Automatically resize images and save them as webp

cmd/backend/config.go

@@ -12,36 +12,40 @@ import (
 )
 
 type Config struct {
-	ArticleDir  string
-	ConfigFile  string
-	DBName      string
-	Description string
-	Domain      string
-	FirebaseKey string
-	KeyFile     string
-	Link        string
-	LogFile     string
-	PDFDir      string
-	PicsDir     string
-	Port        string
-	RSSFile     string
-	Title       string
-	WebDir      string
+	ArticleDir   string
+	ConfigFile   string
+	DBName       string
+	Description  string
+	Domain       string
+	FirebaseKey  string
+	KeyFile      string
+	Link         string
+	LogFile      string
+	PDFDir       string
+	PicsDir      string
+	Port         string
+	RSSFile      string
+	Title        string
+	WebDir       string
+	MaxImgHeight int
+	MaxImgWidth  int
 }
 
 func newConfig() *Config {
 	return &Config{
-		ArticleDir:  "/var/www/cpolis/articles",
-		ConfigFile:  "/etc/cpolis/config.toml",
-		DBName:      "cpolis",
-		FirebaseKey: "/var/www/cpolis/serviceAccountKey.json",
-		KeyFile:     "/var/www/cpolis/cpolis.key",
-		LogFile:     "/var/log/cpolis.log",
-		PDFDir:      "/var/www/cpolis/pdfs",
-		PicsDir:     "/var/www/cpolis/pics",
-		Port:        ":8080",
-		RSSFile:     "/var/www/cpolis/cpolis.rss",
-		WebDir:      "/var/www/cpolis/web",
+		ArticleDir:   "/var/www/cpolis/articles",
+		ConfigFile:   "/etc/cpolis/config.toml",
+		DBName:       "cpolis",
+		FirebaseKey:  "/var/www/cpolis/serviceAccountKey.json",
+		KeyFile:      "/var/www/cpolis/cpolis.key",
+		LogFile:      "/var/log/cpolis.log",
+		MaxImgHeight: 1080,
+		MaxImgWidth:  1920,
+		PDFDir:       "/var/www/cpolis/pdfs",
+		PicsDir:      "/var/www/cpolis/pics",
+		Port:         ":8080",
+		RSSFile:      "/var/www/cpolis/cpolis.rss",
+		WebDir:       "/var/www/cpolis/web",
 	}
 }
 
@@ -110,6 +114,8 @@ func (c *Config) handleCliArgs() error {
 	flag.StringVar(&c.RSSFile, "rss", c.RSSFile, "RSS file")
 	flag.StringVar(&c.Title, "title", c.Title, "channel title")
 	flag.StringVar(&c.WebDir, "web", c.WebDir, "web directory")
+	flag.IntVar(&c.MaxImgHeight, "height", c.MaxImgHeight, "maximum image height")
+	flag.IntVar(&c.MaxImgWidth, "width", c.MaxImgWidth, "maximum image width")
 	flag.IntVar(&port, "port", port, "port")
 	flag.Parse()
 
@@ -186,6 +192,14 @@ func (c *Config) setupConfig(cliConfig *Config) error {
 		return fmt.Errorf("error setting up file: %v", err)
 	}
 
+	if cliConfig.MaxImgHeight != defaultConfig.MaxImgHeight {
+		c.MaxImgHeight = cliConfig.MaxImgHeight
+	}
+
+	if cliConfig.MaxImgWidth != defaultConfig.MaxImgWidth {
+		c.MaxImgWidth = cliConfig.MaxImgWidth
+	}
+
 	if cliConfig.PDFDir != defaultConfig.PDFDir {
 		c.PDFDir = cliConfig.PDFDir
 	}

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
+}