Source code for django_tables2.data

from django.utils.functional import cached_property

from .utils import OrderBy, OrderByTuple, segment


[docs]class TableData(object): ''' Base class for table data containers. ''' def __init__(self, data, table): self.data = data self.table = table super(TableData, self).__init__()
[docs] def __getitem__(self, key): ''' Slicing returns a new `.TableData` instance, indexing returns a single record. ''' return self.data[key]
[docs] def __iter__(self): ''' for ... in ... default to using this. There's a bug in Django 1.3 with indexing into querysets, so this side-steps that problem (as well as just being a better way to iterate). ''' return iter(self.data)
def get_model(self): return getattr(self.data, 'model', None) @property def ordering(self): return None @property def verbose_name(self): return 'item' @property def verbose_name_plural(self): return 'items' @staticmethod def from_data(data, table): if TableQuerysetData.validate(data): return TableQuerysetData(data, table) elif TableListData.validate(data): return TableListData(list(data), table) raise ValueError( 'data must be QuerySet-like (have count() and order_by()) or support' ' list(data) -- {} has neither'.format(type(data).__name__) )
class TableListData(TableData): ''' Table data container for a list of dicts, for example:: [ {'name': 'John', 'age': 20}, {'name': 'Brian', 'age': 25} ] .. note:: Other structures might have worked in the past, but are not explicitly supported or tested. ''' @staticmethod def validate(data): ''' Validates `data` for use in this container ''' return ( hasattr(data, '__iter__') or (hasattr(data, '__len__') and hasattr(data, '__getitem__')) ) def __len__(self): return len(self.data) @property def verbose_name(self): return getattr(self.data, 'verbose_name', super(TableListData, self).verbose_name) @property def verbose_name_plural(self): return getattr(self.data, 'verbose_name_plural', super(TableListData, self).verbose_name_plural) def order_by(self, aliases): ''' Order the data based on order by aliases (prefixed column names) in the table. Arguments: aliases (`~.utils.OrderByTuple`): optionally prefixed names of columns ('-' indicates descending order) in order of significance with regard to data ordering. ''' accessors = [] for alias in aliases: bound_column = self.table.columns[OrderBy(alias).bare] # bound_column.order_by reflects the current ordering applied to # the table. As such we need to check the current ordering on the # column and use the opposite if it doesn't match the alias prefix. if alias[0] != bound_column.order_by_alias[0]: accessors += bound_column.order_by.opposite else: accessors += bound_column.order_by self.data.sort(key=OrderByTuple(accessors).key) class TableQuerysetData(TableData): ''' Table data container for a queryset. ''' @staticmethod def validate(data): ''' Validates `data` for use in this container ''' return ( hasattr(data, 'count') and callable(data.count) and hasattr(data, 'order_by') and callable(data.order_by) ) def __len__(self): if not hasattr(self, '_length'): # Use the queryset count() method to get the length, instead of # loading all results into memory. This allows, for example, # smart paginators that use len() to perform better. self._length = self.data.count() return self._length @property def ordering(self): ''' Returns the list of order by aliases that are enforcing ordering on the data. If the data is unordered, an empty sequence is returned. If the ordering can not be determined, `None` is returned. This works by inspecting the actual underlying data. As such it's only supported for querysets. ''' aliases = {} for bound_column in self.table.columns: aliases[bound_column.order_by_alias] = bound_column.order_by try: return next(segment(self.data.query.order_by, aliases)) except StopIteration: pass def order_by(self, aliases): ''' Order the data based on order by aliases (prefixed column names) in the table. Arguments: aliases (`~.utils.OrderByTuple`): optionally prefixed names of columns ('-' indicates descending order) in order of significance with regard to data ordering. ''' modified_any = False accessors = [] for alias in aliases: bound_column = self.table.columns[OrderBy(alias).bare] # bound_column.order_by reflects the current ordering applied to # the table. As such we need to check the current ordering on the # column and use the opposite if it doesn't match the alias prefix. if alias[0] != bound_column.order_by_alias[0]: accessors += bound_column.order_by.opposite else: accessors += bound_column.order_by if bound_column: queryset, modified = bound_column.order(self.data, alias[0] == '-') if modified: self.data = queryset modified_any = True # custom ordering if modified_any: return # Traditional ordering if accessors: order_by_accessors = (a.for_queryset() for a in accessors) self.data = self.data.order_by(*order_by_accessors) @cached_property def verbose_name(self): ''' The full (singular) name for the data. Model's `~django.db.Model.Meta.verbose_name` is honored. ''' return self.data.model._meta.verbose_name @cached_property def verbose_name_plural(self): ''' The full (plural) name for the data. Model's `~django.db.Model.Meta.verbose_name` is honored. ''' return self.data.model._meta.verbose_name_plural