google_auth.ts

import * as googleAuth from 'google-auth-library';
import { Credentials } from 'google-auth-library/build/src/auth/credentials';
import * as fs from 'fs';
import * as readline from 'readline';


// TODO 
// * Get credentials from file in config.yaml -> google_credentials_file
// * Generate auth URL
// * Wait for user to come back with code
// * Take code and get the access token
// * Dump credentials data to file
//     * Have main app read from the seprate file, rather than config.yaml
//     * Have main app update access, refresh, and expiration configs 
//       automatically
const scopes: Array<string> = [
    'https://www.googleapis.com/auth/admin.directory.group.member'
    ,'https://www.googleapis.com/auth/admin.directory.group'
    ,'https://mail.google.com/'
    ,'https://www.googleapis.com/auth/gmail.modify'
    ,'https://www.googleapis.com/auth/gmail.compose'
    ,'https://www.googleapis.com/auth/gmail.send'
];


/**
 * Step 0: Create OAuth2 credentials at the Google Console (make sure to download JSON, not only just get key and secret)
 */

/**
 * Step 1: Authorize in the browser
 */

export function getAuthorizeUrl(
    credentials
    ,callback: (err: any, url: string) => any
): void {
    const oauth2Client = new googleAuth.OAuth2Client(
        credentials.installed.client_id
        ,credentials.installed.client_secret
        ,credentials.installed.redirect_uris[0]
    );

	const authUrl = oauth2Client.generateAuthUrl({
		access_type: 'offline',
		scope: scopes
	});

	callback(null, authUrl);
}


/**
 * Step 2: Get auth token
 */


export function getAccessToken(
    code
    ,credentials
    ,callback: (err: any, token?: Credentials | null) => any): void
{
    const oauth2Client = new googleAuth.OAuth2Client(
        credentials.installed.client_id
        ,credentials.installed.client_secret
        ,credentials.installed.redirect_uris[0]
    );

	oauth2Client.getToken( code, (err, token) => {
		if(err) return console.log(err);

		callback(null, token);
	});
}


fs.readFile( 'google-credentials.json', (err, content) => {
    if (err) return console.log('Error loading client secret file:', err);
    let credentials = JSON.parse( content.toString() );

    getAuthorizeUrl(
        credentials
        ,(err, url) => {
            if(err) return console.log(err);
            console.log("Auth url is: ", url);

            let rl = readline.createInterface({
                input: process.stdin
                ,output: process.stdout
            });

            rl.question( "Input token: ", (token) => {
                getAccessToken( token, credentials, (err, access) => {
                    if(err) return console.log(err);
                    //console.log("Auth token is: ", token);
                    console.log( "google_client_token: " + token );
                    console.log( "google_access_token: "
                        + access['access_token'] );
                    console.log( "google_token_type: "
                        + access['token_type'] );
                    console.log( "google_refresh_token: " 
                        + access['refresh_token'] );
                    console.log( "google_expires_date: "
                        + access['expiry_date'] );
                });
            });
        }
    );
});