From 9c0d959181ec3e26c6d3a1980f38e8ff9ceb00a4 Mon Sep 17 00:00:00 2001
From: Sebastian Frank <frank@basiskonfiguration.de>
Date: Sun, 10 Mar 2019 16:36:20 +0100
Subject: [PATCH] dont read local image file if target exists

---
 helper/template_filters.go | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/helper/template_filters.go b/helper/template_filters.go
index 3307137..a14b437 100644
--- a/helper/template_filters.go
+++ b/helper/template_filters.go
@@ -152,6 +152,12 @@ func ImageProcessFilter(in *pongo2.Value, param *pongo2.Value) (*pongo2.Value, *
 	if strings.HasPrefix(imgSource, "http://") || strings.HasPrefix(imgSource, "https://") {
 		// remote file
 		img, p.Format, err = getImageFromURL(imgSource)
+		if err != nil {
+			return nil, &pongo2.Error{
+				Sender:    "filter:image_resize",
+				OrigError: fmt.Errorf("could not open image '%s': %s", imgSource, err),
+			}
+		}
 		// build filename
 		if p.Filename == "" {
 			var fBase string
@@ -170,7 +176,6 @@ func ImageProcessFilter(in *pongo2.Value, param *pongo2.Value) (*pongo2.Value, *
 	} else {
 		// local file
 		imgSource = ResolveInputPath(imgSource)
-		img, err = imaging.Open(imgSource, imaging.AutoOrientation(true))
 		if p.Filename == "" {
 			p.Filename = fmt.Sprintf(
 				"%s_%s",
@@ -179,12 +184,6 @@ func ImageProcessFilter(in *pongo2.Value, param *pongo2.Value) (*pongo2.Value, *
 			)
 		}
 	}
-	if err != nil {
-		return nil, &pongo2.Error{
-			Sender:    "filter:image_resize",
-			OrigError: fmt.Errorf("could not open image '%s': %s", imgSource, err),
-		}
-	}
 
 	imgTarget := ResolveOutputPath(p.Filename)
 
@@ -192,6 +191,17 @@ func ImageProcessFilter(in *pongo2.Value, param *pongo2.Value) (*pongo2.Value, *
 		Log.Noticef("skipped processing image from %s to %s, file already exists", imgSource, imgTarget)
 	} else {
 		Log.Noticef("processing image from %s to %s", imgSource, imgTarget)
+		if strings.HasPrefix(imgSource, "http://") || strings.HasPrefix(imgSource, "https://") {
+			// webrequest before finding target filename, because of file format in filename
+		} else {
+			img, err = imaging.Open(imgSource, imaging.AutoOrientation(true))
+			if err != nil {
+				return nil, &pongo2.Error{
+					Sender:    "filter:image_resize",
+					OrigError: fmt.Errorf("could not open image '%s': %s", imgSource, err),
+				}
+			}
+		}
 
 		switch p.Process {
 		case "resize":