Automatically resize images and save them as webp

cmd/backend/images.go

@@ -0,0 +1,38 @@
+package backend
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/chai2010/webp"
+	"github.com/disintegration/imaging"
+	"github.com/google/uuid"
+)
+
+func SaveImage(c *Config, src io.Reader) (string, error) {
+	img, err := imaging.Decode(src, imaging.AutoOrientation(true))
+	if err != nil {
+		return "", fmt.Errorf("error decoding image: %v", err)
+	}
+
+	if img.Bounds().Dy() > c.MaxImgHeight {
+		img = imaging.Resize(img, 0, c.MaxImgHeight, imaging.Lanczos)
+	}
+	if img.Bounds().Dx() > c.MaxImgWidth {
+		img = imaging.Resize(img, c.MaxImgWidth, 0, imaging.Lanczos)
+	}
+
+	filename := fmt.Sprint(c.PicsDir, "/", uuid.New(), ".webp")
+	file, err := os.Create(filename)
+	if err != nil {
+		return "", fmt.Errorf("error creating new image file: %v", err)
+	}
+	defer file.Close()
+
+	if err = webp.Encode(file, img, &webp.Options{Lossless: true}); err != nil {
+		return "", fmt.Errorf("error encoding image as webp: %v", err)
+	}
+
+	return filename, nil
+}