updates

Former-commit-id: 9c36dea485ddd16a90f0a615e20baddaee6b9cde

http_checksum.go

@@ -0,0 +1,50 @@
+package filemanager
+
+import (
+	"crypto/md5"
+	"crypto/sha1"
+	"crypto/sha256"
+	"crypto/sha512"
+	"encoding/hex"
+	e "errors"
+	"hash"
+	"io"
+	"net/http"
+	"os"
+)
+
+// checksum calculates the hash of a file. Supports MD5, SHA1, SHA256 and SHA512.
+func checksum(w http.ResponseWriter, r *http.Request, i *FileInfo) (int, error) {
+	query := r.URL.Query().Get("checksum")
+
+	file, err := os.Open(i.Path)
+	if err != nil {
+		return errorToHTTP(err, true), err
+	}
+
+	defer file.Close()
+
+	var h hash.Hash
+
+	switch query {
+	case "md5":
+		h = md5.New()
+	case "sha1":
+		h = sha1.New()
+	case "sha256":
+		h = sha256.New()
+	case "sha512":
+		h = sha512.New()
+	default:
+		return http.StatusBadRequest, e.New("Unknown HASH type")
+	}
+
+	_, err = io.Copy(h, file)
+	if err != nil {
+		return http.StatusInternalServerError, err
+	}
+
+	val := hex.EncodeToString(h.Sum(nil))
+	w.Write([]byte(val))
+	return http.StatusOK, nil
+}