leancloud-better-storage-python

better leancloud storage wrapper. Simple and lightweight.

Sorry for my bad grammar and spell :)

Installation

install by easy_install or pip.

pip install leancloud-better-storage

Quick start

Simple model declaration and query syntax.

Model declaration

from datetime import datetime
from leancloud_better_storage.storage.models import Model
from leancloud_better_storage.storage.fields import Field

class Product(Model):
    name = Field(nullable=False)
    price = Field(nullable=False)
    publish_at = Field()

Field constructor accept series option arguments.

name, specify field name in database.
nullable, should you provide initial value for this field when you create new record.
default, if you are not set default value, commit will not create new field or set null in leancloud storage. Because undefined and null is different in javascript :( . leancloud storage based on MongoDB, and MongoDB use JavaScript as first class citizen.
type_ not used yet.

CRUD operations

You can use Model.create to create new record, this method should check your record has been correctly initialized.

product = Product.create(name='FirstProduct', price=100)
product.commit()

# v0.1.3 now default null value
assert product.publish_at is None

If you are not pass default initial value for non-default field, it will be null (in storage, undefined).

Read & Query

use filter and/or filter_by to select records.

filter support more human readable condition selection.

>, <, >=, <=, == compare field with some value. Not supprot compare between fields in same or not same model.
contains simple pattern match for string field.
and_, or_ between two or more queries.

See examples below.

# find by simple equation
products = Product.query().filter_by(name='product').find()

# support >,<,>=,<=,==.but not support compare to another field.
products = Product.query().filter(Product.price < 10).find()

# support contains
products = Product.query().filter(Product.name.contains('art')).find()

# support and_(), or_().
products = Product.query().filter(Product.created_at > datetime(2018,8,1)).and_() \
    .filter(Product.created_at < datetime(2018,9,1)).find()

# find support limit and skip argument.
products = Product.query().order_by(Product.price.desc).find(limit=10)

# support pagination, start from page 0 and 10 elements per page.
pages = Product.query().paginate(0, 10)
for page in pages:
    print(page.items) # access elements

Update

You can update record by assign new value and commit change.

product = Product.query().filter_by(name='FirstProduct').first()
product.name = 'LastProduct'
product.commit()

Delete

drop method will delete record and set object invalid. Use drop_all for bulk operation.

product = Product.query().filter_by(name='FirstProduct').first()
product.drop()

products = Product.query().filter_by().find()
Product.drop_all(products)

Known limit

Some bulk modification/deletion does not support execute with conditions. It's limited by leancloud storage service. For more detail, see document below.

Change log

0.1.7 修复初始值 null 覆盖了存储服务生成字段值的问题。

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