How do I register a custom URL protocol in Windows? - windows

Question

How do I register a custom protocol with Windows so that when clicking a link in an email or on a web page my application is opened and the parameters from the URL are passed to it?

Answer 1

Go to Start then in Find type regedit -> it should open Registry editor
Click Right Mouse on HKEY_CLASSES_ROOT then New -> Key
In the Key give the lowercase name by which you want urls to be called (in my case it will be testus://sdfsdfsdf) then Click Right Mouse on testus -> then New -> String Value and add URL Protocol without value.
Then add more entries like you did with protocol ( Right Mouse New -> Key ) and create hierarchy like testus -> shell -> open -> command and inside command change (Default) to the path where .exe you want to launch is, if you want to pass parameters to your exe then wrap path to exe in "" and add "%1" to look like: "c:\testing\test.exe" "%1"
To test if it works go to Internet Explorer (not Chrome or Firefox) and enter testus:have_you_seen_this_man this should fire your .exe (give you some prompts that you want to do this - say Yes) and pass into args testus://have_you_seen_this_man.
Here's sample console app to test:
using System;
namespace Testing
{
class Program
{
static void Main(string[] args)
{
if (args!= null && args.Length > 0)
Console.WriteLine(args[0]);
Console.ReadKey();
}
}
}
Hope this saves you some time.

Answer 2

The MSDN link is nice, but the security information there isn't complete. The handler registration should contain "%1", not %1. This is a security measure, because some URL sources incorrectly decode %20 before invoking your custom protocol handler.
PS. You'll get the entire URL, not just the URL parameters. But the URL might be subject to some mistreatment, besides the already mentioned %20->space conversion. It helps to be conservative in your URL syntax design. Don't throw in random // or you'll get into the mess that file:// is.

Answer 3

If anyone wants a .reg file for creating the association, see below:
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\duck]
"URL Protocol"=""
[HKEY_CLASSES_ROOT\duck\shell]
[HKEY_CLASSES_ROOT\duck\shell\open]
[HKEY_CLASSES_ROOT\duck\shell\open\command]
#="\"C:\\Users\\duck\\source\\repos\\ConsoleApp1\\ConsoleApp1\\bin\\Debug\\net6.0\\ConsoleApp1.exe\" \"%1\""
Pasted that into notepad, the file -> save as -> duck.reg, and then run it. After running it, when you type duck://arg-here into chrome, ConsoleApp1.exe will run with "arg-here" as an argument. Double slashes are required for the path to the exe and double quotes must be escaped.
Tested and working on Windows 11 with Edge (the chrome version) and Chrome

Answer 4

There is an npm module for this purpose.
link :https://www.npmjs.com/package/protocol-registry
So to do this in nodejs you just need to run the code below:
First Install it
npm i protocol-registry
Then use the code below to register you entry file.
const path = require('path');
const ProtocolRegistry = require('protocol-registry');
console.log('Registering...');
// Registers the Protocol
ProtocolRegistry.register({
protocol: 'testproto', // sets protocol for your command , testproto://**
command: `node ${path.join(__dirname, './index.js')} $_URL_`, // $_URL_ will the replaces by the url used to initiate it
override: true, // Use this with caution as it will destroy all previous Registrations on this protocol
terminal: true, // Use this to run your command inside a terminal
script: false
}).then(async () => {
console.log('Successfully registered');
});
Then suppose someone opens testproto://test
then a new terminal will be launched executing :
node yourapp/index.js testproto://test
It also supports all other operating system.