Convert HTML to PDF file in Azure Functions on Windows

23 Jul 202413 minutes to read

As the Azure Windows platform is a Sandbox environment, the default HTML rendering engine Blink used in our HTML to PDF conversion is incompatible due to GDI Limitations. It is recommended that you use Azure functions in Linux For converting HTML to PDF in Azure Functions on Windows you can use the following approach that fit your requirement,

• CefSharp - this open-source library comes under a BSD license.

• Legacy WebKit - this open-source library comes under LGPL license. It has some known rendering issues and limitations, and some of the advanced Bootstrap CSS styles are not supported.

Steps to convert HTML to PDF file in Azure Functions on Windows using CefSharp

Step 1: Create the Azure functions project.

Step 2: Create a project name and select the location.

Step 3: Select the function worker as .NET 8.0 isolated (Long-term support), and the selected HTTP triggers as follows.

NOTE

We have ensured the conversion in Azure functions isolated app and the conversion supports Azure functions isolated app only. The normal Azure Function app has a limitation of copying the runtime files at publish.

Step 4: Install the Syncfusion.HtmlToPdfConverter.Cef.Net.Windows NuGet package to reference your project using the nuget.org.

NOTE

Starting with v16.2.0.x, if you reference Syncfusion assemblies from the trial setup or NuGet feed, you also have to add the “Syncfusion.Licensing” assembly reference and include a license key in your projects. Please refer to this link to learn about registering the Syncfusion license key in your application to use our components.

Step 5: Include the following namespaces in the Function1.cs file.

C#

using Syncfusion.HtmlConverter;
    using Syncfusion.Pdf;
    using Syncfusion.Pdf.Graphics;

Step 6: Add the following code example in the Run method of the Function1 class to convert HTML to PDF document in Azure Functions and return the resultant PDF document.

C#

[FunctionName("Function1")]
    public static async Task<HttpResponseMessage> Run(
        [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
        ILogger log)
    {
        MemoryStream ms = new MemoryStream();
        try
        {
            //Initialize HTML to PDF converter.
            HtmlToPdfConverter htmlConverter = new HtmlToPdfConverter(HtmlRenderingEngine.Cef);
            CefConverterSettings settings = new CefConverterSettings();
            //Assign the CEF converter settings to the HTML to PDF converter.
            htmlConverter.ConverterSettings = settings;
            //Convert URL to PDF.
            PdfDocument document = htmlConverter.Convert("https://www.google.com/");
            //Save and close the PDF document.
            document.Save(ms);
            document.Close();
            ms.Position = 0;
        }

        catch (Exception ex)
        {
            //Create a new PDF document.
            PdfDocument document = new PdfDocument();
            //Add a page to the document.
            PdfPage page = document.Pages.Add();
            //Create PDF graphics for the page.
            PdfGraphics graphics = page.Graphics;

            //Set the standard font.
            PdfFont font = new PdfStandardFont(PdfFontFamily.Helvetica, 5);
            //Draw the text.
            graphics.DrawString(ex.ToString(), font, PdfBrushes.Black, new Syncfusion.Drawing.PointF(0, 0));

            //Creating the stream object.
            ms = new MemoryStream();
            //Save the document into memory stream.
            document.Save(ms);
            //Close the document.
            document.Close(true);
            ms.Position = 0;
        }
        HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
        response.Content = new ByteArrayContent(ms.ToArray());
        response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
        {
            FileName = "Sample.pdf"
        };
        response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/pdf");
        return response;
    }

Step 7: Refer the steps to publish as Azure Function on Windows.

Step 8: After publish open the created web app service in the Azure portal. Go to Settings -> Configuration -> Platform settings and change the platform to 64-bit.

You can download a complete working sample from GitHub.

Steps to convert HTML to PDF file in Azure Functions on Windows using legacy WebKit

Step 1: Create the Azure functions project.

Step 2: Create a project name and select the location.

Step 3: Select the function worker as .NET 6.0(Long-term support), and the selected HTTP triggers as follows.

Step 4: Install the Syncfusion.HtmlToPdfConverter.QtWebKit.Net.Core NuGet package as a reference to your project using Package Manager Console.

NOTE

Starting with v16.2.0.x, if you reference Syncfusion assemblies from the trial setup or NuGet feed, you also have to add the “Syncfusion.Licensing” assembly reference and include a license key in your projects. Please refer to this link to learn about registering the Syncfusion license key in your application to use our components.

Step 5: Include the following namespaces in the Function1.cs file.

C#

using Syncfusion.HtmlConverter;
using Syncfusion.Pdf;

Step 6: Add the following code example in the Run method of the Function1 class to convert HTML to PDF document in Azure Functions and return the resultant PDF document.

C#

[FunctionName("Function1")]
    public static async Task<HttpResponseMessage> Run(
        [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
        ILogger log, ExecutionContext context)
    {
        MemoryStream ms = new MemoryStream();
        try {
            //Initialize HTML to PDF converter.
            HtmlToPdfConverter htmlConverter = new HtmlToPdfConverter(HtmlRenderingEngine.WebKit);
            WebKitConverterSettings settings = new WebKitConverterSettings();
            //Set WebKit path.
            settings.WebKitPath = Path.Combine(context.FunctionAppDirectory, "bin/runtimes/win-x64/native");            
            //Assign WebKit settings to HTML converter.
            htmlConverter.ConverterSettings = settings;
            //Convert URL to PDF.
            PdfDocument document = htmlConverter.Convert("https://www.google.com");
            //Save and close the PDF document.  
            document.Save(ms);
            document.Close();
            ms.Position = 0;
            }
            catch (Exception ex) {
                //Create a new PDF document.
                PdfDocument document = new PdfDocument();
                //Add a page to the document.
                PdfPage page = document.Pages.Add();
                //Create PDF graphics for the page.
                PdfGraphics graphics = page.Graphics;
                //Set the standard font.
                PdfFont font = new PdfStandardFont(PdfFontFamily.Helvetica, 5);
                //Draw the text.
                graphics.DrawString(ex.ToString(), font, PdfBrushes.Black, new Syncfusion.Drawing.PointF(0, 0));
                //Creating the stream object.
                ms = new MemoryStream();
                //Save the document into memory stream.
                document.Save(ms);
                //Close the document.
                document.Close(true);
                ms.Position = 0;
            }
            HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
            response.Content = new ByteArrayContent(ms.ToArray());
            response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment") {
                FileName = "Sample.pdf"
            };
            response.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/pdf");
            return response;
    }

Step 7: Copy the OpenSSL assemblies and paste them into the runtimes/win-x64/native folder containing the HTML_to_PDF_Azure_Functions.csproj file.

NOTE

The OpenSSL libraries can be installed by downloading their setup from this link.

Step 8: Set Copy if newer for all the OpenSSL assemblies.

Step 9: Refer the steps to publish as Azure Function on Windows.

You can download a complete working sample from GitHub.

Steps to publish as Azure Function on Windows

Step 1: Right-click the project and select Publish. Then, create a new profile in the Publish Window.

Step 2: Select the target as Azure and click Next.

Step 3: Select the Azure Function App (Windows) and click Next.

Step 4: Select the Create new.

Step 5: Click Create.

Step 6: After creating the function app service, click Finish.

Step 7: Click Publish.

Step 8: Now, Publish has succeeded.

Step 9: Now, go to the Azure portal and select App Services. After running the service, click Get function URL > Copy. Include the URL as a query string in the URL. Then, paste it into a new browser tab. You will get a PDF document as follows.