Attempt to add some basic caching of tag details to tikitag

pytikitag/tikitag.py

@@ -4,15 +4,39 @@ from smartcard.util import toHexString, toASCIIString
 
 class TikiTag(mifareul.MiFareUltralight):
 
+    _tag = None
+    _uid = None
+
     def get_uid(self):
+    
             d = self.read_block(0)
             d = d+ self.read_block(1)        
+            
+            uid = toHexString(d).replace(" ", "")[:16]
 
-            return toHexString(d).replace(" ", "")[:16]
+            return uid
+    
+    def _check_uid(self):
+        uid = self.get_uid()
+        if (not self._uid == uid):
+            self._tag = None
+            self._uid = uid  
+            return False
+        else:
+            return True  
             
     def get_tag_url(self):
+        """ Retreives the tag's URL stored in NDEF format """
         
-        self._tag = type2.NFCType2(self.read_tag())
+        # The tikitag usually has a single NDEF with a single URI record type
+        # so assumptions can be made here.
+        
+        self._check_uid()
+               
+        if not self._tag:
+            d = self.read_tag()
+            self._tag = type2.NFCType2(d)
+    
         return self._tag.ndefs[0].items[0][1]
         
         

test.py

@@ -3,6 +3,7 @@ import logging, sys
 from pytikitag import reader, tikitag
 from pytikitag.nfc import type2
 from smartcard.util import toHexString, toASCIIString
+import time
 
 log = logging.getLogger('pytikitag.mifareul')
 h = logging.StreamHandler(sys.stdout)
@@ -15,9 +16,12 @@ print "Tikitag ID: " + m.get_uid()
 print "Manf: " + m.get_manf_ascii() + ", Serial: " + m.get_serial()
 print ""
 print "Reading Tikitag Data..."
-print m.get_tag_url()
 
-#tag = type2.NFCType2(d)
-#print tag.ndefs[0].items
-#print toHexString(value)
-#print toASCIIString(value)
+i = 0
+
+try:
+    while not i == 1:
+        print m.get_tag_url()
+        time.sleep(1)
+except KeyboardInterrupt:
+    pass