update

utils/gravatar/gravatar.go

@@ -0,0 +1,23 @@
+package gravatar
+
+import (
+	"crypto/sha256"
+	"fmt"
+	"strings"
+)
+
+const baseUrl = "https://www.gravatar.com/avatar"
+const defaultSize = 80
+const maxSize = 2048
+
+func Url(email string, size int) string {
+	email = strings.ToLower(email)
+	email = strings.TrimSpace(email)
+	hash := sha256.Sum256([]byte(email))
+	if size < 1 {
+		size = defaultSize
+	}
+	size = min(maxSize, size)
+
+	return fmt.Sprintf("%s/%x?s=%d", baseUrl, hash, size)
+}