Vue Chat - File Attachments

The DevExtreme Chat allows users to attach files. When this feature is activated (fileUploaderOptions.uploadFile is specified), an “Attach” button appears in the message input field, allowing users to add files to their messages.

When users attach files, each file is displayed in the input area with a file-type icon, basic details (name and size), upload status, and an option to remove files before sending.

Backend API

<template> <div class="chat-container"> <DxChat :height="710" :data-source="dataSource" :reload-on-change="false" :user="currentUser" @message-entered="onMessageEntered($event)" @attachment-download-click="onAttachmentDownloadClick($event)" > <DxFileUploaderOptions :upload-file="uploadFile" @uploaded="onUploaded" /> </DxChat> </div> </template> <script setup lang="ts"> import { ref } from 'vue'; import DxChat, { DxFileUploaderOptions, type DxChatTypes } from 'devextreme-vue/chat'; import { type DxFileUploaderTypes } from 'devextreme-vue/file-uploader'; import { Guid } from 'devextreme-vue/common'; import { dataSource, currentUser, } from './data.ts'; const uploadedFilesMap = ref(new Map<string, string>()); function getFileUrl(filename: string): string | undefined { return uploadedFilesMap.value.get(filename); } function uploadFile(): void {} function onUploaded({ file }: DxFileUploaderTypes.UploadedEvent): void { const url = URL.createObjectURL(file); uploadedFilesMap.value.set(file.name, url); } function onMessageEntered({ message }: DxChatTypes.MessageEnteredEvent): void { const attachmentsWithUrls = message.attachments?.map((attachment: DxChatTypes.Attachment) => ({ ...attachment, url: getFileUrl(attachment.name), })); dataSource.store().push([{ type: 'insert', data: { id: new Guid().toString(), ...message, attachments: attachmentsWithUrls, }, }]); } function onAttachmentDownloadClick({ attachment }: DxChatTypes.AttachmentDownloadClickEvent): void { if (!attachment?.url) { return; } const link = document.createElement('a'); link.setAttribute('href', attachment.url); link.setAttribute('download', attachment.name); document.body.appendChild(link); link.click(); document.body.removeChild(link); } </script> <style scoped> .demo-container { min-width: 720px; } .chat-container { display: flex; flex-grow: 1; align-items: center; justify-content: center; } .dx-chat { max-width: 480px; } .caption { font-size: var(--dx-font-size-sm); font-weight: 500; } .dx-avatar { border: 1px solid var(--dx-color-border); } </style>

import { CustomStore, DataSource } from 'devextreme-vue/common/data'; import { type DxChatTypes } from 'devextreme-vue/chat'; import { Guid } from 'devextreme-vue/common'; function getTimestamp(date: Date, offsetMinutes = 0): number { return date.getTime() + offsetMinutes * 60000; } const date = new Date(); date.setHours(0, 0, 0, 0); export const currentUser = { id: 'c94c0e76-fb49-4b9b-8f07-9f93ed93b4f3', name: 'John Doe', }; export const supportAgent = { id: 'd16d1a4c-5c67-4e20-b70e-2991c22747c3', name: 'Support Agent', avatarUrl: '../../../../images/petersmith.png', }; const messages: DxChatTypes.Message[] = [ { id: new Guid().toString(), timestamp: getTimestamp(date, -7), author: currentUser, text: 'Hi! I\'m having trouble accessing my account.\nThe website says my password is incorrect. I\'m sending a few screenshots so you can see where I get the error.', attachments: [ { name: 'Pic1.png', url: '../../../../images/Chat/FileAttachments/Pic1.png', size: 1024 * 10, }, { name: 'Pic2.png', url: '../../../../images/Chat/FileAttachments/Pic2.png', size: 1024 * 10, }, { name: 'Pic3.png', url: '../../../../images/Chat/FileAttachments/Pic3.png', size: 1024 * 10, }, ], }, { id: new Guid().toString(), timestamp: getTimestamp(date, -7), author: supportAgent, text: 'Hello! Thanks for including screenshots. To restore access, please follow instructions in the attached file.\nLet me know if you need anything else.', attachments: [ { name: 'Instructions.pdf', url: '../../../../images/Chat/FileAttachments/Instructions.pdf', size: 1024 * 10, }, ], }, ]; const customStore = new CustomStore<DxChatTypes.Message>({ key: 'id', load: () => Promise.resolve([...messages]), insert: (message: DxChatTypes.Message) => { messages.push(message); return Promise.resolve(message); }, }); export const dataSource = new DataSource({ store: customStore, paginate: false, });

import { createApp } from 'vue'; import App from './App.vue'; createApp(App).mount('#app');

<!DOCTYPE html> <html lang="en"> <head> <title>DevExtreme Demo</title> <meta http-equiv="X-UA-Compatible" content="IE=edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=5.0" /> <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/25.2.3/css/dx.light.css" /> <script type="module"> import * as vueCompilerSFC from "https://cdn.jsdelivr.net/npm/@vue/compiler-sfc@3.4.27/dist/compiler-sfc.esm-browser.js"; window.vueCompilerSFC = vueCompilerSFC; </script> <script src="https://cdn.jsdelivr.net/npm/typescript@5.9.3/lib/typescript.js"></script> <script src="https://cdn.jsdelivr.net/npm/core-js@2.6.12/client/shim.min.js"></script> <script src="https://cdn.jsdelivr.net/npm/systemjs@0.21.3/dist/system.js"></script> <script type="text/javascript" src="config.js"></script> <script type="text/javascript"> System.import("./index.ts"); </script> </head> <body class="dx-viewport"> <div class="demo-container"> <div id="app"></div> </div> </body> </html>

You can customize the file upload process with the following fileUploaderOptions properties:

maxFileSize
Specifies maximum allowed file size.
minFileSize
Specifies minimum allowed file size.
multiple
When set to false, limits uploads to a single file.
allowedFileExtensions
Restricts accepted file types.

For the complete list of configuration options, refer to the following API section: fileUploaderOptions.

Attachment type includes name and size fields. To add custom fields (such as url in this demo), handle the onMessageEntered event and update the message object’s attachments array as needed. You can use this handler to save files to your server.

After a user sends a message, attachments appear in the corresponding message bubble. To allow users to download attachments, implement the onAttachmentDownloadClick event handler. You can define custom download logic within the handler.