pyjon.versionning 0.4.2

Pyjon.Versionning 是一个小的助手，用于使用mercurial对应用程序中的对象进行版本控制。

这些对象可以存储在数据库中，例如，允许从文件系统到数据库的更改同步，反之亦然（同时保留历史记录）。

版本控制管理器是类，它们接收存储库文件夹并在不存在的情况下初始化它。

可用的基本管理器有

• pyjon.versionning.Repository：基本存储库。

• pyjon.versionning.SARepository：用于版本化sqlalchemy对象的基存储库。

基本上，默认类假设您的对象中有一个有效载荷或payload_xml字段，并且该字段将被写入文件。

如果您想要其他字段（或将整个对象序列化为例），您必须创建自己的基于基本存储库的存储库类。

使用简单的json序列化器示例

import simplejson
from myapp import get_vehicles, get_people, get_adresses
from pyjon.versionning import Repository

# for an sqlalchemy repository :
# class MyRepository(SARepository):
# for a normal one (or manual fetching) :
class MyRepository(Repository):
     def get_file_content(self, item):
        # we will assume your objects have an "serializable_fields" attribute
        # this is to support multiple object types (each object type will be stored in a separate folder)

        output_dict = dict()
        for field in item.serializable_fields:
            output_dict[field] = getattr(item, field)

        return simplejson.dumps(output_dict)



    def update_content(self, item, value):

        input_dict = simplejson.loads(value)
        for field in item.serializable_fields:
            setattr(item, field, input_dict[field])

        return simplejson.dumps(my_output_dict)

    # this is used to init the repository with all existing data
    # not necessary with SARepository as it will do it himself with the given classes and dbsession
    def get_all_objects(self):
        for item in get_vehicle():
            yield item

        for item in get_people():
            yield item

        for item in get_adresses():
            yield item

要调用它，以下是方法

# it's thread safe, so you can define it as a global var (imported like "from my_app.versionning import repository")
repository = MyRepository('./repository',
                          default_user="our_great_app <system@ourgreatapp.com>")

# if you have an SARepository, here is how to call it:
from my_app.model import session, vehicles, people, adresses
repository = MyRepository('./repository', session,
                          [vehicles, people, adresses],
                          default_user="our_great_app <system@ourgreatapp.com>")

# now, before using an item in your app (to check changes in the repo), just do that:
repository.check_item(item)

# after saving or creating an item:
repository.store_item(item) # you can define user= to specify the user who did that

# after deleting an item:
repository.delete_item(item) # you can define user= to specify the user who did that