esc embeds files into go programs and provides http.FileSystem interfaces to them.
It adds all named files or files recursively under named directories at the path specified. The output file provides an http.FileSystem interface with zero dependencies on packages outside the standard library.
Usage:
esc [flag] [name ...]
The flags are:
-o=""
output filename, defaults to stdout
-pkg="main"
package name of output file, defaults to main
-prefix=""
strip given prefix from filenames
-ignore=""
regular expression for files to ignore
-modtime=""
Unix timestamp to override as modification time for all files
-private
unexport functions by prefixing them with esc, e.g. FS -> escFS
After producing an output file, the assets may be accessed with the FS() function, which takes a flag to use local assets instead (for local development).
- (_esc)?FS(Must)?(Byte|String) returns an asset as a (byte slice|string).
- (_esc)?FSMust(Byte|String) panics if the asset is not found.
esc can be invoked by go generate:
//go:generate esc -o static.go -pkg server static
Embedded assets can be served with HTTP using the http.FileServer. Assuming you have a directory structure similar to the following:
.
├── main.go
└── static
├── css
│ └── style.css
└── index.html
Where main.go contains:
package main
import (
"log"
"net/http"
)
func main() {
// FS() is created by esc and returns a http.Filesystem.
http.Handle("/static/", http.FileServer(FS(false)))
log.Fatal(http.ListenAndServe(":8080", nil))
}
- Generate the embedded data:
esc -o static.go static - Start the server:
go run main.go static.go - Access http://localhost:8080/static/index.html to view the files.