[json_rows.py] #python #json #json_rows #cache

json_rows.py

#!/usr/bin/env python

import datetime
import json


#######################################################################################################################
def replace_suffix(s, suffix, replace):
    """
    replace suffix if exists
    :param s: str
    :param suffix: str
    :param replace: str
    :return: str
    >>> replace_suffix('file.JPG', '.JPG', '.jpeg')
    'file.jpeg'
    >>> replace_suffix('file.txt', '.JPG', '.jpeg')
    'file.txt'
    """
    if s.endswith(suffix):
        return s[:-len(suffix)] + replace
    else:
        return s


#######################################################################################################################
def json_serial(obj):
    """JSON serializer for objects not serializable by default json code"""
    if isinstance(obj, (datetime.datetime, datetime.date)):
        return obj.isoformat()
    raise TypeError("Type %s not serializable" % type(obj))


def json_unserial(data):
    key = 'created_at'
    dt = data.get(key, None)
    if dt is not None:
        data[key] = datetime.datetime.fromisoformat(dt)
    return data


def jsr_cache_filename():
    return replace_suffix(__file__, '.py', '.cache.jsonrows')


def jsr_json_params():
    return dict(ensure_ascii=False, default=json_serial)


def jsr_rows_iterator(filename):
    for ln in open(filename, encoding='utf8').readlines():
        ln = ln.strip()
        if ln:
            data = json.loads(ln)
            data = json_unserial(data)
            yield data


def jsr_append(filename, data):
    with open(filename, 'a', encoding='utf8') as f:
        data = json.dumps(data, **jsr_json_params())
        f.write(data)
        f.write('\n')


def jsr_dump(filename):
    for data in jsr_rows_iterator(filename):
        print(data)