For some time now I have wanted the ability to route paths for a
gh-pages site to its
index.html for handling as a single-page app. This ability is table stakes for single-page apps because you need all requests to be routed to one HTML file, unless you want to copy the same file across all your routes every time you make a change to your project. Currently GitHub Pages doesn’t offer a route handling solution; the Pages system is intended to be a flat, simple mechanism for serving basic project content.
If you weren’t aware, GitHub does provide one morsel of customization for your project site: the ability to add a
404.html file and have it served as your custom error page. I took a first stab at doing an SPA hack by simply copying my
index.html file and renaming the copy to
404.html. Turns out many folks have experienced the same issue with GitHub Pages and liked the general idea: https://twitter.com/csuwildcat/status/730558238458937344. The issue that some folks on Twitter correctly raised was that the
404.html page is still served with a status code of 404, which is no bueno for crawlers. The gauntlet had been thrown down, but I decided to answer, and answer with vigor!
One more time, with feeling
After sleeping on it, I thought to myself: “Self, we’re deep in fuck-it territory, so why don’t I make this hack even dirtier?!” To that end, I developed an even better hack that provides the same functionality and simplicity, while also preserving your site’s crawler juice – and you don’t even need to waste time copying your
index.html file to a
404.html file anymore! The following solution should work in all modern desktop and mobile browsers (Edge, Chrome, Firefox, Safari), and Internet Explorer 10+.
Template & Demo: If you want to skip the explanation and get the goods, here’s a template repo (https://github.com/csuwildcat/sghpa), and a test URL to see it in action: https://csuwildcat.github.io/sghpa/foo/bar
That’s so META
The first thing I did was investigate other options for getting the browser to redirect to the
You’ll need to start by adding a
404.html file to your
gh-pages repo that contains an empty HTML document inside it – but your document must total more than 512 bytes (explained below). Next put the following markup in your
<script> sessionStorage.redirect = location.href; </script> <meta http-equiv="refresh" content="0;URL='/REPO_NAME_HERE'"></meta>
This code sets the attempted entrance URL to a variable on the standard
sessionStorage object and immediately redirects to your project’s
index.html page using a meta refresh tag. If you’re doing a Github Organization site, don’t put a repo name in the
content attribute replacer text, just do this:
Customizing your route handling
href you pass to the
index.html page, which pages should remain on the 404 page (via dynamic removal of the meta tag), and any other logic you want to put in place to dictate what content is shown based on the inbound route.
512 magical bytes:
This is hands down one of the strangest quirks I have ever encountered in web development: You must ensure the total size of your
404.html page is greater than 512 bytes, because if it isn’t IE will disregard it and show a generic browser 404 page instead. When I finally figured this out, I had to crack a beer to help cope with the amount of time it took.
Let’s make history
In order to capture and restore the URL the user initially navigated to, you’ll need to add the following script tag to the
head of your
sessionStorage over on the
404.html page and replaces the current
history entry with it. However you choose to handle things from there is up to you, but I’d use
hashchange if you can.
Well folks, that’s it – now go hug it out and celebrate by writing some single-page apps on GitHub Pages!