Develop Reference

SvelteKit: How to call mongodb without using endpoints?

(1/9/2023) Update : SvelteKit now supports server only load functions and Form actions to send requests to the server.
I want to call my database, but I don't want it be able to get accessed by end users by them going to the API endpoint that I set up. I was wondering how I would be able to just call my database from a file in the lib folder and just returning the data there. When I try it I get the error global not defined:
lib/db.js:
import dotenv from "dotenv";
dotenv.config();
import { MongoClient } from "mongodb";
const uri = process.env["MONGODB_URI"];
const options = {
useUnifiedTopology: true,
useNewUrlParser: true,
};
let client;
let clientPromise;
if (!uri) {
throw new Error("Please add your Mongo URI to .env.local");
}
if (process.env["NODE_ENV"] === "development") {
if (!global._mongoClientPromise) {
client = new MongoClient(uri, options);
global._mongoClientPromise = client.connect();
}
clientPromise = global._mongoClientPromise;
} else {
client = new MongoClient(uri, options);
clientPromise = client.connect();
}
export default clientPromise;
routes/items/index.js:
import clientPromise from "$lib/db";
export async function get() {
const client = await clientPromise;
const db = client.db();
const data = await db.collection("items").find({}).toArray();
const items = data.map(({ name }) => ({ name }));
if (items) {
return {
body: {
items,
},
};
}
}
My attempt:
lib/stores/items.js
import clientPromise from "$lib/db";
import { writable } from "svelte/store";
export const items= writable([]);
const fetchItems = async () => {
const client = await clientPromise;
const db = client.db();
const data = await db.collection("items").find({}).toArray();
const items = data.map(({ name }) => ({ name }));
substances.set(items);
};
fetchItems();
Trying the above code in various places always yields a global not defined error in the client.
I found one question from someone with the same problem, but I couldn't figure out how to create a helper file.

Protecting API is done on back-end side. Usually it either server (like NodeJS) or tools Nginx/Apache (proxy, etc.). You're basically looking for Content-Security-Policy topic, which is vaporous but not related to SvelteKit.
Btw, calling DB directly from the Front-end wouldn't be secure and is not possible.

To get data from any database, you should create enpoint
For user authentication, you can create handle hook:
export async function handle({ request, resolve }) {
let user = await authenticate(request)
request.locals.user = user
request.locals.isAuthenticated = !!user
if (request.path.startsWith('/api')) {
if (!user) {
return {
status: 401,
body: JSON.stringify({
error: {
message: 'Unauthorized'
}
})
}
}
const response = await resolve(request)
return response
}

How do I properly route data through my Node API?

I have the following files:
My routes - where the orders_count route lives:
routes/index.js
const express = require('express');
const router = express.Router();
const transactionsController = require('../controllers/transactionsController');
const ordersController = require('../controllers/ordersController');
const ordersCountController = require('../controllers/ordersCountController');
router.get('/transactions', transactionsController);
router.get('/orders', ordersController);
router.get('/orders_count', ordersCountController);
module.exports = router;
I then have my orders count controller living in the controllers directory:
controllers/ordersCountController.js
const ordersCountService = require('../services/ordersCountService');
const ordersCountController = (req, res) => {
ordersCountService((error, data) => {
if (error) {
return res.send({ error });
}
res.send({ data })
});
};
module.exports = ordersCountController;
My controller then calls my order count service which fetches data from another API.
services/ordersService.js
const fetch = require('node-fetch');
// connect to api and make initial call
const ordersCountService = (req, res) => {
const url = ...;
const settings = { method: 'Get'};
fetch(url, settings)
.then(res => {
if (res.ok) {
res.json().then((data) => {
return data;
});
} else {
throw 'Unable to retrieve data';
}
}).catch(error => {
console.log(error);
});
}
module.exports = ordersCountService;
I'm trying to return the JSON response. I initially had it setup with requests but looking at the NPM site, it appears that it's depreciated so have been digging through how to use node-fetch.
I have tried both 'return data' and res.send({data}), but neither are solving the problem.
I am still new to this so I am likely missing something very obvious, but how come I am not sending the JSON back through so that it displays at the /api/orders_count endpoint?
I keep thinking I messed something up in my controller but have been looking at it for so long and can't seem to figure it out.
Any help would be greatly appreciated and if there is anything I can add for clarity, please don't hesitate to ask.
Best.

please learn promises and await syntax. life will be easier.
never throw a string. always prefer a real error object, like that : throw new Error('xxx'); that way you will always get a stack. its way easier to debug.
avoid the callback hell : http://callbackhell.com/
you need to decide if you want to catch the error in the controller or in the service. no need to do in both.
in the controller you call the service that way :
ordersCountService((error, data) => {
but you declare it like that :
const ordersCountService = (req, res) => {
which is not compatible. it should look like this if you work with callback style :
const ordersCountService = (callback) => {
...
if (error) return callback(error)
...
callback(null, gooddata);
here is an example to flatten your ordersCountService function to await syntax, which allows the "return data" you were trying to do :
const fetch = require('node-fetch');
// connect to api and make initial call
const ordersCountService = async (req, res) => {
const url = ...;
const settings = { method: 'Get'};
try {
const res = await fetch(url, settings);
if (!res.ok) throw new Error('Unable to retrieve data');
return await res.json();
} catch(error) {
console.log(error);
}
}
module.exports = ordersCountService;
in fact i would prefer to error handle in the controller. then this woud be sufficient as a service
const fetch = require('node-fetch');
// connect to api and make initial call
const ordersCountService = async () => {
const url = ...;
const settings = { method: 'Get'};
const res = await fetch(url, settings);
if (!res.ok) throw new Error('Unable to retrieve data');
return await res.json();
}
module.exports = ordersCountService;
then you can call this funtion like this :
try {
const data = await ordersCountService(req, res);
} catch(err) {
console.log(err);
}
//or
ordersCountService(req, res).then((data) => console.log(data)).catch((err) => console.error(err));

How to fix firebase database initialised multiple times due to React SSR initialised database and cloud function firebase initialised database?

I have updated the question as found the root cause of the issue.
As I have hosted my React SSR app which uses firebase database in the client serving by one of the cloud function named app throwing an error of Error: FIREBASE FATAL ERROR: Database initialized multiple times. Please make sure the format of the database URL matches with each database() call.. When I comment out one by one and deploy, works perfectly. But when I deploy together doesn't work. How do I separate these two keeping both at the same repo?
ORIGINAL Question: Why firebase cloud function throwing an error of 'The default Firebase app does not exist.'?
So I am trying out firebase function for the first time. admin.messaging() throwing me the following error. Help me figure out why?
If I look at the console I get results till console.log('deviceToken', deviceToken);
so whats wrong in const messageDone = await admin.messaging().sendToDevice(deviceToken, payload);?
const functions = require('firebase-functions');
const admin = require('firebase-admin');
exports.updateUnreadCount = functions.database.ref('/chats/{chatId}/{messageId}')
.onCreate(async(snap, context) => {
const appOptions = JSON.parse(process.env.FIREBASE_CONFIG);
appOptions.databaseAuthVariableOverride = context.auth;
const adminApp = admin.initializeApp(appOptions, 'app');
const { message, senderId, receiverUid } = snap.val();
console.log(message, senderId, receiverUid);
console.log('------------------------');
const deleteApp = () => adminApp.delete().catch(() => null);
try {
const db = adminApp.database();
const reciverUserRef = await db.ref(`users/${receiverUid}/contacts/${senderId}/`);
console.log('reciverUserRef', reciverUserRef);
const deviceTokenSnapshot = await reciverUserRef.child('deviceToken').once('value');
const deviceToken = await deviceTokenSnapshot.val();
console.log('deviceToken', deviceToken);
const payload = {
notification: {
title: 'Test Notification Title',
body: message,
sound: 'default',
badge: '1'
}
};
const messageDone = await admin.messaging().sendToDevice(deviceToken, payload);
console.log('Successfully sent message: ', JSON.stringify(messageDone));
return deleteApp().then(() => res);
} catch (err) {
console.log('error', err);
return deleteApp().then(() => Promise.reject(err));
}
});
Update1: According to this https://firebase.google.com/docs/cloud-messaging/send-message#send_to_a_topic, admin.messaging().sendToDevice(deviceToken, payload) APIs are only available in the Admin Node.js SDK?
So switched to
const payload = {
data: {
title: 'Test Notification Title',
body: message,
sound: 'default',
badge: '1'
},
token: deviceToken
};
const messageDone = await admin.messaging().send(payload);
Which is not working either. Getting an error Error: The default Firebase app does not exist. Make sure you call initializeApp() before using any of the Firebase services. Any lead will be helpful.
EDIT: Finally got the function working.
My index.js is exporting to functions, follwoing
exports.app = functions.https.onRequest(app); //React SSR
exports.updateChat = functions.database.ref('/chats/{chatId}/{messageId}').onCreate(updateChat);
exports.app is a react ssr function, which I am using to host my site. This uses database too. and throwing error of multiple database instance.
When I comment out one by one and deploy, works perfectly. But when I deploy together doesn't work. How do I separate these two keeping both at the same repo? Any suggestions, please?

You can initialise db outside export function.
const admin = require('firebase-admin');
const adminApp = admin.initializeApp(appOptions, 'app')
//continue code
Update:
const admin = require('firebase-admin');
const adminApp = admin.initializeApp(options);
async function initialize(options, apps = 'app') {
try {
const defaultApp = adminApp.name
if(defaultApp) {
const adminApp1 = admin.initializeApp(apps);
}else {
const adminApp1 = admin.initializeApp(options, apps);
}
}catch(err) {
console.error(err);
}
}
Modify this snippet as per your need and try it out
It abstracts initialize of app in another function. Just call this function at appropriate place in your code.

How to get a mongodb query to frontend code

I'm trying to query a MongoDB database and then display it to the frontend code/page.
Here's what I got so far. Note, it does sucessfully console.log() the search results on the backend just not on the frontend.
Backend File
export async function searching() {
let output = "";
const mongo = require('mongodb').MongoClient
const url = "mongodb+srv://[protected..]";
await mongo.connect(url, {useNewUrlParser: true,useUnifiedTopology: true}, (err, client) => {
const db = client.db('domains')
const collection = db.collection('domains')
collection.find().toArray((err_again, items) => {
output = items
console.log(output)
return output
})
})
}
Frontend
export async function button2_click(event) {
let output = await searching()
console.log(output)
}
Note I'm doing this in Wix code so some of the synctax front-end syntax might be different.
The "console.log(output)" gets an undefined response.
When I console log the backend file the "console.log(output)" successfully outputs the array, but it's now showing on the frontend console.
Please help I've been spending hours on this with no luck. THANK YOU!

I was able to figure this out so I figured I would post the answer here:
export async function findRecord(database, sub_db, query) {
let output = "";
const mongo = require('mongodb').MongoClient
const url = "mongodb+srv://...";
const client = await mongo.connect(url, {useNewUrlParser: true,useUnifiedTopology: true});
const db = client.db(database)
const collection = db.collection(sub_db)
const items = await collection.find(query).toArray();
client.close()
return items;
}

How do I call two different REST api endpoints simultaneously and display the data from both on one endpoint of my app?

I am building a simple application for my portfolio using The Movie Database api. In my GET /movie route, I want to get and display the data about the movie, and the names and photos of the cast members, however the data for the movie and the data for the cast members belong two separate endpoints of the api, and I am at a complete loss as to how to access both response data sets under a single endpoint in my app.
I cannot call axios.get() on both endpoints under the /movie route because I will get a "Headers already sent" error, and I have tried to write a function that uses axios.get for 1 endpoint that returns the response and gets called in my GET /movie route, but that causes the entire GET route to return undefined.
Here is my current code for my /movie route that is incorrect, but closely conveys what I am trying to accomplish
const express = require('express');
const router = express.Router();
const axios = require('axios');
const api_key = require('../config/keys').api_key;
const imgURL = "http://image.tmdb.org/t/p/";
const dateFormat = require('../config/dateFormat');
getActors = movie_id => {
axios.get(`https://api.themoviedb.org/3/movie/${movie_id}/credits?api_key=${api_key}&language=en-US`)
.then(res => {
return res.data;
}).catch(err => console.log(err.message));
}
router.get('/:id', (req, res) => {
const id = req.params.id
axios.get(`https://api.themoviedb.org/3/movie/${id}?api_key=${api_key}&language=en-US`)
.then(res => {
const movieData = res.data;
const actors = getActors(id); //calling above function here, but returns undefined and hangs the application
res.render('movie', {movieInfo: movieData, imgURL: imgURL, releaseDate: dateFormat(movieData.release_date), actors: actors})
})
.catch(err => console.log(err.status_message))
});
module.exports = router;
any help is greatly appreciated.

You can use axios.all to concatenate several promises and executing them in parallel. Then, once all the added requests have been finished, you can handle with the then promise the result of all of them. For instance, in your code:
const express = require('express');
const router = express.Router();
const axios = require('axios');
const api_key = require('../config/keys').api_key;
const imgURL = "http://image.tmdb.org/t/p/";
const dateFormat = require('../config/dateFormat');
axios.all([
axios.get(`https://api.themoviedb.org/3/movie/${movie_id}/credits?api_key=${api_key}&language=en-US`),
axios.get(`https://api.themoviedb.org/3/movie/${id}?api_key=${api_key}&language=en-US`)
])
.then(axios.spread((actorsRes, moviesRes) => {
// Your logic with each response
});
module.exports = router;

I see that getActors is currently returning null. Change it to...
const getActors = movie_id => {
return axios.get(`https://api.themoviedb.org/3/movie/${movie_id}/credits?api_key=${api_key}&language=en-US`)
.then(res => {
return res.data;
}).catch(err => console.log(err.message));
}
Another problem is calling of getActors function. It's a function that contains asynchronous function axios.get(). Change that to ..
router.get('/:id', (req, res) => {
let movieData;
const id = req.params.id
axios.get(`https://api.themoviedb.org/3/movie/${id}?api_key=${api_key}&language=en-US`)
.then(res => {
movieData = res.data;
return getActors(id);
})
.then(actors => {
res.render('movie', {movieInfo: movieData, imgURL: imgURL, releaseDate: dateFormat(movieData.release_date), actors: actors})
})
.catch(err => console.log(err.status_message))
});