The Primary View

By default, CubicWeb provides a view that fits every available entity type. This is the first view you might be interested in modifying. It is also one of the richest and most complex.

It is automatically selected on a one line result set containing an entity.

It lives in the cubicweb.web.views.primary module.

The primary view is supposed to render a maximum of informations about the entity.

Layout

The primary view has the following layout.

../../../_images/primaryview_template.png

Primary view configuration

If you want to customize the primary view of an entity, overriding the primary view class may not be necessary. For simple adjustments (attributes or relations display locations and styles), a much simpler way is to use uicfg.

Attributes/relations display location

In the primary view, there are three sections where attributes and relations can be displayed (represented in pink in the image above):

  • ‘attributes’
  • ‘relations’
  • ‘sideboxes’
Attributes can only be displayed in the attributes section (default
behavior). They can also be hidden. By default, attributes of type Password and Bytes are hidden.

For instance, to hide the title attribute of the Blog entity:

from cubicweb.web.views import uicfg
uicfg.primaryview_section.tag_attribute(('Blog', 'title'), 'hidden')

Relations can be either displayed in one of the three sections or hidden.

For relations, there are two methods:

  • tag_object_of for modifying the primary view of the object
  • tag_subject_of for modifying the primary view of the subject

These two methods take two arguments:

  • a triplet (subject, relation_name, object), where subject or object can be replaced with '*'
  • the section name or hidden
pv_section = uicfg.primaryview_section
# hide every relation `entry_of` in the `Blog` primary view
pv_section.tag_object_of(('*', 'entry_of', 'Blog'), 'hidden')

# display `entry_of` relations in the `relations`
# section in the `BlogEntry` primary view
pv_section.tag_subject_of(('BlogEntry', 'entry_of', '*'), 'relations')

Display content

You can use primaryview_display_ctrl to customize the display of attributes or relations. Values of primaryview_display_ctrl are dictionaries.

Common keys for attributes and relations are:

  • vid: specifies the regid of the view for displaying the attribute or the relation.

    If vid is not specified, the default value depends on the section:
    • attributes section: ‘reledit’ view
    • relations section: ‘autolimited’ view
    • sideboxes section: ‘sidebox’ view
  • order: int used to control order within a section. When not specified, automatically set according to order in which tags are added.

  • label: label for the relations section or side box

  • showlabel: boolean telling whether the label is displayed

# let us remind the schema of a blog entry
class BlogEntry(EntityType):
    title = String(required=True, fulltextindexed=True, maxsize=256)
    publish_date = Date(default='TODAY')
    content = String(required=True, fulltextindexed=True)
    entry_of = SubjectRelation('Blog', cardinality='?*')

# now, we want to show attributes
# with an order different from that in the schema definition
view_ctrl = uicfg.primaryview_display_ctrl
for index, attr in enumerate('title', 'content', 'publish_date'):
    view_ctrl.tag_attribute(('BlogEntry', attr), {'order': index})

By default, relations displayed in the ‘relations’ section are being displayed by the ‘autolimited’ view. This view will use comma separated values, or list view and/or limit your rset if there is too much items in it (and generate the “view all” link in this case).

You can control this view by setting the following values in the primaryview_display_ctrl relation tag:

  • limit, maximum number of entities to display. The value of the ‘navigation.related-limit’ cwproperty is used by default (which is 8 by default). If None, no limit.
  • use_list_limit, number of entities until which they should be display as a list (eg using the ‘list’ view). Below that limit, the ‘csv’ view is used. If None, display using ‘csv’ anyway.
  • subvid, the subview identifier (eg view that should be used of each item in the list)

Notice you can also use the filter key to set up a callback taking the related result set as argument and returning it filtered, to do some arbitrary filtering that can’t be done using rql for instance.

pv_section = uicfg.primaryview_section
# in `CWUser` primary view, display `created_by`
# relations in relations section
pv_section.tag_object_of(('*', 'created_by', 'CWUser'), 'relations')

# display this relation as a list, sets the label,
# limit the number of results and filters on comments
def filter_comment(rset):
    return rset.filtered_rset(lambda x: x.e_schema == 'Comment')
pv_ctrl = uicfg.primaryview_display_ctrl
pv_ctrl.tag_object_of(('*', 'created_by', 'CWUser'),
                      {'vid': 'list', 'label': _('latest comment(s):'),
                       'limit': True,
                       'filter': filter_comment})

Warning

with the primaryview_display_ctrl rtag, the subject or the object of the relation is ignored for respectively tag_object_of or tag_subject_of. To avoid warnings during execution, they should be set to '*'.

Public API of the PrimaryView class

class cubicweb.web.views.primary.PrimaryView(req=None, rset=None, **kwargs)[source]

The basic layout of a primary view is as in the Layout section. This layout is actually drawn by the render_entity method.

The methods you may want to modify while customizing a PrimaryView are:

render_entity_title(entity)[source]

Renders the entity title, by default using entity’s dc_title() method.

render_entity_attributes(entity)[source]

Renders all attributes and relations in the ‘attributes’ section.

render_entity_relations(entity)[source]

Renders all relations in the ‘relations’ section.

render_side_boxes(boxes)[source]

Renders side boxes on the right side of the content. This will generate a box for each relation in the ‘sidebox’ section, as well as explicit box appobjects selectable in this context.

The placement of relations in the relations section or in side boxes can be controlled through the Primary view configuration mechanism.

content_navigation_components(context)[source]

This method is applicable only for entity type implementing the interface IPrevNext. This interface is for entities which can be linked to a previous and/or next entity. This method will render the navigation links between entities of this type, either at the top or at the bottom of the page given the context (navcontent{top|bottom}).

Also, please note that by setting the following attributes in your subclass, you can already customize some of the rendering:

show_attr_label
Renders the attribute label next to the attribute value if set to True. Otherwise, does only display the attribute value.
show_rel_label
Renders the relation label next to the relation value if set to True. Otherwise, does only display the relation value.
main_related_section
Renders the relations of the entity if set to True.

A good practice is for you to identify the content of your entity type for which the default rendering does not answer your need so that you can focus on the specific method (from the list above) that needs to be modified. We do not advise you to overwrite render_entity unless you want a completely different layout.

Views that may be used to display an entity’s attribute or relation

Yoy may easily the display of an attribute or relation by simply configuring the view using one of primaryview_display_ctrl or reledit_ctrl to use one of the views describled below. For instance:

primaryview_display_ctrl.tag_attribute(('Foo', 'bar'), {'vid': 'attribute'})
class cubicweb.web.views.primary.AttributeView(req=None, rset=None, **kwargs)[source]
__regid__:attribute

This view is generally used to disable the reledit feature. It works on both relations and attributes.

class cubicweb.web.views.primary.URLAttributeView(req=None, rset=None, **kwargs)[source]
__regid__:urlattr

This view will wrap an attribute value (hence expect a string) into an ‘<a>’ HTML tag to display a clickable link.

class cubicweb.web.views.primary.VerbatimAttributeView(req=None, rset=None, **kwargs)[source]
__regid__:verbatimattr

This view will wrap an attribute value into an ‘<pre>’ HTML tag to display arbitrary text where EOL will be respected. It usually make sense for attributes whose value is a multi-lines string where new lines matters.

Example of customization and creation

We’ll show you now an example of a primary view and how to customize it.

If you want to change the way a BlogEntry is displayed, just override the method cell_call() of the view primary in BlogDemo/views.py.

from cubicweb.predicates import is_instance
from cubicweb.web.views.primary import Primaryview

class BlogEntryPrimaryView(PrimaryView):
    __select__ = PrimaryView.__select__ & is_instance('BlogEntry')

    def render_entity_attributes(self, entity):
        self.w(u'<p>published on %s</p>' %
               entity.publish_date.strftime('%Y-%m-%d'))
        super(BlogEntryPrimaryView, self).render_entity_attributes(entity)

The above source code defines a new primary view for BlogEntry. The __reid__ class attribute is not repeated there since it is inherited through the primary.PrimaryView class.

The selector for this view chains the selector of the inherited class with its own specific criterion.

The view method self.w() is used to output data. Here lines 08-09 output HTML for the publication date of the entry.

blog entries now look much nicer

Let us now improve the primary view of a blog

from logilab.mtconverter import xml_escape
from cubicweb.predicates import is_instance, one_line_rset
from cubicweb.web.views.primary import Primaryview

class BlogPrimaryView(PrimaryView):
    __regid__ = 'primary'
    __select__ = PrimaryView.__select__ & is_instance('Blog')
    rql = 'Any BE ORDERBY D DESC WHERE BE entry_of B, BE publish_date D, B eid %(b)s'

    def render_entity_relations(self, entity):
        rset = self._cw.execute(self.rql, {'b' : entity.eid})
        for entry in rset.entities():
            self.w(u'<p>%s</p>' % entry.view('inblogcontext'))

class BlogEntryInBlogView(EntityView):
    __regid__ = 'inblogcontext'
    __select__ = is_instance('BlogEntry')

    def cell_call(self, row, col):
        entity = self.cw_rset.get_entity(row, col)
        self.w(u'<a href="%s" title="%s">%s</a>' %
               entity.absolute_url(),
               xml_escape(entity.content[:50]),
               xml_escape(entity.description))

This happens in two places. First we override the render_entity_relations method of a Blog’s primary view. Here we want to display our blog entries in a custom way.

At line 10, a simple request is made to build a result set with all the entities linked to the current Blog entity by the relationship entry_of. The part of the framework handling the request knows about the schema and infers that such entities have to be of the BlogEntry kind and retrieves them (in the prescribed publish_date order).

The request returns a selection of data called a result set. Result set objects have an .entities() method returning a generator on requested entities (going transparently through the ORM layer).

At line 13 the view ‘inblogcontext’ is applied to each blog entry to output HTML. (Note that the ‘inblogcontext’ view is not defined whatsoever in CubicWeb. You are absolutely free to define whole view families.) We juste arrange to wrap each blogentry output in a ‘p’ html element.

Next, we define the ‘inblogcontext’ view. This is NOT a primary view, with its well-defined sections (title, metadata, attribtues, relations/boxes). All a basic view has to define is cell_call.

Since views are applied to result sets which can be tables of data, we have to recover the entity from its (row,col)-coordinates (line 20). Then we can spit some HTML.

Warning

Be careful: all strings manipulated in CubicWeb are actually unicode strings. While web browsers are usually tolerant to incoherent encodings they are being served, we should not abuse it. Hence we have to properly escape our data. The xml_escape() function has to be used to safely fill (X)HTML elements from Python unicode strings.

Assuming we added entries to the blog titled MyLife, displaying it now allows to read its description and all its entries.

a blog and all its entries