Prevent infinite loop bug when index.html is missed

server.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"os"
 	"flag"
 	"log"
 
@@ -10,23 +11,39 @@ import (
 var (
 	addr      = flag.String("h", "0.0.0.0:8080", "TCP address to listen to")
 	root      = flag.String("d", "/usr/share/httpd", "Directory to serve static files from")
+	file      = flag.String("f", "index.html", "File to serve")
 	strip     = flag.Int("s", 0, "Number of mount point to skip")
 	compress  = flag.Bool("c", false, "Enables transparent response compression if set to true")
 	fsHandler fasthttp.RequestHandler
 )
 
 func notFoundHandler(ctx *fasthttp.RequestCtx) {
 	ctx.Logger().Printf("File %s not found, defaulting to index.html", ctx.Path())
-	ctx.Request.SetRequestURI("/index.html")
-	fsHandler(ctx)
+	if isIndexFileExists() {
+		ctx.Request.SetRequestURI("/index.html")
+		fsHandler(ctx)
+	} else {
+		ctx.Error("Internal Server Error", fasthttp.StatusInternalServerError)
+	}
+}
+
+func isIndexFileExists() bool {
+	path := *root + "/" + *file
+	if _, err := os.Stat(path); err != nil {
+		if os.IsNotExist(err) {
+			log.Printf("File %s do not exists", *file)
+			return false
+		}
+	}
+	return true
 }
 
 func requestHandler(ctx *fasthttp.RequestCtx) {
 	fsHandler(ctx)
 }
 
 func createFsHandler(stripSlashes int) fasthttp.RequestHandler {
-	fs := &fasthttp.FS{
+	fs := &fasthttp.FS {
 		Root:               *root,
 		Compress:           *compress,
 		IndexNames:         []string{"index.html"},
@@ -45,7 +62,7 @@ func main() {
 	fsHandler = createFsHandler(*strip)
 
 	// Start HTTP server.
-	if len(*addr) > 0 {
+	if len(*addr) > 0 && isIndexFileExists() {
 		log.Printf("Starting HTTP server on %q", *addr)
 		log.Printf("Serving files from directory %q", *root)
 		if err := fasthttp.ListenAndServe(*addr, requestHandler); err != nil {