utilities.py

import time
import datetime
import json
import random
import string
import hashlib
from pathlib import Path


def random_string(length):
    """return a random string."""
    alphabet = string.ascii_lowercase+string.ascii_uppercase
    return "".join([random.choice(alphabet) for i in range(0, length)])


def human_timestamp(now=None):
    """Return a human readable timestamp."""
    if now is None:
        now = time.time()
    local_time = time.localtime(now)
    return time.strftime("%Z - %A  %Y/%B/%d, %H:%M:%S", local_time)


def json_serial(obj):
    """Serialize the datetime."""
    if isinstance(obj, datetime.datetime):
        timestamp = obj.timestamp()
        return human_timestamp(timestamp)
    return str(obj)


def read_json_file(json_path, default=None):
    """
    Return the given json file as dictionary.

    @param {string} `json_path`
    @return {dictionary}
    """
    json_path = Path(json_path)
    if not json_path.is_file():
        if default is None:
            raise ValueError(f"You try to read {json_path}. "
                             f"The file does not exist and you "
                             f"furnished no default.")
        return default
    with open(json_path, 'r') as json_data:
        try:
            answer = json.load(json_data)
        except json.decoder.JSONDecodeError as err:
            print("JSONDecodeError:", err)
            message = f"Json error in {json_path}:\n {err}"
            raise ValueError(message) from err
    return answer


def json_to_str(json_dict, pretty=False, default=None):
    """Return a string representation of the given json."""
    if pretty:
        return json.dumps(json_dict,
                          sort_keys=True,
                          indent=4,
                          default=json_serial)
    return json.dumps(json_dict, default=default)


def write_json_file(json_dict,
                    filename,
                    pretty=False,
                    default=None):
    """Write the dictionary in the given file."""
    my_str = json_to_str(json_dict, pretty=pretty, default=default)
    with open(filename, 'w') as json_file:
        json_file.write(my_str)


def text_hash(text):
    """Return a hash of a text."""
    m = hashlib.sha256()
    b_text = text.encode("utf8")
    m.update(b_text)
    return m.hexdigest()