Angular File Upload

The file upload is an essential component to make a form that store some image kind of data. It helps in applications using image upload or in the file sharing. This file-upload component uses file.io API for uploading file and in return it provides a shareable link. Furthermore, we can send get request to shareable link to get the file but for now, our only focus is on upload section so we only use the post method.

Approach:

1. Create a new angular app using following command-

   ng new angular-file-upload 

2. Move inside the app by using cd command-

   cd src/app/

3. Generate new component file-upload-

   ng g c file-upload/ 

4. Open src/app folder and start editing app.component.html file.

   <app-file-upload></app-file-upload>
5. Create a service for file-upload component via command-

   ng g s file-upload/

6. Open src/app/file-upload folder and start editing file-upload.component.ts file.

   import { Component, OnInit } from '@angular/core';
   import { FileUploadService } from './file-upload.service';
   
   @Component({
       selector: 'app-file-upload',
       templateUrl: './file-upload.component.html',
       styleUrls: ['./file-upload.component.css']
   })
   export class FileUploadComponent implements OnInit {
   
       // Variable to store shortLink from api response
       shortLink: string = "";
       loading: boolean = false; // Flag variable
       file: File = null; // Variable to store file
   
       // Inject service
       constructor(private fileUploadService: FileUploadService) { }
   
       ngOnInit(): void {
       }
   
       // On file Select
       onChange(event) {
           this.file = event.target.files[0];
       }
   
       // OnClick of button Upload
       onUpload() {
           this.loading = !this.loading;
           console.log(this.file);
           this.fileUploadService.upload(this.file).subscribe(
               (event: any) => {
                   if (typeof (event) === 'object') {
   
                       // Short link via api response
                       this.shortLink = event.link;
   
                       this.loading = false; // Flag variable
                   }
               }
           );
       }
   }
7. Open src/app/file-upload/ and start editing file-upload.service.ts file.

   import { Injectable } from '@angular/core';
   import {HttpClient} from '@angular/common/http';
   import {Observable} from 'rxjs';
   @Injectable({
     providedIn: 'root'
   })
   export class FileUploadService {
   
     // API url
     baseApiUrl = "https://file.io"
   
     constructor(private http:HttpClient) { }
   
     // Returns an observable
     upload(file):Observable<any> {
   
         // Create form data
         const formData = new FormData();
   
         // Store form name as "file" with file data
         formData.append("file", file, file.name);
   
         // Make http post request over api
         // with formData as req
         return this.http.post(this.baseApiUrl, formData)
     }
   }
8. Open src/app/file-upload and start editing file-upload.component.html file.

   <div class="text-center">
       <input class="form-control" type="file"
               (change)="onChange($event)">
   
       <button (click)="onUpload()"
           class="btn btn-success">
           Upload
       </button>
   </div>
   
   <!-- Shareable short link of  uploaded file -->
   <div class="container text-center jumbotron"
       *ngIf="shortLink">
       <h2> Visit Here</h2>
       <a href="{{shortLink}}">{{shortLink}}</a>
   </div>
   
   <!--Flag variable is used here-->
   <div class="container" *ngIf="loading">
       <h3>Loading ...</h3>
   </div>
9. Open src/app/ and start editing app.module.ts file.

   import { BrowserModule } from
       '@angular/platform-browser';
   import { NgModule } from '@angular/core';
   
   import { FileUploadComponent } from
       './file-upload/file-upload.component';
   
   import { AppComponent } from './app.component';
   import {HttpClientModule} from
       '@angular/common/http';
   @NgModule({
     declarations: [
       AppComponent,
       FileUploadComponent,
     ],
     imports: [
       BrowserModule,
       HttpClientModule
     ],
     providers: [],
     bootstrap: [AppComponent]
   })
   export class AppModule { }
10. Now run this command to serve on localhost

    ng serve

Output:

• Before file selection:
  
• After file selection and clicking on button:
  
• After loading is completed:
  

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