Convert base64 to pdf and download

Here's a sample code snippet in C# that converts a Base64 string to a PDF file and then downloads it to the user's Downloads folder using the Response property in an ASP.NET application:

using System;
using System.IO;
using System.Web;

public class PdfHandler : IHttpHandler
{
    public void ProcessRequest(HttpContext context)
    {
        // Base64 string (replace with your actual Base64 string)
        string base64String = "your_base64_string_here";

        // Convert Base64 string to byte array
        byte[] pdfBytes = Convert.FromBase64String(base64String);

        // Set the response content type to PDF
        context.Response.ContentType = "application/pdf";

        // Set the content disposition to attachment to prompt download
        context.Response.AddHeader("Content-Disposition", "attachment; filename=downloadedFile.pdf");

        // Write the byte array to the response
        context.Response.BinaryWrite(pdfBytes);

        // End the response
        context.Response.End();
    }

    public bool IsReusable
    {
        get { return false; }
    }
}

Explanation:

1. Convert Base64 to Byte Array: The Convert.FromBase64String method converts the Base64 string to a byte array.
2. Set Response Content Type: The context.Response.ContentType is set to "application/pdf" to indicate the type of file being sent.
3. Set Content Disposition: The context.Response.AddHeader method sets the "Content-Disposition" header to "attachment" with a filename, prompting the browser to download the file.
4. Write Byte Array to Response: The context.Response.BinaryWrite method writes the byte array to the response.
5. End the Response: The context.Response.End method ends the response, ensuring the file is sent to the client.

Usage:

• Add this handler to your ASP.NET application.
• Make a request to the handler, and it will prompt the user to download the PDF file to their Downloads folder.

This approach ensures the PDF is downloaded directly to the client's machine using the Response property. 

Thanks

Hello Sangitha,

Thanks for reply.

I'll try your code and let you know

Hello Jignesh, 

Thanks for reply.

Your code looks like MVC based code, which does not work in c# asp.net . I am looking for a code in c# .net code. Which will convert base64 to pdf file and then download that pdf to DOWNLOADS folder using RESPONSE property.

Base64 String: Ensure that you have your PDF content as a Base64 string.
File Name: Specify the desired file name (e.g., "document.pdf").
Example 

protected void Page_Load(object sender, EventArgs e)
{
    string base64String = "YourBase64EncodedPDFHere"; 
    string fileName = "downloadedDocument.pdf"; 
    PdfDownloader downloader = new PdfDownloader();
    downloader.DownloadPdf(base64String, fileName);
}

using System;
using System.IO;
using System.Web;

public class PdfDownloader
{
    public void DownloadPdf(string base64String, string fileName)
    {
       // Convert Base64 string to byte array
        byte[] pdfBytes = Convert.FromBase64String(base64String);

        //Set the response content type to PDF
        HttpContext.Current.Response.ContentType = "application/pdf";       
        
        HttpContext.Current.Response.AddHeader("Content-Disposition", $"attachment; filename={fileName}");
        HttpContext.Current.Response.BinaryWrite(pdfBytes);        
     
        HttpContext.Current.Response.End();
    }
}
 

Hello Shusant,

using the below code you can create a pdf from the base64String.

 try
        {
            // Decode the base64 string to a byte array
            byte[] pdfBytes = Convert.FromBase64String(base64String);

            // Set file name and content type
            string fileName = "ConvertedFile.pdf";
            string contentType = "application/pdf";

            // Return the file to the client
            return File(pdfBytes, contentType, fileName);
        }
        catch (FormatException ex)
        {
            return BadRequest($"Invalid base64 string: {ex.Message}");
        }
        catch (Exception ex)
        {
            return StatusCode(500, $"An error occurred: {ex.Message}");
        }

You can write client-side code to download,

function downloadBase64Pdf(base64String) {
    fetch('/File/DownloadPdf', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify(base64String),
    })
        .then((response) => {
            if (!response.ok) {
                throw new Error('Failed to download PDF.');
            }
            return response.blob();
        })
        .then((blob) => {
            
            const link = document.createElement('a');
            link.href = URL.createObjectURL(blob);
            link.download = 'ConvertedFile.pdf'; 
            document.body.appendChild(link);
            link.click();
            link.remove();
        })
        .catch((error) => {
            console.error('Error:', error);
        });
}

// Example usage
const base64String = "JVBERi0xLjQKJ...."; // Replace with your base64 string
downloadBase64Pdf(base64String);