gst.py

import requests

base_url = 'https://gst.customs.gov.my/TAP'
s = requests.session()

# STEP 1
response = s.get('%s/GetWlbToken' % base_url)
print response.headers
token = response.headers['fast-ver-last']

# STEP 2
data = {
    'Load': 1,
    'FAST_VERLAST__': token,
}
response = s.get('%s/_/' % base_url, data=data)
token = response.headers['fast-ver-last']
print response.cookies
print response.content

# STEP 3
data = {
    'DOC_MODAL_ID__': 0,
    'EVENT__': 'b-i',
    'FAST_VERLAST__': token,
}
response = s.post('%s/EventOccured' % base_url, data=data)
token = response.headers['fast-ver-last']

# STEP 4
data = {
    'd-3': 'true', # gst number
    'DOC_MODAL_ID__': 0,
}
response = s.post('https://gst.customs.gov.my/TAP/_/Recalc', data)
token = response.headers['fast-ver-last']

# STEP 5
data = {
    #'d-5': '001784889344',
    'd-5': '000176275456',
    'FAST_VERLAST__': token,
    'DOC_MODAL_ID__': 0,
}
response = s.post('https://gst.customs.gov.my/TAP/_/Recalc', data)
print response.headers
print response.content

import pdb;pdb.set_trace()