From 9bc4847a3bc9cf1bc387774547c61bb58b28cc4e Mon Sep 17 00:00:00 2001
From: admin <markusmorgenstern87@outlook.de>
Date: Mon, 5 May 2025 20:08:29 +0200
Subject: [PATCH] init

---
 go.mod           |  3 +++
 spa/handler.go   | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 spa/helper.go    | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 spa/mime_type.go |  9 +++++++++
 spa/options.go   |  9 +++++++++
 5 files changed, 116 insertions(+)
 create mode 100644 go.mod
 create mode 100644 spa/handler.go
 create mode 100644 spa/helper.go
 create mode 100644 spa/mime_type.go
 create mode 100644 spa/options.go

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..820f3de
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module git.apihub24.de/admin/spa-handler
+
+go 1.22.0
diff --git a/spa/handler.go b/spa/handler.go
new file mode 100644
index 0000000..2feef8b
--- /dev/null
+++ b/spa/handler.go
@@ -0,0 +1,48 @@
+package spa
+
+import (
+	"embed"
+	"fmt"
+	"net/http"
+	"os"
+)
+
+type handler struct {
+	staticFS  embed.FS
+	indexPath string
+}
+
+func (h handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	reqPath := r.URL.Path
+	f, err := h.staticFS.Open(fmt.Sprintf("ng-client/browser%s", reqPath))
+	if f != nil {
+		f.Close()
+	}
+
+	if os.IsNotExist(err) {
+		indexFile, indexErr := h.staticFS.Open(h.indexPath)
+		if indexErr != nil {
+			http.Error(w, "Index file not found", http.StatusInternalServerError)
+			return
+		}
+		defer indexFile.Close()
+		tryToDeliverFile(indexFile, h.indexPath, w, r)
+		return
+	} else if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	tryToDeliverFile(f, h.indexPath, w, r)
+}
+
+func HandleFiles(path string, options HandlerOptions) {
+	if options.AdditionalMimeTypeMapping != nil {
+		for key, value := range options.AdditionalMimeTypeMapping {
+			contentTypeMapping[key] = value
+		}
+	}
+	http.Handle(path, handler{
+		staticFS:  options.Files,
+		indexPath: options.IndexPath,
+	})
+}
diff --git a/spa/helper.go b/spa/helper.go
new file mode 100644
index 0000000..e735201
--- /dev/null
+++ b/spa/helper.go
@@ -0,0 +1,47 @@
+package spa
+
+import (
+	"io"
+	"io/fs"
+	"net/http"
+	"strings"
+)
+
+func tryToDeliverFile(file fs.File, path string, w http.ResponseWriter, r *http.Request) {
+	fileSeeker, ok := file.(io.ReadSeeker)
+	if !ok {
+		file.Close()
+		http.Error(w, "Index file does not implement ReadSeeker", http.StatusInternalServerError)
+		return
+	}
+	stats, statErr := file.Stat()
+	if statErr != nil {
+		http.Error(w, "Cannot stat index file", http.StatusInternalServerError)
+		return
+	}
+	contentType, contentTypeErr := detectContentType(file)
+	if contentTypeErr != nil {
+		contentType = "text/html"
+	}
+	contentType = getContentTypeDetail(contentType, stats)
+	w.Header().Set("Content-Type", contentType)
+	http.ServeContent(w, r, path, stats.ModTime(), fileSeeker)
+}
+
+func detectContentType(file fs.File) (string, error) {
+	buffer := []byte{}
+	_, err := file.Read(buffer)
+	if err != nil {
+		return "", err
+	}
+	return http.DetectContentType(buffer), nil
+}
+
+func getContentTypeDetail(contentType string, info fs.FileInfo) string {
+	for ending, realContentType := range contentTypeMapping {
+		if strings.HasSuffix(info.Name(), ending) {
+			return realContentType
+		}
+	}
+	return contentType
+}
\ No newline at end of file
diff --git a/spa/mime_type.go b/spa/mime_type.go
new file mode 100644
index 0000000..516a6c8
--- /dev/null
+++ b/spa/mime_type.go
@@ -0,0 +1,9 @@
+package spa
+
+var contentTypeMapping = map[string]string{
+	".html": "text/html",
+	".htm":  "text/html",
+	".js":   "text/javascript",
+	".json": "application/json",
+	".css":  "text/css",
+}
\ No newline at end of file
diff --git a/spa/options.go b/spa/options.go
new file mode 100644
index 0000000..db4a6af
--- /dev/null
+++ b/spa/options.go
@@ -0,0 +1,9 @@
+package spa
+
+import "embed"
+
+type HandlerOptions struct {
+	Files                     embed.FS
+	IndexPath                 string
+	AdditionalMimeTypeMapping map[string]string
+}