How to convert Webpage to PDF using Chromium

Overview of Chromium

1. Automating web interactions (e.g., filling forms or clicking buttons).

2. Web scraping for data collection.

3. Generating screenshots of web pages.

4. Converting web pages into PDF documents is the focus of this tutorial.

By leveraging Chromium in headless mode, you can automate these tasks programmatically. This guide will demonstrate how to set up and use Chromium in a C# project to convert web pages to PDFs.

Prerequisites

1. Windows Operating System

   This tutorial is designed for Windows users.

2. Visual Studio (2019 or later)

   An integrated development environment (IDE) for creating C# applications. You can download Visual Studio Community for free from Microsoft's website.

3. NuGet Package Manager

   Comes with Visual Studio and is used to manage dependencies in your project.

4. Basic C# Programming Knowledge

   Familiarity with creating and running C# programs, including understanding namespaces, classes, and methods.

Step-by-Step Guide

Step 1: Set Up a C# Project in Visual Studio

1. Create a New Project:

   1. Click Create a new project.

   2. Select Console App from the list of project templates.

   

2. Configure Your Project:

   1. Name your project WebToPdf.

   2. Choose a suitable location for saving your project files.

   3. Click Create.

   

Step 2: Install Required NuGet Packages

1. Access the NuGet Package Manager:

   1. In Solution Explorer, right-click on your project and select Manage NuGet Packages.

2. Install CefSharp.OffScreen:

   1. In the NuGet Package Manager, go to the Browse tab.

   2. Search for CefSharp.OffScreen.

      

   3. Select the package and click Install.

      

Step 3: Write the Code to Convert a Web Page to PDF

1. Open the Program.cs File:

   1. In Solution Explorer, double-click Program.cs to open the file.

2. Replace the Code:

   1. Replace the existing code with the following:

using System;
using CefSharp;
using CefSharp.OffScreen;
using System.IO;
using System.Threading.Tasks;

namespace WebToPdf
{
    class Program
    {
        private static ChromiumWebBrowser browser;

        static void Main(string[] args)
        {
            // Initialize CefSharp
            var settings = new CefSettings();
            Cef.Initialize(settings);

            // Convert HTML to PDF
            HtmlToPdfHeadless().GetAwaiter().GetResult();

            // Shutdown CefSharp
            Cef.Shutdown();
        }


        private static async Task HtmlToPdfHeadless()
        {
            string inputUrl = "https://example.com";

            // Path to save the PDF
            string outputPath = @"C:\Test\Output.pdf";

            browser = new ChromiumWebBrowser(inputUrl);

            // Wait for browser to load
            await browser.WaitForInitialLoadAsync();

            // Alternatively wait for the browser to stop rendering 
            await browser.WaitForRenderIdleAsync();

            // Save the PDF
            bool success = await browser.PrintToPdfAsync(outputPath);

            if (success)
            {
                Console.WriteLine("PDF successfully saved to {outputPath}");
            }
            else
            {
                Console.WriteLine("Failed to save PDF.");
            }

            // Prevent the application from exiting immediately
            Console.ReadLine();

            // Exit the application
            Environment.Exit(0);
        }
    }
}

Step 4: Run the Application

1. Build and Run:

   1. Press Ctrl+F5 to build and run the application.

2. Observe the Output:

   1. The console will display progress messages.

   2. A PDF named Output.pdf is saved to the folder you specify.

Step 5: Verify the PDF

1. Locate the File:

   1. Navigate to the folder you specified and locate the Output.pdf file.

2. Open the File:

   1. Use any PDF reader to open the file.

   2. Confirm that it reflects the content of the web page you specified.

      

Troubleshooting

1. CefSharp not initialized

   1. Ensure Cef.Initialize(settings) is called before creating the browser instance.

2. Dependencies not found

   1. Confirm that CefSharp.OffScreen is installed via the NuGet Package Manager.

3. Blank PDF

   1. Ensure the URL is accessible and the page fully loads before generating the PDF.

Conclusion

Following these detailed steps, you’ve created an application that converts web pages to PDFs using CefSharp and C#. This guide provides a foundation you can build on to include additional features such as:

1. Customizing PDF layouts.

2. Handling dynamic web pages.

3. Automating bulk web-to-PDF conversions.