dkl-store

cmd/dkl-store/main.go

@@ -0,0 +1,134 @@
+package main
+
+import (
+	"crypto/sha1"
+	"encoding/hex"
+	"flag"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+var (
+	bind        = flag.String("bind", ":8080", "Bind address")
+	uploadToken = flag.String("upload-token", "", "Upload token (not uploads allowed if empty)")
+	storeDir    = flag.String("store-dir", "/srv/dkl-store", "Store directory")
+)
+
+func main() {
+	flag.Parse()
+
+	http.HandleFunc("/", handleHTTP)
+
+	log.Print("listening on ", *bind)
+	http.ListenAndServe(*bind, nil)
+}
+
+func handleHTTP(w http.ResponseWriter, req *http.Request) {
+	filePath := filepath.Join(*storeDir, req.URL.Path)
+
+	stat, err := os.Stat(filePath)
+	if err != nil {
+		writeErr(err, w)
+		return
+	}
+
+	if stat.Mode().IsDir() {
+		http.NotFound(w, req)
+		return
+	}
+
+	l := fmt.Sprintf("%s %s", req.Method, filePath)
+	log.Print(l)
+	defer log.Print(l, " done")
+
+	switch req.Method {
+	case "GET":
+		sha1Hex, err := hashOf(filePath)
+		if err != nil {
+			writeErr(err, w)
+			return
+		}
+
+		w.Header().Set("X-Content-SHA1", sha1Hex)
+		http.ServeFile(w, req, filePath)
+
+	//case "POST":
+	//	// TODO upload
+
+	default:
+		http.NotFound(w, req)
+		return
+	}
+}
+
+func writeErr(err error, w http.ResponseWriter) {
+	if os.IsNotExist(err) {
+		w.WriteHeader(http.StatusNotFound)
+		w.Write([]byte("Not found\n"))
+		return
+	}
+
+	log.Print("internal error: ", err)
+	w.WriteHeader(http.StatusInternalServerError)
+	w.Write([]byte("Internal error\n"))
+}
+
+func hashOf(filePath string) (sha1Hex string, err error) {
+	sha1Path := filePath + ".sha1"
+
+	fileStat, err := os.Stat(filePath)
+	if err != nil {
+		return
+	}
+
+	sha1Stat, err := os.Stat(sha1Path)
+
+	if err == nil {
+		if sha1Stat.ModTime().After(fileStat.ModTime()) {
+			// cached value is up-to-date
+			sha1HexBytes, readErr := ioutil.ReadFile(sha1Path)
+
+			if readErr == nil {
+				sha1Hex = string(sha1HexBytes)
+				return
+			}
+		}
+	} else if !os.IsNotExist(err) {
+		// failed to stat cached value
+		return
+	}
+
+	// no cached value could be read
+	log.Print("hashing ", filePath)
+	start := time.Now()
+
+	// hash the input
+	f, err := os.Open(filePath)
+	if err != nil {
+		return
+	}
+
+	defer f.Close()
+
+	h := sha1.New()
+	_, err = io.Copy(h, f)
+	if err != nil {
+		return
+	}
+
+	sha1Hex = hex.EncodeToString(h.Sum(nil))
+
+	log.Print("hashing ", filePath, " took ", time.Since(start).Truncate(time.Millisecond))
+
+	if writeErr := ioutil.WriteFile(sha1Path, []byte(sha1Hex), 0644); writeErr != nil {
+		log.Printf("WARNING: failed to cache SHA1: %v", writeErr)
+	}
+
+	return
+}