Save PDF file to Google Cloud Storage

6 Dec 20245 minutes to read

To save a PDF file to Google Cloud Storage, you can follow the steps below

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 PDF Viewer Sample in ASP.NET Core

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

Step 3: Modify the Index.cshtml.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 Index.cshtml.cs class, In the constructor, assign the values from the configuration to the corresponding fields

    // Private readonly object _storageClient
    private readonly StorageClient _storageClient;

    private IConfiguration _configuration;

    public readonly string _bucketName;

    public IndexModel(Microsoft.AspNetCore.Hosting.IHostingEnvironment hostingEnvironment, IMemoryCache cache, IConfiguration configuration)
    {
        _hostingEnvironment = hostingEnvironment;
        _cache = cache;
        // The key file is used to authenticate with Google Cloud Storage.
        string keyFilePath = @"path/to/service-account-key.json";

        // 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);

        _configuration = configuration;

        _bucketName = _configuration.GetValue<string>("BucketName");
    }

1. Modify the OnPostDownloadAsync() method to save the downloaded PDF files to Google Cloud Storage bucket

public IActionResult OnPostDownload([FromBody] jsonObjects responseData)
{
        PdfRenderer pdfviewer = new PdfRenderer(_cache);
        var jsonObject = JsonConverterstring(responseData);
        string documentBase = pdfviewer.GetDocumentAsBase64(jsonObject);
        string bucketName = _bucketName;
        string fileName = jsonObject["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);
}

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": "*",
  "BucketName": "Your Bucket name from Google Cloud Storage"
}

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: Set the PDF Viewer Properties in ASP.NET Core PDF viewer component

Set the documentPath property of the PDF viewer component to the desired name of the PDF file you wish to load from Azure Blob Storage. Ensure that you correctly pass the document name from the files available in your azure container to the documentPath property.

@page "{handler?}"
@model IndexModel
@{
    ViewData["Title"] = "Home page";
}

<div class="text-center">
    <ejs-pdfviewer id="pdfviewer" style="height:600px" serviceUrl="/Index" documentPath="PDF_Succinctly.pdf">
    </ejs-pdfviewer>
</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