python-teos/cli/teos_cli.py

import os
import sys
import time
import json
import requests
from sys import argv
from uuid import uuid4
from coincurve import PublicKey
from getopt import getopt, GetoptError
from requests import ConnectTimeout, ConnectionError
from requests.exceptions import MissingSchema, InvalidSchema, InvalidURL

from cli.help import show_usage, help_add_appointment, help_get_appointment
from cli import DEFAULT_CONF, DATA_DIR, CONF_FILE_NAME, LOG_PREFIX

import common.cryptographer
from common.blob import Blob
from common import constants
from common.logger import Logger
from common.appointment import Appointment
from common.config_loader import ConfigLoader
from common.cryptographer import Cryptographer
from common.tools import setup_logging, setup_data_folder
from common.tools import check_sha256_hex_format, check_locator_format, compute_locator, check_compressed_pk_format

logger = Logger(actor="Client", log_name_prefix=LOG_PREFIX)
common.cryptographer.logger = Logger(actor="Cryptographer", log_name_prefix=LOG_PREFIX)


def register(compressed_pk, teos_url):
    if not check_compressed_pk_format(compressed_pk):
        logger.error("The cli public key is not valid")
        return None

    # Send request to the server.
    register_endpoint = "{}/register".format(teos_url)
    data = {"public_key": compressed_pk}

    logger.info("Registering in the Eye of Satoshi")
    server_response = post_request(data, register_endpoint)
    if server_response:
        response_json = process_post_response(server_response)
        return response_json


def add_appointment(appointment_data, cli_sk, teos_pk, teos_url, appointments_folder_path):
    """
    Manages the add_appointment command, from argument parsing, trough sending the appointment to the tower, until
    saving the appointment receipt.

    The life cycle of the function is as follows:
        - Check that the given commitment_txid is correct (proper format and not missing)
        - Check that the transaction is correct (not missing)
        - Create the appointment locator and encrypted blob from the commitment_txid and the penalty_tx
        - Sign the appointment
        - Send the appointment to the tower
        - Wait for the response
        - Check the tower's response and signature
        - Store the receipt (appointment + signature) on disk

    If any of the above-mentioned steps fails, the method returns false, otherwise it returns true.

    Args:
        appointment_data (:obj:`dict`): a dictionary containing the appointment data.
        cli_sk (:obj:`PrivateKey`): the client's private key.
        teos_pk (:obj:`PublicKey`): the tower's public key.
        teos_url (:obj:`str`): the teos base url.
        appointments_folder_path (:obj:`str`): the path to the appointments folder.


    Returns:
        :obj:`bool`: True if the appointment is accepted by the tower and the receipt is properly stored, false if any
        error occurs during the process.
    """

    if appointment_data is None:
        logger.error("The provided appointment JSON is empty")
        return False

    if not check_sha256_hex_format(appointment_data.get("tx_id")):
        logger.error("The provided txid is not valid")
        return False

    tx_id = appointment_data.get("tx_id")
    tx = appointment_data.get("tx")

    if None not in [tx_id, tx]:
        appointment_data["locator"] = compute_locator(tx_id)
        appointment_data["encrypted_blob"] = Cryptographer.encrypt(Blob(tx), tx_id)

    else:
        logger.error("Appointment data is missing some fields")
        return False

    appointment = Appointment.from_dict(appointment_data)
    signature = Cryptographer.sign(appointment.serialize(), cli_sk)

    if not (appointment and signature):
        return False

    data = {"appointment": appointment.to_dict(), "signature": signature}

    # Send appointment to the server.
    add_appointment_endpoint = "{}/add_appointment".format(teos_url)
    logger.info("Sending appointment to the Eye of Satoshi")
    server_response = post_request(data, add_appointment_endpoint)
    if server_response is None:
        return False

    response_json = process_post_response(server_response)

    if response_json is None:
        return False

    signature = response_json.get("signature")
    # Check that the server signed the appointment as it should.
    if signature is None:
        logger.error("The response does not contain the signature of the appointment")
        return False

    rpk = Cryptographer.recover_pk(appointment.serialize(), signature)
    if not Cryptographer.verify_rpk(teos_pk, rpk):
        logger.error("The returned appointment's signature is invalid")
        return False

    logger.info("Appointment accepted and signed by the Eye of Satoshi")
    logger.info("Remaining slots: {}".format(response_json.get("available_slots")))

    # All good, store appointment and signature
    return save_appointment_receipt(appointment.to_dict(), signature, appointments_folder_path)


def get_appointment(locator, cli_sk, teos_pk, teos_url):
    """
    Gets information about an appointment from the tower.

    Args:
        locator (:obj:`str`): the appointment locator used to identify it.
        cli_sk (:obj:`PrivateKey`): the client's private key.
        teos_pk (:obj:`PublicKey`): the tower's public key.
        teos_url (:obj:`str`): the teos base url.

    Returns:
        :obj:`dict` or :obj:`None`: a dictionary containing thew appointment data if the locator is valid and the tower
        responds. ``None`` otherwise.
    """

    # FIXME: All responses from the tower should be signed. Not using teos_pk atm.

    valid_locator = check_locator_format(locator)

    if not valid_locator:
        logger.error("The provided locator is not valid", locator=locator)
        return None

    message = "get appointment {}".format(locator)
    signature = Cryptographer.sign(message.encode(), cli_sk)
    data = {"locator": locator, "signature": signature}

    # Send request to the server.
    get_appointment_endpoint = "{}/get_appointment".format(teos_url)
    logger.info("Sending appointment to the Eye of Satoshi")
    server_response = post_request(data, get_appointment_endpoint)
    response_json = process_post_response(server_response)

    return response_json


def load_keys(teos_pk_path, cli_sk_path, cli_pk_path):
    """
    Loads all the keys required so sign, send, and verify the appointment.

    Args:
        teos_pk_path (:obj:`str`): path to the TEOS public key file.
        cli_sk_path (:obj:`str`): path to the client private key file.
        cli_pk_path (:obj:`str`): path to the client public key file.

    Returns:
        :obj:`tuple` or ``None``: a three item tuple containing a teos_pk object, cli_sk object and the cli_sk_der
        encoded key if all keys can be loaded. ``None`` otherwise.
    """

    if teos_pk_path is None:
        logger.error("TEOS's public key file not found. Please check your settings")
        return None

    if cli_sk_path is None:
        logger.error("Client's private key file not found. Please check your settings")
        return None

    if cli_pk_path is None:
        logger.error("Client's public key file not found. Please check your settings")
        return None

    try:
        teos_pk_der = Cryptographer.load_key_file(teos_pk_path)
        teos_pk = PublicKey(teos_pk_der)

    except ValueError:
        logger.error("TEOS public key is invalid or cannot be parsed")
        return None

    cli_sk_der = Cryptographer.load_key_file(cli_sk_path)
    cli_sk = Cryptographer.load_private_key_der(cli_sk_der)

    if cli_sk is None:
        logger.error("Client private key is invalid or cannot be parsed")
        return None

    try:
        cli_pk_der = Cryptographer.load_key_file(cli_pk_path)
        compressed_cli_pk = Cryptographer.get_compressed_pk(PublicKey(cli_pk_der))

    except ValueError:
        logger.error("Client public key is invalid or cannot be parsed")
        return None

    return teos_pk, cli_sk, compressed_cli_pk


def post_request(data, endpoint):
    """
    Sends a post request to the tower.

    Args:
        data (:obj:`dict`): a dictionary containing the data to be posted.
        endpoint (:obj:`str`): the endpoint to send the post request.

    Returns:
        :obj:`dict` or ``None``: a json-encoded dictionary with the server response if the data can be posted.
        None otherwise.
    """

    try:
        return requests.post(url=endpoint, json=data, timeout=5)

    except ConnectTimeout:
        logger.error("Can't connect to the Eye of Satoshi's API. Connection timeout")

    except ConnectionError:
        logger.error("Can't connect to the Eye of Satoshi's API. Server cannot be reached")

    except (InvalidSchema, MissingSchema, InvalidURL):
        logger.error("Invalid URL. No schema, or invalid schema, found ({})".format(endpoint))

    except requests.exceptions.Timeout:
        logger.error("The request timed out")

    return None


def process_post_response(response):
    """
    Processes the server response to an post request.

    Args:
        response (:obj:`requests.models.Response`): a ``Response`` object obtained from the sent request.

    Returns:
        :obj:`dict` or :obj:`None`: a dictionary containing the tower's response data if it can be properly parsed and
        the response type is ``HTTP_OK``. ``None`` otherwise.
    """

    if not response:
        return None

    try:
        response_json = response.json()

    except (json.JSONDecodeError, AttributeError):
        logger.error(
            "The server returned a non-JSON response", status_code=response.status_code, reason=response.reason
        )
        return None

    if response.status_code != constants.HTTP_OK:
        logger.error(
            "The server returned an error", status_code=response.status_code, reason=response.reason, data=response_json
        )
        return None

    return response_json


def parse_add_appointment_args(args):
    """
    Parses the arguments of the add_appointment command.

    Args:
        args (:obj:`list`): a list of arguments to pass to ``parse_add_appointment_args``. Must contain a json encoded
            appointment, or the file option and the path to a file containing a json encoded appointment.

    Returns:
        :obj:`dict` or :obj:`None`: A dictionary containing the appointment data if it can be loaded. ``None``
        otherwise.
    """

    use_help = "Use 'help add_appointment' for help of how to use the command"

    if not args:
        logger.error("No appointment data provided. " + use_help)
        return None

    arg_opt = args.pop(0)

    try:
        if arg_opt in ["-h", "--help"]:
            sys.exit(help_add_appointment())

        if arg_opt in ["-f", "--file"]:
            fin = args.pop(0)
            if not os.path.isfile(fin):
                logger.error("Can't find file", filename=fin)
                return None

            try:
                with open(fin) as f:
                    appointment_data = json.load(f)

            except IOError as e:
                logger.error("I/O error", errno=e.errno, error=e.strerror)
                return None
        else:
            appointment_data = json.loads(arg_opt)

    except json.JSONDecodeError:
        logger.error("Non-JSON encoded data provided as appointment. " + use_help)
        return None

    return appointment_data


def save_appointment_receipt(appointment, signature, appointments_folder_path):
    """
    Saves an appointment receipt to disk. A receipt consists in an appointment and a signature from the tower.

    Args:
        appointment (:obj:`Appointment <common.appointment.Appointment>`): the appointment to be saved on disk.
        signature (:obj:`str`): the signature of the appointment performed by the tower.
        appointments_folder_path (:obj:`str`): the path to the appointments folder.

    Returns:
        :obj:`bool`: True if the appointment if properly saved, false otherwise.

    Raises:
        IOError: if an error occurs whilst writing the file on disk.
    """

    # Create the appointments directory if it doesn't already exist
    os.makedirs(appointments_folder_path, exist_ok=True)

    timestamp = int(time.time())
    locator = appointment["locator"]
    uuid = uuid4().hex  # prevent filename collisions

    filename = "{}/appointment-{}-{}-{}.json".format(appointments_folder_path, timestamp, locator, uuid)
    data = {"appointment": appointment, "signature": signature}

    try:
        with open(filename, "w") as f:
            json.dump(data, f)
            logger.info("Appointment saved at {}".format(filename))
            return True

    except IOError as e:
        logger.error("There was an error while saving the appointment", error=e)
        return False


def main(args, command_line_conf):
    # Loads config and sets up the data folder and log file
    config_loader = ConfigLoader(DATA_DIR, CONF_FILE_NAME, DEFAULT_CONF, command_line_conf)
    config = config_loader.build_config()

    setup_data_folder(DATA_DIR)
    setup_logging(config.get("LOG_FILE"), LOG_PREFIX)

    # Set the teos url
    teos_url = "{}:{}".format(config.get("TEOS_SERVER"), config.get("TEOS_PORT"))
    # If an http or https prefix if found, leaves the server as is. Otherwise defaults to http.
    if not teos_url.startswith("http"):
        teos_url = "http://" + teos_url

    keys = load_keys(config.get("TEOS_PUBLIC_KEY"), config.get("CLI_PRIVATE_KEY"), config.get("CLI_PUBLIC_KEY"))
    if keys is not None:
        teos_pk, cli_sk, compressed_cli_pk = keys

        try:
            if args:
                command = args.pop(0)

                if command in commands:
                    if command == "register":
                        register_data = register(compress_cli_pk, teos_url)
                        if register_data:
                            print(register_data)

                    if command == "add_appointment":
                        # Get appointment data from user.
                        appointment_data = parse_add_appointment_args(args)
                        add_appointment(
                            appointment_data, cli_sk, teos_pk, teos_url, config.get("APPOINTMENTS_FOLDER_NAME")
                        )

                    elif command == "get_appointment":
                        if not args:
                            logger.error("No arguments were given")

                        else:
                            arg_opt = args.pop(0)

                            if arg_opt in ["-h", "--help"]:
                                sys.exit(help_get_appointment())

                            appointment_data = get_appointment(arg_opt, cli_sk, teos_pk, teos_url)
                            if appointment_data:
                                print(appointment_data)

                    elif command == "help":
                        if args:
                            command = args.pop(0)

                            if command == "add_appointment":
                                sys.exit(help_add_appointment())

                            elif command == "get_appointment":
                                sys.exit(help_get_appointment())

                            else:
                                logger.error("Unknown command. Use help to check the list of available commands")

                        else:
                            sys.exit(show_usage())

                else:
                    logger.error("Unknown command. Use help to check the list of available commands")

            else:
                logger.error("No command provided. Use help to check the list of available commands")

        except json.JSONDecodeError:
            logger.error("Non-JSON encoded appointment passed as parameter")


if __name__ == "__main__":
    command_line_conf = {}
    commands = ["register", "add_appointment", "get_appointment", "help"]

    try:
        opts, args = getopt(argv[1:], "s:p:h", ["server", "port", "help"])

        for opt, arg in opts:
            if opt in ["-s", "--server"]:
                if arg:
                    command_line_conf["TEOS_SERVER"] = arg

            if opt in ["-p", "--port"]:
                if arg:
                    try:
                        command_line_conf["TEOS_PORT"] = int(arg)
                    except ValueError:
                        sys.exit("port must be an integer")

            if opt in ["-h", "--help"]:
                sys.exit(show_usage())

        main(args, command_line_conf)

    except GetoptError as e:
        logger.error("{}".format(e))