angular-11-file-upload-example-progress-bar-feature-image

Angular 11 File upload example with progress bar & Bootstrap

In this tutorial, I will show you way to build an Angular 11 File upload example using Bootstrap, FormData and Progress Bar.

More Practice:
Angular 11 JWT Authentication example with Web Api
Angular 11 CRUD Application example with Web API

Serverless with Firebase:
Angular 11 Upload File to Firebase Storage example


Overview

We’re gonna create an Angular 11 File upload application in that user can:

  • see the upload process (percentage)
  • view all uploaded files
  • download by clicking on the file name

angular-11-file-upload-example-progress-bar-bootstrap

Technology

  • Angular 11
  • RxJS 6
  • Bootstrap 4

Web API for File Upload & Storage

Here is the API that our Angular App will work with:

MethodsUrlsActions
POST/uploadupload a File
GET/filesget List of Files (name & url)
GET/files/[filename]download a File

You can find how to implement the Rest APIs Server at one of following posts:
Node.js Express File Upload Rest API example
Spring Boot Multipart File upload (to static folder) example

Or: Spring Boot Multipart File upload (to database) example

Setup Angular 11 Project

Let’s open cmd and use Angular CLI to create a new Angular 11 Project as following command:

ng new Angular11UploadFile
? Would you like to add Angular routing? No
? Which stylesheet format would you like to use? CSS

We also need to generate some Components and Services:

ng g s services/upload-files
ng g c components/upload-files

Now you can see that our project directory structure looks like this.

Angular 11 App for uploading File

angular-11-file-upload-example-progress-bar-project-structure

Let me explain it briefly.

– We import necessary library, components in app.module.ts.
upload-file.service provides methods to save File and get Files from Spring Boot Server.
upload-files.component contains upload form, progress bar, display of list files.
app.component is the container that we embed all components.
index.html for importing the Bootstrap.

Set up App Module

Open app.module.ts and import HttpClientModule:

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { HttpClientModule } from '@angular/common/http';

import { AppComponent } from './app.component';
import { UploadFilesComponent } from './components/upload-files/upload-files.component';

@NgModule({
  declarations: [
    AppComponent,
    UploadFilesComponent
  ],
  imports: [
    BrowserModule,
    HttpClientModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

Add Bootstrap to the project

Open index.html and add following line into <head> tag:

<!DOCTYPE html>
<html lang="en">
  <head>
    ...
    <link type="text/css" rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" />
  </head>
  ...
</html>

Create Angular Service for Upload Files

This service will use Angular HTTPClient to send HTTP requests.
There are 2 functions:

  • upload(file): returns Observable<HttpEvent<any>> that we’re gonna use for tracking progress
  • getFiles(): returns a list of Files’ information as Observable object

services/upload-file.service.ts

import { Injectable } from '@angular/core';
import { HttpClient, HttpRequest, HttpEvent } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class UploadFilesService {
  private baseUrl = 'http://localhost:8080';

  constructor(private http: HttpClient) { }

  upload(file: File): Observable<HttpEvent<any>> {
    const formData: FormData = new FormData();

    formData.append('file', file);

    const req = new HttpRequest('POST', `${this.baseUrl}/upload`, formData, {
      reportProgress: true,
      responseType: 'json'
    });

    return this.http.request(req);
  }

  getFiles(): Observable<any> {
    return this.http.get(`${this.baseUrl}/files`);
  }
}

FormData is a data structure that can be used to store key-value pairs. We use it to build an object which corresponds to an HTML form with append() method.

– We set reportProgress: true to exposes progress events. Notice that this progress event are expensive (change detection for each event), so you should only use when you want to monitor it.

– We call the request(PostRequest) & get() method of HttpClient to send an HTTP POST & Get request to the Spring Boot File Upload server.

Create Component for Upload Files

Let’s create a File Upload UI with Progress Bar, Card, Button and Message.

First we need to use the following imports:

upload-files.component.ts

import { Component, OnInit } from '@angular/core';

import { UploadFileService } from 'src/app/services/upload-file.service';
import { HttpEventType, HttpResponse } from '@angular/common/http';
import { Observable } from 'rxjs';

Then we define the some variables and inject UploadFileService as follows:

export class UploadFilesComponent implements OnInit {

  selectedFiles?: FileList;
  currentFile?: File;
  progress = 0;
  message = '';

  fileInfos?: Observable<any>;

  constructor(private uploadService: UploadFileService) { }

}

Next we define selectFile() method. It helps us to get the selected Files.

selectFile(event: any): void {
  this.selectedFiles = event.target.files;
}

Next we write upload() method for upload file:

upload(): void {
  this.progress = 0;

  if (this.selectedFiles) {
    const file: File | null = this.selectedFiles.item(0);

    if (file) {
      this.currentFile = file;

      this.uploadService.upload(this.currentFile).subscribe(
        (event: any) => {
          if (event.type === HttpEventType.UploadProgress) {
            this.progress = Math.round(100 * event.loaded / event.total);
          } else if (event instanceof HttpResponse) {
            this.message = event.body.message;
            this.fileInfos = this.uploadService.getFiles();
          }
        },
        (err: any) => {
          console.log(err);
          this.progress = 0;

          if (err.error && err.error.message) {
            this.message = err.error.message;
          } else {
            this.message = 'Could not upload the file!';
          }

          this.currentFile = undefined;
        });
    }

    this.selectedFiles = undefined;
  }
}

We use selectedFiles for accessing current File as the first Item. Then we call uploadService.upload() method on the currentFile.

The progress will be calculated basing on event.loaded and event.total.
If the transmission is done, the event will be a HttpResponse object. At this time, we call uploadService.getFiles() to get the files’ information and assign the result to fileInfos variable.

We also need to do this work in ngOnInit() method:

ngOnInit(): void {
  this.fileInfos = this.uploadService.getFiles();
}

Now we create the HTML template of the Upload File UI. Add the following content to upload-files.component.html file:

<div class="row">
  <div class="col-8">
    <label class="btn btn-default p-0">
      <input type="file" (change)="selectFile($event)" />
    </label>
  </div>

  <div class="col-4">
    <button class="btn btn-success btn-sm" [disabled]="!selectedFiles" (click)="upload()">
      Upload
    </button>
  </div>
</div>

<div *ngIf="currentFile" class="progress my-3">
  <div
    class="progress-bar progress-bar-info progress-bar-striped"
    role="progressbar"
    attr.aria-valuenow="{{ progress }}"
    aria-valuemin="0"
    aria-valuemax="100"
    [ngStyle]="{ width: progress + '%' }"
  >
    {{ progress }}%
  </div>
</div>

<div *ngIf="message" class="alert alert-secondary" role="alert">{{ message }}</div>

<div class="card mt-3">
  <div class="card-header">List of Files</div>
  <ul
    class="list-group list-group-flush"
    *ngFor="let file of fileInfos | async"
  >
    <li class="list-group-item">
      <a href="{{ file.url }}">{{ file.name }}</a>
    </li>
  </ul>
</div>

Add Upload File Component to App Component

Open app.component.html and embed the UploadFile Component with <app-upload-files> tag.

<div class="container" style="width:600px">
  <div class="my-3">
    <h3>bezkoder.com</h3>
    <h4>{{ title }}</h4>
  </div>

  <app-upload-files></app-upload-files>
</div>

app.component.ts

import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'Angular 11 File Upload';
}

Run the App

You can find how to implement the Rest APIs Server at one of following posts:
Node.js Express File Upload Rest API example
Spring Boot Multipart File upload (to static folder) example

Because we configure CORS for origin: http://localhost:8081, so you need to run Angular 11 Client with command:
ng serve --port 8081

Open Browser with url http://localhost:8081/ and check the result.

Further Reading

Conclusion

Today we’re learned how to build an example for File upload using Angular 11 and FormData. We also provide the ability to show list of files, upload progress using Bootstrap, and to download file from the server.

If you want to upload multiple files at once like this:

angular-11-multiple-files-upload-example

You can find the instruction here:
Angular 11 Multiple Files upload example with Progress Bar

Or Serverless with Firebase:
Angular 11 Upload File to Firebase Storage example

Happy Learning! See you again.

Source Code

The source code for the Angular 11 App is uploaded to Github.

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