python3pickledb.py

#!/usr/bin/env python
# -*- coding: utf8 -*-

# Copyright (c) 2011, Harrison Erd
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without modification,
# are permitted provided that the following conditions are met:
#
# Redistributions of source code must retain the above copyright notice, this
# list of conditions and the following disclaimer.
# Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
# Neither the name of the Harrison Erd nor the names of its contributors
# may be used to endorse or promote products derived from this software
# without specific prior written permission.
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "
# AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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# THE POSSIBILITY OF SUCH DAMAGE.

import os
import json
import io

"""
This version of pickleDB is has not been tested. It should only be used for
testing or development. It was made to work with Python 3.x. There have been
some issues with Python 2.x. python3pickledb.py written by olivierlemoal.
Please report issues to bitbucket (patx/pickledb).
"""

def load(location, option):
    '''Return a pickledb object. location is the path to the json file.'''
    return pickledb(location, option)


class pickledb(object):

    def __init__(self, location, option):
        '''Creates a database object and loads the data from the location path.
        If the file does not exist it will be created on the first update.'''
        self.load(location, option)

    def load(self, location, option):
        '''Loads, reloads or changes the path to the db file.
        DO NOT USE this method has it may be deprecated in the future.'''
        location = os.path.expanduser(location)
        self.loco = location
        self.fsave = option
        if os.path.exists(location):
            self._loaddb()
        else:
            self.db = {}
        return True

    def dump(self):
        '''Force dump memory db to file.'''
        self._dumpdb(True)
        return True

    def set(self, key, value):
        '''Set the (string,int,whatever) value of a key'''
        self.db[key] = value
        self._dumpdb(self.fsave)
        return True

    def get(self, key):
        '''Get the value of a key'''
        try:
            return self.db[key]
        except KeyError:
            return None

    def getall(self):
        '''Return a list of all keys in db'''
        return self.db.keys()

    def rem(self, key):
        '''Delete a key'''
        del self.db[key]
        self._dumpdb(self.fsave)
        return True

    def lcreate(self, name):
        '''Create a list'''
        self.db[name] = []
        self._dumpdb(self.fsave)
        return True

    def ladd(self, name, value):
        '''Add a value to a list'''
        self.db[name].append(value)
        self._dumpdb(self.fsave)
        return True

    def lgetall(self, name):
        '''Return all values in a list'''
        return self.db[name]

    def lget(self, name, pos):
        '''Return one value in a list'''
        return self.db[name][pos]

    def lrem(self, name):
        '''Remove a list and all of its values'''
        number = len(self.db[name])
        del self.db[name]
        self._dumpdb(self.fsave)
        return number

    def lpop(self, name, pos):
        '''Remove one value in a list'''
        value = self.db[name][pos]
        del self.db[name][pos]
        self._dumpdb(self.fsave)
        return value

    def llen(self, name):
        '''Returns the length of the list'''
        return len(self.db[name])

    def append(self, key, more):
        '''Add more to a key's value'''
        tmp = self.db[key]
        self.db[key] = ('%s%s' % (tmp, more))
        self._dumpdb(self.fsave)
        return True

    def lappend(self, name, pos, more):
        '''Add more to a value in a list'''
        tmp = self.db[name][pos]
        self.db[name][pos] = ('%s%s' % (tmp, more))
        self._dumpdb(self.fsave)
        return True

    def dcreate(self, name):
        '''Create a dict'''
        self.db[name] = {}
        self._dumpdb(self.fsave)
        return True

    def dadd(self, name, pair):
        '''Add a key-value pair to a dict, "pair" is a tuple'''
        self.db[name][pair[0]] = pair[1]
        self._dumpdb(self.fsave)
        return True

    def dget(self, name, key):
        '''Return the value for a key in a dict'''
        return self.db[name][key]

    def dgetall(self, name):
        '''Return all key-value pairs from a dict'''
        return self.db[name]

    def drem(self, name):
        '''Remove a dict and all of its pairs'''
        del self.db[name]
        self._dumpdb(self.fsave)
        return True

    def dpop(self, name, key):
        '''Remove one key-value in a dict'''
        value = self.db[name][key]
        del self.db[name][key]
        self._dumpdb(self.fsave)
        return value

    def dkeys(self, name):
        '''Return all the keys for a dict'''
        return self.db[name].keys()

    def dvals(self, name):
        '''Return all the values for a dict'''
        return self.db[name].values()

    def dexists(self, name, key):
        '''Determine if a key exists or not'''
        if self.db[name][key] is not None:
            return 1
        else:
            return 0

    def deldb(self):
        '''Delete everything from the database'''
        self.db = {}
        self._dumpdb(self.fsave)
        return True

    def _loaddb(self):
        '''Load or reload the json info from the file'''
        self.db = json.load(io.open(self.loco, 'r', encoding='utf-8'))

    def _dumpdb(self, forced):
        '''Dump (write, save) the json dump into the file'''
        if forced:
            f = io.open(self.loco, 'w', encoding='utf-8')
            f.write(json.dumps(self.db, ensure_ascii=False))