To-do app with Firebase Cloud Functions and Database

February 2nd, 2018

Hi, today we will make a to-do app using just Firebase Database and Firebase Cloud Functions, accessing functions through URL requests. Cloud Functions for Firebase

Recipe

Ingredients

Directions

We will have 3 cloud functions:

  • Add: To add a new item;
  • List: To list all items;
  • Remove: To remove an item;

All following code must be written on index.js file.

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);

List Function

exports.list = functions.https.onRequest(
  (req,res) => {            
    //get all data in todo node on Firebase Database
    admin.database().ref().child('todo').once('value')
    .then(data => {
      //send data to whom requested
      res.send(data);
    });                   
  }
);

Add Function

exports.add = functions.https.onRequest(
  (req,res) => {
    //getting latestId
    admin.database().ref(`/settings`).once('value')
    .then(snapshot => {
      //incrementing id - this is not the best option but it works for our example
      let id = snapshot.val().latestId + 1;  
      //getting TEXT parameter    
      if (req.query.text) {
        item = `${id} - ${req.query.text}`;
        //adding item to todo node
        admin.database().ref(`/todo/${id}`).set({item})
        .then(snapshot => {
          //updating latestId
          admin.database().ref(`/settings`).set({latestId: id});        
        });        
      }      
    } 
  }
);

In order to control the itemId, you must to add a /settings/latestId node with initial Id. Or Import the following json

{
  "settings" : {
    "latestId" : 0
  }
}

You can upload this json on firebase database through the console: Import json firebase

Remove Function

exports.remove = functions.https.onRequest(
  (req,res) => {   
    //getting text parameter     
    if (req.query.text) {
      id = req.query.text;
      //removing node by id 
      admin.database().ref(`/todo/${id}`).remove()
      .then(snapshot => {
        res.send("Remove Item Ok");           
      });         
    }     
  }
);

Deploy

Don´t forget to install all dependencies on functions dir: npm install. On console:

$ firebase deploy --only functions

You will receive the URLS to call:

✔  functions[add]: Successful create operation. 
Function URL (add): https://us-central1-todo-cf.cloudfunctions.net/add
✔  functions[list]: Successful create operation. 
Function URL (list): https://us-central1-todo-cf.cloudfunctions.net/list
✔  functions[remove]: Successful create operation. 
Function URL (remove): https://us-central1-todo-cf.cloudfunctions.net/remove

Tests

Atention

  • In this case we don’t catch errors neihter logs. So go deep and improve your project.
  • List command provides a JSON response;

Furthermore

Daniel Antonio Conte

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