Develop Reference

Unsubscribe email using Fetch api Javascript

I have a form where i enter an email and it gets ''subscribed'' in a user.json file using a fetch api on node server.My task is to :
upon clicking on the "Unsubscribe" button, implement the functionality for unsubscribing from the community list. For that, make POST Ajax request using http://localhost:3000/unsubscribe endpoint.
I tried to make the function but it wasnt succeseful so i deleted it. Also,i need to do the following :
While the requests to http://localhost:3000/subscribe and
http://localhost:3000/unsubscribe endpoints are in progress, prevent
additional requests upon clicking on "Subscribe" and "Unsubscribe".
Also, disable them (use the disabled attribute) and style them using
opacity: 0.5.
For me ajax requests,fetch and javascript is something new,so i dont know really well how to do this task,if you could help me i'll be happy,thanks in advance.
fetch code for subscribing:
import { validateEmail } from './email-validator.js'
export const sendSubscribe = (emailInput) => {
const isValidEmail = validateEmail(emailInput)
if (isValidEmail === true) {
sendData(emailInput);
}
}
export const sendHttpRequest = (method, url, data) => {
return fetch(url, {
method: method,
body: JSON.stringify(data),
headers: data ? {
'Content-Type': 'application/json'
} : {}
}).then(response => {
if (response.status >= 400) {
return response.json().then(errResData => {
const error = new Error('Something went wrong!');
error.data = errResData;
throw error;
});
}
return response.json();
});
};
const sendData = (emailInput) => {
sendHttpRequest('POST', 'http://localhost:8080/subscribe', {
email: emailInput
}).then(responseData => {
return responseData
}).catch(err => {
console.log(err, err.data);
window.alert(err.data.error)
});
}
index.js from route node server:
const express = require('express');
const router = express.Router();
const FileStorage = require('../services/FileStorage');
/* POST /subscribe */
router.post('/subscribe', async function (req, res) {
try {
if (!req.body || !req.body.email) {
return res.status(400).json({ error: "Wrong payload" });
}
if (req.body.email === 'forbidden#gmail.com') {
return res.status(422).json({ error: "Email is already in use" });
}
const data = {email: req.body.email};
await FileStorage.writeFile('user.json', data);
await res.json({success: true})
} catch (e) {
console.log(e);
res.status(500).send('Internal error');
}
});
/* GET /unsubscribe */
router.post('/unsubscribe ', async function (req, res) {
try {
await FileStorage.deleteFile('user.json');
await FileStorage.writeFile('user-analytics.json', []);
await FileStorage.writeFile('performance-analytics.json', []);
await res.json({success: true})
} catch (e) {
console.log(e);
res.status(500).send('Internal error');
}
});
module.exports = router;
And user.json file looks like this :
{"email":"Email#gmail.com"}
This is my attempt for unsubscribing :
export const unsubscribeUser = () => {
try {
const response = fetch('http://localhost:8080/unsubscribe', {
method: "POST"
});
if (!response.ok) {
const message = 'Error with Status Code: ' + response.status;
throw new Error(message);
}
const data = response.json();
console.log(data);
} catch (error) {
console.log('Error: ' + error);
}
}
It gives the following errors:
Error: Error: Error with Status Code: undefined
main.js:2
main.js:2 POST http://localhost:8080/unsubscribe 404 (Not Found)
FileStorage.js:
const fs = require('fs');
const fsp = fs.promises;
class FileStorage {
static getRealPath(path) {
return `${global.appRoot}/storage/${path}`
}
static async checkFileExist(path, mode = fs.constants.F_OK) {
try {
await fsp.access(FileStorage.getRealPath(path), mode);
return true
} catch (e) {
return false
}
}
static async readFile(path) {
if (await FileStorage.checkFileExist(path)) {
return await fsp.readFile(FileStorage.getRealPath(path), 'utf-8');
} else {
throw new Error('File read error');
}
}
static async readJsonFile(path) {
const rawJson = await FileStorage.readFile(path);
try {
return JSON.parse(rawJson);
} catch (e) {
return {error: 'Non valid JSON in file content'};
}
}
static async writeFile(path, content) {
const preparedContent = typeof content !== 'string' && typeof content === 'object' ? JSON.stringify(content) : content;
return await fsp.writeFile(FileStorage.getRealPath(path), preparedContent);
}
static async deleteFile(path) {
if (!await FileStorage.checkFileExist(path, fs.constants.F_OK | fs.constants.W_OK)) {
return await fsp.unlink(FileStorage.getRealPath(path));
}
return true;
}
}
module.exports = FileStorage;

You should consider using a database for handling CRUD operations on your persisted data. If you must use filestorage, theres a flat file DB library called lowdb that can make working the files easier.
As for preventing duplicate requests, you can track if user has already made a request.
let fetchBtn = document.getElementById('fetch')
let isFetching = false
fetchBtn.addEventListener('click', handleClick)
async function handleClick(){
if (isFetching) return // do nothing if request already made
isFetching = true
disableBtn()
const response = await fetchMock()
isFetching = false
enableBtn()
}
function fetchMock(){
// const response = await fetch("https://example.com");
return new Promise(resolve => setTimeout (() => resolve('hello'), 2000))
}
function disableBtn(){
fetchBtn.setAttribute('disabled', 'disabled');
fetchBtn.style.opacity = "0.5"
}
function enableBtn(){
fetchBtn.removeAttribute('disabled');
fetchBtn.style.opacity = "1"
}
<button type="button" id="fetch">Fetch</button>

Is there a correct way to handle promisified stream error in Nodejs

I am trying to catch an error in the controller and send status(500) to the front-end to let the user know that there is a streaming error. But for some reason the error is not caught and I am sending status(200) to the user. Let me know if i am doing something wrong.
file - utils.js
import WebSocket from 'ws';
import Twitter from 'twitter-lite';
import ck from 'ckey';
export const stream = (term, clients, twitterStream) => {
try {
const twitter = new Twitter({
// subdomain: 'api', // "api" is the default (change for other subdomains)
// version: '1.1', // version "1.1" is the default (change for other subdomains)
version: '2', // version "1.1" is the default (change for v2)
extension: false, // true is the default (this must be set to false for v2 endpoints)
consumer_key: ck.TWITTER_CONSUMER_KEY,
consumer_secret: ck.TWITTER_CONSUMER_SECRET,
access_token_key: ck.TWITTER_ACCESS_TOKEN_KEY,
access_token_secret: ck.TWITTER_ACCESS_TOKEN_SECRET,
});
let stream = twitter.stream('statuses/filter', { track: term });
new Promise(function (resolve, reject) {
stream.on('data', function (tweet) {
console.log('tweet');
resolve(broadcast(clients, JSON.stringify(tweet)));
});
stream.on('error', function (error) {
reject(error);
});
}).catch(function (e) {
console.log('stream error catch: ', e);
// throw e;
});
twitterStream = stream;
return twitterStream;
} catch (error) {
console.log('error from util', error);
// throw error;
}
};
const broadcast = (clients, message) => {
clients.forEach((client) => {
if (client.readyState === WebSocket.OPEN) {
client.send(message);
}
});
};
controller
import { stream } from './utils.js';
let twitterStream;
// Sets search term for twitter stream.
export const setSearchTerm = (req, res) => {
try {
const { term } = req.params;
console.log('setSearchTerm');
console.log('term: ', term);
if (twitterStream) {
console.log('getTweetPause');
twitterStream.destroy();
}
twitterStream = stream(term, req.app.locals.clients, twitterStream);
res.status(200).json({ message: 'Successful search request' });
} catch (error) {
res.status(500).json({ message: error });
}
};

file - utils.js
import WebSocket from 'ws';
import Twitter from 'twitter-lite';
import ck from 'ckey';
export const stream = (term) => {
const twitter = new Twitter({
// subdomain: 'api', // "api" is the default (change for other subdomains)
// version: '1.1', // version "1.1" is the default (change for other subdomains)
version: '2', // version "1.1" is the default (change for v2)
extension: false, // true is the default (this must be set to false for v2 endpoints)
consumer_key: ck.TWITTER_CONSUMER_KEY,
consumer_secret: ck.TWITTER_CONSUMER_SECRET,
access_token_key: ck.TWITTER_ACCESS_TOKEN_KEY,
access_token_secret: ck.TWITTER_ACCESS_TOKEN_SECRET,
});
let stream = twitter.stream('statuses/filter', { track: term });
return stream;
};
export const broadcast = (clients, message) => {
clients.forEach((client) => {
if (client.readyState === WebSocket.OPEN) {
client.send(message);
}
});
};
controller
import { stream, broadcast } from './utils.js';
let twitterStream;
// Sets search term for twitter stream.
export const setSearchTerm = async (req, res) => {
try {
const { term } = req.params;
console.log('setSearchTerm');
console.log('term: ', term);
if (twitterStream) {
console.log('getTweetPause');
twitterStream.destroy();
}
const currentStream = stream(term);
twitterStream = currentStream;
await new Promise((resolve, reject) => {
currentStream.on('data', function (tweet) {
console.log('tweets: ');
broadcast(req.app.locals.clients, JSON.stringify(tweet));
resolve(tweet);
});
currentStream.on('error', function (error) {
reject(error);
});
});
res.status(200).json({ message: 'Successful HTTP request' });
} catch (error) {
console.log('error catch: ');
res.status(500).json({ message: error });
}
};

Nodejs async/await mysql queries

I have a nodejs project with the current structure below, I need to insert a registry on clients table and return the last inserted ID from this table so I can use it in a second table, but I need to wait until the insert is completed in clients table, before insert the client ID on my second table. I'm trying to use async/await, but I'm always getting a null value.
My MYSQL connection: db.model.js
const config = require('config');
const mysql = require("mysql");
const connection = mysql.createConnection({
host: config.get('mysql.host'),
user: config.get('mysql.user'),
password: config.get('mysql.password'),
database: config.get('mysql.database')
});
connection.connect(function (err) {
if (err) {
console.error(`MySQL Connection Error: ${err.stack}`);
return;
}
console.log(`MySQL connected successfully!`);
});
module.exports = connection;
My CLIENT model
const mysql = require("./db.model");
const Client = function(client) {
this.login = client.login;
};
Client.create = (newClient, result) => {
mysql.query("INSERT INTO clients SET ?", newClient,
(err, res) => {
if (err) {
console.log("error: ", err);
result(err, null);
return;
}
result(null, {
id: res.insertId,
...newClient
});
}
);
};
module.exports = Client;
this is the client controller (i'm trying to use async/await here)
const Client = require('../models/client.model');
exports.create = (login) => {
const client = new Client({
login: login
});
Client.create(client, async (err, data) => {
if(!err) {
return await data.id;
} else {
return false;
}
});
}
And this is another controller, where I want to use methods from my client controller:
const ClientController = require('../controllers/client.controller');
...
utils.connect()
.then(clt => clt.sub.create(data))
.then((sub) => {
let lastInsertedId = ClientController.create(sub.login);
// lastInsertedId always return null here,
// but I know ClientController return a value after some time.
// method below will fail because lastInsertedId cannot be null
TransactionController.transactionCreate(lastInsertedId,
sub.id,
sub.param);
})
.catch(error => res.send(error.response.errors))
any help appreciated.

File to create database connection
const config = require('config');
const mysql = require('mysql2');
const bluebird = require('bluebird');
const dbConf = {
host: config.dbhost,
user: config.dbuser,
password: config.dbpassword,
database: config.database,
Promise: bluebird
};
class Database {
static async getDBConnection() {
try {
if (!this.db) {
// to test if credentials are correct
await mysql.createConnection(dbConf);
const pool = mysql.createPool(dbConf);
// now get a Promise wrapped instance of that pool
const promisePool = pool.promise();
this.db = promisePool;
}
return this.db;
} catch (err) {
console.log('Error in database connection');
console.log(err.errro || err);
}
}
}
module.exports = Database;
Use connection to execute your native query
const database = require('./database');
let query = 'select * from users';
let conn = await dl.getDBConnection();
let [data, fields] = await conn.query(query);

So I'm still using only the npm mysql package, but now I transformed all my queries into promises like below, so I can just wait until all the queries are completed.
const create = (idCliente, transactionId, amount, status) => {
const sql = "INSERT INTO transactions SET ?";
const params = {
id_cliente: idCliente,
transaction_id: transactionId,
amount: amount,
status: status
};
return new Promise((resolve, reject) => {
pool.query(sql, params, (err, result) => {
if (err) {
return reject(err);
}
resolve(result);
});
});
};
then I use like this:
create(params)
.then((result) => {
//call more queries here if needed
})
.catch((err) => { });

You can use sync-sql package of npm for execute async queries.
https://www.npmjs.com/package/sync-sql
Here is an example of it:
const express = require('express')
const mysql = require('mysql')
const app = express()
var syncSql = require('sync-sql');
// Create Connection
const connect = {
host: 'localhost',
user: 'root',
password: '',
database: 'ddd_test'
}
const db = mysql.createConnection(connect)
db.connect((err) => {
if (err) {
throw err
}
console.log("Connected");
})
function getDbData(query) {
return syncSql.mysql(connect, query).data.rows
}
app.get("/getData", async (req, res, next) => {
let sql = 'SELECT * from registration';
res.json({
data:getDbData(sql)
});
})
app.listen(3000, () => {
console.log('App listening on port 3000!');
});

How can I access a function within a router javascript file via node?

I'm handling with an webapplication that is not mine and now I've got to send a hundred e-mails.
Unfortunately, the code is not documented and not so well written, that means i have to go testing it to discover what I am able to do and what I'm not. but I don't know how to access this function that is on the code via node. Is it actually possible to do it? Here's the code:
router.post('/aprovadosemail', miPermiso("3"), (req, res) => {
var templatesDir = path.resolve(__dirname, '..', 'templates');
var emailTemplates = require('email-templates');
// Prepare nodemailer transport object
emailTemplates(templatesDir, function(err, template) {
if (err) {
console.log(err);
} else {
var users = [];
projetoSchema.find({"aprovado":true, "categoria":"Fundamental II (6º ao 9º anos)"}, function (err, docs) {
if (err) throw err;
//console.log(docs);
docs.forEach(function(usr) {
let url = "http://www.movaci.com.b/projetos/confirma/"+usr._id+"/2456";
let url2 = "http://www.movaci.com.br/projetos/confirma/"+usr._id+"/9877";
users.push({'email': usr.email, 'projeto': usr.nomeProjeto, 'url': url, 'url2': url2});
});
for (var i = 0; i < users.length; i++) {
console.log(users[i]);
}
const transporter = nodemailer.createTransport(smtpTransport({
host: 'smtp.zoho.com',
port: 587,
auth: {
user: "generic#mail.com",
pass: "genericpassword"
},
getSocket: true
}));
var Render = function(locals) {
this.locals = locals;
this.send = function(err, html, text) {
if (err) {
console.log(err);
} else {
transporter.sendMail({
from: 'no-reply4#movaci.com.br',
to: locals.email,
subject: 'MOVACI - Projeto aprovado!',
html: html,
text: text
}, function(err, responseStatus) {
if (err) {
console.log(err);
} else {
console.log(responseStatus.message);
}
});
}
};
this.batch = function(batch) {
batch(this.locals, templatesDir, this.send);
};
};
// Load the template and send the emails
template('rateada', true, function(err, batch) {
for(var user in users) {
var render = new Render(users[user]);
render.batch(batch);
};
});
res.send('ok');
});
};
});
});

Seems like previous dev did not knew email-templates package deeply (at least have not read how it works).
So in fact it has send method, You can create an email object from email-templates and pass necessary defaults, then You call .send method of it by passing dynamical parts - it just simply merge additional params passed in send arguments, sends mail using nodemailer inside of promise which it returns.
If it's interesting for You - read source code of it: https://github.com/niftylettuce/email-templates/blob/master/index.js
I tried to simplify it modular parts using promises.
I've not debugged it, but You may check my solution and fix it as You wish.
Have 2 files (to routing from handler separately, it may have variables that may conflict and etc):
1) methods/users/aprovadosEmail.js:
const
Email = require('email-templates'),
const
emailTemplatesDir = path.resolve(__dirname + '/../../templates'),
smtpTransportConfig = {
host: 'smtp.zoho.com',
port: 587,
secure: false,
auth: {
user: "no-reply4#movaci.com.br",
pass: "some-password-here"
}
},
createEmail = (template, subject) => {
return new Email({
views: {
root: emailTemplatesDir,
},
transport: smtpTransportConfig,
template,
message: {
from: 'no-reply4#movaci.com.br',
subject
}
});
},
getApprovedUsers = () => {
return new Promise((resolve, reject) => {
const criteria = {
aprovado: true,
categoria:"Fundamental II (6º ao 9º anos)"
};
projetoSchema.find(
criteria,
(error, docs) => {
if(error) return reject(error);
const users = docs.map(doc => {
return {
email: doc.email,
projeto: doc.nomeProjeto,
url: "http://www.movaci.com.b/projetos/confirma/"+doc._id+"/2456",
url2: "http://www.movaci.com.br/projetos/confirma/"+doc._id+"/9877"
};
});
resolve(users);
});
});
},
sendMailToUser = (mail, user) => {
return mail.send({
message: {
to: user.email
},
locals: user
});
},
broadcastMailToUsers = (mail, users) => {
return Promise
.all(
users
.map(user => sendMailToUser(mail, user))
);
};
module.exports = (req, res) => {
const mail = createEmail('rateada', 'MOVACI - Projeto aprovado!'); // mail object
getApprovedUsers()
.then(users => broadcastMailToUsers(mail, users))
.then(result => {
console.log('Result of broadcast:', result);
res.send('ok');
})
.catch(error => {
res.status(500).send(error);
});
};
2) current routes file where routing part that uses module file:
router.post(
'/aprovadosemail',
miPermiso("3"),
require(__dirname+'/../methods/users/aprovadosEmail')
);

Using Node.js to connect to a REST API

Is it sensible to use Node.js to write a stand alone app that will connect two REST API's?
One end will be a POS - Point of sale - system
The other will be a hosted eCommerce platform
There will be a minimal interface for configuration of the service. nothing more.

Yes, Node.js is perfectly suited to making calls to external APIs. Just like everything in Node, however, the functions for making these calls are based around events, which means doing things like buffering response data as opposed to receiving a single completed response.
For example:
// get walking directions from central park to the empire state building
var http = require("http");
url = "http://maps.googleapis.com/maps/api/directions/json?origin=Central Park&destination=Empire State Building&sensor=false&mode=walking";
// get is a simple wrapper for request()
// which sets the http method to GET
var request = http.get(url, function (response) {
// data is streamed in chunks from the server
// so we have to handle the "data" event
var buffer = "",
data,
route;
response.on("data", function (chunk) {
buffer += chunk;
});
response.on("end", function (err) {
// finished transferring data
// dump the raw data
console.log(buffer);
console.log("\n");
data = JSON.parse(buffer);
route = data.routes[0];
// extract the distance and time
console.log("Walking Distance: " + route.legs[0].distance.text);
console.log("Time: " + route.legs[0].duration.text);
});
});
It may make sense to find a simple wrapper library (or write your own) if you are going to be making a lot of these calls.

Sure. The node.js API contains methods to make HTTP requests:
http.request
http.get
I assume the app you're writing is a web app. You might want to use a framework like Express to remove some of the grunt work (see also this question on node.js web frameworks).

/*Below logics covered in below sample GET API
-DB connection created in class
-common function to execute the query
-logging through bunyan library*/
const { APIResponse} = require('./../commonFun/utils');
const createlog = require('./../lib/createlog');
var obj = new DB();
//Test API
routes.get('/testapi', (req, res) => {
res.status(201).json({ message: 'API microservices test' });
});
dbObj = new DB();
routes.get('/getStore', (req, res) => {
try {
//create DB instance
const store_id = req.body.storeID;
const promiseReturnwithResult = selectQueryData('tablename', whereField, dbObj.conn);
(promiseReturnwithResult).then((result) => {
APIResponse(200, 'Data fetched successfully', result).then((result) => {
res.send(result);
});
}).catch((err) => { console.log(err); throw err; })
} catch (err) {
console.log('Exception caught in getuser API', err);
const e = new Error();
if (err.errors && err.errors.length > 0) {
e.Error = 'Exception caught in getuser API';
e.message = err.errors[0].message;
e.code = 500;
res.status(404).send(APIResponse(e.code, e.message, e.Error));
createlog.writeErrorInLog(err);
}
}
});
//create connection
"use strict"
const mysql = require("mysql");
class DB {
constructor() {
this.conn = mysql.createConnection({
host: 'localhost',
user: 'root',
password: 'pass',
database: 'db_name'
});
}
connect() {
this.conn.connect(function (err) {
if (err) {
console.error("error connecting: " + err.stack);
return;
}
console.log("connected to DBB");
});
}
//End class
}
module.exports = DB
//queryTransaction.js File
selectQueryData= (table,where,db_conn)=>{
return new Promise(function(resolve,reject){
try{
db_conn.query(`SELECT * FROM ${table} WHERE id = ${where}`,function(err,result){
if(err){
reject(err);
}else{
resolve(result);
}
});
}catch(err){
console.log(err);
}
});
}
module.exports= {selectQueryData};
//utils.js file
APIResponse = async (status, msg, data = '',error=null) => {
try {
if (status) {
return { statusCode: status, message: msg, PayLoad: data,error:error }
}
} catch (err) {
console.log('Exception caught in getuser API', err);
}
}
module.exports={
logsSetting: {
name: "USER-API",
streams: [
{
level: 'error',
path: '' // log ERROR and above to a file
}
],
},APIResponse
}
//createlogs.js File
var bunyan = require('bunyan');
const dateFormat = require('dateformat');
const {logsSetting} = require('./../commonFun/utils');
module.exports.writeErrorInLog = (customError) => {
let logConfig = {...logsSetting};
console.log('reached in writeErrorInLog',customError)
const currentDate = dateFormat(new Date(), 'yyyy-mm-dd');
const path = logConfig.streams[0].path = `${__dirname}/../log/${currentDate}error.log`;
const log = bunyan.createLogger(logConfig);
log.error(customError);
}

A more easy and useful tool is just using an API like Unirest; URest is a package in NPM that is just too easy to use jus like
app.get('/any-route', function(req, res){
unirest.get("https://rest.url.to.consume/param1/paramN")
.header("Any-Key", "XXXXXXXXXXXXXXXXXX")
.header("Accept", "text/plain")
.end(function (result) {
res.render('name-of-the-page-according-to-your-engine', {
layout: 'some-layout-if-you-want',
markup: result.body.any-property,
});
});