Open PDF from Google Cloud Storage in ASP.NET MVC

17 Nov 20254 minutes to read

Follow these steps to load a PDF from Google Cloud Storage using the server-backed PDF Viewer.

Step 1: Create a Service Account

Open the Google Cloud Console. Navigate to IAM & Admin > Service accounts. Click Create Service Account.` Enter a name, assign roles (e.g., Storage Object Admin), and create a key in JSON format. Download the key file securely. Utilize the downloaded key file in your applications or services for authentication and access to the Google Cloud Storage bucket. For additional details, refer to the official documentation.

Step 2: Create a PDF Viewer sample in ASP.NET MVC

Follow instructions provided in the Syncfusion^® PDF Viewer Getting Started Guide to create a simple PDF Viewer sample in ASP.NET MVC

Step 3: Modify the HomeController.cs file in the project

1. Import the required namespaces at the top of the file.

using System.IO;
using Google.Cloud.Storage.V1;
using Google.Apis.Auth.OAuth2;

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

    // The key file is used to authenticate with Google Cloud Storage.
    private string keyFilePath = @"path/to/service-account-key.json";
    private readonly string _bucketName = "Your Bucket name from Google Cloud Storage";
    private readonly StorageClient _storageClient;

    public HomeController()
    {
        // Load the service account credentials from the key file.
        var credentials = GoogleCredential.FromFile(keyFilePath);

        // Create a storage client with Application Default Credentials
        _storageClient = StorageClient.Create(credentials);
    }

1. Modify the Load() method to load the PDF files from Google Cloud Storage bucket.

public ActionResult Load(jsonObjects jsonObject)
{
    PdfRenderer pdfviewer = new PdfRenderer();
    MemoryStream stream = new MemoryStream();
    var jsonData = JsonConverter(jsonObject);
    object jsonResult = new object();
    if (jsonObject != null && jsonData.ContainsKey("document"))
    {
        if (bool.Parse(jsonData["isFileName"]))
        {


            string bucketName = _bucketName;
            string fileName = jsonData["document"];
            _storageClient.DownloadObject(bucketName, fileName, stream);
            stream.Position = 0;

        }
        else
        {
            byte[] bytes = Convert.FromBase64String(jsonData["document"]);
            stream = new MemoryStream(bytes);

        }
    }
    jsonResult = pdfviewer.Load(stream, jsonData);
    return Content(JsonConvert.SerializeObject(jsonResult));
}

NOTE

Replace Your Bucket name from Google Cloud Storage with the actual name of your Google Cloud Storage bucket

NOTE

Replace path/to/service-account-key.json with the actual file path to your service account key JSON file. Make sure to provide the correct path and filename.

Step 4: Configure the PDF Viewer component

Set the documentPath property of the PDF Viewer to the PDF file name to load from Google Cloud Storage. Ensure the document name exists in your bucket.

@{
    ViewBag.Title = "Home Page";
}

<div>
    <div style="height:500px;width:100%;">
        @Html.EJS().PdfViewer("pdfviewer").ServiceUrl(VirtualPathUtility.ToAbsolute("~/Home/")).DocumentPath("PDF_Succinctly.pdf").Render()
    </div>
</div>

NOTE

The Google.Cloud.Storage.V1 NuGet package must be installed in your application to use the previous code example.

View sample in GitHub