Save PDF files to Google Cloud Storage

21 Oct 20254 minutes to read

To save a PDF file to Google Cloud Storage using the ASP.NET MVC PDF Viewer, follow the steps below. This approach uses a server-backed web service.

Step 1: Create a service account

Open the Google Cloud Console and navigate to IAM & Admin > Service accounts. Click Create Service Account, enter a name, assign roles (for example, Storage Object Admin), and create a key in JSON format. Download the key file securely and use it in your application for authentication and access to the Google Cloud Storage bucket. For more details, see the official documentation

Step 2: Create an ASP.NET MVC PDF Viewer sample

Follow the instructions in this 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 Download() method to save the downloaded PDF files to the Google Cloud Storage bucket.

    public ActionResult Download(jsonObjects jsonObject)
    {
        PdfRenderer pdfviewer = new PdfRenderer();
        var jsonData = JsonConverter(jsonObject);
        string documentBase = pdfviewer.GetDocumentAsBase64(jsonData);
        string bucketName = _bucketName;
        string fileName = jsonData["documentId"];

        // Convert the base64 string back to bytes
        string result = Path.GetFileNameWithoutExtension(fileName);
        byte[] documentBytes = Convert.FromBase64String(documentBase.Split(',')[1]);

        // Upload the document to Google Cloud Storage
        using (var memoryStream = new MemoryStream(documentBytes))
        {
            _storageClient.UploadObject(bucketName, result + "_downloaded.pdf", null, memoryStream);
        }
        return Content(documentBase);
    }

NOTE

Replace the placeholder with the actual Google Cloud Storage bucket name.

NOTE

Replace path/to/service-account-key.json with the actual file path to your service account key JSON file.

Step 5: Set the PDF Viewer properties in the ASP.NET MVC PDF Viewer component

Set the documentPath property of the PDF Viewer component to the desired PDF file name that you wish to load from Google Cloud Storage. Ensure that the document exists in the target 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

Install the Google.Cloud.Storage.V1 NuGet package in the application to use the previous code example.

View sample in GitHub