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from collections import OrderedDict
from django.contrib.admin import FieldListFilter
from django.contrib.admin.exceptions import (
DisallowedModelAdminLookup, DisallowedModelAdminToField,
from django.contrib.admin.options import (
IS_POPUP_VAR, TO_FIELD_VAR, IncorrectLookupParameters,
from django.contrib.admin.utils import (
get_fields_from_path, lookup_needs_distinct, prepare_lookup_value, quote,
from django.core.exceptions import (
FieldDoesNotExist, ImproperlyConfigured, SuspiciousOperation,
from django.core.paginator import InvalidPage
from django.db import models
from django.urls import reverse
from django.utils.encoding import force_text
from django.utils.http import urlencode
from django.utils.translation import gettext
# Changelist settings
ALL_VAR = 'all'
PAGE_VAR = 'p'
class ChangeList:
def __init__(self, request, model, list_display, list_display_links,
list_filter, date_hierarchy, search_fields, list_select_related,
list_per_page, list_max_show_all, list_editable, model_admin):
self.model = model
self.opts = model._meta
self.lookup_opts = self.opts
self.root_queryset = model_admin.get_queryset(request)
self.list_display = list_display
self.list_display_links = list_display_links
self.list_filter = list_filter
self.date_hierarchy = date_hierarchy
self.search_fields = search_fields
self.list_select_related = list_select_related
self.list_per_page = list_per_page
self.list_max_show_all = list_max_show_all
self.model_admin = model_admin
self.preserved_filters = model_admin.get_preserved_filters(request)
# Get search parameters from the query string.
self.page_num = int(request.GET.get(PAGE_VAR, 0))
except ValueError:
self.page_num = 0
self.show_all = ALL_VAR in request.GET
self.is_popup = IS_POPUP_VAR in request.GET
to_field = request.GET.get(TO_FIELD_VAR)
if to_field and not model_admin.to_field_allowed(request, to_field):
raise DisallowedModelAdminToField("The field %s cannot be referenced." % to_field)
self.to_field = to_field
self.params = dict(request.GET.items())
if PAGE_VAR in self.params:
del self.params[PAGE_VAR]
if ERROR_FLAG in self.params:
del self.params[ERROR_FLAG]
if self.is_popup:
self.list_editable = ()
self.list_editable = list_editable
self.query = request.GET.get(SEARCH_VAR, '')
self.queryset = self.get_queryset(request)
if self.is_popup:
title = gettext('Select %s')
title = gettext('Select %s to change')
self.title = title % force_text(self.opts.verbose_name)
self.pk_attname =
def get_filters_params(self, params=None):
Return all params except IGNORED_PARAMS.
if not params:
params = self.params
lookup_params = params.copy() # a dictionary of the query string
# Remove all the parameters that are globally and systematically
# ignored.
for ignored in IGNORED_PARAMS:
if ignored in lookup_params:
del lookup_params[ignored]
return lookup_params
def get_filters(self, request):
lookup_params = self.get_filters_params()
use_distinct = False
for key, value in lookup_params.items():
if not self.model_admin.lookup_allowed(key, value):
raise DisallowedModelAdminLookup("Filtering by %s not allowed" % key)
filter_specs = []
if self.list_filter:
for list_filter in self.list_filter:
if callable(list_filter):
# This is simply a custom list filter class.
spec = list_filter(request, lookup_params, self.model, self.model_admin)
field_path = None
if isinstance(list_filter, (tuple, list)):
# This is a custom FieldListFilter class for a given field.
field, field_list_filter_class = list_filter
# This is simply a field name, so use the default
# FieldListFilter class that has been registered for
# the type of the given field.
field, field_list_filter_class = list_filter, FieldListFilter.create
if not isinstance(field, models.Field):
field_path = field
field = get_fields_from_path(self.model, field_path)[-1]
lookup_params_count = len(lookup_params)
spec = field_list_filter_class(
field, request, lookup_params,
self.model, self.model_admin, field_path=field_path
# field_list_filter_class removes any lookup_params it
# processes. If that happened, check if distinct() is
# needed to remove duplicate results.
if lookup_params_count > len(lookup_params):
use_distinct = use_distinct or lookup_needs_distinct(self.lookup_opts, field_path)
if spec and spec.has_output():
# At this point, all the parameters used by the various ListFilters
# have been removed from lookup_params, which now only contains other
# parameters passed via the query string. We now loop through the
# remaining parameters both to ensure that all the parameters are valid
# fields and to determine if at least one of them needs distinct(). If
# the lookup parameters aren't real fields, then bail out.
for key, value in lookup_params.items():
lookup_params[key] = prepare_lookup_value(key, value)
use_distinct = use_distinct or lookup_needs_distinct(self.lookup_opts, key)
return filter_specs, bool(filter_specs), lookup_params, use_distinct
except FieldDoesNotExist as e:
raise IncorrectLookupParameters(e) from e
def get_query_string(self, new_params=None, remove=None):
if new_params is None:
new_params = {}
if remove is None:
remove = []
p = self.params.copy()
for r in remove:
for k in list(p):
if k.startswith(r):
del p[k]
for k, v in new_params.items():
if v is None:
if k in p:
del p[k]
p[k] = v
return '?%s' % urlencode(sorted(p.items()))
def get_results(self, request):
paginator = self.model_admin.get_paginator(request, self.queryset, self.list_per_page)
# Get the number of objects, with admin filters applied.
result_count = paginator.count
# Get the total number of objects, with no admin filters applied.
if self.model_admin.show_full_result_count:
full_result_count = self.root_queryset.count()
full_result_count = None
can_show_all = result_count <= self.list_max_show_all
multi_page = result_count > self.list_per_page
# Get the list of objects to display on this page.
if (self.show_all and can_show_all) or not multi_page:
result_list = self.queryset._clone()
result_list = + 1).object_list
except InvalidPage:
raise IncorrectLookupParameters
self.result_count = result_count
self.show_full_result_count = self.model_admin.show_full_result_count
# Admin actions are shown if there is at least one entry
# or if entries are not counted because show_full_result_count is disabled
self.show_admin_actions = not self.show_full_result_count or bool(full_result_count)
self.full_result_count = full_result_count
self.result_list = result_list
self.can_show_all = can_show_all
self.multi_page = multi_page
self.paginator = paginator
def _get_default_ordering(self):
ordering = []
if self.model_admin.ordering:
ordering = self.model_admin.ordering
elif self.lookup_opts.ordering:
ordering = self.lookup_opts.ordering
return ordering
def get_ordering_field(self, field_name):
Return the proper model field name corresponding to the given
field_name to use for ordering. field_name may either be the name of a
proper model field or the name of a method (on the admin or model) or a
callable with the 'admin_order_field' attribute. Return None if no
proper model field name can be matched.
field = self.lookup_opts.get_field(field_name)
except FieldDoesNotExist:
# See whether field_name is a name of a non-field
# that allows sorting.
if callable(field_name):
attr = field_name
elif hasattr(self.model_admin, field_name):
attr = getattr(self.model_admin, field_name)
attr = getattr(self.model, field_name)
return getattr(attr, 'admin_order_field', None)
def get_ordering(self, request, queryset):
Return the list of ordering fields for the change list.
First check the get_ordering() method in model admin, then check
the object's default ordering. Then, any manually-specified ordering
from the query string overrides anything. Finally, a deterministic
order is guaranteed by ensuring the primary key is used as the last
ordering field.
params = self.params
ordering = list(self.model_admin.get_ordering(request) or self._get_default_ordering())
if ORDER_VAR in params:
# Clear ordering and used params
ordering = []
order_params = params[ORDER_VAR].split('.')
for p in order_params:
none, pfx, idx = p.rpartition('-')
field_name = self.list_display[int(idx)]
order_field = self.get_ordering_field(field_name)
if not order_field:
continue # No 'admin_order_field', skip it
# reverse order if order_field has already "-" as prefix
if order_field.startswith('-') and pfx == "-":
ordering.append(pfx + order_field)
except (IndexError, ValueError):
continue # Invalid ordering specified, skip it.
# Add the given query's ordering fields, if any.
# Ensure that the primary key is systematically present in the list of
# ordering fields so we can guarantee a deterministic order across all
# database backends.
pk_name =
if not (set(ordering) & {'pk', '-pk', pk_name, '-' + pk_name}):
# The two sets do not intersect, meaning the pk isn't present. So
# we add it.
return ordering
def get_ordering_field_columns(self):
Return an OrderedDict of ordering field column numbers and asc/desc.
# We must cope with more than one column having the same underlying sort
# field, so we base things on column numbers.
ordering = self._get_default_ordering()
ordering_fields = OrderedDict()
if ORDER_VAR not in self.params:
# for ordering specified on ModelAdmin or model Meta, we don't know
# the right column numbers absolutely, because there might be more
# than one column associated with that ordering, so we guess.
for field in ordering:
if field.startswith('-'):
field = field[1:]
order_type = 'desc'
order_type = 'asc'
for index, attr in enumerate(self.list_display):
if self.get_ordering_field(attr) == field:
ordering_fields[index] = order_type
for p in self.params[ORDER_VAR].split('.'):
none, pfx, idx = p.rpartition('-')
idx = int(idx)
except ValueError:
continue # skip it
ordering_fields[idx] = 'desc' if pfx == '-' else 'asc'
return ordering_fields
def get_queryset(self, request):
# First, we collect all the declared list filters.
(self.filter_specs, self.has_filters, remaining_lookup_params,
filters_use_distinct) = self.get_filters(request)
# Then, we let every list filter modify the queryset to its liking.
qs = self.root_queryset
for filter_spec in self.filter_specs:
new_qs = filter_spec.queryset(request, qs)
if new_qs is not None:
qs = new_qs
# Finally, we apply the remaining lookup parameters from the query
# string (i.e. those that haven't already been processed by the
# filters).
qs = qs.filter(**remaining_lookup_params)
except (SuspiciousOperation, ImproperlyConfigured):
# Allow certain types of errors to be re-raised as-is so that the
# caller can treat them in a special way.
except Exception as e:
# Every other error is caught with a naked except, because we don't
# have any other way of validating lookup parameters. They might be
# invalid if the keyword arguments are incorrect, or if the values
# are not in the correct type, so we might get FieldError,
# ValueError, ValidationError, or ?.
raise IncorrectLookupParameters(e)
if not qs.query.select_related:
qs = self.apply_select_related(qs)
# Set ordering.
ordering = self.get_ordering(request, qs)
qs = qs.order_by(*ordering)
# Apply search results
qs, search_use_distinct = self.model_admin.get_search_results(request, qs, self.query)
# Remove duplicates from results, if necessary
if filters_use_distinct | search_use_distinct:
return qs.distinct()
return qs
def apply_select_related(self, qs):
if self.list_select_related is True:
return qs.select_related()
if self.list_select_related is False:
if self.has_related_field_in_list_display():
return qs.select_related()
if self.list_select_related:
return qs.select_related(*self.list_select_related)
return qs
def has_related_field_in_list_display(self):
for field_name in self.list_display:
field = self.lookup_opts.get_field(field_name)
except FieldDoesNotExist:
if isinstance(field.remote_field, models.ManyToOneRel):
# <FK>_id field names don't require a join.
if field_name == field.get_attname():
return True
return False
def url_for_result(self, result):
pk = getattr(result, self.pk_attname)
return reverse('admin:%s_%s_change' % (self.opts.app_label,