Bundle and serve admin (#317)

* WIP with admin bundling

* Current state of the admin is bundled

* Update admin bundler to work with binary bundling

* Log detail about the admin interface. Closes #312

* Move bundle script to the build dir

* Update to current version of admin

* Commit updated API documentation

Co-authored-by: Owncast <owncast@owncast.online>

controllers/admin/index.go

@@ -0,0 +1,44 @@
+package admin
+
+import (
+	"io/ioutil"
+	"mime"
+	"net/http"
+	"path/filepath"
+
+	"github.com/markbates/pkger"
+	"github.com/owncast/owncast/router/middleware"
+	log "github.com/sirupsen/logrus"
+)
+
+// ServeAdmin will return admin web assets
+func ServeAdmin(w http.ResponseWriter, r *http.Request) {
+	// Set a cache control max-age header
+	middleware.SetCachingHeaders(w, r)
+
+	path := r.URL.Path
+	if path == "/admin" || path == "/admin/" {
+		path = "/admin/index.html"
+	}
+
+	f, err := pkger.Open(path)
+	if err != nil {
+		log.Warnln(err, path)
+		errorHandler(w, r, http.StatusNotFound)
+		return
+	}
+
+	b, err := ioutil.ReadAll(f)
+	if err != nil {
+		log.Warnln(err)
+		return
+	}
+
+	mimeType := mime.TypeByExtension(filepath.Ext(path))
+	w.Header().Set("Content-Type", mimeType)
+	w.Write(b)
+}
+
+func errorHandler(w http.ResponseWriter, r *http.Request, status int) {
+	w.WriteHeader(status)
+}