Extending

Note

This document is part of brain storming the project of cihai. It’s for historic purposes only.

Written Late 2013

Minimum usage

  1. Create a python module
  2. The module has a class with a get.() to look up characters by signature (request, response, *args, **kwargs).

With .get(), your class may be instantiated and passed into Cihai. When a user runs .get() inside of Cihai, it will check your module’s .get() also:

+----------+
| Cihai    |  The Cihai Class
+----------+

It is instantiated with a database to connect to (sqlalchemy.schema.MetaData):

c = Cihai(metadata=metadata)

MetaData is part of the sqlalchemy library. It holds connection and table information. In this instance, cihai shares this information across all plugins that attach to it.

To attach a plugin:

from MyCihaiModule import MyDataset
mydata = MyDataSet()
c.use(mydata)

c, the instance of Cihai, may now access MyDataSet’s information.

Code

c = Cihai()

c.use(DatasetExample)
print(c.reverse('hao'))
>>> {
    'definition': 'hao'
}

print(c.get('你'))
>>> {
    'definition': 'hao'
}

Growing big

The above was an example of the minimum requirement to have your dataset compatible.

Importing data into database

One of the goals of Cihai is to provide a common way to access to Chinese data. To import the data, you must create an SQL schema / table for your data.

The pristine format of your data may be in CSV, excel or another format. As long as your data is normalized into a dict that is compatible with the sql table, it is ok.

To accomodate this, Cihai provides all plugins a instance of sqlalchemy.schema.MetaData on creation. sqlalchemy is the swiss army knife of databases in the python programming language.

With an instance of MetaData, you will be able to create SQL tables, import and retrieve data.

Deeper

In previous examples, the plugin class with .get and .reverse character lookups was merged with 1 SQL table.

As said previously, it doesn’t matter how or where the data comes from. As long as Cihai can retrieve data via .get with the correct arguments and response. The prior example had the data class combined with a single table.

In databases that use multiple tables, you may create a central dataset class with .get() and access the tables from there.