spa.go

package http

import (
	"embed"
	"errors"
	"io/fs"
	"net/http"
	"path/filepath"

	"github.com/gin-contrib/static"
)

var (
	//go:embed all:static/*
	staticFS embed.FS
)

type SpaHandler struct {
	httpFS http.FileSystem
	root   string
	fs     *embed.FS
}

func NewSpaHandler() *SpaHandler {
	return &SpaHandler{
		fs:     &staticFS,
		httpFS: http.FS(staticFS),
		root:   "static",
	}
}

func (s *SpaHandler) Exists(_, _ string) bool {
	return true
}

func (s *SpaHandler) Open(name string) (http.File, error) {
	p := filepath.Join(s.root, name)

	_, err := fs.Stat(s.fs, p)
	if err != nil {
		var rootErr *fs.PathError
		if !errors.As(err, &rootErr) {
			return nil, err
		}
		if !errors.Is(rootErr.Err, fs.ErrNotExist) {
			return nil, err
		}

		p = filepath.Join(s.root, static.INDEX)
	}

	return s.httpFS.Open(p)
}