feat: add webui

web/build.go

@@ -0,0 +1,61 @@
+// Package web web/build.go
+package web
+
+import (
+	"embed"
+	"html/template"
+	"io"
+	"io/fs"
+	"net/http"
+	"os"
+	"path"
+)
+
+//go:embed build
+var Assets embed.FS
+
+// fsFunc is short-hand for constructing a http.FileSystem
+// implementation
+type fsFunc func(name string) (fs.File, error)
+
+func (f fsFunc) Open(name string) (fs.File, error) {
+	return f(name)
+}
+
+// AssetHandler returns a http.Handler that will serve files from
+// the Assets embed.FS.  When locating a file, it will strip the given
+// prefix from the request and prepend the root to the filesystem
+// lookup: typical prefix might be /web/, and root would be build.
+func AssetHandler(prefix, root string) http.Handler {
+	handler := fsFunc(func(name string) (fs.File, error) {
+		assetPath := path.Join(root, name)
+
+		// If we can't find the asset, return the default index.html
+		// content
+		f, err := Assets.Open(assetPath)
+		if os.IsNotExist(err) {
+			return Assets.Open("build/index.html")
+		}
+
+		// Otherwise, assume this is a legitimate request routed
+		// correctly
+		return f, err
+	})
+
+	return http.StripPrefix(prefix, http.FileServer(http.FS(handler)))
+}
+
+type IndexParams struct {
+	Title   string
+	Version string
+	BaseUrl string
+}
+
+func Index(w io.Writer, p IndexParams) error {
+	return parseIndex().Execute(w, p)
+}
+
+func parseIndex() *template.Template {
+	return template.Must(
+		template.New("index.html").ParseFS(Assets, "build/index.html"))
+}