cerberedis 1.0.5

A Cerberus powered frontend for Redis

CerbeRedis

De/serialise Cerberus data to a Redis database.

Installation

$ pip install cerberedis

Example

A basic example:

from cerberus import Validator, TypeDefinition
from redis import Redis
from cerberedis import CerbeRedis

schema = {
    'name': {'type': 'string', 'required': True},
    'email': {'type': 'string', 'required': True},
}
data = {'name': 'Bob', 'email': '[e-mail]'}

# connect to our redis server
r = Redis()
db = CerbeRedis(r)

# save the schema under the type name 'User'
# with a document id of 1
model_name, id = 'User', 1
db.save(model_name, schema, id, document)

# print the key the model is stored under

print(db.key(model_name, id))

# reload the document
loaded_document = db.load(model_name, schema, id)

A full featured example, including custom types:

from ipaddress import ip_address, IPv4Address, IPv6Address
from datetime import date, datetime
from cerberus import Validator, TypeDefinition
from redis import Redis
# alternatively use redis_mock (https://github.com/adamlwgriffiths/redis-mock)
# from redis_mock import Redis
from cerberedis import CerbeRedis

# Add custom types to both Cerberus
# https://docs.python-cerberus.org/en/stable/customize.html
Validator.types_mapping.update({
    'ipaddress': TypeDefinition('ipaddress', (IPv4Address, IPv6Address), ()),
    'ipv4address': TypeDefinition('ipv4address', (IPv4Address,), ()),
    'ipv6address': TypeDefinition('ipv6address', (IPv6Address,), ()),
})
# Provide CerbeRedis with information on how to handle these new Cerberus types
CerbeRedis.rules.update({
    # dictionary of: <cerberus type name>: [to redis function, from redis function]
    'ipaddress': [lambda x: str(x), lambda x: ip_address(x.decode('utf-8'))],
    'ipv4address': [lambda x: str(x), lambda x: IPv4Address(x.decode('utf-8'))],
    'ipv6address': [lambda x: str(x), lambda x: IPv6Address(x.decode('utf-8'))],
})

# An example Cerberus schema that uses all the built-in Cerberus types
# and the custom ones we defined above
schema = {
    'boolean': {'type': 'boolean', 'required': True},
    'binary': {'type': 'binary', 'required': True},
    'date': {'type': 'date', 'required': True},
    'datetime': {'type': 'datetime', 'required': True},
    'float': {'type': 'float', 'required': True},
    'integer': {'type': 'integer', 'required': True},
    'number': {'type': 'number', 'required': True},
    'string': {'type': 'string', 'required': True},
    'dict': {'type': 'dict', 'schema': {
        'dict_a': {'type': 'string', 'required': True},
        'dict_b': {'type': 'integer', 'required': True},
    }},
    'list': {'type': 'list', 'schema': {'type': 'integer'}},
    'set': {'type': 'set', 'schema': {'type': 'string'}},
    'ipv4address': {'type': 'ipv4address', 'required': True},
}

data = {
    'boolean': True,
    'binary': b'123',
    'date': date.today(),
    'datetime': datetime.now(),
    'float': 1.23,
    'integer': 456,
    'number': 789.0,
    'string': 'abcdefg',
    'dict': {
        'dict_a': 'dict_a_value',
        'dict_b': 9999,
    },
    'list': [1,2,3,4,5],
    'set': {'a', 'b', 'c'},
    'ipv4address': IPv4Address('127.0.0.1'),
}

# Use cerberus to validate and normalise the data
validator = Validator(schema)
document = validator.normalized(data)
if not document:
    raise ValueError(str(validator.errors))

# connect to our redis server
r = Redis()
db = CerbeRedis(r)
model_name, id = 'TestModel', 1
db.save(model_name, schema, id, document)

# reload the document
loaded_document = db.load(model_name, schema, id)

# verify the data is laid out how we expect
assert document == loaded_document

Supported Types

All existing Cerberus Types:

• boolean

• binary

• date

• datetime

• float

• integer

• number

• string

• dict

• list

• set

Limitations

• Containers cannot be nested. Ie. lists and sets cannot contain lists, sets, or dicts.

Future Work

• Use a Redis Pipeline for the load function

Changelog

1.0.5

• Return None rather than empty containers. Permits us to know if the value actually exists.

1.0.4

• Fix image link

1.0.3

• Fix handling of None values for non-required fields

1.0.2

• Expose key function

1.0.1

• Version bump due to PyPi version pedantry

1.0.0

• Initial release

BSD 2-Clause License

Copyright (c) 2021, Adam Griffiths All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. 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.

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 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.