[Go] Strip embed FS’s directory name

In Go 1.16, embed package rolled out. I used to package all kinds of resources with packr. Now I can replace it with embed .

Assuming there’s a directoryasset in the project and with two subdirectories: images and webapp . In order to package these files into the binary, we can create a file asset.go inside the dir.

/asset
    /images
        /a.png 
        /b.png    
    /webapp 
        /index.js 
        /index.css 
        /index.html
    /asset.go

The content of asset.go :

package asset

import (
   "embed"
   "github.com/gopub/wine"
)

//go:embed images webapp
var Content embed.FS

Now we can access files inside images and webapp

asset.Content.ReadFile("images/a.png")
asset.Content.ReadFile("webapp/index.html")

It’s tricky to serve a http file service, then we can embed a website inside. It’s pretty cool.

http.FileServer(http.FS(asset.Content))

However, the url would be like http://yourdomain/webapp/index.html . In most conditions, what we want is http://yourdomain/index.html . webapp is just a directory to contain all html, js, css files, which should not be present in the url path.

How to strip it?

There are two ways:

1. Embed current directory
   As the example above is embeding a sub directory webapp , we can add a file webapp.go inside dir webapp , and…