SPA Serve

spaserve serves "Single Page Applications" (SPAs) from Go that are using...

...client-side DOM routing,
...varying base paths in different deployments or even within the same deployment because of multiple access paths.

And all this without the need to rebuild your SPA production code just because the (HTML) "base URL" changes.

Usage

prepare your SPA index.html template (such as public/index.html) by adding a base element, if not done already; set its href attribute to ./:

<!doctype html>
<html lang="en">
<head>
    <base href="./" />
    <!-- ... -->
 </head>
 <body>
     <!-- ... -->
 </body>
 </html>

In case of CRA (Create React App), set the homepage field in package.json to "." (not the root slash ~~"/"~~):
```
{
  "homepage": ".",
}
```

add a basename helper to your SPA sources, such as a new file src/util/basename.ts:

export const basename = new URL(
        ((document.querySelector('base') || {}).href || '/')
    ).pathname.replace(/\/$/, '')

in your App.tsx ensure that you tell your client-side DOM router to correctly pick up the basename; this makes reloading the SPA from any route and bookmarking routes possible:
```
import { basename } from 'utils/basename'

<Router basename={basename}>
    
</Router>
```
Make sure that all links (and asset references) are relative, such as ./view2, et cetera.

in your service, create your HTTP route muxer and set up your API handlers as usual, then create a SPAHandler and register it as the route handler to be used when all other handlers don't match:

r := mux.NewRouter() // or whatever you prefer
// (set up all your API routes)

// finally create a suitable fs.FS to be used with the SPAHandler
// and register it so that it serves on all routes not handled by
// the more specific (API) handlers. Here, we assume the SPA assets
// to be rooted in web/build.
spa := spaserve.NewSPAHandler(os.DirFS("web/build"), "index.html")
r.PathPrefix("/").Handler(spa)

References

Useful background knowledge when dealing with serving HTTP resources, base(names), et cetera...

An elegant solution of deploying React app into a subdirectory (Sergey Kryvets) – a rare competent analysis and introduction to the base HTML element. This post shows how to get SPAs working with base for a fixed, hardcoded base path. In contrast, spaserver dynamically rewrites the base element when serving an SPA, as needed.
answer to "Golang. What to use? http.ServeFile(..) or http.FileServer(..)?" (stackoverflow) – and yes, spaserve uses http.FileServer which supports fs.FS via an http.FS adaptor.

Go Version Support

spaserve supports versions of Go that are noted by the Go release policy, that is, major versions N and N-1 (where N is the current major version).

thediveo/spaserve

SPA Serve

Usage

References

Go Version Support

Copyright and License