Headless Firefox in Selenium C#

Question

I want to run firefox headless.

Not hide the browser window or open it in a virtual desktop, Firefox supports headless mode by using "-headless" flag.

Problem is I know how to do it in chrome but not in Firefox.

My code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using OpenQA.Selenium;
using OpenQA.Selenium.Firefox;

namespace MyApp {
public partial class Form1: Form {
    public Form1() {
        InitializeComponent();
    }

    private void StartBtn_Click(object sender, EventArgs e) {

        IWebDriver driver;
        FirefoxOptions options = new FirefoxOptions();
        options.AddArguments("--headless");
        driver = new FirefoxDriver(options);
    }
}
}

My WinForm application only has a button with name StartBtn. On clicking of the button Firefox should run headless, but it opens in a normal window.

---

Update I updated firefox to 56.0.1

Now I get a different error:

An unhandled exception of type 'OpenQA.Selenium.WebDriverException' occurred in WebDriver.dll

Additional information: Expected browser binary location, but unable to find binary in default location, no 'moz:firefoxOptions.binary' capability provided, and no binary flag set on the command line

Solution

Headless mode in Firefox is supported from version 56 on Windows and Mac OS. Ensure that you have the correct version installed.

https://developer.mozilla.org/en-US/Firefox/Headless_mode#Browser_support

With Firefox v56.0.1, Selenium.WebDriver v3.6.0 and geckodriver v0.19.0 (x64) this works correctly for me.

Regarding the error:

An unhandled exception of type 'OpenQA.Selenium.WebDriverException' occurred in WebDriver.dll

Ensure you're using the correct version of geckodriver. I suspect you're using the x32 build on an x64 machine, get the x64 build.

https://github.com/mozilla/geckodriver/releases

Comments

[Biswajit Chopdar]

it shows an exception when I use --headless. All arguments must start with two dashes ('--'); argument '-headless' does not.

[Biswajit Chopdar]

I updated firefox to the latest version, I now get a different error. Please check my updated question.

[Equalsk]

@Raven Which version of geckodriver are you using? I think you're probably using 32-bit on a 64-bit system. Try the x64 version: github.com/mozilla/geckodriver/releases

[Biswajit Chopdar]

Replacing the 32bit geckodriver with the 64bit worked. Big Thank you!