Function1.cs

using CefSharp.OffScreen;
using CefSharp;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.Functions.Worker;
using Microsoft.Extensions.Logging;
using System.IO;

namespace AzureCEF_HTMLtoPDFConversion
{
    public class Function1
    {
        private readonly ILogger<Function1> _logger;

        public Function1(ILogger<Function1> logger)
        {
            _logger = logger;
        }

        [Function("Function1")]
        public async Task<IActionResult> RunAsync([HttpTrigger(AuthorizationLevel.Function, "get", "post")] HttpRequest req)
        {
            _logger.LogInformation("C# HTTP trigger function processed a request.");

            MemoryStream memoryStream = null;
            // Initialize CefSharp
            var settings = new CefSettings()
            {
                LogSeverity = LogSeverity.Disable,
                CachePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "CefSharp\\Cache")
            };
            _logger.LogInformation("Initializing CefSharp settings.");
            if (!Cef.IsInitialized)
            {
                var success = Cef.Initialize(settings, performDependencyCheck: false, browserProcessHandler: null);
            }
            try
            {
                // Create a browser instance
                var browser = new ChromiumWebBrowser("https://www.google.com/");

                _logger.LogInformation("Waiting for initial loading.");
                await browser.WaitForInitialLoadAsync();

                string fileName = Guid.NewGuid().ToString();
                string tempFilePath = Path.Combine(Path.GetTempPath(), fileName + ".pdf");
                _logger.LogInformation($"Generating the pdf file.");
                await browser.PrintToPdfAsync(tempFilePath);
                memoryStream = new MemoryStream();
                byte[] bytes = File.ReadAllBytes(tempFilePath);
                memoryStream.Write(bytes, 0, bytes.Length);
                memoryStream.Position = 0;
            }
            catch (Exception ex)
            {
                _logger.LogError(ex.Message.ToString());
            }
            var fileStreamResult = new FileStreamResult(memoryStream, "application/pdf")
            {
                FileDownloadName = "Html-to-PDF-Output.pdf"
            };
            return fileStreamResult;
        }
    }
}