Put different transforms into different functions

main.go

@@ -1,10 +1,12 @@
-// vi:ts=4:sts=4:sw=4:noet:tw=72
+// (c) 2018 Karthik Karanth (https://github.com/medakk/gotiny)
+// (c) 2018-2021 Andreas Neue <an@dnix.de>
 
 package main
 
 import (
 	"flag"
 	"fmt"
+	"io"
 	"log"
 	"net/http"
 	"strconv"
@@ -23,7 +25,7 @@ func init() {
 	flag.Parse()
 }
 
-func resizeHandler(w http.ResponseWriter, r *http.Request) {
+func transform(w http.ResponseWriter, r *http.Request) {
 	// Get the query parameters from the request URL
 	path := r.URL.EscapedPath()
 	parm := strings.Split(path, "/")
@@ -43,9 +45,42 @@ func resizeHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	defer resp.Body.Close()
+	// Ensure that a valid response was given
+	if resp.StatusCode/100 != 2 {
+		writeError(w, imgPath, method, fmt.Sprintf("failed to fetch image (%v)", resp.StatusCode), http.StatusBadRequest)
+		return
+	}
+
+	buf := []byte{}
+	errMsg := ""
+	errCode := 200
 
 	switch method {
+	case "pass":
+		break
+		
 	case "resize":
+		buf, errMsg, errCode = doResize(resp.Body, args)
+		if buf == nil {
+			writeError(w, imgPath, method, errMsg, errCode)
+		}
+
+	case "thumbnail":
+		break
+
+	default:
+		writeError(w, imgPath, method, "unknown method", http.StatusBadRequest)
+		return
+	}
+
+	_, err = w.Write(buf)
+	if err != nil {
+		writeError(w, imgPath, method, fmt.Sprintf("%v", err), http.StatusInternalServerError)
+		return
+	}
+}
+
+func doResize(body io.ReadCloser, args string) ([]byte, string, int) {
 	allowed := strings.Split(*sizesFilter, ",")
 	forbidden := true
 	if allowed[0] == "*" {
@@ -59,65 +94,43 @@ func resizeHandler(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 	if forbidden {
-			writeError(w, imgPath, method, "size is not allowed", http.StatusForbidden)
-			return
+		return nil, "size is not allowed", http.StatusForbidden
 	}
 
 	size := strings.Split(args, "x")
 	if len(size) < 2 {
-			writeError(w, imgPath, method, "url, width, and height are required", http.StatusBadRequest)
-			return
+		return nil, "width and height are required", http.StatusBadRequest
 	}
 	width := size[0]
 	height := size[1]
 
 	// Validate that all three required fields are present
-		if imgPath == "" || width == "" || height == "" {
-			writeError(w, imgPath, method, "url, width, and height are required", http.StatusBadRequest)
-			return
+	if width == "" || height == "" {
+		return nil, "width and height are required", http.StatusBadRequest
 	}
 
 	// Convert width and height to integers
 	iw, errW := strconv.Atoi(width)
 	ih, errH := strconv.Atoi(height)
 	if errW != nil || errH != nil {
-			writeError(w, imgPath, method, "width and height must be integers", http.StatusBadRequest)
-			return
-		}
-
-		// Ensure that a valid response was given
-		if resp.StatusCode/100 != 2 {
-			writeError(w, imgPath, method, fmt.Sprintf("failed to fetch image (%v)", resp.StatusCode), http.StatusBadRequest)
-			return
+		return nil, "width and height must be integers", http.StatusBadRequest
 	}
 
 	// Read from response body, convert and write to output buffer
-		img, err := vips.NewImageFromReader(resp.Body)
+	img, err := vips.NewImageFromReader(body)
 	if err != nil {
-			writeError(w, imgPath, method, fmt.Sprintf("%v", err), http.StatusInternalServerError)
-			return
+		return nil, fmt.Sprintf("%v", err), http.StatusInternalServerError
 	}
 	err = img.Thumbnail(iw, ih, 0)
 	if err != nil {
-			writeError(w, imgPath, method, fmt.Sprintf("%v", err), http.StatusInternalServerError)
-			return
+		return nil, fmt.Sprintf("%v", err), http.StatusInternalServerError
 	}
 	ep := vips.NewDefaultExportParams() // default export params are sufficient
 	buf, _, _ := img.Export(ep)
-		_, err = w.Write(buf)
 	if err != nil {
-			writeError(w, imgPath, method, fmt.Sprintf("%v", err), http.StatusInternalServerError)
-			return
+		return nil, fmt.Sprintf("%v", err), http.StatusInternalServerError
 	}
-	
-		
-	case "thumbnail":
-
-	default:
-		writeError(w, imgPath, method, "unknown method", http.StatusBadRequest)
-		return
-	}
-
+	return buf, "", 0
 }
 
 func writeError(w http.ResponseWriter, imgPath, method, err string, status int) {
@@ -130,6 +143,6 @@ func main() {
 	vips.Startup(nil)
 	defer vips.Shutdown()
 
-	http.HandleFunc("/", resizeHandler)
+	http.HandleFunc("/", transform)
 	log.Fatal(http.ListenAndServe(*listenAddr, nil))
 }