cleaned up some code

main.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"path/filepath"
 	"text/template"
+	"time"
 
 	"gocv.io/x/gocv"
 )
@@ -46,26 +47,17 @@ func stream(w http.ResponseWriter, r *http.Request) {
 	}
 	w.Header().Set("Content-Type", "image/jpeg")
 	URL := r.FormValue("URL")
-	resp, err := http.Get(URL)
+
-	if err != nil {
+	img := getStreamInstant(URL)
-		log.Fatal(err)
-	}
-	img, err := ioutil.ReadAll(resp.Body)
-	defer resp.Body.Close()
 
 	// TODO async for this?
 	saveStreamInstant(URL, img)
 
-	h := sha256.New()
+	streamDir := URLToBase64(URL)
-	h.Write([]byte(URL))
-	streamDir := base64.URLEncoding.EncodeToString(h.Sum(nil))
 	streamStoreDir := filepath.Join(".", "streams", string(streamDir))
 	previousStreamInstantPath := filepath.Join(streamStoreDir, "previous.jpg")
 
-	_, err = os.Stat(previousStreamInstantPath)
+	if fileExists(previousStreamInstantPath) {
-	previousExists := !os.IsNotExist(err)
-
-	if previousExists {
 		newMat := gocv.NewMat()
 
 		mat, err := gocv.IMDecode(img, gocv.IMReadColor)
@@ -91,24 +83,33 @@ func stream(w http.ResponseWriter, r *http.Request) {
 	w.Write(img)
 }
 
+func getStreamInstant(URL string) []byte {
+	resp, err := http.Get(URL)
+	if err != nil {
+		log.Fatal(err)
+	}
+	img, err := ioutil.ReadAll(resp.Body)
+	defer resp.Body.Close()
+	return img
+}
+
 func saveStreamInstant(URL string, img []byte) {
-	h := sha256.New()
+	streamDir := URLToBase64(URL)
-	h.Write([]byte(URL))
-	streamDir := base64.URLEncoding.EncodeToString(h.Sum(nil))
 	streamStoreDir := filepath.Join(".", "streams", string(streamDir))
 	os.MkdirAll(streamStoreDir, os.ModePerm)
 
 	currentStreamInstantPath := filepath.Join(streamStoreDir, "current.jpg")
-	_, err := os.Stat(currentStreamInstantPath)
+	swap := fileExists(streamStoreDir)
-	swap := !os.IsNotExist(err)
 
 	if swap {
 		currentStreamInstantPath = filepath.Join(streamStoreDir, "next.jpg")
 	}
-	err = ioutil.WriteFile(currentStreamInstantPath, img, os.ModePerm)
+
+	err := ioutil.WriteFile(currentStreamInstantPath, img, os.ModePerm)
 	if err != nil {
 		log.Fatal("Can't write latest stream instant.")
 	}
+
 	if swap {
 		previousStreamInstantPath := filepath.Join(streamStoreDir, "previous.jpg")
 		nextStreamInstantPath := currentStreamInstantPath
@@ -119,7 +120,7 @@ func saveStreamInstant(URL string, img []byte) {
 	}
 }
 
-func main() {
+func listenAndServe() {
 	staticFileServer := http.FileServer(http.Dir("./static"))
 	http.Handle("/static/", http.StripPrefix("/static/", staticFileServer))
 
@@ -127,3 +128,26 @@ func main() {
 	http.HandleFunc("/stream", stream)
 	log.Fatal(http.ListenAndServe(":8080", nil))
 }
+
+func backend() {
+	for {
+
+		time.Sleep(time.Second)
+	}
+}
+
+func main() {
+	go listenAndServe()
+	backend()
+}
+
+func fileExists(path string) bool {
+	_, err := os.Stat(path)
+	return !os.IsNotExist(err)
+}
+
+func URLToBase64(URL string) (hash string) {
+	h := sha256.New()
+	h.Write([]byte(URL))
+	return base64.URLEncoding.EncodeToString(h.Sum(nil))
+}