Merge pull request #31 from isd-sgcu/compress-image

compress image

docker-compose.qa.template.yml

@@ -112,6 +112,7 @@ services:
       STORE_ENDPOINT: endpoint
       STORE_ACCESS_KEY: access_key
       STORE_SECRET_KEY: secret_key
+      STORE_REGION: ap-southeast-1
       STORE_USE_SSL: true
       STORE_BUCKET_NAME: rpkm67-local
     networks:

internal/context/context.utils.go

@@ -4,7 +4,8 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"io"
+	"image"
+	"image/jpeg"
 	"mime/multipart"
 	"strings"
 )
@@ -14,23 +15,15 @@ func ExtractFile(file *multipart.FileHeader, allowedContent map[string]struct{},
 		return nil, errors.New("Allowed content type is " + fmt.Sprint(strings.Join(mapToArr(allowedContent), ", ")))
 	}
 
-	if file.Size > maxSize*1000000000 {
-		return nil, fmt.Errorf("max file size is %v", maxSize)
-	}
-
-	fileBytes, err := file.Open()
+	maxSizeMB := maxSize * 1024 * 1024
+	fileBytes, err := compressImage(file, int(maxSizeMB))
 	if err != nil {
 		return nil, err
 	}
 
-	defer fileBytes.Close()
-
-	buf := bytes.NewBuffer(nil)
-	if _, err := io.Copy(buf, fileBytes); err != nil {
-		return nil, err
-	}
+	println("File size: ", len(fileBytes))
 
-	return buf.Bytes(), nil
+	return fileBytes, nil
 }
 
 func isExisted(e map[string]struct{}, key string) bool {
@@ -45,3 +38,39 @@ func mapToArr(m map[string]struct{}) []string {
 	}
 	return arr
 }
+
+func compressImage(fileHeader *multipart.FileHeader, maxSizeMB int) ([]byte, error) {
+	file, err := fileHeader.Open()
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	img, _, err := image.Decode(file)
+	if err != nil {
+		return nil, err
+	}
+
+	var quality int = 80
+	var compressed []byte
+
+	for {
+		buf := new(bytes.Buffer)
+		if err := jpeg.Encode(buf, img, &jpeg.Options{Quality: quality}); err != nil {
+			return nil, err
+		}
+		compressed = buf.Bytes()
+
+		if len(compressed) <= maxSizeMB {
+			break
+		}
+
+		// Reduce quality if size is still too large
+		quality -= 10
+		if quality <= 0 {
+			return nil, fmt.Errorf(fmt.Sprintf("unable to compress image to %v MB", maxSizeMB/(1024*1024)))
+		}
+	}
+
+	return compressed, nil
+}