Chrome Native Messaging using Executable Jar file

Question

I have created a Chrome extension with the nativeMessaging permission added to the manifest.

I am opening a port to the native messaging host.

The manifest for my native messaging host points to an executable jar file.

When I launch my extension, there are no errors, the connection seems fine, but the code in my jar file never seems to run. (For testing I show a new JFrame that is created in the main() method. When double-clicking the jar file it shows the JFrame. But when running the jar file via Chrome Native Messaging, the JFrame doesn't show up.

Is there something I am missing?

Answer 1

I've managed to do this using a Java executable wrapper (I used Launch4j).

This is the manifest file:

{
    "name": "com.your.application",
    "description": "Your description.",
    "path": "path\\to\\wrapped\\java\\host.exe",
    "type": "stdio",
    "allowed_origins": [
        "chrome-extension://idofyourchromeextension/"
    ]
}

This is the native host application I wrapped:

import javax.swing.*;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.net.URISyntaxException;

public class ChromeHandler
{
    static public void main(String[] args)
    {
        InputStream input = System.in;
        try
        {
            System.in.available();
        }
        catch (Exception e)
        {
            return;
        }
        char receivedChar;
        try{
            FileOutputStream output = new FileOutputStream("PathToTextFile");
            while((receivedChar = (char) input.read()) != -1)
            {
                output.write(receivedChar);
                //My messages only have the '}' character at the end.
                if(receivedChar == '}')
                {
                    return;
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Answer 2

I managed to get it to work by letting chrome start a bat file with the following content:

@echo off
java -jar your_file.jar %*

The echo off was a detail which took me some time to figure out.

Answer 3

do you have uppercase letters in your mainfest name ? i had this issue+same symptoms and this fixed it for me (although i get a different error now)

{ "name": "com.google.chrome.example.echoUppercase", <- wont work ....

"name": "com.google.chrome.example.echouppercase", <- works }