Save PDF file to Dropbox cloud file storage

5 Aug 202411 minutes to read

PDF Viewer allows to save PDF file to Drop Box using either the Standalone or Server-backed PDF Viewer. Below are the steps and a sample to demonstrate how to save a PDF to Drop Box.

Using Standalone PDF Viewer

To save a PDF file to Dropbox cloud file storage, you can follow the steps below

Step 1 Create a Dropbox API

To create a Dropbox API App, you should follow the official documentation provided by Dropbox link. The process involves visiting the Dropbox Developer website and using their App Console to set up your API app. This app will allow you to interact with Dropbox programmatically, enabling secure access to files and data.

Step 2: Create a PDF Viewer sample in Angular

Follow the instructions provided in this link to create a simple PDF Viewer sample in Angular. This will set up the basic structure of your PDF Viewer application.

Step 3: Modify the src/app/app.component.ts File in the Angular Project

Import the required namespaces at the top of the file:

import { Dropbox } from 'dropbox';

Configure a custom toolbar item for the download function to save a PDF file in Azure Blob Storage.

@Component({
  selector: 'app-root',
  template: `<div class="content-wrapper">
                <ejs-pdfviewer id="pdfViewer"
                    [resourceUrl]='resource' 
                    [toolbarSettings]="toolbarSettings"
                    (toolbarClick)="toolbarClick($event)"
                    style="height:640px;display:block">
                </ejs-pdfviewer>
             </div>`,
  providers: [ LinkAnnotationService, BookmarkViewService, MagnificationService,
               ThumbnailViewService, ToolbarService, NavigationService,
               TextSearchService, TextSelectionService, PrintService,
               AnnotationService, FormDesignerService, FormFieldsService, PageOrganizerService]
})

export class AppComponent implements OnInit {
  public resource: string = "https://cdn.syncfusion.com/ej2/23.1.43/dist/ej2-pdfviewer-lib";

  public toolItem1: CustomToolbarItemModel = {
    prefixIcon: 'e-icons e-pv-download-document-icon',
    id: 'download_pdf',
    tooltipText: 'Download file',
    align: 'right'
  };

  public toolbarSettings = {
    showTooltip: true,
    toolbarItems: ['OpenOption', 'PageNavigationTool', 'MagnificationTool', 'PanTool', 'SelectionTool', 'SearchOption', 'PrintOption', this.toolItem1, 'UndoRedoTool', 'AnnotationEditTool', 'FormDesignerEditTool', 'CommentTool', 'SubmitForm']
  };

  public toolbarClick(args: any): void {
    if (args.item && args.item.id === 'download_pdf') {
      this.SavePdfToBlob();
    }
  }
}

Retrieve the PDF viewer instance and save the current PDF as a Blob. Then, read the Blob using a FileReader to convert it into an ArrayBuffer, and upload the ArrayBuffer to Drop Box using the filesUpload method of the Drop Box instance.

NOTE

Replace Your Access Token with the actual Access Token of your Drop Box account.

saveDocument() {
  var proxy = this
  var viewer = (<any>document.getElementById("pdfViewer")).ej2_instances[0];  
  this.fileName = viewer.fileName;
  viewer.saveAsBlob().then((value: Blob) => {
    const reader = new FileReader();
    reader.onload = async () => {
      let dbx = new Dropbox({ accessToken: 'Your Access Token' });
      const uint8Array = new Uint8Array(reader.result as ArrayBuffer);
      dbx.filesUpload({ path: '/' + proxy.fileName , contents: uint8Array })
        .then(function (response) {
          console.log(response);
        })
        .catch(function (error) {
          console.error(error);
        });
    };
    reader.readAsArrayBuffer(value);
  });
}

NOTE

The npm install dropbox package must be installed in your application to use the previous code example.

View sample in GitHub

Using Server-Backed PDF Viewer

To save a PDF file to Dropbox cloud file storage, you can follow the steps below

Step 1 Create a Dropbox API

Step 2: Create a PDF Viewer sample in Angular

Follow the instructions provided in this link to create a simple PDF Viewer sample in Angular. This will set up the basic structure of your PDF Viewer application.

Step 3: Modify the PdfViewerController.cs File in the Web Service Project

Create a web service project in .NET Core 3.0 or above. You can refer to this link for instructions on how to create a web service project.
Open the PdfViewerController.cs file in your web service project.
Import the required namespaces at the top of the file:

using System.IO;
using Dropbox.Api;
using Dropbox.Api.Files;

Add the following private fields and constructor parameters to the PdfViewerController class, In the constructor, assign the values from the configuration to the corresponding fields

private IConfiguration _configuration;
public readonly string _accessToken;
public readonly string _folderName;

public PdfViewerController(IWebHostEnvironment hostingEnvironment, IMemoryCache cache, IConfiguration configuration)
{
  _hostingEnvironment = hostingEnvironment;
  _cache = cache;
   _configuration = configuration;
  _accessToken = _configuration.GetValue<string>("AccessToken");
  _folderName = _configuration.GetValue<string>("FolderName");
}

Modify the Download() method to save the downloaded PDF files to Dropbox cloud file storage bucket

[HttpPost("Download")]
[Microsoft.AspNetCore.Cors.EnableCors("MyPolicy")]
[Route("[controller]/Download")]
//Post action for downloading the PDF documents

public async Task<IActionResult> Download([FromBody] Dictionary<string, string> jsonObject)
{
  //Initialize the PDF Viewer object with memory cache object
  PdfRenderer pdfviewer = new PdfRenderer(_cache);

  string documentBase = pdfviewer.GetDocumentAsBase64(jsonObject);
  byte[] documentBytes = Convert.FromBase64String(documentBase.Split(",")[1]);

  string documentId = jsonObject["documentId"];
  string result = Path.GetFileNameWithoutExtension(documentId);
  string fileName = result + "_downloaded.pdf";

  using (var dropBox = new DropboxClient(_accessToken))
  {
    using (var stream = new MemoryStream(documentBytes))
    {
      // Upload the document to Dropbox
      var uploadedFile = await dropBox.Files.UploadAsync(
        _folderName + "/" + fileName,
        WriteMode.Overwrite.Instance,
        body: stream
      );
    }
  }
  return Content(documentBase);
}

Open the appsettings.json file in your web service project, Add the following lines below the existing "AllowedHosts" configuration

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "AccessToken": "Your_Dropbox_Access_Token",
  "FolderName": "Your_Folder_Name"
}

NOTE

Replace Your_Dropbox_Access_Token with your actual Dropbox access token and Your_Folder_Name with your folder name.

Step 4: Set the PDF Viewer Properties in Angular PDF viewer component

Modify the serviceUrl property of the PDF viewer component with the accurate URL of your web service project, replacing https://localhost:44396/pdfviewer with the actual URL of your server. Set the documentPath property of the PDF viewer component to the desired name of the PDF file you wish to load from Dropbox cloud file storage. Ensure that you correctly pass the document name from the files available in your dropbox folder to the documentPath property.

import { Component, OnInit } from '@angular/core';
import { LinkAnnotationService, BookmarkViewService, MagnificationService,
         ThumbnailViewService, ToolbarService, NavigationService,
         TextSearchService, AnnotationService, TextSelectionService,
         PrintService, FormDesignerService, FormFieldsService} from '@syncfusion/ej2-angular-pdfviewer';

@Component({
  selector: 'app-container',
  // specifies the template string for the PDF Viewer component
  template: `<div class="content-wrapper">
                  <ejs-pdfviewer id="pdfViewer"
                                [serviceUrl]='service'
                                [documentPath]='documentPath'
                                style="height:640px;display:block">
                  </ejs-pdfviewer>
            </div>`,
  providers: [ LinkAnnotationService, BookmarkViewService, MagnificationService,ThumbnailViewService, 
               ToolbarService, NavigationService, AnnotationService, TextSearchService,
                TextSelectionService, PrintService, FormDesignerService, FormFieldsService]
  })
  export class AppComponent implements OnInit {
    // Replace the "localhost:44396" with the actual URL of your server
    public service = 'https://localhost:44396/pdfviewer';
    public documentPath = 'PDF_Succinctly.pdf';
  }

NOTE

The Dropbox.Api NuGet package must be installed in your application to use the previous code example.

NOTE

Replace PDF_Succinctly.pdf with the actual document name that you want to load from Dropbox cloud file storage. Make sure to pass the document name from the dropbox folder to the documentPath property of the PDF viewer component

View sample in GitHub