A Python Library for Simple Models and Containers Persisted in Redis

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redisco
Overview

Redisco

Python Containers and Simple Models for Redis

Description

Redisco allows you to store objects in Redis. It is inspired by the Ruby library Ohm and its design and code are loosely based on Ohm and the Django ORM. It is built on top of redis-py. It includes container classes that allow easier access to Redis sets, lists, and sorted sets.

Installation

Redisco requires redis-py 2.0.0 so get it first.

pip install redis

Then install redisco.

pip install redisco

Documentation

The documentation is available at : https://redisco.readthedocs.org

Which version should I consider ?

  • v0.1

https://secure.travis-ci.org/kiddouk/redisco.png?branch=0.1

If you want something that is compatible with the original project developed by you should consider v0.1. It works.

  • v0.2

https://secure.travis-ci.org/kiddouk/redisco.png?branch=0.2

If you are adventurous and want to try a version that is going closer to Ohm project you should consider v0.2. Warning, your indexing keys will be broken (if you are planning to migrate).

  • master

https://secure.travis-ci.org/kiddouk/redisco.png?branch=master

Well, expect things to be broken. Really broken.

Models

from redisco import models
class Person(models.Model):
    name = models.Attribute(required=True)
    created_at = models.DateTimeField(auto_now_add=True)
    fave_colors = models.ListField(str)

>>> person = Person(name="Conchita")
>>> person.is_valid()
True
>>> person.save()
True
>>> conchita = Person.objects.filter(name='Conchita')[0]
>>> conchita.name
'Conchita'
>>> conchita.created_at
datetime.datetime(2010, 5, 24, 16, 0, 31, 954704)

Model Attributes

Attribute
Stores unicode strings. If used for large bodies of text, turn indexing of this field off by setting indexed=False.
IntegerField
Stores an int. Ints are stringified using unicode() before saving to Redis.
Counter
An IntegerField that can only be accessed via Model.incr and Model.decr.
DateTimeField
Can store a DateTime object. Saved in the Redis store as a float.
DateField
Can store a Date object. Saved in Redis as a float.
TimeDeltaField
Can store a TimeDelta object. Saved in Redis as a float.
FloatField
Can store floats.
BooleanField
Can store bools. Saved in Redis as 1's and 0's.
ReferenceField
Can reference other redisco model.
ListField
Can store a list of unicode, int, float, as well as other redisco models.

Attribute Options

required
If True, the attirbute cannot be None or empty. Strings are stripped to check if they are empty. Default is False.
default
Sets the default value of the attribute. Default is None.
indexed
If True, redisco will create index entries for the attribute. Indexes are used in filtering and ordering results of queries. For large bodies of strings, this should be set to False. Default is True.
validator
Set this to a callable that accepts two arguments -- the field name and the value of the attribute. The callable should return a list of tuples with the first item is the field name, and the second item is the error.
unique
The field must be unique. Default is False.

DateField and DateTimeField Options

auto_now_add
Automatically set the datetime/date field to now/today when the object is first created. Default is False.
auto_now
Automatically set the datetime/date field to now/today everytime the object is saved. Default is False.

Class options

You can specify some options in your Model to control the behaviour of the back scene.

class User(models.Model):
    firstname = models.Attribute()
    lastname = models.Attribute()

    @property
    def fullname(self):
        return "%s %s" % (self.firstname, self.lastname)

    class Meta:
        indices = ['fullname']
        db = redis.Redis(host="localhost", db="6666")
        key = 'Account'

indices is used to add extra indices that will be saved in the model. db object will be used instead of the global redisco redis_client key will be used as the main key in the redis Hash (and sub objects) instead of the class name.

Custom Managers

Managers are attached to Model attributes by looking for a __attr_name__ class attribute. If not present, then it defaults to the lowercase attribute name in the Model.

class User(models.Model):
    firstname = models.Attribute()
    lastname = models.Attribute()
    active = models.BooleanField(default=True)

    class History(models.managers.Manager):
        pass

    class ObjectsManager(models.managers.Manager):
        __attr_name__ = "objects"
        def get_model_set(self):
            return super(User.ObjectsManager, self).\
                get_model_set().filter(active=True)

Saving and Validating

To save an object, call its save method. This returns True on success (i.e. when the object is valid) and False otherwise.

Calling Model.is_valid will validate the attributes and lists. Model.is_valid is called when the instance is being saved. When there are invalid fields, Model.errors will hold the list of tuples containing the invalid fields and the reason for its invalidity. E.g. [('name', 'required'),('name', 'too short')]

Fields can be validated using the validator argument of the attribute. Just pass a callable that accepts two arguments -- the field name and the value of the attribute. The callable should return a list of errors.

Model.validate will also be called before saving the instance. Override it to validate instances not related to attributes.

def not_me(field_name, value):
    if value == 'Me':
        return ((field_name, 'it is me'),)

class Person(models.Model):
    name = models.Attribute(required=True, validator=not_me)
    age = models.IntegerField()

    def validate(self):
        if self.age and self.age < 21:
            self._errors.append(('age', 'below 21'))

>>> person = Person(name='Me')
>>> person.is_valid()
False
>>> person.errors
[('name', 'it is me')]

Queries

Queries are executed using a manager, accessed via the objects class attribute.

Person.objects.all()
Person.objects.filter(name='Conchita')
Person.objects.filter(name='Conchita').first()
Person.objects.all().order('name')
Person.objects.filter(fave_colors='Red')

Ranged Queries

Redisco has a limited support for queries involving ranges -- it can only filter fields that are numeric, i.e. DateField, DateTimeField, IntegerField, and FloatField. The zfilter method of the manager is used for these queries.

Person.objects.zfilter(created_at__lt=datetime(2010, 4, 20, 5, 2, 0))
Person.objects.zfilter(created_at__gte=datetime(2010, 4, 20, 5, 2, 0))
Person.objects.zfilter(created_at__in=(datetime(2010, 4, 20, 5, 2, 0), datetime(2010, 5, 1)))

Containers

Redisco has three containers that roughly match Redis's supported data structures: lists, sets, sorted set. Anything done to the container is persisted to Redis.

Sets
>>> from redisco.containers import Set
>>> s = Set('myset')
>>> s.add('apple')
>>> s.add('orange')
>>> s.add('bananas', 'tomatoes')
>>> s.add(['blackberries', 'strawberries'])
>>> s.members
set(['apple', 'blackberries', 'strawberries', 'orange', 'tomatoes', 'bananas'])
>>> s.remove('apple', 'orange')
True
set(['strawberries', 'bananas', 'tomatoes', 'blackberries'])
>>> s.remove(['bananas', 'blackberries'])
True
>> s.members
set(['strawberries', 'bananas', 'tomatoes'])
>>> t = Set('nset')
>>> t.add('kiwi')
>>> t.add('guava')
>>> t.members
set(['kiwi', 'guava'])
>>> s.update(t)
>>> s.members
set(['kiwi', 'orange', 'guava', 'apple'])
Lists
>>> from redisco.containers import List
>>> l = List('alpha')
>>> l.append('a')
>>> l.append(['b', 'c'])
>>> l.append('d', 'e', 'f')
>>> 'a' in l
True
>>> 'd' in l
False
>>> len(l)
6
>>> l.index('b')
1
>>> l.members
['a', 'b', 'c', 'd', 'e', 'f']
Sorted Sets
>>> zset = SortedSet('zset')
>>> zset.members
['d', 'a', 'b', 'c']
>>> 'e' in zset
False
>>> 'a' in zset
True
>>> zset.rank('d')
0
>>> zset.rank('b')
2
>>> zset[1]
'a'
>>> zset.add({'f' : 200, 'e' : 201})
>>> zset.members
['d', 'a', 'b', 'c', 'f', 'e']
>>> zset.add('d', 99)
>>> zset.members
['a', 'b', 'c', 'd', 'f', 'e']
Dicts/Hashes
>>> h = cont.Hash('hkey')
>>> len(h)
0
>>> h['name'] = "Richard Cypher"
>>> h['real_name'] = "Richard Rahl"
>>> h
<Hash 'hkey' {'name': 'Richard Cypher', 'real_name': 'Richard Rahl'}>
>>> h.dict
{'name': 'Richard Cypher', 'real_name': 'Richard Rahl'}

Additional Info on Containers

Some methods of the Redis client that require the key as the first argument can be accessed from the container itself.

>>> l = List('mylist')
>>> l.lrange(0, -1)
0
>>> l.rpush('b')
>>> l.rpush('c')
>>> l.lpush('a')
>>> l.lrange(0, -1)
['a', 'b', 'c']
>>> h = Hash('hkey')
>>> h.hset('name', 'Richard Rahl')
>>> h
<Hash 'hkey' {'name': 'Richard Rahl'}>

Connecting to Redis

All models and containers use a global Redis client object to interact with the key-value storage. By default, it connects to localhost:6379, selecting db 0. If you wish to specify settings:

import redisco
redisco.connection_setup(host='localhost', port=6380, db=10)

The arguments to connect are simply passed to the redis.Redis init method.

For the containers, you can specify a second argument as the Redis client. That client object will be used instead of the default.

>>> import redis
>>> r = redis.Redis(host='localhost', port=6381)
>>> Set('someset', r)

Unit tests

Redisco uses nose for testing.

Install nosetests:

$ pip install nose

And test:

$ nosetests

Credits

Most of the concepts are taken from Soveran's Redis related Ruby libraries. cyx for sharing his expertise in indexing in Redis. Django, of course, for the popular model API.

Issues
  • Python 3 support

    Python 3 support

    opened by tanbro 14
  • Timedelta

    Timedelta

    Timedelta field backed by a float()

    Note - contains the fix_errors fix, so that CI will pass.

    opened by stuaxo 4
  • Setting None to ReferenceField raises AttributeError

    Setting None to ReferenceField raises AttributeError

    Having the following models:

    class Video(Model):
        title = Attribute()
    
    class Playlist(Model):
        now_playing = ReferenceField(Video)
    
    

    I can save the playlist model without having to assign the now_playing attribute, but if I assign None to the attribute, I get

    line 346, in __set__
        setattr(instance, self.attname, value.id)
    AttributeError: 'NoneType' object has no attribute 'id'
    

    I'm currently using redisco 0.1.4.

    I think I know where the problem is, should i send a pull request?

    opened by cinemascop89 4
  • Added `install_requires` to setup.py

    Added `install_requires` to setup.py

    This will automatically install dependencies from requirements.txt when redisco is installed via pip.

    opened by jakubroztocil 4
  • can't save the model object second time if some attribute is unique.

    can't save the model object second time if some attribute is unique.

    is_valid() will return False.

    opened by hanbaga 3
  • fix _max_score always return None

    fix _max_score always return None

    I made some changes.Please review. No test case because _max_score is not used now.

    opened by baijinping 3
  • Adding support for multiple managers

    Adding support for multiple managers

    Hi, I'm working on a project where we use multiple managers (like the django orm) to keep models and logic separated from the rest of our code. We patched Redisco to add such functionality, and we though you might be interested on it.

    opened by pcostesi 3
  • Add the implicit id to attributes_dict...

    Add the implicit id to attributes_dict...

    Or facilitate json serialization in some other way, right now doing a naive json.dumps(obj.attributes_dict) missed the object id which is kind of important.

    opened by tutuca 2
  • Travis tests all failing with connection refused

    Travis tests all failing with connection refused

    Will see if there is anything obvious:

    ======================================================================
    
    ERROR: test_CharField (redisco.tests.BooleanFieldTestCase)
    
    ----------------------------------------------------------------------
    
    Traceback (most recent call last):
    
      File "/home/travis/build/kiddouk/redisco/redisco/models/basetests.py", line 26, in setUp
    
        self.client.flushdb()
    
      File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/redis/client.py", line 652, in flushdb
    
        return self.execute_command('FLUSHDB')
    
      File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/redis/client.py", line 578, in execute_command
    
        connection.send_command(*args)
    
      File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/redis/connection.py", line 563, in send_command
    
        self.send_packed_command(self.pack_command(*args))
    
      File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/redis/connection.py", line 538, in send_packed_command
    
        self.connect()
    
      File "/home/travis/virtualenv/python2.7.9/lib/python2.7/site-packages/redis/connection.py", line 442, in connect
    
        raise ConnectionError(self._error_message(e))
    
    ConnectionError: Error 111 connecting to localhost:6379. Connection refused.
    
    opened by stuaxo 2
  • Is `redisco` dead?

    Is `redisco` dead?

    Are there any forks that are still being maintained

    opened by lovetoburnswhen 0
  • Fix simple typo: upports -> supports

    Fix simple typo: upports -> supports

    There is a small typo in models.rst. Should read supports rather than upports.

    Closes #77

    opened by timgates42 0
  • Fix simple typo: upports -> supports

    Fix simple typo: upports -> supports

    There is a small typo in models.rst. Should read supports rather than upports.

    opened by timgates42 0
  • Use code blocks in readme

    Use code blocks in readme

    This makes syntax highlighting work correctly and makes it look nicer

    opened by MatthewScholefield 0
  • python3 compatibility

    python3 compatibility

    hi, I submitted python3 compatibility, And updated the test case with python3. But the test case can not be compatible with python2

    opened by chen2aaron 0
  • Merge python 3.5 compatability fork

    Merge python 3.5 compatability fork

    https://github.com/dongweiming/redisco/commit/aa93f31f81bf3f163b29f2783a70748ec4479f22

    Without it one gets an Import Error can not import * from base.

    opened by vanpelt 1
  • way to expire object in some time

    way to expire object in some time

    if I use redisco to store a model's instance How can I expire the object in 15 minunts> automatically????

    opened by ghost 0
  • Modelset filter doesn't work in other DB except 0

    Modelset filter doesn't work in other DB except 0

    I have multiple dbs to store data. If I specify the db 1 in model class as below: class Param(models.Model): Name = models.Attribute(required=True, unique=True) class Meta: indices = ['Name'] db = redis.Redis(host="127.0.0.1", port=6379, db='1')

    The object creation is successful, the object will be created and stored in db 1. But with Param.objects.filter(Name='xxxx'), the resultset is empty. If I don't have this db specification in model class meta, the creation and query both work.

    Anyone aware of this issue?

    opened by XinfuZheng 0
  • Update (.save()) do not work if the object fetched using .filter()

    Update (.save()) do not work if the object fetched using .filter()

    p = Person.objects.filter(name="Granny")
    # Assuming only one record fetched.
    p[0].first_name = "Morgan"
    p[0].last_name = "Stanley"
    p.save()
    

    Above case do not update the values in DB. even

    p[0].update_attributes(first_name="Morgan", last_name="Stanley")
    p[0].save()
    

    doesn't work.

    Instead following work as expected.

    p = Person.objects.get_by_id('1')
    p.first_name = "Morgan"
    p.last_name = Stanley
    p.save()
    

    I believe this is critical issue.

    opened by kishorpawar 0
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sebastien requiem
Myeah.
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