add confirmation of zonefile upload and add mimetype validation to only allow users to upload text/plain

internal/api/zone.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"io"
 	"log"
@@ -64,6 +65,12 @@ func ReceiveFile(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	ok := validateContentType(file)
+	if !ok {
+		http.Error(w, "file must be text/plain", http.StatusUnsupportedMediaType)
+
+		return
+	}
 	defer file.Close() //nolint: errcheck
 
 	name := strings.Split(header.Filename, ".")
@@ -97,6 +104,20 @@ func ReceiveFile(w http.ResponseWriter, r *http.Request) {
 		})
 
 	buf.Reset()
+
+	w.WriteHeader(http.StatusCreated)
+	w.Header().Set("Content-Type", "application/json")
+	err = json.NewEncoder(w).Encode(
+		internal.Response{
+			HTTPResponse: http.StatusCreated,
+			Message:      "Successfully uploaded zonefile",
+		})
+
+	if err != nil {
+		internalServerError(w, "internal server error")
+
+		return
+	}
 }
 
 // Parse godoc
@@ -197,3 +218,20 @@ func (zone *ZoneRequest) Parse() error {
 
 	return nil
 }
+
+func validateContentType(file io.Reader) bool {
+	bytes, err := io.ReadAll(file)
+	if err != nil {
+		return false
+	}
+
+	mimeType := http.DetectContentType(bytes)
+	mime := strings.Contains(mimeType, "text/plain")
+
+	switch mime {
+	case true:
+		return true
+	default:
+		return false
+	}
+}