[js] Add a User-Agent header for #5657

Author: jleyba

javascript/node/selenium-webdriver/CHANGES.md

@@ -3,6 +3,8 @@
 ### API Changes
 
 *  Export `lib/input.Origin` from the top level `selenium-webdriver` module.
+*  HTTP requests from this library will now include a User-Agent of the form
+   `selenium/${VERSION} (js ${PLATFORM})`.
 
 
 ## v4.0.0-alpha.1

javascript/node/selenium-webdriver/http/index.js

@@ -59,6 +59,15 @@ function getRequestOptions(aUrl) {
 }
 
 
+/** @const {string} */
+const USER_AGENT = (function() {
+  const version = require('../package.json').version;
+  const platform =
+      ({'darwin': 'mac', 'win32': 'windows'}[process.platform]) || 'linux';
+  return `selenium/${version} (js ${platform})`;
+})();
+
+
 /**
  * A basic HTTP client used to send messages to a remote end.
  *
@@ -97,6 +106,7 @@ class HttpClient {
       headers[name] = value;
     });
 
+    headers['User-Agent'] = USER_AGENT;
     headers['Content-Length'] = 0;
     if (httpRequest.method == 'POST' || httpRequest.method == 'PUT') {
       data = JSON.stringify(httpRequest.data);
@@ -209,7 +219,8 @@ function sendRequest(options, onOk, onError, opt_data, opt_proxy, opt_retries) {
         search: location.search,
         hash: location.hash,
         headers: {
-          'Accept': 'application/json; charset=utf-8'
+          'Accept': 'application/json; charset=utf-8',
+          'User-Agent': USER_AGENT,
         }
       }, onOk, onError, undefined, opt_proxy);
       return;

javascript/node/selenium-webdriver/test/http/http_test.js

@@ -32,8 +32,8 @@ describe('HttpClient', function() {
     let parsedUrl = url.parse(req.url);
 
     if (req.method == 'GET' && req.url == '/echo') {
-      res.writeHead(200, req.headers);
-      res.end();
+      res.writeHead(200);
+      res.end(JSON.stringify(req.headers));
 
     } else if (req.method == 'GET' && req.url == '/redirect') {
       res.writeHead(303, {'Location': server.url('/hello')});
@@ -118,9 +118,16 @@ describe('HttpClient', function() {
     var client = new HttpClient(server.url(), agent);
     return client.send(request).then(function(response) {
       assert.equal(200, response.status);
-      assert.equal(response.headers.get('content-length'), '0');
-      assert.equal(response.headers.get('connection'), 'keep-alive');
-      assert.equal(response.headers.get('host'), server.host());
+
+      const headers = JSON.parse(response.body);
+      assert.equal(headers['content-length'], '0');
+      assert.equal(headers['connection'], 'keep-alive');
+      assert.equal(headers['host'], server.host());
+
+      const regex = /^selenium\/.* \(js (windows|mac|linux)\)$/;
+      assert.ok(
+        regex.test(headers['user-agent']),
+        `${headers['user-agent']} does not match ${regex}`);
 
       assert.equal(request.headers.get('Foo'), 'Bar');
       assert.equal(