Source code for horizon.tabs.base

# Copyright 2012 Nebula, Inc.
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

from collections import OrderedDict
import logging
import operator

from django.conf import settings
from django.template.loader import render_to_string
from django.template import TemplateSyntaxError
from django.utils import module_loading

from horizon import exceptions
from horizon.utils import html
from horizon.utils import settings as utils_settings

LOG = logging.getLogger(__name__)

CSS_TAB_GROUP_CLASSES = ["nav", "nav-tabs", "ajax-tabs"]

[docs]class TabGroup(html.HTMLElement): """A container class which knows how to manage and render Tab objects. .. attribute:: slug The URL slug and pseudo-unique identifier for this tab group. .. attribute:: tabs A list of :class:`.Tab` classes. Tabs specified here are displayed in the order of the list. .. attribute:: template_name The name of the template which will be used to render this tab group. Default: ``"horizon/common/_tab_group.html"`` .. attribute:: sticky Boolean to control whether the active tab state should be stored across requests for a given user. (State storage is all done client-side.) .. attribute:: show_single_tab Boolean to control whether the tab bar is shown when the tab group has only one tab. Default: ``False`` .. attribute:: param_name The name of the GET request parameter which will be used when requesting specific tab data. Default: ``tab``. .. attribute:: classes A list of CSS classes which should be displayed on this tab group. .. attribute:: attrs A dictionary of HTML attributes which should be rendered into the markup for this tab group. .. attribute:: selected Read-only property which is set to the instance of the currently-selected tab if there is one, otherwise ``None``. .. attribute:: active Read-only property which is set to the value of the current active tab. This may not be the same as the value of ``selected`` if no specific tab was requested via the ``GET`` parameter. """ slug = None template_name = "horizon/common/_tab_group.html" param_name = 'tab' sticky = False show_single_tab = False _selected = None _active = None @property def selected(self): return self._selected @property def active(self): return self._active def __init__(self, request, **kwargs): super().__init__() if not hasattr(self, "tabs"): raise NotImplementedError('%s must declare a "tabs" attribute.' % self.__class__) if not self.slug: raise NotImplementedError('%s must declare a "slug" attribute.' % self.__class__) self.request = request self.kwargs = kwargs self._data = None self._tabs = self._load_tabs(request) if self.sticky: self.attrs['data-sticky-tabs'] = 'sticky' if not self._set_active_tab(): self.tabs_not_available() def _load_tabs(self, request): tabs = tuple(self.tabs) tabs += self._load_tabs_from_config() return OrderedDict([(tab.slug, tab(self, request)) for tab in tabs]) def _load_tabs_from_config(self): my_name = '.'.join([self.__class__.__module__, self.__class__.__name__]) horizon_config = settings.HORIZON_CONFIG.get('extra_tabs', {}) tabs_config = [self._load_tab_config(tab_config, my_name) for tab_config in horizon_config.get(my_name, [])] tabs_config = [t for t in tabs_config if t] tabs_config.sort(key=operator.itemgetter(0)) LOG.debug('Loaded extra tabs for %s: %s', my_name, tabs_config) return tuple(x[1] for x in tabs_config) @staticmethod def _load_tab_config(tab_config, my_name): if isinstance(tab_config, str): tab_config = (0, tab_config) if not isinstance(tab_config, (tuple, list)): LOG.error('Extra tab definition must be a string or ' 'a tuple/list (tab group "%s")', my_name) return if len(tab_config) != 2: LOG.error('Entry must be a format of (priority, tab class) ' '(tab group "%s")', my_name) return priority, tab_class = tab_config if not isinstance(priority, int): LOG.error('Priority of tab entry must be an integer ' '(tab group "%s")', my_name) return try: class_ = module_loading.import_string(tab_class) except ImportError: LOG.error('Tab class "%s" is not found (tab group "%s")', tab_class, my_name) return return priority, class_ def __repr__(self): return "<%s: %s>" % (self.__class__.__name__, self.slug)
[docs] def load_tab_data(self): """Preload all data that for the tabs that will be displayed.""" for tab in self._tabs.values(): if tab.load and not tab.data_loaded: try: tab._data = tab.get_context_data(self.request) except Exception: tab._data = False exceptions.handle(self.request)
[docs] def get_id(self): """Returns the id for this tab group. Defaults to the value of the tab group's :attr:`horizon.tabs.Tab.slug`. """ return self.slug
[docs] def get_default_classes(self): """Returns a list of the default classes for the tab group. Defaults to ``["nav", "nav-tabs", "ajax-tabs"]``. """ default_classes = super().get_default_classes() default_classes.extend(CSS_TAB_GROUP_CLASSES) return default_classes
[docs] def tabs_not_available(self): """The fallback handler if no tabs are either allowed or enabled. In the event that no tabs are either allowed or enabled, this method is the fallback handler. By default it's a no-op, but it exists to make redirecting or raising exceptions possible for subclasses. """
def _set_active_tab(self): marked_active = None # See if we have a selected tab via the GET parameter. tab = self.get_selected_tab() if tab: tab._active = True self._active = tab marked_active = tab # Iterate through to mark them all accordingly. for tab in self._tabs.values(): if tab._allowed and tab._enabled and not marked_active: tab._active = True self._active = tab marked_active = True elif tab == marked_active: continue else: tab._active = False return marked_active
[docs] def render(self): """Renders the HTML output for this tab group.""" return render_to_string(self.template_name, {"tab_group": self})
[docs] def get_tabs(self): """Returns a list of the allowed tabs for this tab group.""" return [tab for tab in self._tabs.values() if tab._allowed]
[docs] def get_tab(self, tab_name, allow_disabled=False): """Returns a specific tab from this tab group. If the tab is not allowed or not enabled this method returns ``None``. If the tab is disabled but you wish to return it anyway, you can pass ``True`` to the allow_disabled argument. """ tab = self._tabs.get(tab_name, None) if tab and tab._allowed and (tab._enabled or allow_disabled): return tab return None
def get_loaded_tabs(self): return [tab for tab in self._tabs.values() if self.get_tab(tab.slug)]
[docs] def get_selected_tab(self): """Returns the tab specific by the GET request parameter. In the event that there is no GET request parameter, the value of the query parameter is invalid, or the tab is not allowed/enabled, the return value of this function is None. """ selected = self.request.GET.get(self.param_name, None) if selected: try: tab_group, tab_name = selected.split(SEPARATOR) except ValueError: return None if tab_group == self.get_id(): self._selected = self.get_tab(tab_name) return self._selected
[docs]class Tab(html.HTMLElement): """A reusable interface for constructing a tab within a TabGroup. .. attribute:: name The display name for the tab which will be rendered as the text for the tab element in the HTML. Required. .. attribute:: slug The URL slug and id attribute for the tab. This should be unique for a given tab group. Required. .. attribute:: preload Determines whether the contents of the tab should be rendered into the page's HTML when the tab group is rendered, or whether it should be loaded dynamically when the tab is selected. Default: ``True``. .. attribute:: classes A list of CSS classes which should be displayed on this tab. .. attribute:: attrs A dictionary of HTML attributes which should be rendered into the markup for this tab. .. attribute:: load Read-only access to determine whether or not this tab's data should be loaded immediately. .. attribute:: permissions A list of permission names which this tab requires in order to be displayed. Defaults to an empty list (``[]``). """ name = None slug = None preload = True _active = None permissions = [] policy_rules = None def __init__(self, tab_group, request=None, policy_rules=None): super().__init__() # Priority: constructor, class-defined, fallback if not raise ValueError("%s must have a name." % self.__class__.__name__) if not self.slug: raise ValueError("%s must have a slug." % self.__class__.__name__) self.tab_group = tab_group self.request = request if request: self._allowed = self.allowed(request) and ( self._has_permissions(request)) self._enabled = self.enabled(request) self.policy_rules = policy_rules or [] def __repr__(self): return "<%s: %s>" % (self.__class__.__name__, self.slug) def _has_permissions(self, request): return request.user.has_perms(self.permissions)
[docs] def is_active(self): """Method to access whether or not this tab is the active tab.""" if self._active is None: self.tab_group._set_active_tab() return self._active
@property def load(self): load_preloaded = self.preload or self.is_active() return load_preloaded and self._allowed and self._enabled @property def data(self): if getattr(self, "_data", None) is None: self._data = self.get_context_data(self.request) return self._data @property def data_loaded(self): return getattr(self, "_data", None) is not None
[docs] def render(self): """Renders the tab to HTML. :meth:`~horizon.tabs.Tab.get_context_data` method and the :meth:`~horizon.tabs.Tab.get_template_name` method are called. If :attr:`~horizon.tabs.Tab.preload` is ``False`` and ``force_load`` is not ``True``, or either :meth:`~horizon.tabs.Tab.allowed` or :meth:`~horizon.tabs.Tab.enabled` returns ``False`` this method will return an empty string. """ if not self.load: return '' try: context = except exceptions.Http302: raise except Exception as e: raise TemplateSyntaxError from e return render_to_string(self.get_template_name(self.request), context)
[docs] def get_id(self): """Returns the id for this tab. Defaults to ``"{{ tab_group.slug }}__{{ tab.slug }}"``. """ return SEPARATOR.join([self.tab_group.slug, self.slug])
def get_query_string(self): return "=".join((self.tab_group.param_name, self.get_id()))
[docs] def get_default_classes(self): """Returns a list of the default classes for the tab. Defaults to and empty list (``[]``), however additional classes may be added depending on the state of the tab as follows: If the tab is the active tab for the tab group, in which the class ``"active"`` will be added. If the tab is not enabled, the classes the class ``"disabled"`` will be added. """ default_classes = super().get_default_classes() if self.is_active(): default_classes.extend(CSS_ACTIVE_TAB_CLASSES) if not self._enabled: default_classes.extend(CSS_DISABLED_TAB_CLASSES) return default_classes
[docs] def get_template_name(self, request): """Returns the name of the template to be used for rendering this tab. By default it returns the value of the ``template_name`` attribute on the ``Tab`` class. """ if not hasattr(self, "template_name"): raise AttributeError("%s must have a template_name attribute or " "override the get_template_name method." % self.__class__.__name__) return self.template_name
[docs] def get_context_data(self, request, **kwargs): """Return a dictionary of context data used to render the tab. Required. """ return kwargs
[docs] def enabled(self, request): """Determines whether or not the tab should be accessible. For example, the tab should be rendered into the HTML on load and respond to a click event. If a tab returns ``False`` from ``enabled`` it will ignore the value of ``preload`` and only render the HTML of the tab after being clicked. The default behavior is to return ``True`` for all cases. """ return True
[docs] def allowed(self, request): """Determines whether or not the tab is displayed. Tab instances can override this method to specify conditions under which this tab should not be shown at all by returning ``False``. """ if not self.policy_rules: return True policy_check = utils_settings.import_setting("POLICY_CHECK_FUNCTION") if policy_check: return policy_check(self.policy_rules, request) return True
[docs] def post(self, request, *args, **kwargs): """Handles POST data sent to a tab. Tab instances can override this method to have tab-specific POST logic without polluting the TabView code. The default behavior is to ignore POST data. """
[docs]class TableTab(Tab): """A Tab class which knows how to deal with DataTable classes inside of it. This distinct class is required due to the complexity involved in handling both dynamic tab loading, dynamic table updating and table actions all within one view. .. attribute:: table_classes An iterable containing the :class:`~horizon.tables.DataTable` classes which this tab will contain. Equivalent to the :attr:`~horizon.tables.MultiTableView.table_classes` attribute on :class:`~horizon.tables.MultiTableView`. For each table class you need to define a corresponding ``get_{{ table_name }}_data`` method as with :class:`~horizon.tables.MultiTableView`. """ table_classes = [] def __init__(self, tab_group, request): super().__init__(tab_group, request) if not self.table_classes: class_name = self.__class__.__name__ raise NotImplementedError("You must define a table_class " "attribute on %s" % class_name) # Instantiate our table classes but don't assign data yet if self._allowed: table_instances = [(, table(request, **tab_group.kwargs)) for table in self.table_classes] else: # When a corresponding tab is not allowed, there is no need to # instantiate table classes (Related to bug 1791296). table_instances = [] self._tables = OrderedDict(table_instances) self._table_data_loaded = False
[docs] def load_table_data(self): """Calls the ``get_{{ table_name }}_data`` methods for each table class. When returning, the loaded data is set on the tables. """ # We only want the data to be loaded once, so we track if we have... if not self._table_data_loaded: for table_name, table in self._tables.items(): # Fetch the data function. func_name = "get_%s_data" % table_name data_func = getattr(self, func_name, None) if data_func is None: cls_name = self.__class__.__name__ raise NotImplementedError( "You must define a %(func_name)s method on" " %(cls_name)s." % {'func_name': func_name, 'cls_name': cls_name}) # Load the data. = data_func() table._meta.has_prev_data = self.has_prev_data(table) table._meta.has_more_data = self.has_more_data(table) # Mark our data as loaded so we don't run the loaders again. self._table_data_loaded = True
[docs] def get_context_data(self, request, **kwargs): """Adds a ``{{ table_name }}_table`` item to the context for each table. The target tables are specified by the :attr:`~horizon.tabs.TableTab.table_classes` attribute. If only one table class is provided, a shortcut ``table`` context variable is also added containing the single table. """ context = super().get_context_data(request, **kwargs) # If the data hasn't been manually loaded before now, # make certain it's loaded before setting the context. self.load_table_data() for table_name, table in self._tables.items(): # If there's only one table class, add a shortcut name as well. if len(self.table_classes) == 1: context["table"] = table context["%s_table" % table_name] = table return context
def has_prev_data(self, table): return False def has_more_data(self, table): return False
class DetailTabsGroup(TabGroup): template_name = "horizon/common/_detail_tab_group.html"