https://github.com/alexei/python-adapters

Adapters allow converting data from one structure to another
https://github.com/alexei/python-adapters

adapter-pattern python

Last synced: 11 months ago
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Adapters allow converting data from one structure to another

• Host: GitHub
• URL: https://github.com/alexei/python-adapters
• Owner: alexei
• License: bsd-3-clause
• Created: 2017-04-02T17:43:41.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2022-06-09T09:46:48.000Z (over 3 years ago)
• Last Synced: 2025-03-18T08:21:41.161Z (11 months ago)
• Topics: adapter-pattern, python
• Language: Python
• Homepage: https://pypi.python.org/pypi/python-adapters
• Size: 42 KB
• Stars: 10
• Watchers: 6
• Forks: 2
• Open Issues: 14
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# Adapters

[![Build Status](https://travis-ci.org/alexei/python-adapters.svg?branch=master)](https://travis-ci.org/alexei/python-adapters)

Adapters allow converting data from one structure to another.

The adapters work very similar to `Serializers` in Django REST framework. They are not tied with Django nor DRF in any way, instead they provide a generic way of transforming an object to another.

The are intended to be used when working with 3rd party APIs and as View-Models.

## Example

Suppose you're dealing with an API that returns a profile in the following format:

    {

        "first_name": "Alexandra",

        "last_name": "Johnson",

        "dob": "2/27/1985",

        "address_street": ["71 Boat Lane"],

        "address_zip": "EH45 0ZQ",

        "address_city": "Alderton",

        "address_country": "GB"

    }

But your local models are a little different:

    class Address(object):

        def __init__(self, **kwargs):

            self.line1 = kwargs.get('line1', None)

            self.line2 = kwargs.get('line2', None)

            self.postal_code = kwargs.get('postal_code', None)

            self.city = kwargs.get('city', None)

            self.region = kwargs.get('region', None)

            self.country = kwargs.get('country', None)

    class Profile(object):

        def __init__(self, **kwargs):

            self.first_name = kwargs.get('first_name', None)

            self.last_name = kwargs.get('last_name', None)

            self.birthday = kwargs.get('birthday', None)

            self.address = kwargs.get('address', None)

How do you create local instances from the result returned by the API? Enter adapters:

    import adapters

    class AddressAdapter(adapters.Adapter):

        class Meta(object):

            model = Address

        line1 = adapters.CharField(source='address_street.0')

        line2 = adapters.CharField(source='address_street.1', default='')

        postal_code = adapters.CharField(source='address_zip')

        city = adapters.CharField(source='address_city')

        region = adapters.CharField(source='address_region', default='')

        country = adapters.CharField(source='address_country')

    class ProfileAdapter(adapters.Adapter):

        class Meta(object):

            model = Profile

        first_name = adapters.CharField()

        first_name = adapters.CharField()

        birthday = adapters.DateField(source='dob')

        address = AddressAdapter(source='*')

    ProfileAdapter().adapt(remote_data)

## Declaring adapters

Declaring an adapter is as simple as inheriting from `adapters.Adapter`.

The `data` argument can be omitted and passed to the `.adapt()` method. See [Adapting data](#adapting-data) below.

The `instance` argument is optional and it allows converting to an existing instance i.e. instead of creating a new one.

### Meta options

The `Meta.model` field specifies the type of the end result. Defaults to `dict` and as such the data is converted to a dictionary.

### Adapting data

To convert data from one format to another, call the `Adapter.adapt()` method. It accepts an optional `data` argument which refers to the data to be converted.

## Fields

Each field accepts the following arguments:

* `source` refers to the attribute that will be used to populate the field; the default is to use the same name as the field;

The `source` argument can use dotted notation to traverse objects e.g. `profile.birthday`.

The value `*` can be used to indicate the adapter to pass the entire object to the field.

* `default` specifies the default value of the resulting field; if not set and the field is required, it will raise an error

* `required` indicates whether the field should be required or not; default is `True`

The following field types are available:

### AdapterMethodField

The field gets it's value by calling a method defined on the adapter class. It can be used to manipulate the data.

The `method_name` argument refers to the name of the method. It defaults to `get_`.

### BooleanField

Converts the result to a boolean value.

### CharField

A Unicode field.

### DateField

Parses the value into a `datetime.date` object.

### DateTimeField

Parses the value into a `datetime.datetime` object.

### DecimalField

Parses the value into a `Decimal` object.

### FloatField

A float field.

### IntField

An integer field.

### TimeField

Parses the value into a `datetime.time` object.

### VerbatimField

Copy the value as is.