A protocol handler allows your computer to recognize and handle custom URL schemes, directing them to specific applications or services. For example, http:// is a protocol handler for web browsers, while mailto: is for email applications. By creating custom protocol handlers, you can create specialized workflows, such as triggering a specific program when a custom URL is accessed.

In this article, we’ll walk through the steps for creating a custom protocol handler in Windows, allowing you to open a specific application (such as DNS Changer.exe) by entering a URL like dnschanger:// in your browser or command prompt.

آنچه خواهیم دید

Step-by-Step Guide

1. Understanding the Registry Structure

Windows uses the Registry to associate URL schemes with programs. The Registry keys for custom protocols are stored in HKEY_CLASSES_ROOT. By creating and modifying these keys, you can define your own protocols and tell Windows which application should handle them.

The basic structure you need to add for a custom protocol looks like this:

  • HKEY_CLASSES_ROOT\[protocol_name]: The main key for the protocol.
  • URL Protocol: A string value to define the protocol type.
  • DefaultIcon: Optionally, specify an icon that represents the protocol.
  • shell\open\command: Specifies the command to execute when the protocol is triggered.

2. Creating a Custom Protocol Handler

Let’s take a practical example where we create a custom protocol called dnsfucker://, which will run DNS Changer.exe from a predefined path when invoked.

Creating Registry Entries
  1. Open the Registry Editor:
    • Press Windows + R, type regedit, and hit Enter.
  2. Navigate to HKEY_CLASSES_ROOT:
    • This is where you will add the keys for your custom protocol.
  3. Create the Custom Protocol:
    • Right-click on HKEY_CLASSES_ROOT and select New > Key.
    • Name the new key dnsfucker.
  4. Add a URL Protocol:
    • In the dnsfucker key, right-click in the right pane and select New > String Value.
    • Name the value URL Protocol and leave it empty. This tells Windows that it’s a protocol handler.
  5. Define the Protocol’s Icon:
    • Under the dnsfucker key, create a subkey called DefaultIcon.
    • Set the default value to the path of your desired icon. For example, "C:\\dns.exe,1".
  6. Specify the Command to Execute:
    • Under the dnsfucker key, create a subkey shell > open > command.
    • Set the default value of command to the full path of your application. For example:
"C:\\dns.exe" -- "%1"

Final Structure in the Registry

After the modifications, the structure in the Registry should look something like this:

[HKEY_CLASSES_ROOT\dnsfucker]
"URL Protocol"=""
@="URL:Dnsfucker Link"

[HKEY_CLASSES_ROOT\dnsfucker\DefaultIcon]
@="\"C:\\dns.exe,1\""

[HKEY_CLASSES_ROOT\dnsfucker\shell]

[HKEY_CLASSES_ROOT\dnsfucker\shell\open]

[HKEY_CLASSES_ROOT\dnsfucker\shell\open\command]
@="\"C:\\dns.exe\" -- \"%1\""

3. Testing the Custom Protocol Handler

Once you’ve updated the Registry, the next step is testing the custom protocol handler.

  • Test using a Browser:
    • Open any web browser and enter dnsfucker:// in the address bar. If everything is set up correctly, it should trigger the DNS Changer.exe application.
  • Test using Command Prompt:
    • Open the Command Prompt and type:
start dnsfucker://
    • This will also launch the specified program (in this case, dns.exe).

4. Troubleshooting

If the handler doesn’t work, here are a few things to check:

  • Verify the Registry Entries: Make sure the paths and commands are correctly set. Double-check that there are no typos.
  • Run the Command Manually: Ensure that the command itself works in Command Prompt. If it doesn’t, there may be an issue with the program’s path or execution.
  • Permissions: Ensure that you have the necessary permissions to modify the Registry and run programs from custom protocols.

5. Additional Uses for Custom Protocol Handlers

Custom protocol handlers can be used for a wide variety of purposes:

  • Launching Applications: You can create a protocol handler that opens specific programs (e.g., vpn:// to launch a VPN client).
  • Automation: Create workflows that trigger scripts or automation tasks with custom URLs.
  • Web Integration: For web-based applications, a custom protocol can be used to integrate with desktop software.

Conclusion

Creating and using custom protocol handlers in Windows can be an effective way to integrate your desktop applications with web-based workflows or streamline repetitive tasks. By modifying the Windows Registry, you can define your own protocol schemes and associate them with specific programs. Whether you’re trying to launch a particular app or automate a process, this method provides a seamless and customizable solution.