fix: unset content length in rest-json when payload is undefined (#4219)

.changes/next-release/bugfix-rest-json-a441c484.json

@@ -0,0 +1,5 @@
+{
+  "type": "bugfix",
+  "category": "rest-json",
+  "description": "unset content length in rest-json when payload is undefined"
+}

lib/event_listeners.js

@@ -678,6 +678,7 @@ AWS.EventListeners = {
     add('BUILD', 'build', svc.buildRequest);
     add('EXTRACT_DATA', 'extractData', svc.extractData);
     add('EXTRACT_ERROR', 'extractError', svc.extractError);
+    add('UNSET_CONTENT_LENGTH', 'afterBuild', svc.unsetContentLength);
   }),
 
   RestXml: new SequentialExecutor().addNamedListeners(function(add) {

lib/protocol/rest_json.js

@@ -4,6 +4,18 @@ var Json = require('./json');
 var JsonBuilder = require('../json/builder');
 var JsonParser = require('../json/parser');
 
+var METHODS_WITHOUT_BODY = ['GET', 'HEAD', 'DELETE'];
+
+function unsetContentLength(req) {
+  var payloadMember = util.getRequestPayloadShape(req);
+  if (
+    payloadMember === undefined &&
+    METHODS_WITHOUT_BODY.indexOf(req.httpRequest.method) >= 0
+  ) {
+    delete req.httpRequest.headers['Content-Length'];
+  }
+}
+
 function populateBody(req) {
   var builder = new JsonBuilder();
   var input = req.service.api.operations[req.operation].input;
@@ -40,7 +52,7 @@ function buildRequest(req) {
   Rest.buildRequest(req);
 
   // never send body payload on GET/HEAD/DELETE
-  if (['GET', 'HEAD', 'DELETE'].indexOf(req.httpRequest.method) < 0) {
+  if (METHODS_WITHOUT_BODY.indexOf(req.httpRequest.method) < 0) {
     populateBody(req);
   }
 }
@@ -89,5 +101,6 @@ function extractData(resp) {
 module.exports = {
   buildRequest: buildRequest,
   extractError: extractError,
-  extractData: extractData
+  extractData: extractData,
+  unsetContentLength: unsetContentLength
 };