Open PDF from Box cloud storage in React

17 Nov 20257 minutes to read

Follow these steps to load a PDF from Box cloud storage using the server-backed PDF Viewer.

Step 1: Set up a Box developer account and create a Box application

Create a developer account and Box application in the Box Developer Console. Note the Client ID and Client Secret. Use OAuth 2.0 to authenticate the application.

Step 2: Create a PDF Viewer sample in React

Start by following the steps provided in this link to create a simple PDF viewer sample in React. This will give you a basic setup of the PDF viewer component.

Step 3: Modify the PdfViewerController.cs file in the web service project

1. 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.

2. Open the PdfViewerController.cs file in your web service project.

3. Import the required namespaces at the top of the file:

using Box.V2;
using Box.V2.Auth;
using Box.V2.Config;
using Box.V2.Models;

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

private IConfiguration _configuration;
public readonly string _accessToken;
public readonly string _clientID;
public readonly string _clientSecret;
public readonly string _folderID;

public PdfViewerController(IWebHostEnvironment hostingEnvironment, IMemoryCache cache, IConfiguration configuration)
{
  _hostingEnvironment = hostingEnvironment;
  _cache = cache;
   _configuration = configuration;
  _accessToken = _configuration.GetValue<string>("AccessToken");
  _clientID = _configuration.GetValue<string>("ClientID");
  _clientSecret = _configuration.GetValue<string>("ClientSecret");
  _folderID = _configuration.GetValue<string>("FolderID");
}

1. Modify the Load() method to load PDF files from Box cloud storage.

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

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

  MemoryStream stream = new MemoryStream();
  object jsonResult = new object();
  if (jsonObject != null && jsonObject.ContainsKey("document"))
  {
    if (bool.Parse(jsonObject["isFileName"]))
    {
      string objectName = jsonObject["document"];

      // Initialize the Box API client with your authentication credentials
      var auth = new OAuthSession(_accessToken, "YOUR_REFRESH_TOKEN", 3600, "bearer");
      var config = new BoxConfigBuilder(_clientID, _clientSecret, new Uri("http://boxsdk")).Build();
      var client = new BoxClient(config, auth);

      // Download the file from Box storage
      var items = await client.FoldersManager.GetFolderItemsAsync(_folderID, 1000, autoPaginate: true);
      var files = items.Entries.Where(i => i.Type == "file");

      // Filter the files based on the objectName
      var matchingFile = files.FirstOrDefault(file => file.Name == objectName);

      // Fetch the file from Box storage by its name
      var fileStream = await client.FilesManager.DownloadAsync(matchingFile.Id);
      stream = new MemoryStream();
      await fileStream.CopyToAsync(stream);

      // Reset the position to the beginning of the stream
      stream.Position = 0;
    }
    else
    {
      byte[] bytes = Convert.FromBase64String(jsonObject["document"]);
      stream = new MemoryStream(bytes);
    }
  }
  jsonResult = pdfviewer.Load(stream, jsonObject);
  return Content(JsonConvert.SerializeObject(jsonResult));
}

1. 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_Box_Storage_Access_Token",
  "FolderID": "Your_Folder_ID",
  "ClientID": "Your_Box_Storage_ClientID",
  "ClientSecret": "Your_Box_Storage_ClientSecret"
}

NOTE

Replace the placeholders with your actual Box values: Access Token, Folder ID, Client ID, and Client Secret.

Step 4: Configure the PDF Viewer component

Set the serviceUrl to your web service endpoint (replace the localhost URL with your server URL). Set documentPath to the PDF file name to load from Box cloud storage. Ensure the document name exists in your Box folder.

import * as ReactDOM from 'react-dom';
import * as React from 'react';
import { PdfViewerComponent, Toolbar, Magnification, Navigation, LinkAnnotation, BookmarkView, ThumbnailView,
         Print, TextSelection, Annotation, TextSearch, Inject, FormDesigner, FormFields} from '@syncfusion/ej2-react-pdfviewer';

function App() {
  return (<div>
    <div className='control-section'>
      {/* Render the PDF Viewer */}
        <PdfViewerComponent
          id="container"
          documentPath="PDF_Succinctly.pdf"
          // Replace the "localhost:44396" with the actual URL of your server
          serviceUrl="https://localhost:44396/pdfviewer"
          style={{ 'height': '640px' }}>

              <Inject services={[ Toolbar, Magnification, Navigation, Annotation, LinkAnnotation, BookmarkView, ThumbnailView,
                                  Print, TextSelection, TextSearch, FormDesigner, FormFields ]} />

        </PdfViewerComponent>
    </div>
  </div>);
}
const root = ReactDOM.createRoot(document.getElementById('sample'));
root.render(<App />);

NOTE

The Box.V2.Core 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 Box cloud file storage. Make sure to pass the document name from the box folder to the documentPath property of the PDF viewer component

View sample in GitHub