I want to use the Gmail API for a project in Node.js
1-I have an Ubuntu server on which I ran the following exercise link , it worked for me without problems.
2-I wanted to do the same exercise (create another project in google with other credentials) but locally (Windows 10) and although I follow the same process, everything is exactly the same, at the time of running the file I marked the following error:
undefined: 1
SyntaxError: Unexpected end of JSON input at JSON.parse () at C: \ Users \ Emmanuel \ Desktop \ Nodejs \ Gmail Win \ quickstart.js: 45: 39 at FSReqWrap.readFileAfterClose [as oncomplete] (fs.js: 511: 3)
This is the code of the quickstart.js file
var fs = require('fs');
var readline = require('readline');
var google = require('googleapis');
var googleAuth = require('google-auth-library');
// If modifying these scopes, delete your previously saved credentials
// at ~/.credentials/gmail-nodejs-quickstart.json
var SCOPES = ['https://www.googleapis.com/auth/gmail.readonly'];
var TOKEN_DIR = (process.env.HOME || process.env.HOMEPATH ||
process.env.USERPROFILE) + '/.credentials/';
var TOKEN_PATH = TOKEN_DIR + 'gmail-nodejs-quickstart.json';
// Load client secrets from a local file.
fs.readFile('client_secret.json', function processClientSecrets(err, content) {
if (err) {
console.log('Error loading client secret file: ' + err);
return;
}
// Authorize a client with the loaded credentials, then call the
// Gmail API.
authorize(JSON.parse(content), listLabels);
});
/**
* Create an OAuth2 client with the given credentials, and then execute the
* given callback function.
*
* @param {Object} credentials The authorization client credentials.
* @param {function} callback The callback to call with the authorized client.
*/
function authorize(credentials, callback) {
var clientSecret = credentials.installed.client_secret;
var clientId = credentials.installed.client_id;
var redirectUrl = credentials.installed.redirect_uris[0];
var auth = new googleAuth();
var oauth2Client = new auth.OAuth2(clientId, clientSecret, redirectUrl);
// Check if we have previously stored a token.
fs.readFile(TOKEN_PATH, function(err, token) {
if (err) {
getNewToken(oauth2Client, callback);
} else {
oauth2Client.credentials = JSON.parse(token);
callback(oauth2Client);
}
});
}
/**
* Get and store new token after prompting for user authorization, and then
* execute the given callback with the authorized OAuth2 client.
*
* @param {google.auth.OAuth2} oauth2Client The OAuth2 client to get token for.
* @param {getEventsCallback} callback The callback to call with the authorized
* client.
*/
function getNewToken(oauth2Client, callback) {
var authUrl = oauth2Client.generateAuthUrl({
access_type: 'offline',
scope: SCOPES
});
console.log('Authorize this app by visiting this url: ', authUrl);
var rl = readline.createInterface({
input: process.stdin,
output: process.stdout
});
rl.question('Enter the code from that page here: ', function(code) {
rl.close();
oauth2Client.getToken(code, function(err, token) {
if (err) {
console.log('Error while trying to retrieve access token', err);
return;
}
oauth2Client.credentials = token;
storeToken(token);
callback(oauth2Client);
});
});
}
/**
* Store token to disk be used in later program executions.
*
* @param {Object} token The token to store to disk.
*/
function storeToken(token) {
try {
fs.mkdirSync(TOKEN_DIR);
} catch (err) {
if (err.code != 'EEXIST') {
throw err;
}
}
fs.writeFile(TOKEN_PATH, JSON.stringify(token));
console.log('Token stored to ' + TOKEN_PATH);
}
/**
* Lists the labels in the user's account.
*
* @param {google.auth.OAuth2} auth An authorized OAuth2 client.
*/
function listLabels(auth) {
var gmail = google.gmail('v1');
gmail.users.labels.list({
auth: auth,
userId: 'me',
}, function(err, response) {
if (err) {
console.log('The API returned an error: ' + err);
return;
}
var labels = response.labels;
if (labels.length == 0) {
console.log('No labels found.');
} else {
console.log('Labels:');
for (var i = 0; i < labels.length; i++) {
var label = labels[i];
console.log('- %s', label.name);
}
}
});
}