[IMPROVE] Cache renders and use WEBP instead of png. Lowers overall CPU usage and render performance

Author: hypherionmc

go.mod

@@ -12,6 +12,7 @@ require (
 
 require (
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/chai2010/webp v1.1.1 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
 	golang.org/x/net v0.38.0 // indirect
 	golang.org/x/sys v0.31.0 // indirect

go.sum

@@ -1,5 +1,7 @@
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/chai2010/webp v1.1.1 h1:jTRmEccAJ4MGrhFOrPMpNGIJ/eybIgwKpcACsrTEapk=
+github.com/chai2010/webp v1.1.1/go.mod h1:0XVwvZWdjjdxpUEIf7b9g9VkHFnInUSYujwqTLEuldU=
 github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
 github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
 github.com/fsnotify/fsnotify v1.4.9 h1:hsms1Qyu0jgnwNXIxa+/V/PDsU6CfLf6CNO8H7IWoS4=

http.go

@@ -2,11 +2,15 @@ package main
 
 import (
 	"fmt"
+	"github.com/chai2010/webp"
 	"github.com/gorilla/mux"
-	"image/png"
+	"io"
 	"net/http"
+	"os"
+	"path"
 	"strconv"
 	"strings"
+	"time"
 )
 
 // Init the HTTP (or rest api) server
@@ -52,6 +56,14 @@ func handleAvatar(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
+	// To prevent overload on the server, we enforce some limits on scaling.
+	// Not smaller than 16, so that it's visible, and not more than 1024px
+	if scale < 16 {
+		scale = 16
+	} else if scale > 1024 {
+		scale = 1024
+	}
+
 	var uuid string
 	var err error
 
@@ -72,6 +84,18 @@ func handleAvatar(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
+	cachePath := path.Join(renderDir, fmt.Sprintf("%s_%s_%s.web", mode, uuid, strconv.Itoa(scale)))
+	cachedFile, err := os.Open(cachePath)
+	if err == nil {
+		w.Header().Set("Content-Type", "image/webp")
+		_, err = io.Copy(w, cachedFile)
+		if err != nil {
+			http.Error(w, "Failed to read image: "+err.Error(), http.StatusInternalServerError)
+		}
+		return
+	}
+	defer cachedFile.Close()
+
 	// Request the skin from the MOJANG servers
 	skinPath, err := fetchSkin(uuid)
 	if err != nil {
@@ -86,10 +110,18 @@ func handleAvatar(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Encode the image ready for browser rendering
-	w.Header().Set("Content-Type", "image/png")
-	err = png.Encode(w, img)
+	f, _ := os.Create(cachePath)
+	err = webp.Encode(f, img, &webp.Options{
+		Lossless: true,
+		Quality:  100,
+		Exact:    true,
+	})
+
 	if err != nil {
-		http.Error(w, "Failed to encode image", http.StatusInternalServerError)
+		http.Error(w, "Failed to encode image: "+err.Error(), http.StatusInternalServerError)
 		return
 	}
+
+	w.Header().Set("Content-Type", "image/webp")
+	http.ServeContent(w, r, cachePath, time.Now(), f)
 }

main.go

@@ -6,10 +6,12 @@ import (
 
 // Storage directory for skin cache
 const skinCacheDir = "cached_skins"
+const renderDir = "cached_skins/render"
 
 // Main entry point
 func main() {
 	os.MkdirAll(skinCacheDir, os.ModePerm)
+	os.MkdirAll(renderDir, os.ModePerm)
 	cleanupCache()
 	initRedis()
 	initHttp()

skins.go

@@ -4,9 +4,9 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
+	"github.com/chai2010/webp"
 	"github.com/mineatar-io/skin-render"
 	"image"
-	"image/png"
 	"io/ioutil"
 	"net/http"
 	"os"
@@ -15,7 +15,7 @@ import (
 
 // Skin fetcher. Here, we try to fetch the skin from the cache, via mojangs servers, and finally, fall back to crafthead.
 func fetchSkin(uuid string) (string, error) {
-	cachePath := filepath.Join(skinCacheDir, uuid+".png")
+	cachePath := filepath.Join(skinCacheDir, uuid+".webp")
 	if _, err := os.Stat(cachePath); err == nil {
 		return cachePath, nil
 	}
@@ -75,19 +75,11 @@ func renderSkin(skinPath string, mode string, scale int, uid string, overlay boo
 	}
 	defer file.Close()
 
-	img, err := png.Decode(file)
+	img, err := webp.Decode(file)
 	if err != nil {
 		return nil, err
 	}
 
-	// To prevent overload on the server, we enforce some limits on scaling.
-	// Not smaller than 16, so that it's visible, and not more than 1024px
-	if scale < 16 {
-		scale = 16
-	} else if scale > 1024 {
-		scale = 1024
-	}
-
 	switch mode {
 	// Plain Avatar
 	case "avatar":

utils.go

@@ -4,10 +4,10 @@ import (
 	"crypto/md5"
 	"encoding/json"
 	"fmt"
+	"github.com/chai2010/webp"
 	"github.com/google/uuid"
 	"image"
 	"image/draw"
-	"image/png"
 	"io"
 	"io/ioutil"
 	"net"
@@ -45,12 +45,17 @@ func downloadAndCacheSkin(skinURL string, cachePath string, uuid string) (string
 	}
 	defer file.Close()
 
-	// Decode the image and re-encode to PNG format
+	// Decode the image and re-encode to WEBP format
 	img, _, err := image.Decode(skinResp.Body)
 	if err != nil {
 		return "", err
 	}
-	png.Encode(file, img)
+
+	webp.Encode(file, img, &webp.Options{
+		Lossless: true,
+		Quality:  100,
+		Exact:    true,
+	})
 
 	cacheSkin(uuid, cachePath)
 	return cachePath, nil