Add embedding files to binary

Now this app is truly portable! You don't even need the assets folder
when using a compiled binary, as the HTML and CSS are now embedded to
the file itself

main.go

@@ -1,29 +1,20 @@
 package main
 
 import (
+	"embed"
 	"fmt"
 	"io"
+	"io/fs"
 	"log"
 	"net/http"
 	"os"
 )
 
-// func getRoot(w http.ResponseWriter, r *http.Request) {
+//go:embed assets
-// 	fmt.Printf("Received connection\n")
+var assetsFolder embed.FS
-// 	file, err := os.Open("./index.html")
-// 	if err != nil {
-// 		log.Printf("Error happened opening index.html: %v\n", err)
-// 	}
-// 	defer file.Close()
-// 	data, err := io.ReadAll(file)
-// 	if err != nil {
-// 		log.Printf("Error happened reading data: %v\n", err)
-// 	}
-// 	fmt.Fprint(w, string(data))
-// }
 
 func uploadFile(w http.ResponseWriter, r *http.Request) {
-	fmt.Fprintln(w, "You have uploaded something")
+	fmt.Fprintln(w, "Successful upload!")
 
 	file, header, err := r.FormFile("file")
 
@@ -31,6 +22,8 @@ func uploadFile(w http.ResponseWriter, r *http.Request) {
 		log.Printf("Error happened receiving file: %v\n", err)
 	}
 
+	defer file.Close()
+
 	_, err = os.Stat("./temp/")
 	if os.IsNotExist(err) {
 		os.Mkdir("./temp/", 0700)
@@ -40,19 +33,23 @@ func uploadFile(w http.ResponseWriter, r *http.Request) {
 	if err != nil {
 		log.Printf("Error happened opening file: %v\n", err)
 	}
+
 	log.Printf("[%v] Received file \"%v\" from %v\n", r.RemoteAddr, header.Filename, r.UserAgent())
 	io.Copy(f, file)
-
-	defer file.Close()
 }
 
 func main() {
-	http.Handle("/", http.FileServer(http.Dir("./assets")))
+	serverRoot, err := fs.Sub(assetsFolder, "assets")
+	if err != nil {
+		log.Fatalf("Error occurred setting HTML root: %v\n", err)
+	}
+
+	http.Handle("/", http.FileServer(http.FS(serverRoot)))
 	http.HandleFunc("/api/upload", uploadFile)
 
 	fmt.Println("Listening on port 8080...")
 
-	err := http.ListenAndServe(":8080", nil)
+	err = http.ListenAndServe(":8080", nil)
 	if err != nil {
 		log.Fatal(err)
 	}