#!/usr/bin/env python

# crawl along a hub channel, next or previous, for an arbitrary number of steps

import os

import sys

import urllib2

def hubcrawl(url, direction, num_steps):

for i in range(num_steps):

print(url)

request = urllib2.Request("%s/%s" % (url, direction[1:]))

response = urllib2.urlopen(request)

url = response.geturl()

def validate(url, direction, num_steps):

if direction != "-n" and direction != "-p":

print("%s should be either -n or -p" % direction)

sys.exit(1)

import re

r = re.compile('^[0-9]+$')

if not(r.match(num_steps)):

print("%s should be an integer" % num_steps)

sys.exit(2)

def main():

if len(sys.argv) == 4:

_, url, direction, num_steps = sys.argv

validate(url, direction, num_steps)

hubcrawl(url, direction, int(num_steps))

else:

print("Usage: ")

print(" hubcrawl http://hub/foo/2018/05/23/01/01/01/01/cxhDs -n 10")

print " or "

print(" hubcrawl http://hub/foo/2018/05/23/01/01/01/01/cxhDs -p 10")

if __name__ == '__main__':

try:

main()

except urllib2.HTTPError, KeyboardInterrupt:

try:

sys.exit(0)

except SystemExit:

os._exit(0)