Open document from Google Drive

20 Jan 20248 minutes to read

To load a document from Google Drive in a Document editor, you can follow the steps below

Step 1: Set up Google Drive API

You must set up a project in the Google Developers Console and enable the Google Drive API. Obtain the necessary credentials to access the API. For more information, view the official link.

Step 2: Create a Simple Document Editor Sample in ASP.NET MVC

Start by following the steps provided in this link to create a simple Document Editor sample in ASP.NET MVC. This will give you a basic setup of the Document Editor component.

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

  • Open the DocumentEditorController.cs file in your web service project.

  • Import the required namespaces at the top of the file:

using System.IO;
using Google.Apis.Drive.v3;
using Google.Apis.Util.Store;
  • Add the following private fields and constructor parameters to the DocumentEditorController class, In the constructor, assign the values from the configuration to the corresponding fields
private IConfiguration _configuration;
public readonly string folderId;
public readonly string applicationName;
public readonly string credentialPath;
private static readonly string[] Scopes = { DriveService.Scope.DriveFile, DriveService.Scope.DriveReadonly};

public DocumentEditorController(IWebHostEnvironment hostingEnvironment, IMemoryCache cache, IConfiguration configuration)
{
  _hostingEnvironment = hostingEnvironment;
  _cache = cache;
  _configuration = configuration;
  folderId = _configuration.GetValue<string>("FolderId");
  credentialPath = _configuration.GetValue<string>("CredentialPath");
  applicationName = _configuration.GetValue<string>("ApplicationName");
}
  • Create the LoadFromGoogleDrive() method to load the document from Google Drive.
[AcceptVerbs("Post")]
[HttpPost]
[EnableCors("AllowAllOrigins")]
[Route("LoadFromGoogleDrive")]
//Post action for Loading the documents
public async Task<string> LoadFromGoogleDrive([FromBody] Dictionary<string, string> jsonObject)
{

  MemoryStream stream = new MemoryStream();
  UserCredential credential;
  using (var stream1 = new FileStream(credentialPath, FileMode.Open, FileAccess.Read))
  {
    string credPath = "token.json";
    credential = await GoogleWebAuthorizationBroker.AuthorizeAsync(
      GoogleClientSecrets.Load(stream1).Secrets,
      Scopes,
      "user",
      CancellationToken.None,
      new FileDataStore(credPath, true));
  }

  // Create Google Drive API service.
  var service = new DriveService(new BaseClientService.Initializer()
  {
    HttpClientInitializer = credential,
    ApplicationName = applicationName,
  });
  // List DOCX files in Google Drive
  listRequest.Q = "mimeType='application/vnd.openxmlformats-officedocument.wordprocessingml.document' and '" + folderId + "' in parents and trashed=false";
  listRequest.Fields = "files(id, name)";
  var files = await listRequest.ExecuteAsync();
  string fileIdToDownload = string.Empty;
  foreach (var file in files.Files)
  { 
    string fileId = file.Id;
    string fileName = file.Name;
    if (fileName == objectName)
    {
      // Save the matching fileId
      fileIdToDownload = fileId;
      break;
    }
  }
  string fileIds = fileIdToDownload;
  var request = service.Files.Get(fileIds);
  await request.DownloadAsync(stream);
  stream.Position = 0;   
  
  WordDocument document = WordDocument.Load(stream, FormatType.Docx);
  string json = Newtonsoft.Json.JsonConvert.SerializeObject(document);
  document.Dispose();
  stream.Close();
  return json;
}
  • 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": "*",
  "FolderId": "Your Google Drive Folder ID",
  "CredentialPath": "Your Path to the OAuth 2.0 Client IDs json file",
  "ApplicationName": "Your Application name"
}

NOTE

Replace Your Google Drive Folder ID, Your Application name, and Your Path to the OAuth 2.0 Client IDs json file with your actual Google drive folder ID , Your name for your application and the path for the JSON file.

NOTE

The FolderId part is the unique identifier for the folder. For example, if your folder URL is: https://drive.google.com/drive/folders/abc123xyz456, then the folder ID is abc123xyz456.

Step 4: Modify the Index.cshtml File in the Document Editor sample

In the client-side, the document is returned from the web service is opening using open method.

@Html.EJS().Button("load").Content("Open Document From Google Drive").Render()
@Html.EJS().DocumentEditorContainer("container").EnableToolbar(true).Render()

<script>
    var container;
    document.addEventListener('DOMContentLoaded', function () {
        var documenteditorElement = document.getElementById("container");        
        container = documenteditorElement.ej2_instances[0];
        document.getElementById('load').addEventListener('click', function () {
            fetch(
                window.baseurl + 'api/documenteditor/LoadFromGoogleDrive',
                {
                    method: 'Post',
                    headers: { 'Content-Type': 'application/json;charset=UTF-8' },
                    body: JSON.stringify({ documentName: 'Getting Started.docx' })
                }
            )
                .then(response => {
                    if (response.status === 200 || response.status === 304) {
                        return response.json(); // Return the Promise
                    } else {
                        throw new Error('Error loading data');
                    }
                })
                .then(json => {
                    container.documentEditor.open(JSON.stringify(json));
                })
                .catch(error => {
                    console.error(error);
                });
        });
    }); 
</script>
public ActionResult Default()
{
    return View();
}

NOTE

The Google.Apis.Drive.v3 NuGet package must be installed in your application to use the previous code example.