URLProtocol

Project Overview

URLProtocol is a small Windows utility that solves the case where an app has not registered a custom URL protocol. Many programs can be launched from a browser through a "protocol name plus argument" link, such as media players and editors, but some deliberately do not offer this for security reasons. This tool registers itself as any custom protocol; when the browser opens the protocol it launches this program first, which looks up the real target application, passes the arguments through, and starts it.

Give Windows apps that lack protocol support a browser-triggered launch.

Key Features

• Register any protocol: enter a protocol name and it becomes a custom protocol a browser can launch
• Relay launch: opening the protocol starts this tool, which then locates and launches the real target
• Argument passthrough: the launch arguments carried by the protocol are passed to the target unchanged
• Target selection: pick the executable to call from the interface and update it at any time
• Test mode: passing --cat-catch-test shows the final command string before you decide whether to continue
• Multi-language docs: the repository provides Chinese, English, and Spanish documentation

Target Audience

• Users who want protocol launching for apps such as VLC
• Users of extensions like cat-catch that call external programs
• Advanced users who route browser links to local programs

Quick Start

1. Download URLProtocol from Releases and place it in a fixed location
2. Open URLProtocol.exe and enter the protocol name you want (without the :)
3. Click "Select target program" and choose the executable to be launched
4. Click "Add/Update" to save the configuration
5. Type the custom protocol plus a colon (for example test:) in the browser address bar and confirm the target launches
6. In an extension such as cat-catch, set the calling program to this tool to trigger it from a web page

Core Advantages

• Generic relay: works with any executable that needs protocol launching
• Simple setup: name a protocol, pick a program, save, and you are done
• No lost arguments: protocol arguments reach the target unchanged
• Verifiable first: test mode shows the full command line before the real call

System Requirements

Item	Requirement
OS	Windows 10 1709 or newer
Runtime	.NET Framework 4.7.2

Notes

• URLProtocol.exe must stay in a fixed location; deleting or moving it breaks registered protocols
• Do not include a colon in the protocol name
• Opening a custom protocol from a browser usually requires confirming the launch once