cic-cli/cic/proof.py

# standard imports
import os
import json
import logging
import tempfile
import cbor2

# external imports
from hexathon import strip_0x

# local imports
from .base import *

logg = logging.getLogger(__name__)


class Proof(Data):

    def __init__(self, path='.', attachments=None, writer=None):
        super(Proof, self).__init__()
        self.namespace = 'ge'
        self.description = None
        self.path = path
        self.writer = writer
        self.extra_attachments = attachments
        self.attachments = {}
        self.proof_path = os.path.join(self.path, 'proof.json')
        self.temp_proof_path = tempfile.mkstemp()[1]
                

    def load(self):
        super(Proof, self).load()

        f = open(self.proof_path, 'r')
        o = json.load(f)
        f.close()

        self.set_version(o['version'])
        self.description = o['description']
        self.namespace = o['namespace']
        self.issuer = o['issuer']

        self.inited = True


    def start(self):
        super(Proof, self).start()

        proof_template_file_path = os.path.join(data_dir, 'proof_template_v{}.json'.format(self.version()))
        
        f = open(proof_template_file_path)
        o = json.load(f)
        f.close() 
       
        f = open(self.proof_path, 'w')
        json.dump(o, f, sort_keys=True, indent="\t")
        f.close()


    def asdict(self):
        return {
            'version': self.version(),
            'namespace': self.namespace,
            'description': self.description,
            'issuer': self.issuer,
                }


    def __get_ordered_hashes(self):
        ks = list(self.attachments.keys())
        ks.sort()

        return ks


    def get(self):
        v = self.asdict() 
        b = cbor2.dumps(v)

        f = open(self.temp_proof_path, 'wb')
        f.write(b)
        f.close()

        hsh = self.hash(b).hex()
        self.attachments[hsh] = self.temp_proof_path
        logg.debug('cbor of {} is {} hashes to {}'.format(v, b.hex(), hsh))

        if self.extra_attachments != None:
            a = self.extra_attachments.asdict()
            for k in a.keys():
                self.attachments[k] = a[k]

        hshs = self.__get_ordered_hashes()

        return (hsh, hshs)


    def process(self, token_address=None, writer=None):
        if writer == None:
            writer = self.writer

        (hsh, hshs) = self.get()
        hshs = list(map(strip_0x, hshs))
        hshs_bin = list(map(bytes.fromhex, hshs))
        hshs_cat = b''.join(hshs_bin)

        f = open(self.temp_proof_path, 'rb')
        v = f.read()
        f.close()
        writer.write(hsh, v)

        r = self.hash(hshs_cat)
        r_hex = r.hex()

        logg.debug('generated proof {} for hashes {}'.format(r_hex, hshs))

        writer.write(r_hex, hshs_cat)
        
        return r_hex


    def __str__(self):
        return "description = {}\n".format(self.description)