How to Create a CRUD Application with Koa.js?

introduction in this guide, you'll learn how to develop a crud (create, read, update, delete) application using koa js this tutorial will walk you through the essential steps of managing data and constructing a functional api by integrating your koa js backend with back4app you'll begin by setting up a back4app project called basic crud app koajs , which serves as a powerful backend for your application afterward, you'll design a flexible database schema by establishing collections and defining fields—either manually or with the aid of the back4app ai agent this setup ensures that your data is organized for smooth crud operations next, you'll utilize the back4app admin app, a no code, drag and drop tool that simplifies data management tasks like creating, reading, updating, and deleting records finally, you will configure your koa js server to interact with back4app via rest apis, all while implementing robust access controls to secure your backend by the end of this tutorial, you'll have built a production ready server side application that not only supports basic crud operations but also includes user authentication and secure data handling key takeaways discover how to construct crud applications with koa js while leveraging a reliable cloud backend gain insights into designing a scalable backend and integrating it with a restful api learn to use the intuitive back4app admin app to simplify crud operations explore deployment strategies, including containerization with docker, to launch your koa js application swiftly prerequisites before diving in, make sure you have the following a back4app account with an active project check out getting started with back4app https //www back4app com/docs/get started/new parse app for guidance a working node js development environment install node js (v14 or later) and set up your koa js project basic knowledge of javascript, koa js, and rest apis review the koa js documentation https //koajs com/ if needed step 1 – setting up your back4app project creating a new back4app project log into your back4app account click on the “new app” button from your dashboard name your project basic crud app koajs and follow the instructions to complete the setup create new project once your project is established, it will be visible on your dashboard, providing the backend framework required for your application step 2 – crafting the database schema designing your data model for this crud application, you'll need to set up several collections below are sample collections with suggested fields and types to help you configure your database schema effectively 1\ items collection this collection holds details for each item field type description id objectid auto generated unique identifier title string the item’s title description string a short description of the item created at date timestamp when the item was created updated at date timestamp for the most recent update 2\ users collection this collection manages user data and authentication credentials field type description id objectid auto generated primary key username string a unique username for the user email string unique email address of the user password hash string securely hashed password created at date timestamp of account creation updated at date timestamp of the last account update you can create these collections via the back4app dashboard by adding a new class for each and defining the corresponding columns create new class you can define fields by selecting the appropriate type, setting default values, and specifying whether the field is mandatory create column leveraging the back4app ai agent for schema setup the back4app ai agent, available within your dashboard, can automatically generate your database schema from a detailed prompt describing your collections and fields this feature expedites project setup and ensures a consistent schema for crud operations how to use the ai agent open the ai agent from your back4app dashboard or within project settings provide a descriptive prompt outlining the collections and fields you require review the generated schema and apply the configuration to your project example prompt create these collections in my back4app project 1\) collection items \ fields \ id objectid (auto generated) \ title string \ description string \ created at date (auto generated) \ updated at date (auto updated) 2\) collection users \ fields \ id objectid (auto generated) \ username string (unique) \ email string (unique) \ password hash string \ created at date (auto generated) \ updated at date (auto updated) this approach saves time and helps ensure that your schema is both consistent and optimized step 3 – activating the admin app & crud functionality overview of the admin app the back4app admin app is a user friendly interface that lets you manage your backend data effortlessly through drag and drop controls this no code tool simplifies operations such as creating, reading, updating, and deleting records activating the admin app go to the “more” menu in your back4app dashboard select “admin app” and click on “enable admin app ” set up your initial admin account; this process establishes system roles like b4aadminuser and prepares system collections enable admin app once activated, log into the admin app to manage your collections and records admin app dashboard within the admin app, you can add new records use the “add record” button in any collection (e g , items) to create new entries view and edit records select a record to inspect its details or modify its fields remove records delete entries that are no longer required step 4 – connecting your koa js backend with back4app now that your backend is configured and managed, it’s time to set up your koa js server to interact with back4app using rest apis with koa js this tutorial will demonstrate how to use rest api calls from your koa js server to perform crud operations on your back4app collections setting up a basic koa js server install koa js and necessary middleware npm install koa koa router koa bodyparser node fetch create the server file (e g , server js ) // server js const koa = require('koa'); const router = require('koa router'); const bodyparser = require('koa bodyparser'); const fetch = require('node fetch'); const app = new koa(); const router = new router(); const application id = 'your application id'; const rest api key = 'your rest api key'; const base url = 'https //parseapi back4app com'; // fetch all items router get('/items', async (ctx) => { try { const response = await fetch(`${base url}/classes/items`, { headers { 'x parse application id' application id, 'x parse rest api key' rest api key } }); const data = await response json(); ctx body = data results; } catch (error) { ctx status = 500; ctx body = { error 'failed to fetch items' }; } }); // create a new item router post('/items', async (ctx) => { const { title, description } = ctx request body; try { const response = await fetch(`${base url}/classes/items`, { method 'post', headers { 'x parse application id' application id, 'x parse rest api key' rest api key, 'content type' 'application/json' }, body json stringify({ title, description }) }); const newitem = await response json(); ctx body = newitem; } catch (error) { ctx status = 500; ctx body = { error 'error creating item' }; } }); // update an item router put('/items/\ id', async (ctx) => { const { id } = ctx params; const { title, description } = ctx request body; try { const response = await fetch(`${base url}/classes/items/${id}`, { method 'put', headers { 'x parse application id' application id, 'x parse rest api key' rest api key, 'content type' 'application/json' }, body json stringify({ title, description }) }); const updateditem = await response json(); ctx body = updateditem; } catch (error) { ctx status = 500; ctx body = { error 'error updating item' }; } }); // delete an item router delete('/items/\ id', async (ctx) => { const { id } = ctx params; try { await fetch(`${base url}/classes/items/${id}`, { method 'delete', headers { 'x parse application id' application id, 'x parse rest api key' rest api key } }); ctx body = { message 'item deleted successfully' }; } catch (error) { ctx status = 500; ctx body = { error 'error deleting item' }; } }); app use(bodyparser()); app use(router routes()) use(router allowedmethods()); const port = process env port || 3000; app listen(port, () => { console log(`server is running on port ${port}`); }); this setup gives you a koa js server that communicates with back4app through rest calls, handling all crud operations step 5 – securing your backend implementing access controls protect your data by applying access control lists (acls) at the object level for instance, when creating a private item, set acls to restrict access async function createsecureitem(itemdata, ownersessiontoken) { try { const response = await fetch(`${base url}/classes/items`, { method 'post', headers { 'x parse application id' application id, 'x parse rest api key' rest api key, 'content type' 'application/json', 'x parse session token' ownersessiontoken }, body json stringify({ title itemdata title, description itemdata description, acl { " " { "read" false, "write" false }, "owner" { "read" true, "write" true } } }) }); const result = await response json(); console log('secure item created ', result); } catch (error) { console error('error creating secure item ', error); } } setting class level permissions (clps) within your back4app dashboard, configure clps for each collection to establish default rules, ensuring that only authorized users can access sensitive data step 6 – user authentication configuring user accounts back4app utilizes a user class for handling authentication in your koa js server, manage user registration and login by interfacing with the back4app rest api example user registration endpoint router post('/signup', async (ctx) => { const { username, password, email } = ctx request body; try { const response = await fetch(`${base url}/users`, { method 'post', headers { 'x parse application id' application id, 'x parse rest api key' rest api key, 'content type' 'application/json' }, body json stringify({ username, password, email }) }); const userdata = await response json(); ctx body = userdata; } catch (error) { ctx status = 500; ctx body = { error 'error signing up' }; } }); you can build similar endpoints for login and session management as needed step 7 – deploying your koa js application back4app’s web deployment feature allows you to host your koa js server by linking it to your github repository 7 1 – build and organize your project ensure your project is properly structured a sample layout might be basic crud app koajs/ ├── node modules/ ├── server js ├── package json └── readme md commit all your source files to a git repository sample git commands git init git add git commit m "initial commit of koa js backend" git remote add origin https //github com/your username/basic crud app koajs git git push u origin main 7 2 – integrate with back4app web deployment log in to your back4app dashboard, open your project basic crud app koajs , and navigate to the web deployment section connect your github account if you haven’t done so already select your repository and the relevant branch (e g , main ) 7 3 – configure your deployment settings build command if your project needs to be built (for example, transpiling modern javascript), specify a build command such as npm run build output directory indicate the folder containing your production ready files, if applicable environment variables add any necessary environment variables (like api keys) in the deployment configuration 7 4 – optional dockerize your koa js server if you want to deploy your application as a container, include a dockerfile in your repository \# use the official node js image as a base from node 16 alpine \# set the working directory workdir /app \# copy package files and install dependencies copy package json / run npm install \# copy the rest of the application code copy \# expose the desired port expose 3000 \# run the application cmd \["node", "server js"] 7 5 – launch your application click the deploy button on back4app monitor the deployment logs to ensure your app is built and deployed successfully once finished, back4app will provide a url where your koa js server is accessible 7 6 – validate your deployment visit the provided url to verify that your application is running test each endpoint (crud operations, user authentication) to confirm proper functionality if issues occur, review your logs and deployment settings for troubleshooting step 8 – conclusion and future enhancements great work! you have now built a fully operational crud application using koa js integrated with back4app your project basic crud app koajs features carefully designed collections for items and users, a user friendly admin app for data management, and a secure backend next steps expand your api enhance your koa js server with additional routes, middleware, or even real time features improve authentication consider implementing token based authentication, social logins, or multi factor verification explore further documentation check out the back4app documentation https //www back4app com/docs and koa js guides https //koajs com/ for more advanced topics and optimizations by following this tutorial, you now possess the skills to build a scalable, secure, and efficient crud backend with koa js and back4app enjoy