get rid of duplicate bytes.Buffer, use bytes.Reader instead, #39

ad.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2023 Thomas von Dein
+Copyright © 2023-2024 Thomas von Dein
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by

config.go

@@ -34,7 +34,7 @@ import (
 )
 
 const (
-	VERSION    string = "0.3.2"
+	VERSION    string = "0.3.3"
 	Baseuri    string = "https://www.kleinanzeigen.de"
 	Listuri    string = "/s-bestandsliste.html"
 	Defaultdir string = "."

image.go

@@ -33,7 +33,7 @@ const MaxDistance = 3
 type Image struct {
 	Filename string
 	Hash     *goimagehash.ImageHash
-	Data     *bytes.Buffer
+	Data     *bytes.Reader
 	URI      string
 }
 
@@ -49,7 +49,7 @@ func (img *Image) LogValue() slog.Value {
 // holds all images of an ad
 type Cache []*goimagehash.ImageHash
 
-func NewImage(buf *bytes.Buffer, filename string, uri string) *Image {
+func NewImage(buf *bytes.Reader, filename string, uri string) *Image {
 	img := &Image{
 		Filename: filename,
 		URI:      uri,
@@ -131,7 +131,9 @@ func ReadImages(addir string, dont bool) (Cache, error) {
 				return nil, err
 			}
 
-			img := NewImage(data, filename, "")
+			reader := bytes.NewReader(data.Bytes())
+
+			img := NewImage(reader, filename, "")
 			if err = img.CalcHash(); err != nil {
 				return nil, err
 			}

scrape.go

@@ -168,14 +168,15 @@ func ScrapeImages(fetch *Fetcher, advertisement *Ad, addir string) error {
 			}
 
 			buf := new(bytes.Buffer)
+
 			_, err = buf.ReadFrom(body)
 			if err != nil {
 				return fmt.Errorf("failed to read from image buffer: %w", err)
 			}
 
-			buf2 := buf.Bytes() // needed for image writing
+			reader := bytes.NewReader(buf.Bytes())
 
-			image := NewImage(buf, file, imguri)
+			image := NewImage(reader, file, imguri)
 			err = image.CalcHash()
 			if err != nil {
 				return err
@@ -189,12 +190,13 @@ func ScrapeImages(fetch *Fetcher, advertisement *Ad, addir string) error {
 				}
 			}
 
-			err = WriteImage(file, buf2)
+			reader.Seek(0, 0)
+			err = WriteImage(file, reader)
 			if err != nil {
 				return err
 			}
 
-			slog.Debug("wrote image", "image", image, "size", len(buf2), "throttle", throttle)
+			slog.Debug("wrote image", "image", image, "size", buf.Len(), "throttle", throttle)
 
 			return nil
 		})

store.go

@@ -89,14 +89,14 @@ func WriteAd(conf *Config, advertisement *Ad) (string, error) {
 	return addir, nil
 }
 
-func WriteImage(filename string, buf []byte) error {
+func WriteImage(filename string, reader *bytes.Reader) error {
 	file, err := os.Create(filename)
 	if err != nil {
 		return fmt.Errorf("failed to open image file: %w", err)
 	}
 	defer file.Close()
 
-	_, err = file.Write(buf)
+	_, err = reader.WriteTo(file)
 
 	if err != nil {
 		return fmt.Errorf("failed to write to image file: %w", err)

store_test.go

@@ -18,6 +18,7 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
 package main
 
 import (
+	"bytes"
 	"testing"
 )
 
@@ -28,10 +29,10 @@ import (
 func TestWriteImage(t *testing.T) {
 	t.Parallel()
 
-	buf := []byte{1, 2, 3, 4, 5, 6, 7, 8}
+	reader := bytes.NewReader([]byte{1, 2, 3, 4, 5, 6, 7, 8})
 	file := "t/out/t.jpg"
 
-	err := WriteImage(file, buf)
+	err := WriteImage(file, reader)
 	if err != nil {
 		t.Errorf("Could not write mock image to %s: %s", file, err.Error())
 	}

util.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2023 Thomas von Dein
+Copyright © 2023-2024 Thomas von Dein
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by