thanks for your time! Im working with MFRC522-Python library, i READ the RFid Uid then i open a webbrowser with a specific url composed by the uid of each card.

    #!/usr/bin/python
import signal
import time
import sys
import os
import webbrowser
from pirc522 import RFID
#chrome = chromium-browser()

run = True
rdr = RFID()
util = rdr.util()
util.debug = True

def end_read(signal,frame):
    global run
    print("\nCtrl+C captured, ending read.")
    run = False
    rdr.cleanup()
    sys.exit()

signal.signal(signal.SIGINT, end_read)

print("Starting")
os.system('chromium-browser --app=http://localhost/ --kiosk --user-data-dir /home/pi & ')

while run:
    rdr.wait_for_tag()

    (error, data) = rdr.request()
    if not error:
        print("\nDetected: " + format(data, "02x"))

    (error, uid) = rdr.anticoll()
    if not error:
        print("Card read UID: "+str(uid[0])+","+str(uid[1])+","+str(uid[2])+","+str(uid[3]))

        print("Setting tag")
        util.set_tag(uid)
    
    os.system('chromium-browser --app=http://localhost/verperfil/rfid.php?rfid='+str(uid[0])+''+str(uid[1])+''+str(uid[2])+''+str(uid[3])+'')
        print("\nAuthorizing")
        #util.auth(rdr.auth_a, [0x12, 0x34, 0x56, 0x78, 0x96, 0x92])
        #util.auth(rdr.auth_b, [0x74, 0x00, 0x52, 0x35, 0x00, 0xFF])
        print("\nReading")
        util.read_out(4)
        print("\nDeauthorizing")
        util.deauth()

        time.sleep(1)

    pi@raspberrypi:~ $ python /var/www/html/pi-rc522/examples/asigna.py
Traceback (most recent call last):
  File "/var/www/html/pi-rc522/examples/asigna.py", line 11, in <module>
    rdr = RFID()
  File "build/bdist.linux-armv7l/egg/pirc522/rfid.py", line 78, in __init__
RuntimeError: No access to /dev/mem.  Try running as root!
pi@raspberrypi:~ $

    sudo python /var/www/html/pi-rc522/examples/asigna.py
/usr/local/lib/python2.7/dist-packages/pi_rc522-2.2.1-py2.7.egg/pirc522/rfid.py:78: RuntimeWarning: This channel is already in use, continuing anyway.  Use GPIO.setwarnings(False) to disable warnings.
Starting
--user-data-dir --disable-quic --enable-tcp-fast-open --ppapi-flash-path=/usr/lib/chromium-browser/libpepflashplayer.so --ppapi-flash-args=enable_stagevideo_auto=0 --ppapi-flash-version=
No protocol specified
[4692:4692:0807/011632.383841:ERROR:browser_main_loop.cc(596)] Failed to put Xlib into threaded mode.
No protocol specified

(chromium-browser-v7:4692): Gtk-WARNING **: 01:16:32.388: cannot open display: :10.0

HELP!! I NEED to open the chrome browser xD

Thanksss

Im working with MFRC522-Python library, I READ the RFid Uid then I open a webbrowser with a specific URL composed by the uid of each card.

#!/usr/bin/python
import signal
import time
import sys
import os
import webbrowser
from pirc522 import RFID
#chrome = chromium-browser()

run = True
rdr = RFID()
util = rdr.util()
util.debug = True

def end_read(signal,frame):
    global run
    print("\nCtrl+C captured, ending read.")
    run = False
    rdr.cleanup()
    sys.exit()

signal.signal(signal.SIGINT, end_read)

print("Starting")
os.system('chromium-browser --app=http://localhost/ --kiosk --user-data-dir /home/pi & ')

while run:
    rdr.wait_for_tag()

    (error, data) = rdr.request()
    if not error:
        print("\nDetected: " + format(data, "02x"))

    (error, uid) = rdr.anticoll()
    if not error:
        print("Card read UID: "+str(uid[0])+","+str(uid[1])+","+str(uid[2])+","+str(uid[3]))

        print("Setting tag")
        util.set_tag(uid)
    
    os.system('chromium-browser --app=http://localhost/verperfil/rfid.php?rfid='+str(uid[0])+''+str(uid[1])+''+str(uid[2])+''+str(uid[3])+'')
        print("\nAuthorizing")
        #util.auth(rdr.auth_a, [0x12, 0x34, 0x56, 0x78, 0x96, 0x92])
        #util.auth(rdr.auth_b, [0x74, 0x00, 0x52, 0x35, 0x00, 0xFF])
        print("\nReading")
        util.read_out(4)
        print("\nDeauthorizing")
        util.deauth()

        time.sleep(1)

pi@raspberrypi:~ $ python /var/www/html/pi-rc522/examples/asigna.py
Traceback (most recent call last):
  File "/var/www/html/pi-rc522/examples/asigna.py", line 11, in <module>
    rdr = RFID()
  File "build/bdist.linux-armv7l/egg/pirc522/rfid.py", line 78, in __init__
RuntimeError: No access to /dev/mem.  Try running as root!
pi@raspberrypi:~ $

sudo python /var/www/html/pi-rc522/examples/asigna.py
/usr/local/lib/python2.7/dist-packages/pi_rc522-2.2.1-py2.7.egg/pirc522/rfid.py:78: RuntimeWarning: This channel is already in use, continuing anyway.  Use GPIO.setwarnings(False) to disable warnings.
Starting
--user-data-dir --disable-quic --enable-tcp-fast-open --ppapi-flash-path=/usr/lib/chromium-browser/libpepflashplayer.so --ppapi-flash-args=enable_stagevideo_auto=0 --ppapi-flash-version=
No protocol specified
[4692:4692:0807/011632.383841:ERROR:browser_main_loop.cc(596)] Failed to put Xlib into threaded mode.
No protocol specified

(chromium-browser-v7:4692): Gtk-WARNING **: 01:16:32.388: cannot open display: :10.0