ChromiumHtmlToPdf

What is ChromiumHtmlToPdf?

ChromiumHtmlToPdf is a 100% managed C# .NETStandard 2.0 library and .NET 6 console application (that also works on Linux and macOS) that can be used to convert HTML to PDF format with the use of Google Chromemium (Google Chrome and Microsoft Edge browser)

From version 4.0 and up the library is now fully async but you can still use it without this if you want.

Why did I make this?

I needed a replacement for wkHtmlToPdf, a great tool but the project is archived on GitHub and no new features are added anymore, also it's not 100% compatible with HTML5.

License Information

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NON INFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

Installing via NuGet

The easiest way to install ChromiumHtmlToPdf is via NuGet (Yes I know the nuget package has another name, this is because there is already a package with the new name I used).

In Visual Studio's Package Manager Console, simply enter the following command:

Install-Package ChromeHtmlToPdf

Converting a file or url from code

var pageSettings = new PageSettings()
using (var converter = new Converter())
{
    converter.ConvertToPdf(new Uri("http://www.google.nl"), @"c:\google.pdf", pageSettings);
}

// Show the PDF
System.Diagnostics.Process.Start(@"c:\google.pdf");

or if you want to do it the async way

var pageSettings = new PageSettings()
using var converter = new Converter();
await converter.ConvertToPdfAsync(new Uri("http://www.google.nl"), @"c:\google.pdf", pageSettings);

// Show the PDF
System.Diagnostics.Process.Start(@"c:\google.pdf");

Enable extra logging when having weird issues with Chrome or Edge

When Chromium exits unexpectedly it does this most of the time without giving a meaningfull error. When this is the case than try to turn on Chromium Debug logging to get extra information about why it crashes

/// <summary>
///     Enables Chromium logging;<br/>
///     - The output will be saved to the file <b>chrome_debug.log</b> in Chrome's user data directory<br/>
///     - Logs are overwritten each time you restart chrome<br/>
/// </summary>
/// <remarks>
///     If the environment variable CHROME_LOG_FILE is set, Chrome will write its debug log to its specified location.<br/>
///     Example: Setting CHROME_LOG_FILE to "chrome_debug.log" will cause the log file to be written to the Chrome process's<br/>
///     current working directory while setting it to "D:\chrome_debug.log" will write the log to the root of your computer's D: drive.
/// </remarks>
public bool EnableChromiumLogging { get; set; }

Converting from Internet Information Services (IIS)

Download Google Chrome or Microsoft Edge portable and extract it
Let your website run under the ApplicationPool identity
Copy the files to the same location as where your project exists on the webserver
Reference the ChromeHtmlToPdfLib.dll from your webproject
Call the converter.ConverToPdf method from code

Thats it.

If you get strange errors when starting Google Chrome or Microsoft Edge than this is due to the account that is used to run your site. I had a simular problem and solved it by hosting ChromiumHtmlToPdf in a Windows service and making calls to it with a WCF service.

Converting from the command line

ChromiumHtmlToPdfConsole --input https://www.google.com --output c:\google.pdf

Console app exit codes

0 = successful, 1 = an error occurred

Installing on Linux or macOS

Installing .NET

See this url about how to install .NET on Linux

https://docs.microsoft.com/en-us/dotnet/core/install/linux

And this url about how to install .NET on macOS

https://docs.microsoft.com/en-us/dotnet/core/install/macos

Installing Chrome

See this url about how to install Chrome on Linux

https://support.google.com/chrome/a/answer/9025903?hl=en

And this url about how to install Chrome on macOS

https://support.google.com/chrome/a/answer/7550274?hl=en

Example installing Chrome on Linux Ubuntu

wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add -

sudo sh -c 'echo "deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google.list'

sudo apt-get update

sudo apt-get install google-chrome-stable

google-chrome --version

google-chrome --no-sandbox --user-data-dir

Pre compiled binaries

You can find pre compiled binaries for Windows, Linux and macOS over here

Latest version (.net 6)

https://github.com/Sicos1977/ChromiumHtmlToPdf/releases/download/4.2.1/ChromiumHtmlToPdf_4_2_1.zip

.NET 6.0 for the console app

The console app needs .NET 6 to run, you can download this framework from here

https://dotnet.microsoft.com/en-us/download/dotnet/6.0

Older versions (.net core 3.1 - end of life)

.NET Core 3.1 for the console app (end of life)

The console app needs .NET Core 3.1 to run, you can download this framework from here

https://dotnet.microsoft.com/en-us/download/dotnet/3.1

Installing it from scoop the package manager

See this for more information about scoop --> https://scoop.sh/#/

Just run the command from any PowerShell window (thanks to https://github.com/arnos-stuff)

scoop install https://gist.githubusercontent.com/arnos-stuff/4f9b2d92d812b25d0ee8335c543cba78/raw/cfa861ab3078a20c69157ab45daf33f26005fd63/chrome-html-to-pdf.json

Logging

From version 2.5.0 ChromiumHtmlToPdfLib uses the Microsoft ILogger interface (https://docs.microsoft.com/en-us/dotnet/api/microsoft.extensions.logging.ilogger?view=dotnet-plat-ext-5.0). You can use any logging library that uses this interface.

ChromiumHtmlToPdfLib has some build in loggers that can be found in the ChromiumHtmlToPdfLib.Logger namespace.

For example

var logger = !string.IsNullOrWhiteSpace(<some logfile>)
                ? new ChromiumHtmlToPdfLib.Loggers.Stream(File.OpenWrite(<some logfile>))
                : new ChromiumHtmlToPdfLib.Loggers.Console();

Setting a common Google Chrome or Microsoft Edge cache directory

You can not share a cache directory between a Google Chrome or Microsoft Edge instances because the first instance that is using the cache directory will lock it for its own use. The most efficient way to make optimal use of a cache directory is to create one for each instance that you are running.

I'm using Google Chrome from a WCF service and used the class below to make optimal use of cache directories. The class will create an instance id that I use to create a cache directory for each running Chrome instance. When the instance shuts down the instance id is put back in a stack so that the next executing instance can use this directory again.

public static class InstanceId
{
    #region Fields
    private static readonly ConcurrentStack<string> ConcurrentStack;
    #endregion

    #region Constructor
    static InstanceId()
    {
        ConcurrentStack = new ConcurrentStack<string>();

        for(var i = 100000; i > 0; i--)
            ConcurrentStack.Push(i.ToString().PadLeft(6, '0'));
    }
    #endregion

    #region Pop
    /// <summary>
    /// Returns an instance id and pops it from the <see cref="ConcurrentStack"/>
    /// </summary>
    /// <returns></returns>
    public static string Pop()
    {
        if (ConcurrentStack.TryPop(out var instanceId))
            return instanceId;

        throw new Exception("Instance id stack is empty");
    }
    #endregion

    #region Push
    /// <summary>
    /// Pushes the <paramref name="instanceId"/> back on top of the <see cref="ConcurrentStack"/>
    /// </summary>
    /// <param name="instanceId"></param>
    public static void Push(string instanceId)
    {
        ConcurrentStack.Push(instanceId);
    }
    #endregion
}

Using it in a Docker container

# Suppress an apt-key warning about standard out not being a terminal. Use in this script is safe.
ENV APT_KEY_DONT_WARN_ON_DANGEROUS_USAGE=DontWarn

# export DEBIAN_FRONTEND="noninteractive"
ENV DEBIAN_FRONTEND noninteractive

# Install deps + add Chrome Stable + purge all the things
RUN apt-get update && apt-get install -y \
	apt-transport-https \
	ca-certificates \
	curl \
	gnupg \
	--no-install-recommends \
	&& curl -sSL https://dl.google.com/linux/linux_signing_key.pub | apt-key add - \
	&& echo "deb [arch=amd64] https://dl.google.com/linux/chrome/deb/ stable main" > /etc/apt/sources.list.d/google-chrome.list \
	&& apt-get update && apt-get install -y \
	google-chrome-stable \
	--no-install-recommends \
	&& apt-get purge --auto-remove -y curl gnupg \
	&& rm -rf /var/lib/apt/lists/*

# Chrome Driver
RUN apt-get update && \
    apt-get install -y unzip && \
    wget https://chromedriver.storage.googleapis.com/2.31/chromedriver_linux64.zip && \
    unzip chromedriver_linux64.zip && \
    mv chromedriver /usr/bin && rm -f chromedriver_linux64.zip

See this issue for more information --> #39

Using this library on Linux or from a docker container

To make the library work the flag --no-sandbox will be set by default (on Windows this flag is not set). The library automaticly detect on which system you are running the code and sets the flag when needed. If for whatever reason you get a converting error then check if this flag is set and if not then add it manually.

converter.AddChromiumArgument("--no-sandbox")

When Chrome crashes for unknown reasons in a docker container

On most desktop Linux distributions, the default /dev/shm partition is large enough. However, on many cloud providers using Docker containers (such as the Google App Engine Flexible Environment) or Heroku, the default /dev/shm size is appreciably smaller (64MB and 5MB, respectively). On these platforms it's impossible to change the size of /dev/shm, which makes using Chrome difficult or impossible. This is particularly an issue for those who want to take advantage of its new headless mode.

If it is not possible to change the partition size than add the flag --disable-dev-shm-usage to tell Chrome not to use this parition

converter.AddChromiumArgument("--disable-dev-shm-usage")

Core Team

Sicos1977 (Kees van Spelde)

Reporting Bugs

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README.md

README.md

ChromiumHtmlToPdf

What is ChromiumHtmlToPdf?

Why did I make this?

License Information

Installing via NuGet

Converting a file or url from code

Enable extra logging when having weird issues with Chrome or Edge

Converting from Internet Information Services (IIS)

Converting from the command line

Console app exit codes

Installing on Linux or macOS

Installing .NET

Installing Chrome

Example installing Chrome on Linux Ubuntu

Pre compiled binaries

Latest version (.net 6)

.NET 6.0 for the console app

Older versions (.net core 3.1 - end of life)

.NET Core 3.1 for the console app (end of life)

Installing it from scoop the package manager

Logging

Setting a common Google Chrome or Microsoft Edge cache directory

Using it in a Docker container

Using this library on Linux or from a docker container

When Chrome crashes for unknown reasons in a docker container

Core Team

Reporting Bugs

Files

README.md

Latest commit

History

README.md

File metadata and controls

ChromiumHtmlToPdf

What is ChromiumHtmlToPdf?

Why did I make this?

License Information

Installing via NuGet

Converting a file or url from code

Enable extra logging when having weird issues with Chrome or Edge

Converting from Internet Information Services (IIS)

Converting from the command line

Console app exit codes

Installing on Linux or macOS

Installing .NET

Installing Chrome

Example installing Chrome on Linux Ubuntu

Pre compiled binaries

Latest version (.net 6)

.NET 6.0 for the console app

Older versions (.net core 3.1 - end of life)

.NET Core 3.1 for the console app (end of life)

Installing it from scoop the package manager

Logging

Setting a common Google Chrome or Microsoft Edge cache directory

Using it in a Docker container

Using this library on Linux or from a docker container

When Chrome crashes for unknown reasons in a docker container

Core Team

Reporting Bugs