remove EXIF header from the uploaded pic

pkg/backend/posts/controllers.go

@@ -179,7 +179,7 @@ func addNewPost(w http.ResponseWriter, r *http.Request) {
 
 		content := key + "." + extension
 
-		// image pkg magic
+		// decode image from []byte stream
 		img, format, err := decodeImage(post.Data)
 		if err != nil {
 			resp.Message = "backend error: cannot decode given byte stream"
@@ -190,21 +190,43 @@ func addNewPost(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
-		// upload to local storage
-		//if err := os.WriteFile("/opt/pix/"+content, post.Data, 0600); err != nil {
-		if err := os.WriteFile("/opt/pix/"+content, post.Data, 0600); err != nil {
-			resp.Message = "backend error: couldn't save a figure to a file: " + err.Error()
+		// fix the image orientation for decoded image
+		img, err = fixOrientation(img, post.Data)
+		if err != nil {
+			resp.Message = "backend error: cannot fix image's oriantation: " + err.Error()
 			resp.Code = http.StatusInternalServerError
 
 			l.Println(resp.Message, resp.Code)
 			resp.Write(w)
 			return
 		}
 
-		// fix the image orientation for thumbnail
-		img, err = fixOrientation(img, post.Data)
+		// re-encode the image
+		newBytes, err := encodeImage(img, format)
 		if err != nil {
-			resp.Message = "backend error: cannot fix image's oriantation: " + err.Error()
+			resp.Message = "backend error: cannot re-encode the novel image"
+			resp.Code = http.StatusBadRequest
+
+			l.Println(resp.Message, resp.Code)
+			resp.Write(w)
+			return
+		}
+
+		// remove EXIF metadata
+		_, newBytes, err = removeExif(newBytes, format)
+		if err != nil {
+			resp.Message = "backend error: cannot remove EXIF metadata"
+			resp.Code = http.StatusBadRequest
+
+			l.Println(resp.Message, resp.Code)
+			resp.Write(w)
+			return
+		}
+
+		// upload to local storage
+		//if err := os.WriteFile("/opt/pix/"+content, post.Data, 0600); err != nil {
+		if err := os.WriteFile("/opt/pix/"+content, newBytes, 0600); err != nil {
+			resp.Message = "backend error: couldn't save a figure to a file: " + err.Error()
 			resp.Code = http.StatusInternalServerError
 
 			l.Println(resp.Message, resp.Code)

pkg/backend/posts/image.go

@@ -14,6 +14,33 @@ import (
 	_ "image/png"
 )
 
+func removeExif(imgBytes []byte, format string) (image.Image, []byte, error) {
+	// Decode the image
+	img, _, err := image.Decode(bytes.NewReader(imgBytes))
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Create a buffer to hold the new image data (without EXIF metadata)
+	var buf bytes.Buffer
+
+	// Encode the image without EXIF metadata
+	switch format {
+	case "jpeg":
+		err = jpeg.Encode(&buf, img, nil)
+	case "png":
+		err = png.Encode(&buf, img)
+	default:
+		return nil, nil, err
+	}
+
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return img, buf.Bytes(), nil
+}
+
 // ResizeImage resizes an image to a target width and height while maintaining aspect ratio
 /*func resizeImage(img image.Image, targetWidth, targetHeight int) image.Image {
 	thumb := image.NewRGBA(image.Rect(0, 0, targetWidth, targetHeight))
@@ -121,7 +148,7 @@ func fixOrientation(img image.Image, imgBytes []byte) (image.Image, error) {
 	// Find the Orientation tag
 	for _, entry := range entries {
 		if entry.TagName == "Orientation" {
-			fmt.Printf("orientation: entry.Value: %v\n", entry.Value)
+			//fmt.Printf("orientation: entry.Value: %v\n", entry.Value)
 			orientationRaw := entry.Value.([]uint16) // Orientation should be a uint16 value
 			orientation := orientationRaw[0]