How to Create a CRUD Application with Elm?

overview in this walkthrough, you will learn how to build a complete crud (create, read, update, delete) application using elm we'll employ back4app as our backend service to manage data effortlessly this guide explains how to configure a back4app project, design a flexible data schema, and integrate crud operations into an elm application using rest api calls initially, you'll set up a back4app project, here named basic crud app elm , which provides a robust, non relational database you will design your data model—either manually or using back4app’s intelligent ai agent next, you will manage your backend with the back4app admin app, which offers an intuitive drag and drop interface for data manipulation finally, you'll connect your elm app to back4app by making restful api requests while ensuring secure data operations by the end of this tutorial, you’ll have a production ready elm application that supports core crud functionalities and secure user authentication essential insights learn how to build an elm crud application paired with a non relational backend understand how to structure a scalable backend and connect it with an elm front end use the back4app admin app for seamless create, read, update, and delete actions explore deployment options, including docker, to launch your elm application with ease prerequisites before you begin, ensure you have a back4app account with a project set up need help? visit getting started with back4app https //www back4app com/docs/get started/new parse app an elm development environment install elm and use your favorite editor familiarity with elm basics, functional programming, and http requests check the elm guide https //guide elm lang org/ if needed step 1 – initializing your project creating a new back4app project log in to your back4app account click on the “new app” button from your dashboard name your project basic crud app elm and follow the instructions to complete setup create new project once your project is ready, it will appear on your dashboard, setting the stage for your backend configuration step 2 – crafting the data schema setting up your data structures for this crud application, you will create several collections (or classes) in back4app below are examples of the main collections and their fields to support crud operations 1\ items collection this collection stores details about each entry field type details id objectid auto generated unique identifier title string name of the item description string brief description of the item createdat date timestamp marking creation updatedat date timestamp marking last update 2\ users collection this collection handles user authentication and credentials field type details id objectid auto generated unique identifier username string unique username for the user email string unique email address passwordhash string encrypted password for security createdat date timestamp for when the account was created updatedat date timestamp for the last account update you can add these collections and fields manually via the back4app dashboard create new class you may add fields by selecting the appropriate type, naming the field, and specifying if it’s mandatory create column using the back4app ai agent for schema configuration the back4app ai agent simplifies the creation of your data schema based on your description this automated process ensures your schema is set up for all necessary crud actions to use the ai agent access the ai agent sign in to your back4app dashboard and locate the ai agent in your project settings detail your data schema describe the collections and fields you need review and confirm check the proposed schema and approve it to configure your backend example prompt create the following collections in my back4app project 1\) collection items \ fields \ id objectid (auto generated) \ title string \ description string \ createdat date (auto generated) \ updatedat date (auto updated) 2\) collection users \ fields \ id objectid (auto generated) \ username string (unique) \ email string (unique) \ passwordhash string \ createdat date (auto generated) \ updatedat date (auto updated) this smart approach saves time and ensures a robust, consistent data schema step 3 – activating the admin interface & handling crud operations introduction to the admin interface back4app’s admin app gives you a no code interface to manage your backend data its user friendly design allows you to perform crud actions such as adding, viewing, editing, and deleting records enabling the admin app go to the “more” menu on your back4app dashboard select “admin app” and click “enable admin app ” create your admin account, which will also set up roles like b4aadminuser and system collections enable admin app once activated, log in to the admin app to manage your data admin app dashboard performing crud actions in the admin app within the admin app, you can insert records choose “add record” in a collection (e g , items) to create new entries inspect/edit records click on any record to view details or modify data remove records delete entries that are no longer required this easy to use interface streamlines data management step 4 – connecting your elm application to back4app with your backend configured, it’s time to link your elm application to back4app using rest api calls in elm since elm doesn’t support a dedicated parse sdk, we will use its built in http capabilities to interact with back4app's rest endpoints example fetching data from the items collection below is an elm module example using the http package to retrieve a list of items module items exposing (item, fetchitems, itemdecoder) import http import json decode as decode exposing (decoder) type alias item = { id string , title string , description string } itemdecoder decoder item itemdecoder = decode map3 item (decode field "objectid" decode string) (decode field "title" decode string) (decode field "description" decode string) fetchitems cmd msg fetchitems = http get { url = "https //parseapi back4app com/classes/items" , expect = http expectjson handleresponse (decode field "results" (decode list itemdecoder)) } handleresponse result http error (list item) > msg handleresponse result = \ map the http result to your application's message type debug todo "handle the response appropriately" example creating a new item you can also implement post requests in elm to add new records createitem string > string > cmd msg createitem title description = let body = http jsonbody <| encode object \[ ( "title", encode string title ) , ( "description", encode string description ) ] in http post { url = "https //parseapi back4app com/classes/items" , body = body , expect = http expectjson handlepostresponse decode value } handlepostresponse result http error decode value > msg handlepostresponse result = debug todo "process the post response" repeat similar patterns for update and delete operations using put and delete methods step 5 – safeguarding your backend configuring access controls (acls) protect your data by setting up acls on your objects for example, to restrict an item to its creator, you could use \ in elm, you can add acl details to your json payload createprivateitem string > string > string > cmd msg createprivateitem title description ownerid = let acl = encode object \[ ( ownerid, encode object \[ ("read", encode bool true), ("write", encode bool true) ] ) , ( " ", encode object \[ ("read", encode bool false), ("write", encode bool false) ] ) ] body = http jsonbody <| encode object \[ ( "title", encode string title ) , ( "description", encode string description ) , ( "acl", acl ) ] in http post { url = "https //parseapi back4app com/classes/items" , body = body , expect = http expectjson handlepostresponse decode value } setting class level permissions (clps) define clps in the back4app dashboard so that only authenticated users can access specific collections step 6 – implementing user authentication managing user accounts back4app leverages the built in user collection for handling authentication in your elm app, you will manage sign ups and logins via rest api calls example user sign up request signupuser string > string > string > cmd msg signupuser username password email = let body = http jsonbody <| encode object \[ ( "username", encode string username ) , ( "password", encode string password ) , ( "email", encode string email ) ] in http post { url = "https //parseapi back4app com/users" , body = body , expect = http expectjson handleauthresponse decode value } handleauthresponse result http error decode value > msg handleauthresponse result = debug todo "process the authentication response" follow a similar approach for login and session management step 7 – deploying your elm application back4app supports seamless deployment you can deploy your elm application using various methods including docker 7 1 building your elm application compile your elm code run the elm compiler to generate javascript elm make src/main elm output=dist/main js prepare your assets ensure your generated javascript and html files are ready for deployment 7 2 organizing your project structure a typical elm project layout might look like basic crud app elm/ \| src/ \| | main elm \| | api elm \| dist/ \| | index html \| | main js \| elm json \| package json \| dockerfile 7 3 dockerizing your elm application if containerizing, add a dockerfile \# use a lightweight node image for serving static files from node 16 alpine \# set the working directory workdir /app \# copy compiled files copy dist/ /app/dist/ \# expose the desired port expose 8080 \# serve the static files using a simple server cmd \["npx", "http server", "dist", " p", "8080"] 7 4 deploying with back4app’s web deployment link your repository host your elm project on github configure deployment settings in the back4app dashboard, choose the web deployment feature, connect your repository (e g , basic crud app elm ), and select the desired branch set build commands specify the build command (e g , elm make src/main elm output=dist/main js ) and the artifact location deploy your app hit deploy and monitor the logs until your app is live step 8 – final thoughts and future directions congratulations! you have built an elm based crud application integrated with back4app you set up a project named basic crud app elm , designed collections for items and users, and managed data via the back4app admin app furthermore, you connected your elm application using rest api calls and implemented security measures future enhancements expand features integrate advanced search capabilities, detailed views, or real time updates boost backend functions experiment with cloud functions, third party integrations, or role based access deepen your knowledge visit the back4app documentation https //www back4app com/docs and other resources to refine your app happy coding and enjoy building with elm and back4app!