1. Added login.js to support refresh token authentication.

2. Bump dependency versions.
3. Update plug-in version to 4.6.0.

login.js

@@ -0,0 +1,89 @@
+// Based on login.ts from homebridge-nest-cam - thank you, @Brandawg93!
+
+const readline = require('readline');
+const querystring = require('querystring');
+const axios = require('axios');
+
+// Timeout other API calls after this number of seconds
+const API_TIMEOUT_SECONDS = 40;
+
+// URL for refresh token generation
+const TOKEN_URL = 'https://oauth2.googleapis.com/token';
+
+// Client ID of the Nest iOS application
+const CLIENT_ID = '733249279899-1gpkq9duqmdp55a7e5lft1pr2smumdla.apps.googleusercontent.com';
+
+// Client ID of the Test Flight Beta Nest iOS application
+const CLIENT_ID_FT = '384529615266-57v6vaptkmhm64n9hn5dcmkr4at14p8j.apps.googleusercontent.com';
+
+const NestEndpoints = require('./lib/nest-endpoints.js');
+
+const prompt = query =>
+    new Promise(async (resolve, reject) => {
+        const rl = readline.createInterface({
+            input: process.stdin,
+            output: process.stdout,
+        });
+        try {
+            rl.question(query, value => {
+                resolve(value);
+                rl.close();
+            });
+        } catch (err) {
+            reject(err);
+        }
+    });
+
+/**
+ * Generate url required to retrieve a refresh token
+ */
+function generateToken(ft = false) {
+    const data = {
+        access_type: 'offline',
+        response_type: 'code',
+        scope: 'openid profile email https://www.googleapis.com/auth/nest-account',
+        redirect_uri: 'urn:ietf:wg:oauth:2.0:oob',
+        client_id: ft ? CLIENT_ID_FT : CLIENT_ID,
+    };
+    return `https://accounts.google.com/o/oauth2/auth/oauthchooseaccount?${querystring.stringify(data)}`;
+}
+
+async function getRefreshToken(code, ft = false) {
+    const req = {
+        method: 'POST',
+        timeout: API_TIMEOUT_SECONDS * 1000,
+        url: TOKEN_URL,
+        headers: {
+            'Content-Type': 'application/x-www-form-urlencoded',
+            'User-Agent': NestEndpoints.USER_AGENT_STRING,
+        },
+        data: querystring.stringify({
+            code: code,
+            redirect_uri: 'urn:ietf:wg:oauth:2.0:oob',
+            client_id: ft ? CLIENT_ID_FT : CLIENT_ID,
+            grant_type: 'authorization_code',
+        }),
+    };
+    const result = (await axios(req)).data;
+    return result.refresh_token;
+}
+
+(async () => {
+    const ft = process.argv.includes('-ft');
+    const url = generateToken(ft);
+    console.log(`1. Open the url below in a browser to continue:\n\n${url}\n`);
+    const code = await prompt('2. Copy the code here: ');
+    try {
+        const refreshToken = await getRefreshToken(code, ft);
+        console.log('3. Copy the refresh token below to your config.json.');
+        console.log(`Refresh Token: ${refreshToken}`);
+    } catch (err) {
+        let msg = err;
+        if (err.response && err.response.data && err.response.data.error_description) {
+            msg = err.response.data.error_description;
+        } else if (err.message) {
+            msg = err.message;
+        }
+        console.error(msg);
+    }
+})();