[Quick & Dirty Forking](https://remysharp.com/2013/03/18/quick-dirty-forking "Permanent Link: Quick & Dirty Forking")

The concept is simple, but requires a non-blocking server if I wanted to make the service public - which I’ll explain why in a moment:

I knew this should be simple with [Node.js](http://nodejs.org) mostly because I needed to send off the clone process in the background (to the main application) and only once it’s returned, do I serve up the forked content.

Using the [connect](https://github.com/senchalabs/connect) library I have my own custom router that does most of the work.

Then clones are spawned out to a separate process, and once completed, a unique hash is created as a new subdomain for the server with it’s own router pointing to the new clone. After 5 minutes of idle time, the clone is automatically removed and cleaned up.

When you request anything off the default root of the server, it assumes (unless the resource is found in the public directory) that you’re referring to a github repo, ie. https://github.com/remy/5minfork

The problem was that usernames and repos are case sensitive, but urls aren’t. So when you redirect to the subdomain (which I wanted to be remy-5minfork), it wouldn’t work, because subdomain switch to lowercase, and now it doesn’t know the difference between 5MINFORK and 5minfork. So to get around this, a hash is made for the path, stored in a JavaScript object in the server, and immediately [redirected](https://github.com/remy/5minutefork/blob/master/index.js#L71) to http://<hash>.5minfork.com.

This subdomain then [looks up](https://github.com/remy/5minutefork/blob/master/index.js#L20) the original github repo url, and kicks off the fork process.

I apologise for my interchangeable use of fork & clone - blame github (apparently).

My exceptionally short [fmf.js](https://github.com/remy/5minutefork/blob/master/lib/fmf.js) script works out the github repo url, and spawns a [fork](https://github.com/remy/5minutefork/blob/master/lib/fmf.js#L51). Once all the spawn’s data has ended, it triggers the callback, that tells my server the fork was [successful](https://github.com/remy/5minutefork/blob/master/index.js#L39).

This is the "clever bit" (given how short the code is, don’t expect to be wowed).

A [new router is created](https://github.com/remy/5minutefork/blob/master/index.js#L41) for this specific fork, and stored against the hashed url (so we know when we hit http://abc321.5minfork.com it has a bunch of info associated with it).

Then with that new router, it [passes](https://github.com/remy/5minutefork/blob/master/index.js#L56) the original request and response objects, which then handle the entire http request - thus being able to serve up the static previewed repo.

The new router is made up of the [static](http://www.senchalabs.org/connect/static.html) router, and the [directory](http://www.senchalabs.org/connect/directory.html) router (specifically because most repos without a preview, don’t have an index.html page).

You might think I was using the vhosts connect module, but I’m not, a simple bit of middleware is parsing the host out of the request header and making up the req.subdomain property, which I use to match up to the hash that links to the repo data.

A simple timer fires every 10 seconds to see when the repo was last accessed, and if that difference is more than 5 minutes, it blows away the directory.

Like I said, quick and dirty.

Of course all the code is up [on github](https://github.com/remy/5minutefork). Hopefully this write up or the tool itself is useful to you, I know I’ve already started using it. Now all I need is a little browser plugin to add a preview icon next on the github repo page, so it’s even faster to get the 5 minute fork!

Published 18-Mar 2013 under #code & #git & #github & #project. [Edit this post](https://github.com/remy/remysharp.com/blob/main/public/blog/quick-dirty-forking.md)

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Anonymous

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10 years ago

This is awesome, great project and thanks for taking the time to explain how you did it. If you do something like this again, I’d love to see a screencast of the process from start to finish.

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Anonymous

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10 years ago

I’ve found this project really valuable since I heard about it, thanks a lot for pulling this out.

I have a minor feature request: since github uses https, it would be super awesome if [5minfork.com](http://5minfork.com) was also available on https. Most of the time I just replace the domain name, forget about the protocol and wonder why it fails :)

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Anonymous

0 points

11 years ago

This is great!! I wish this existed a long time ago, what a great idea!

In fact, I like it so much I decided to create both a chrome extension and a userscript that would add a '5 min fork' button to github pages so you can just click one button!

Here they are:\ [https://github.com/Sembianc…​;](https://github.com/Sembiance/5minfork-chrome-extension)\ [https://github.com/Sembianc…​;](https://github.com/Sembiance/5minfork-userscript)

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