implement convert function and simple cache logic

.gitignore

@@ -18,3 +18,4 @@ vendor/
 
 .idea/
 
+cache/

main.go

@@ -1,48 +1,113 @@
 package main
 
 import (
+	"crypto/md5"
 	"fmt"
 	"golang.org/x/image/webp"
 	"image/jpeg"
 	"io"
 	"log"
+	"net/http"
 	"os"
+	"strings"
 	"time"
 )
 
 func main() {
-	var (
-		inFile  io.Reader
-		outFile io.Writer
-	)
+	_, err := os.Stat("cache")
+	if err == nil {
+		err := os.RemoveAll("cache")
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+	err = os.Mkdir("cache", os.ModeDir|os.ModePerm)
+	if err != nil {
+		log.Fatal(err)
+	}
 
-	iFile, err := os.OpenFile("/home/debuggerx/Pictures/test.webp", os.O_RDONLY, 0)
+	http.HandleFunc("/", wepb2jpgHandler)
+	err = http.ListenAndServe(":9999", nil)
 	if err != nil {
 		log.Fatal(err)
 	}
-	defer iFile.Close()
-	inFile = iFile
+}
+
+func hitCache(md5Path string, writer http.ResponseWriter) bool {
+	startTime := time.Now().UnixNano()
+	_, err := os.Stat("cache/" + md5Path)
+	if err != nil {
+		return false
+	}
 
-	oFile, err := os.OpenFile("/home/debuggerx/Pictures/test.jpg", os.O_CREATE|os.O_WRONLY|os.O_APPEND, os.FileMode(0644))
+	file, err := os.OpenFile("cache/"+md5Path, os.O_RDONLY, os.FileMode(0644))
+	defer file.Close()
 	if err != nil {
 		log.Fatal(err)
 	}
-	defer oFile.Close()
-	outFile = oFile
 
+	header := writer.Header()
+	header.Set("Access-Control-Allow-Origin", "*")
+	header.Set("content-type", "image/jpeg")
+
+	if _, err := io.Copy(writer, file); err != nil {
+		log.Fatal(err)
+	}
+	endTime := time.Now().UnixNano()
+	fmt.Printf("命中缓存：%dμs\n", (endTime-startTime)/1e3)
+
+	return true
+}
+
+func wepb2jpg(path string, md5Path string, writer http.ResponseWriter) {
 	startTime := time.Now().UnixNano()
-	m, err := webp.Decode(inFile)
+
+	resp, getErr := http.Get(path)
+	if getErr != nil {
+		log.Fatal(getErr)
+	}
 	endTime := time.Now().UnixNano()
-	fmt.Println((endTime - startTime) / 1e6)
+
+	fmt.Printf("下载耗时：%dms\n", (endTime-startTime)/1e6)
+
+	startTime = time.Now().UnixNano()
+	m, err := webp.Decode(resp.Body)
 	if err != nil {
 		log.Fatal(err)
 	}
+	endTime = time.Now().UnixNano()
+	fmt.Printf("解码耗时：%dms\n", (endTime-startTime)/1e6)
+
+	header := writer.Header()
+	header.Set("Access-Control-Allow-Origin", "*")
+	header.Set("content-type", "image/jpeg")
 
+	file, err := os.OpenFile("cache/"+md5Path, os.O_CREATE|os.O_WRONLY, os.FileMode(0644))
+	defer file.Close()
+	if err != nil {
+		log.Fatal(err)
+	}
 	startTime = time.Now().UnixNano()
-	err = jpeg.Encode(outFile, m, &jpeg.Options{Quality: 50})
-	endTime = time.Now().UnixNano()
-	fmt.Println((endTime - startTime) / 1e6)
+	err = jpeg.Encode(io.MultiWriter(writer, file), m, &jpeg.Options{Quality: 50})
 	if err != nil {
 		log.Fatal(err)
 	}
+	endTime = time.Now().UnixNano()
+	fmt.Printf("编码耗时：%dms\n", (endTime-startTime)/1e6)
+}
+
+func wepb2jpgHandler(writer http.ResponseWriter, request *http.Request) {
+	if !(strings.HasPrefix(request.URL.RawQuery, "http") && strings.HasSuffix(request.URL.RawQuery, ".webp")) {
+		writer.WriteHeader(404)
+		return
+	}
+
+	m := md5.Sum([]byte(request.URL.RawQuery))
+	md5Path := fmt.Sprintf("%x", m)
+
+	if hitCache(md5Path, writer) {
+		return
+	}
+
+	wepb2jpg(request.URL.RawQuery, md5Path, writer)
 }