Download PDF file, Angular 6 and Web API

Download PDF file, Angular 6 and Web API

To download a PDF file from an Angular 6 application using a Web API, you can follow these steps:

1. Set Up the Web API

Ensure your Web API has an endpoint that serves the PDF file. Here's an example using ASP.NET Core:

Example API Endpoint:

[HttpGet("download-pdf")] public IActionResult DownloadPdf() { var filePath = "path/to/your/file.pdf"; var fileBytes = System.IO.File.ReadAllBytes(filePath); return File(fileBytes, "application/pdf", "downloaded-file.pdf"); }

2. Create a Service in Angular

Create a service to handle the HTTP request for downloading the PDF.

Generate the Service:

ng generate service pdf

PDF Service (pdf.service.ts):

import { Injectable } from '@angular/core'; import { HttpClient } from '@angular/common/http'; import { Observable } from 'rxjs'; @Injectable({ providedIn: 'root' }) export class PdfService { private apiUrl = 'https://your-api-url/api/download-pdf'; // Replace with your API URL constructor(private http: HttpClient) {} downloadPdf(): Observable<Blob> { return this.http.get(this.apiUrl, { responseType: 'blob' }); } }

3. Create a Component to Trigger the Download

Create a component where you will trigger the PDF download.

Generate the Component:

ng generate component pdf-download

PDF Download Component (pdf-download.component.ts):

import { Component } from '@angular/core'; import { PdfService } from '../pdf.service'; @Component({ selector: 'app-pdf-download', template: `<button (click)="downloadPdf()">Download PDF</button>`, }) export class PdfDownloadComponent { constructor(private pdfService: PdfService) {} downloadPdf() { this.pdfService.downloadPdf().subscribe(blob => { const url = window.URL.createObjectURL(blob); const a = document.createElement('a'); a.href = url; a.download = 'downloaded-file.pdf'; // Set the desired file name document.body.appendChild(a); a.click(); document.body.removeChild(a); window.URL.revokeObjectURL(url); }); } }

4. Import HttpClientModule

Make sure to import HttpClientModule in your main module:

App Module (app.module.ts):

import { BrowserModule } from '@angular/platform-browser'; import { NgModule } from '@angular/core'; import { HttpClientModule } from '@angular/common/http'; import { AppComponent } from './app.component'; import { PdfDownloadComponent } from './pdf-download/pdf-download.component'; @NgModule({ declarations: [AppComponent, PdfDownloadComponent], imports: [BrowserModule, HttpClientModule], bootstrap: [AppComponent] }) export class AppModule {}

5. Use the Component in Your Application

Now, include the PdfDownloadComponent in your main application template:

App Component Template (app.component.html):

<app-pdf-download></app-pdf-download>

Conclusion

With this setup, when the user clicks the "Download PDF" button, it triggers a request to your Web API, retrieves the PDF file as a blob, and initiates a download in the browser. Make sure your API endpoint correctly returns the PDF file with appropriate headers.

Examples

  1. "Angular 6 download PDF file from Web API endpoint"

    • Description: This query shows how to download a PDF file from a Web API endpoint and trigger a download in an Angular 6 application.
    • Code:
      // In your Angular service import { Injectable } from '@angular/core'; import { HttpClient } from '@angular/common/http'; import { saveAs } from 'file-saver'; @Injectable({ providedIn: 'root' }) export class PdfService { constructor(private http: HttpClient) {} downloadPdf() { this.http.get('https://your-api-endpoint/pdf', { responseType: 'blob' }).subscribe(blob => { saveAs(blob, 'file.pdf'); }); } } // In your Angular component import { Component } from '@angular/core'; import { PdfService } from './pdf.service'; @Component({ selector: 'app-root', template: `<button (click)="download()">Download PDF</button>` }) export class AppComponent { constructor(private pdfService: PdfService) {} download() { this.pdfService.downloadPdf(); } }

  2. "Angular 6 handle PDF download with authentication token"

    • Description: This query handles downloading a PDF file with an authentication token in the request header.
    • Code:
      // In your Angular service import { Injectable } from '@angular/core'; import { HttpClient, HttpHeaders } from '@angular/common/http'; import { saveAs } from 'file-saver'; @Injectable({ providedIn: 'root' }) export class PdfService { constructor(private http: HttpClient) {} downloadPdfWithToken(token: string) { const headers = new HttpHeaders().set('Authorization', `Bearer ${token}`); this.http.get('https://your-api-endpoint/pdf', { headers, responseType: 'blob' }).subscribe(blob => { saveAs(blob, 'file.pdf'); }); } }

  3. "Angular 6 download PDF file from Web API and show download progress"

    • Description: This query demonstrates showing download progress when fetching a PDF file from a Web API.
    • Code:
      // In your Angular service import { Injectable } from '@angular/core'; import { HttpClient, HttpEvent, HttpEventType } from '@angular/common/http'; import { saveAs } from 'file-saver'; import { Observable } from 'rxjs'; @Injectable({ providedIn: 'root' }) export class PdfService { constructor(private http: HttpClient) {} downloadPdfWithProgress(): Observable<number> { return new Observable(observer => { this.http.get('https://your-api-endpoint/pdf', { responseType: 'blob', observe: 'events', reportProgress: true }) .subscribe((event: HttpEvent<any>) => { if (event.type === HttpEventType.DownloadProgress) { const percentDone = Math.round((100 * event.loaded) / (event.total || 1)); observer.next(percentDone); } else if (event.type === HttpEventType.Response) { saveAs(event.body, 'file.pdf'); observer.complete(); } }); }); } } // In your Angular component import { Component } from '@angular/core'; import { PdfService } from './pdf.service'; @Component({ selector: 'app-root', template: ` <button (click)="download()">Download PDF</button> <p *ngIf="progress !== undefined">Progress: {{ progress }}%</p> ` }) export class AppComponent { progress?: number; constructor(private pdfService: PdfService) {} download() { this.pdfService.downloadPdfWithProgress().subscribe(progress => { this.progress = progress; }); } }

  4. "Angular 6 trigger PDF file download from Web API in a new tab"

    • Description: This query demonstrates how to open the PDF file in a new browser tab.
    • Code:
      // In your Angular service import { Injectable } from '@angular/core'; import { HttpClient } from '@angular/common/http'; @Injectable({ providedIn: 'root' }) export class PdfService { constructor(private http: HttpClient) {} openPdfInNewTab() { this.http.get('https://your-api-endpoint/pdf', { responseType: 'blob' }).subscribe(blob => { const url = window.URL.createObjectURL(blob); window.open(url); }); } } // In your Angular component import { Component } from '@angular/core'; import { PdfService } from './pdf.service'; @Component({ selector: 'app-root', template: `<button (click)="openPdf()">Open PDF in New Tab</button>` }) export class AppComponent { constructor(private pdfService: PdfService) {} openPdf() { this.pdfService.openPdfInNewTab(); } }

  5. "Angular 6 download and preview PDF file from Web API"

    • Description: This query shows how to download and preview the PDF file within an Angular application.
    • Code:
      // In your Angular service import { Injectable } from '@angular/core'; import { HttpClient } from '@angular/common/http'; @Injectable({ providedIn: 'root' }) export class PdfService { constructor(private http: HttpClient) {} getPdfBlob() { return this.http.get('https://your-api-endpoint/pdf', { responseType: 'blob' }); } } // In your Angular component import { Component } from '@angular/core'; import { PdfService } from './pdf.service'; @Component({ selector: 'app-root', template: ` <button (click)="previewPdf()">Preview PDF</button> <iframe *ngIf="pdfSrc" [src]="pdfSrc | safe: 'resourceUrl'" width="600" height="500"></iframe> ` }) export class AppComponent { pdfSrc?: string; constructor(private pdfService: PdfService) {} previewPdf() { this.pdfService.getPdfBlob().subscribe(blob => { this.pdfSrc = URL.createObjectURL(blob); }); } } // In app.module.ts import { NgModule } from '@angular/core'; import { BrowserModule } from '@angular/platform-browser'; import { AppComponent } from './app.component'; import { SafePipe } from './safe.pipe'; @NgModule({ declarations: [ AppComponent, SafePipe ], imports: [ BrowserModule ], providers: [], bootstrap: [AppComponent] }) export class AppModule { }

  6. "Angular 6 download PDF file using Angular HttpClient and file-saver library"

    • Description: This query covers using the file-saver library to download a PDF file fetched using Angular's HttpClient.
    • Code:
      // Install file-saver // npm install file-saver // In your Angular service import { Injectable } from '@angular/core'; import { HttpClient } from '@angular/common/http'; import { saveAs } from 'file-saver'; @Injectable({ providedIn: 'root' }) export class PdfService { constructor(private http: HttpClient) {} downloadPdf() { this.http.get('https://your-api-endpoint/pdf', { responseType: 'blob' }).subscribe(blob => { saveAs(blob, 'file.pdf'); }); } }

  7. "Angular 6 download and display PDF file in a modal"

    • Description: This query shows how to download a PDF file and display it in a modal dialog.
    • Code:
      // In your Angular service import { Injectable } from '@angular/core'; import { HttpClient } from '@angular/common/http'; @Injectable({ providedIn: 'root' }) export class PdfService { constructor(private http: HttpClient) {} getPdfBlob() { return this.http.get('https://your-api-endpoint/pdf', { responseType: 'blob' }); } } // In your Angular component import { Component } from '@angular/core'; import { PdfService } from './pdf.service'; @Component({ selector: 'app-root', template: ` <button (click)="openModal()">Open PDF in Modal</button> <ngb-modal #pdfModal> <ng-template> <iframe *ngIf="pdfSrc" [src]="pdfSrc | safe: 'resourceUrl'" width="600" height="500"></iframe> </ng-template> </ngb-modal> ` }) export class AppComponent { pdfSrc?: string; constructor(private pdfService: PdfService, private modalService: NgbModal) {} openModal() { this.pdfService.getPdfBlob().subscribe(blob => { this.pdfSrc = URL.createObjectURL(blob); this.modalService.open('pdfModal'); }); } }

  8. "Angular 6 download PDF file and handle errors"

    • Description: This query demonstrates how to handle errors when downloading a PDF file from a Web API.
    • Code:
      // In your Angular service import { Injectable } from '@angular/core'; import { HttpClient } from '@angular/common/http'; import { catchError } from 'rxjs/operators'; import { throwError } from 'rxjs'; import { saveAs } from 'file-saver'; @Injectable({ providedIn: 'root' }) export class PdfService { constructor(private http: HttpClient) {} downloadPdf() { this.http.get('https://your-api-endpoint/pdf', { responseType: 'blob' }) .pipe(catchError(error => { console.error('Download error:', error); return throwError(error); })) .subscribe(blob => { saveAs(blob, 'file.pdf'); }); } }

  9. "Angular 6 download PDF file and show loading spinner"

    • Description: This query demonstrates showing a loading spinner while the PDF file is being downloaded.
    • Code:
      // In your Angular component import { Component } from '@angular/core'; import { PdfService } from './pdf.service'; @Component({ selector: 'app-root', template: ` <button (click)="download()">Download PDF</button> <div *ngIf="loading" class="spinner"></div> `, styles: [` .spinner { border: 4px solid rgba(0, 0, 0, 0.1); border-left: 4px solid #3498db; border-radius: 50%; width: 40px; height: 40px; animation: spin 1s linear infinite; } @keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } } `] }) export class AppComponent { loading = false; constructor(private pdfService: PdfService) {} download() { this.loading = true; this.pdfService.downloadPdf().add(() => this.loading = false); } }

  10. "Angular 6 download PDF file from Web API and handle CORS issues"

    • Description: This query addresses handling CORS issues when downloading a PDF file from a Web API.
    • Code:
      // Ensure CORS is handled on the server side // In your Angular service import { Injectable } from '@angular/core'; import { HttpClient } from '@angular/common/http'; @Injectable({ providedIn: 'root' }) export class PdfService { constructor(private http: HttpClient) {} downloadPdf() { this.http.get('https://your-api-endpoint/pdf', { responseType: 'blob' }).subscribe( blob => { const url = window.URL.createObjectURL(blob); const a = document.createElement('a'); a.href = url; a.download = 'file.pdf'; a.click(); window.URL.revokeObjectURL(url); }, error => console.error('Download error:', error) ); } }

More Tags

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