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Direktori : /opt/alt/python38/lib64/python3.8/site-packages/playhouse/ |
Current File : //opt/alt/python38/lib64/python3.8/site-packages/playhouse/djpeewee.py |
""" Simple translation of Django model classes to peewee model classes. """ from functools import partial import logging from peewee import * logger = logging.getLogger('peewee.playhouse.djpeewee') class AttrDict(dict): def __getattr__(self, attr): return self[attr] class DjangoTranslator(object): def __init__(self): self._field_map = self.get_django_field_map() def get_django_field_map(self): from django.db.models import fields as djf return [ (djf.AutoField, PrimaryKeyField), (djf.BigIntegerField, BigIntegerField), # (djf.BinaryField, BlobField), (djf.BooleanField, BooleanField), (djf.CharField, CharField), (djf.DateTimeField, DateTimeField), # Extends DateField. (djf.DateField, DateField), (djf.DecimalField, DecimalField), (djf.FilePathField, CharField), (djf.FloatField, FloatField), (djf.IntegerField, IntegerField), (djf.NullBooleanField, partial(BooleanField, null=True)), (djf.TextField, TextField), (djf.TimeField, TimeField), (djf.related.ForeignKey, ForeignKeyField), ] def convert_field(self, field): converted = None for django_field, peewee_field in self._field_map: if isinstance(field, django_field): converted = peewee_field break return converted def _translate_model(self, model, mapping, max_depth=None, backrefs=False, exclude=None): if exclude and model in exclude: return if max_depth is None: max_depth = -1 from django.db.models import fields as djf options = model._meta if mapping.get(options.object_name): return mapping[options.object_name] = None attrs = {} # Sort fields such that nullable fields appear last. field_key = lambda field: (field.null and 1 or 0, field) for model_field in sorted(options.fields, key=field_key): # Get peewee equivalent for this field type. converted = self.convert_field(model_field) # Special-case ForeignKey fields. if converted is ForeignKeyField: if max_depth != 0: related_model = model_field.rel.to model_name = related_model._meta.object_name # If we haven't processed the related model yet, do so now. if model_name not in mapping: mapping[model_name] = None # Avoid endless recursion. self._translate_model( related_model, mapping, max_depth=max_depth - 1, backrefs=backrefs, exclude=exclude) if mapping[model_name] is None: # Cycle detected, put an integer field here. logger.warn('Cycle detected: %s: %s', model_field.name, model_name) attrs[model_field.name] = IntegerField( db_column=model_field.column) else: related_name = (model_field.rel.related_name or model_field.related_query_name()) if related_name.endswith('+'): related_name = '__%s:%s:%s' % ( options, model_field.name, related_name.strip('+')) attrs[model_field.name] = ForeignKeyField( mapping[model_name], related_name=related_name, db_column=model_field.column, ) else: attrs[model_field.name] = IntegerField( db_column=model_field.column) elif converted: attrs[model_field.name] = converted( db_column=model_field.db_column) klass = type(options.object_name, (Model,), attrs) klass._meta.db_table = options.db_table klass._meta.database.interpolation = '%s' mapping[options.object_name] = klass if backrefs: # Follow back-references for foreign keys. try: all_related = [(f, f.model) for f in options.get_all_related_objects()] except AttributeError: all_related = [(f, f.field.model) for f in options.get_fields() if (f.one_to_many or f.one_to_one) and f.auto_created and not f.concrete] for rel_obj, model in all_related: if model._meta.object_name in mapping: continue self._translate_model( model, mapping, max_depth=max_depth - 1, backrefs=backrefs, exclude=exclude) # Load up many-to-many relationships. for many_to_many in options.many_to_many: if not isinstance(many_to_many, djf.related.ManyToManyField): continue self._translate_model( many_to_many.rel.through, mapping, max_depth=max_depth, # Do not decrement. backrefs=backrefs, exclude=exclude) def translate_models(self, *models, **options): """ Generate a group of peewee models analagous to the provided Django models for the purposes of creating queries. :param model: A Django model class. :param options: A dictionary of options, see note below. :returns: A dictionary mapping model names to peewee model classes. :rtype: dict Recognized options: `recurse`: Follow foreign keys (default: True) `max_depth`: Max depth to recurse (default: None, unlimited) `backrefs`: Follow backrefs (default: False) `exclude`: A list of models to exclude Example:: # Map Django models to peewee models. Foreign keys and M2M will be # traversed as well. peewee = translate(Account) # Generate query using peewee. PUser = peewee['User'] PAccount = peewee['Account'] query = (PUser .select() .join(PAccount) .where(PAccount.acct_type == 'foo')) # Django raw query. users = User.objects.raw(*query.sql()) """ mapping = AttrDict() recurse = options.get('recurse', True) max_depth = options.get('max_depth', None) backrefs = options.get('backrefs', False) exclude = options.get('exclude', None) if not recurse and max_depth: raise ValueError('Error, you cannot specify a max_depth when ' 'recurse=False.') elif not recurse: max_depth = 0 elif recurse and max_depth is None: max_depth = -1 for model in models: self._translate_model( model, mapping, max_depth=max_depth, backrefs=backrefs, exclude=exclude) return mapping try: import django translate = DjangoTranslator().translate_models except ImportError: pass