scanner.py 0.7 Bob Blanchett (c) 2021

pre-requisites: 
vt-py 		VirusTotal API Python client Library
validators 	Validates conformant IP addresses, URL and FQDN
  both installed from PyPI with pip or your favourite tarball.

My Virus Total Public API key is included in the script. 
    please handle carefully.

Note that ONLY valid URLs are submitted to VT in this release
to keep the code brief to the limits specified for the marker.

BUGS: known bug is an error case with argparse.
usage is delivered twice in one error case.
the problem appears to be with subparsers rendering of usage
and further errors.eg: FileNotFound.
I have not been able to fix these.

I suspect it may be related to:
https://bugs.python.org/issue42297
[argparse] Bad error message formatting when using custom usage text

The VT API has unique API endpoints for each case, which would
increase code markedly, so I decided to handle only URLs.
API Ref: https://virustotal.github.io/vt-py/index.html

Validators was chosen as Python stdlib only included batteries for 
IP addresses
https://validators.readthedocs.io/en/latest/index.html

Included in this submission are several example test datafiles for testing
TEST1.TXT 
TEST2.TXT
MIXEDDATA.TXT
(you'll infer from the files that I have been working on querying filehashes,
domains and IPv4 and IPv6 addresses, which were not possible to implement
within the limits imposed)

and a simple test harness I used during development, TESTER.BAT

The Data in there was primarily obtained from 
spamhaus.de, blocklist.de,scumware.org.

The EICAR (European Institute for Computer Anti-Virus Research) eicar.org
Anti Virus test file is also included as a test of hashlib
 for future implementation.

The script creates a text file ".scanrc" 
which keeps a vestige of State across executions but will be used
 to store details od each run.

# TODO: work below removed to get minimum working code ~150 loc
# 
# handle and locate .scanrc in the home directory in a crossplatform way
# option to handle data rejected from the filters & processing buckets
#    noisily (currently silent) 
# include submission of IP addresss, domains and filehashes.
# sensible runtime debugging and verbosity options
# filter enable this script allowing stdin for scanning
# json, csv and IFS delimited output.
# add subparsers for unimplemented subcommands: list (previous runs etc
# shutdown (handle KeyboardInterrupt Ctrl-C interrupt during scan)
# import hashlib  to submit file hashes for checking.
# pull more detail from the API response object
#   it is an Aladdin's Cave: 
#    \https://developers.virustotal.com/v3.0/reference#url-object
# catch ModuleNotFoundError cleanly module imports of non-stdlib (vt, validators)
# import subprocess to do in-script pip installation of pypi libs on ModuleNotFoundError
# record detailed run information in .scanrc with configparser
#    (a format easily-albeit verbosely programatically accessible via stdlib.)