path: root/factory/django.py

# -*- coding: utf-8 -*-
# Copyright (c) 2010 Mark Sandstrom
# Copyright (c) 2011-2013 Raphaël Barrois
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.


from __future__ import absolute_import
from __future__ import unicode_literals

import os

"""factory_boy extensions for use with the Django framework."""

try:
    from django.core import files as django_files
except ImportError as e:  # pragma: no cover
    django_files = None
    import_failure = e


from . import base
from . import declarations
from .compat import BytesIO, is_string


def require_django():
    """Simple helper to ensure Django is available."""
    if django_files is None:  # pragma: no cover
        raise import_failure


class DjangoModelFactory(base.Factory):
    """Factory for Django models.

    This makes sure that the 'sequence' field of created objects is a new id.

    Possible improvement: define a new 'attribute' type, AutoField, which would
    handle those for non-numerical primary keys.
    """

    ABSTRACT_FACTORY = True  # Optional, but explicit.
    FACTORY_DJANGO_GET_OR_CREATE = ()

    @classmethod
    def _load_target_class(cls, definition):

        if is_string(definition) and '.' in definition:
            app, model = definition.split('.', 1)
            from django.db.models import loading as django_loading
            return django_loading.get_model(app, model)

        return definition

    @classmethod
    def _get_manager(cls, target_class):
        try:
            return target_class._default_manager   # pylint: disable=W0212
        except AttributeError:
            return target_class.objects

    @classmethod
    def _setup_next_sequence(cls):
        """Compute the next available PK, based on the 'pk' database field."""

        model = cls._get_target_class()  # pylint: disable=E1101
        manager = cls._get_manager(model)

        try:
            return 1 + manager.values_list('pk', flat=True
                ).order_by('-pk')[0]
        except (IndexError, TypeError):
            # IndexError: No instance exist yet
            # TypeError: pk isn't an integer type
            return 1

    @classmethod
    def _get_or_create(cls, target_class, *args, **kwargs):
        """Create an instance of the model through objects.get_or_create."""
        manager = cls._get_manager(target_class)

        assert 'defaults' not in cls.FACTORY_DJANGO_GET_OR_CREATE, (
            "'defaults' is a reserved keyword for get_or_create "
            "(in %s.FACTORY_DJANGO_GET_OR_CREATE=%r)"
            % (cls, cls.FACTORY_DJANGO_GET_OR_CREATE))

        key_fields = {}
        for field in cls.FACTORY_DJANGO_GET_OR_CREATE:
            key_fields[field] = kwargs.pop(field)
        key_fields['defaults'] = kwargs

        obj, _created = manager.get_or_create(*args, **key_fields)
        return obj

    @classmethod
    def _create(cls, target_class, *args, **kwargs):
        """Create an instance of the model, and save it to the database."""
        manager = cls._get_manager(target_class)

        if cls.FACTORY_DJANGO_GET_OR_CREATE:
            return cls._get_or_create(target_class, *args, **kwargs)

        return manager.create(*args, **kwargs)

    @classmethod
    def _after_postgeneration(cls, obj, create, results=None):
        """Save again the instance if creating and at least one hook ran."""
        if create and results:
            # Some post-generation hooks ran, and may have modified us.
            obj.save()


class FileField(declarations.PostGenerationDeclaration):
    """Helper to fill in django.db.models.FileField from a Factory."""

    DEFAULT_FILENAME = 'example.dat'

    def __init__(self, **defaults):
        require_django()
        self.defaults = defaults
        super(FileField, self).__init__()

    def _make_data(self, params):
        """Create data for the field."""
        return params.get('data', b'')

    def _make_content(self, extraction_context):
        path = ''
        params = dict(self.defaults)
        params.update(extraction_context.extra)

        if params.get('from_path') and params.get('from_file'):
            raise ValueError(
                "At most one argument from 'from_file' and 'from_path' should "
                "be non-empty when calling factory.django.FileField."
            )

        if extraction_context.did_extract:
            # Should be a django.core.files.File
            content = extraction_context.value
            path = content.name

        elif params.get('from_path'):
            path = params['from_path']
            f = open(path, 'rb')
            content = django_files.File(f, name=path)

        elif params.get('from_file'):
            f = params['from_file']
            content = django_files.File(f)
            path = content.name

        else:
            data = self._make_data(params)
            content = django_files.base.ContentFile(data)

        if path:
            default_filename = os.path.basename(path)
        else:
            default_filename = self.DEFAULT_FILENAME

        filename = params.get('filename', default_filename)
        return filename, content

    def call(self, obj, create, extraction_context):
        """Fill in the field."""
        if extraction_context.did_extract and extraction_context.value is None:
            # User passed an empty value, don't fill
            return

        filename, content = self._make_content(extraction_context)
        field_file = getattr(obj, extraction_context.for_field)
        try:
            field_file.save(filename, content, save=create)
        finally:
            content.file.close()
        return field_file


class ImageField(FileField):
    DEFAULT_FILENAME = 'example.jpg'

    def _make_data(self, params):
        # ImageField (both django's and factory_boy's) require PIL.
        # Try to import it along one of its known installation paths.
        try:
            from PIL import Image
        except ImportError:
            import Image

        width = params.get('width', 100)
        height = params.get('height', width)
        color = params.get('color', 'blue')
        image_format = params.get('format', 'JPEG')

        thumb = Image.new('RGB', (width, height), color)
        thumb_io = BytesIO()
        thumb.save(thumb_io, format=image_format)
        return thumb_io.getvalue()