Allow authorization using queryString when using wss-custom-auth. (#383)

Co-authored-by: Stijn De Pestel <stijn.depestel@gmail.com>

README.md

@@ -368,6 +368,7 @@ follows:
   * `customAuthHeaders`: used to specify your custom authorization headers when `protocol` is set to 'wss-custom-auth'. The fields 'X-Amz-CustomAuthorizer-Name', 'X-Amz-CustomAuthorizer-Signature', and the field for your token name are required.
   * `servername`: used for SNI. If undefined, a value is derived from `host`.
   * `port`: used to specify which port to connect to. If undefined, 443 or 8883 will be chosen depending on `protocol`.
+  * `customAuthQueryString`: used to specify the token credentials in a query string for custom authorization when `protocol` is set to `wss-custom-auth`. More info can be found [here](https://docs.aws.amazon.com/iot/latest/developerguide/custom-auth.html#custom-auth-websockets).
   * `keepalive`: used to specify the time interval for each ping request. Default is set to 300 seconds to connect to AWS IoT.
   * `enableMetrics`: used to report SDK version usage metrics. It is set to true by default. To disable metrics collection, set value to false.
   * `debug`: set to 'true' for verbose logging (default 'false').
@@ -746,8 +747,8 @@ set the `protocol` option to `wss-custom-auth`.
 ### Custom Authorization Configuration
 
 To use custom authorization, you must first set up an authorizer function in Lambda and register it
-with IoT. Once you do, you will be able to authenticate using this function. To use custom auth,
-set the `customAuthHeaders` option to your headers object when instantiating the [awsIotDevice()](#device)
+with IoT. Once you do, you will be able to authenticate using this function. There are two ways to use custom auth:
+* set the `customAuthHeaders` option to your headers object when instantiating the [awsIotDevice()](#device)
 or [awsIot.thingShadow()](#thingShadow) classes. The headers object is an object containing the header name
 and values as key-value pairs:
 
@@ -758,6 +759,11 @@ and values as key-value pairs:
         'TestAuthorizerToken': 'token'
     }
 ```
+* set the `customAuthQueryString` option to your headers object when instantiating the [awsIotDevice()](#device) class. The query string is a string containing the values as key-value pairs:
+
+```js
+    '?X-Amz-CustomAuthorizer-Name=TestAuthorizer&X-Amz-CustomAuthorizer-Signature=signature&TestAuthorizerToken=token'
+```
 
 
 <a name="programs"></a>

device/index.js

@@ -172,7 +172,7 @@ function prepareWebSocketCustomAuthUrl(options) {
       hostName = options.host + ':' + options.port;
    }
 
-   return 'wss://' + hostName + path;
+   return 'wss://' + hostName + path + (options.customAuthQueryString || '');
 }
 
 function arrayEach(array, iterFunction) {
@@ -505,8 +505,8 @@ function DeviceClient(options) {
             throw new Error(exceptions.INVALID_CONNECT_OPTIONS);
          }
       } else {
-         if (isUndefined(options.customAuthHeaders)) {
-            console.log('To authenticate with a custom authorizer, you must provide the required HTTP headers; see README.md');
+         if (isUndefined(options.customAuthHeaders) && isUndefined(options.customAuthQueryString)) {
+            console.log('To authenticate with a custom authorizer, you must provide the required HTTP headers or queryString; see README.md');
             throw new Error(exceptions.INVALID_CONNECT_OPTIONS);
          }
       }

test/device-unit-tests.js

@@ -546,7 +546,7 @@ describe( "device class unit tests", function() {
          );
       });
    });
-   describe("device throws exception if using CustomAuth over websocket without headers", function () {
+   describe("device throws exception if using CustomAuth over websocket without headers or querystring", function () {
       it("throws exception", function () {
          assert.throws(function (err) {
             var device = deviceModule({
@@ -557,6 +557,30 @@ describe( "device class unit tests", function() {
          );
       });
    });
+   describe("device does not throw exception if using CustomAuth over websocket with headers", function () {
+      it("does not throw an exception", function () {
+         assert.doesNotThrow(function (err) {
+            var device = deviceModule({
+               host: 'XXXX.iot.us-east-1.amazonaws.com',
+               protocol: 'wss-custom-auth',
+               customAuthHeaders: {}
+            });
+         }, function (err) { console.log('\t[' + err + ']'); return true; }
+         );
+      });
+   });
+   describe("device does not throw exception if using CustomAuth over websocket with querystring", function () {
+      it("does not throw an exception", function () {
+         assert.doesNotThrow(function (err) {
+            var device = deviceModule({
+               host: 'XXXX.iot.us-east-1.amazonaws.com',
+               protocol: 'wss-custom-auth',
+               customAuthQueryString: ''
+            });
+         }, function (err) { console.log('\t[' + err + ']'); return true; }
+         );
+      });
+   });
    describe("device does not throw exception if using CustomAuth over websocket with non-standard headers", function () {
       it("does not throw an exception", function () {
          assert.doesNotThrow(function (err) {
@@ -1888,6 +1912,15 @@ describe( "device class unit tests", function() {
          assert.equal( url, expectedUrl );
       });
    });
+   describe("websocket http querystring is correctly set when CustomAuth querystring is specified", function() {
+      it("generates the correct url", function() {
+         const queryString = '?X-Amz-CustomAuthorizer-Name=AuthorizerFunctionName&X-Amz-CustomAuthorizer-Signature=Signature&NPAuthorizerToken=Token';
+         const expectedUrl = 'wss://not-a-real-host.com/mqtt' + queryString;
+         const url = deviceModule.prepareWebSocketCustomAuthUrl( { host:'not-a-real-host.com', customAuthQueryString: queryString } );
+         assert.equal( url, expectedUrl );
+      });
+
+   });
    describe("websocket headers are correctly set when CustomAuth headers are specified", function() {
       it("sets the websocket headers correctly", function() {
          var headers = {