Rendering PDFs Containing Images Stored in Azure Blob Storage
Azure Blob Storage is a cloud-based storage service provided by Microsoft Azure. It's designed to store large amounts of unstructured data, such as text or binary data, that can be accessed via HTTP or HTTPS.
Some developers would like to use images stored in Azure Blob Storage. This presents an issue because the image data is stored as binary rather than as a file, which could easily be referenced by HTML. The workaround is to convert images to a base64 string and add them to an img tag.
How to Render Images Stored in Azure Blob Storage
- Download the C# library to render images stored in Azure Blob
- Handle the process of retrieving the blob
- Use the ToBase64String method to convert bytes to base64
- Include the base64 information in the img tag
- Render the HTML to PDF
Install with NuGet
Install-Package IronPdf
Download DLL
Manually install into your project
Install with NuGet
Install-Package IronPdf
Download DLL
Manually install into your project
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Install-Package IronPdf
Consider installing the IronPDF DLL directly. Download and manually install it for your project or GAC form: IronPdf.zip
Manually install into your project
Download DLLConvert Azure Blob to HTML
Assuming you have already set up an Azure Storage account and have a container with blobs, you also need to handle authentication and connection to your Azure Storage in the C# project. Afterward you can use the DownloadToStreamAsync
method to download the image as a stream. The stream information can then be converted to Base64 and embedded in the img tag of HTML. Finally, the imageTag variable can be merged into an HTML document.
// Define your connection string and container name
string connectionString = "your_connection_string";
string containerName = "your_container_name";
// Initialize BlobServiceClient with the connection string
BlobServiceClient blobServiceClient = new BlobServiceClient(connectionString);
// Get the BlobContainerClient for the specified container
BlobContainerClient blobContainer = blobServiceClient.GetBlobContainerClient(containerName);
// Get Blob
var blob = blobContainer.GetBlobReference("867.jpg");
var stream = new MemoryStream();
await blob.DownloadToStreamAsync(stream);
var array = new byte[blob.Properties.Length];
await blob.DownloadToByteArrayAsync(target: array, 0);
// Convert bytes to base64
var base64 = Convert.ToBase64String(array);
var imageTag = $"<img src=\"data:image/jpeg;base64, {base64}\"/><br/>";
// Define your connection string and container name
string connectionString = "your_connection_string";
string containerName = "your_container_name";
// Initialize BlobServiceClient with the connection string
BlobServiceClient blobServiceClient = new BlobServiceClient(connectionString);
// Get the BlobContainerClient for the specified container
BlobContainerClient blobContainer = blobServiceClient.GetBlobContainerClient(containerName);
// Get Blob
var blob = blobContainer.GetBlobReference("867.jpg");
var stream = new MemoryStream();
await blob.DownloadToStreamAsync(stream);
var array = new byte[blob.Properties.Length];
await blob.DownloadToByteArrayAsync(target: array, 0);
// Convert bytes to base64
var base64 = Convert.ToBase64String(array);
var imageTag = $"<img src=\"data:image/jpeg;base64, {base64}\"/><br/>";
' Define your connection string and container name
Dim connectionString As String = "your_connection_string"
Dim containerName As String = "your_container_name"
' Initialize BlobServiceClient with the connection string
Dim blobServiceClient As New BlobServiceClient(connectionString)
' Get the BlobContainerClient for the specified container
Dim blobContainer As BlobContainerClient = blobServiceClient.GetBlobContainerClient(containerName)
' Get Blob
Dim blob = blobContainer.GetBlobReference("867.jpg")
Dim stream = New MemoryStream()
Await blob.DownloadToStreamAsync(stream)
Dim array = New Byte(blob.Properties.Length - 1){}
Await blob.DownloadToByteArrayAsync(target:= array, 0)
' Convert bytes to base64
Dim base64 = Convert.ToBase64String(array)
Dim imageTag = $"<img src=""data:image/jpeg;base64, {base64}""/><br/>"
Convert HTML to PDF
Continuing from the imageTag, it can then be converted to PDF by using the RenderHtmlAsPdf
method of ChromePdfRenderer.
:path=/static-assets/pdf/content-code-examples/how-to/images-azure-blob-storage-html-to-pdf.cs
using IronPdf;
// Instantiate Renderer
var renderer = new ChromePdfRenderer();
// Create a PDF from a HTML string using C#
var pdf = renderer.RenderHtmlAsPdf(imageTag);
// Export to a file
pdf.SaveAs("imageToPdf.pdf");
Imports IronPdf
' Instantiate Renderer
Private renderer = New ChromePdfRenderer()
' Create a PDF from a HTML string using C#
Private pdf = renderer.RenderHtmlAsPdf(imageTag)
' Export to a file
pdf.SaveAs("imageToPdf.pdf")