pass-through behavior', () => {
       awsCompileApigEvents.validated.events = [
         {

lib/plugins/aws/package/compile/events/apiGateway/lib/method/integration.js

@@ -209,7 +209,13 @@ module.exports = {
 
     // set custom request templates if provided
     if (http.request && typeof http.request.template === 'object') {
-      Object.assign(integrationRequestTemplates, http.request.template);
+      _.entries(http.request.template).forEach(([contentType, template]) => {
+        if (template === null) {
+          delete integrationRequestTemplates[contentType];
+        } else {
+          integrationRequestTemplates[contentType] = template;
+        }
+      });
     }
 
     return Object.keys(integrationRequestTemplates).length