basic stream saving working

main.go

@@ -1,9 +1,12 @@
 package main
 
 import (
+	"crypto/sha256"
+	"encoding/base64"
 	"io/ioutil"
 	"log"
 	"net/http"
+	"os"
 	"path/filepath"
 	"text/template"
 )
@@ -38,7 +41,7 @@ func stream(w http.ResponseWriter, r *http.Request) {
 	if r.FormValue("URL") == "" {
 		return
 	}
-	//w.Header().Set("Content-Type", "image/jpeg")
+	w.Header().Set("Content-Type", "image/jpeg")
 	URL := r.FormValue("URL")
 	resp, err := http.Get(URL)
 	if err != nil {
@@ -47,9 +50,40 @@ func stream(w http.ResponseWriter, r *http.Request) {
 	img, err := ioutil.ReadAll(resp.Body)
 	defer resp.Body.Close()
 
+	// TODO async for this?
+	saveStreamInstant(URL, img)
+
 	w.Write([]byte(img))
 }
 
+func saveStreamInstant(URL string, img []byte) {
+	h := sha256.New()
+	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 := !os.IsNotExist(err)
+
+	if swap {
+		currentStreamInstantPath = filepath.Join(streamStoreDir, "next.jpg")
+	}
+	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
+		currentStreamInstantPath = filepath.Join(streamStoreDir, "current.jpg")
+
+		err = os.Rename(currentStreamInstantPath, previousStreamInstantPath)
+		err = os.Rename(nextStreamInstantPath, currentStreamInstantPath)
+	}
+}
+
 func main() {
 	staticFileServer := http.FileServer(http.Dir("./static"))
 	http.Handle("/static/", http.StripPrefix("/static/", staticFileServer))