Add support for image compression

config.go

@@ -9,6 +9,7 @@ import (
 
 var (
 	BlogUrl                      string
+	MediaEndpointUrl             string
 	IgnoredWebmentionUrls        []string
 	SyndicationTargets           []SyndicationTarget
 	SelectedStorage              Storage
@@ -16,7 +17,7 @@ var (
 	SelectedCdn                  Cdn
 	SelectedSocials              Socials
 	SelectedNotificationServices NotificationServices
-	MediaEndpointUrl             string
+	SelectedImageCompression     ImageCompression
 )
 
 type SyndicationTarget struct {
@@ -39,6 +40,7 @@ type config struct {
 	TelegramBotToken      string   `env:"TELEGRAM_BOT_TOKEN"`
 	IgnoredWebmentionUrls []string `env:"WEBMENTION_IGNORED" envSeparator:","`
 	SyndicationTargets    []string `env:"SYNDICATION" envSeparator:","`
+	TinifyKey             string   `env:"TINIFY_KEY"`
 }
 
 func initConfig() (err error) {
@@ -138,5 +140,18 @@ func initConfig() (err error) {
 	if SelectedNotificationServices == nil {
 		log.Println("No notification services configured")
 	}
+	// Find configured image compression service (optional)
+	SelectedImageCompression = func() ImageCompression {
+		// Tinify
+		if len(cfg.TinifyKey) > 0 {
+			return &Tinify{
+				key: cfg.TinifyKey,
+			}
+		}
+		return nil
+	}()
+	if SelectedImageCompression == nil {
+		log.Println("no image compression configured")
+	}
 	return nil
 }

go.mod

@@ -5,6 +5,7 @@ go 1.13
 require (
 	github.com/caarlos0/env/v6 v6.1.0
 	github.com/go-telegram-bot-api/telegram-bot-api v4.6.5-0.20190904012038-b33efeebc785+incompatible
+	github.com/gwpp/tinify-go v0.0.0-20170613055357-77b9df15f343
 	github.com/technoweenie/multipartstreamer v1.0.1 // indirect
 	gopkg.in/yaml.v2 v2.2.7
 	willnorris.com/go/webmention v0.0.0-20191104072158-c7fb13569b62

go.sum

@@ -8,6 +8,8 @@ github.com/go-telegram-bot-api/telegram-bot-api v4.6.5-0.20190904012038-b33efeeb
 github.com/go-telegram-bot-api/telegram-bot-api v4.6.5-0.20190904012038-b33efeebc785+incompatible/go.mod h1:qf9acutJ8cwBUhm1bqgz6Bei9/C/c93FPDljKWwsOgM=
 github.com/google/go-cmp v0.3.0 h1:crn/baboCvb5fXaQ0IJ1SGTsTVrWpDsCWC8EGETZijY=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
+github.com/gwpp/tinify-go v0.0.0-20170613055357-77b9df15f343 h1:QbWv77mi5YeTWR3FxLqx5eeC2H0fUL07Kj2Uhza9/A8=
+github.com/gwpp/tinify-go v0.0.0-20170613055357-77b9df15f343/go.mod h1:FP1q8rlReJYgAj3zqyQfD745uokKzl0baffXAcxDcl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

imagecompression.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"errors"
+	tfgo "github.com/gwpp/tinify-go/tinify"
+	"io/ioutil"
+	"os"
+	"sort"
+	"strings"
+)
+
+type ImageCompression interface {
+	Compress(url string) (location string, err error)
+}
+
+// Tinify
+type Tinify struct {
+	// API Key
+	key string
+}
+
+func (t Tinify) Compress(url string) (location string, err error) {
+	fileExtension := func() string {
+		spliced := strings.Split(url, ".")
+		return spliced[len(spliced)-1]
+	}()
+	supportedTypes := []string{"jpg", "jpeg", "png"}
+	sort.Strings(supportedTypes)
+	i := sort.SearchStrings(supportedTypes, strings.ToLower(fileExtension))
+	if !(i < len(supportedTypes) && supportedTypes[i] == strings.ToLower(fileExtension)) {
+		err = errors.New("file not supported")
+		return
+	}
+	tfgo.SetKey(t.key)
+	s, e := tfgo.FromUrl(url)
+	if e != nil {
+		err = errors.New("failed to compress file")
+		return
+	}
+	file, e := ioutil.TempFile("", "tiny-*."+fileExtension)
+	if e != nil {
+		err = errors.New("failed to create temporary file")
+		return
+	}
+	defer func() {
+		_ = os.Remove(file.Name())
+	}()
+	e = s.ToFile(file.Name())
+	if e != nil {
+		err = errors.New("failed to save compressed file")
+		return
+	}
+	hashFile, e := os.Open(file.Name())
+	defer func() { _ = hashFile.Close() }()
+	if e != nil {
+		err = errors.New("failed to open temporary file")
+		return
+	}
+	fileName, err := getSHA256(hashFile)
+	if err != nil {
+		return
+	}
+	location, err = SelectedMediaStorage.Upload(fileName+"."+fileExtension, file)
+	return
+}

mediaendpoint.go

@@ -1,9 +1,6 @@
 package main
 
 import (
-	"crypto/sha256"
-	"fmt"
-	"io"
 	"mime"
 	"net/http"
 	"path/filepath"
@@ -44,14 +41,13 @@ func HandleMedia(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 		hashFile, _, _ := r.FormFile("file")
-		h := sha256.New()
 		defer func() { _ = hashFile.Close() }()
-		if _, err := io.Copy(h, hashFile); err != nil {
+		fileName, err := getSHA256(hashFile)
+		if err != nil {
 			w.WriteHeader(http.StatusInternalServerError)
-			_, _ = w.Write([]byte("Failed to calculate hash of file"))
+			_, _ = w.Write([]byte(err.Error()))
 			return
 		}
-		fileName := fmt.Sprintf("%x", h.Sum(nil))
 		fileExtension := filepath.Ext(header.Filename)
 		if len(fileExtension) == 0 {
 			// Find correct file extension if original filename does not contain one
@@ -67,9 +63,15 @@ func HandleMedia(w http.ResponseWriter, r *http.Request) {
 		location, err := SelectedMediaStorage.Upload(fileName, file)
 		if err != nil {
 			w.WriteHeader(http.StatusInternalServerError)
-			_, _ = w.Write([]byte("Failed to upload file"))
+			_, _ = w.Write([]byte("Failed to upload original file"))
 			return
 		}
+		if SelectedImageCompression != nil {
+			compressedLocation, err := SelectedImageCompression.Compress(location)
+			if err == nil && len(compressedLocation) > 0 {
+				location = compressedLocation
+			}
+		}
 		w.Header().Add("Location", location)
 		w.WriteHeader(http.StatusCreated)
 	} else {

mediastorage.go

@@ -1,7 +1,10 @@
 package main
 
 import (
+	"crypto/sha256"
 	"errors"
+	"fmt"
+	"io"
 	"mime/multipart"
 	"net/http"
 	"net/url"
@@ -33,3 +36,12 @@ func (b BunnyCdnStorage) Upload(fileName string, file multipart.File) (location
 	}
 	return b.baseLocation + fileName, nil
 }
+
+func getSHA256(file multipart.File) (filename string, err error) {
+	h := sha256.New()
+	if _, e := io.Copy(h, file); e != nil {
+		err = errors.New("failed to calculate hash of file")
+		return
+	}
+	return fmt.Sprintf("%x", h.Sum(nil)), nil
+}