1 files changed, 14 insertions, 0 deletions
diff --git a/storage.go b/storage.go
index ec2d33e..22a226d 100644
--- a/storage.go
+++ b/storage.go
@@ -3,9 +3,11 @@ package main
 import (
 	"crypto/sha1"
 	"encoding/hex"
+	"errors"
 	"io/ioutil"
 	"net/http"
 	"os"
+	"regexp"
 	"sort"
 )
 
@@ -13,6 +15,10 @@ type Storage struct {
 	Path string
 }
 
+var (
+	tokenPattern = regexp.MustCompile(`[a-fA-F0-9]{10,}`)
+)
+
 func (s *Storage) MustInit() error {
 	os.Mkdir(s.Path, 0755)
 	os.Mkdir(s.Path+"/battles", 0755)
@@ -20,6 +26,14 @@ func (s *Storage) MustInit() error {
 	return nil
 }
 
+func (s *Storage) CanPost(token string) (bool, error) {
+	if !tokenPattern.MatchString(token) {
+		return false, errors.New("invalid token")
+	}
+	_, err := os.Stat(s.Path + "/tokens/" + token)
+	return err == nil, nil
+}
+
 func (s *Storage) AddBattle(data []byte) (string, error) {
 	hash := sha1.Sum(data)
 	id := hex.EncodeToString(hash[:])