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+Building my photos web site with |cubicweb| part V: let's make it even more user friendly
+=========================================================================================
+
+.. _uiprops:
+
+Step 1: tired of the default look?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+OK... Now our site has its most desired features. But... I would like to make it look
+somewhat like *my* website. It is not www.cubicweb.org after all. Let's tackle this
+first!
+
+The first thing we can to is to change the logo. There are various way to achieve
+this. The easiest way is to put a :file:`logo.png` file into the cube's :file:`data`
+directory. As data files are looked at according to cubes order (CubicWeb
+resources coming last), that file will be selected instead of CubicWeb's one.
+
+.. Note::
+ As the location for static resources are cached, you'll have to restart
+ your instance for this to be taken into account.
+
+Though there are some cases where you don't want to use a :file:`logo.png` file.
+For instance if it's a JPEG file. You can still change the logo by defining in
+the cube's :file:`uiprops.py` file:
+
+.. sourcecode:: python
+
+ LOGO = data('logo.jpg')
+
+The uiprops machinery is used to define some static file resources,
+such as the logo, default Javascript / CSS files, as well as CSS
+properties (we'll see that later).
+
+.. Note::
+ This file is imported specifically by |cubicweb|, with a predefined name space,
+ containing for instance the `data` function, telling the file is somewhere
+ in a cube or CubicWeb's data directory.
+
+ One side effect of this is that it can't be imported as a regular python
+ module.
+
+The nice thing is that in debug mode, change to a :file:`uiprops.py` file are detected
+and then automatically reloaded.
+
+Now, as it's a photos web-site, I would like to have a photo of mine as background...
+After some trials I won't detail here, I've found a working recipe explained `here`_.
+All I've to do is to override some stuff of the default CubicWeb user interface to
+apply it as explained.
+
+The first thing to to get the ``<img/>`` tag as first element after the
+``<body>`` tag. If you know a way to avoid this by simply specifying the image
+in the CSS, tell me! The easiest way to do so is to override the
+:class:`HTMLPageHeader` view, since that's the one that is directly called once
+the ``<body>`` has been written. How did I find this? By looking in the
+:mod:`cubiweb.web.views.basetemplates` module, since I know that global page
+layouts sits there. I could also have grep the "body" tag in
+:mod:`cubicweb.web.views`... Finding this was the hardest part. Now all I need is
+to customize it to write that ``img`` tag, as below:
+
+.. sourcecode:: python
+
+ class HTMLPageHeader(basetemplates.HTMLPageHeader):
+ # override this since it's the easier way to have our bg image
+ # as the first element following <body>
+ def call(self, **kwargs):
+ self.w(u'<img id="bg-image" src="%sbackground.jpg" alt="background image"/>'
+ % self._cw.datadir_url)
+ super(HTMLPageHeader, self).call(**kwargs)
+
+
+ def registration_callback(vreg):
+ vreg.register_all(globals().values(), __name__, (HTMLPageHeader))
+ vreg.register_and_replace(HTMLPageHeader, basetemplates.HTMLPageHeader)
+
+
+As you may have guessed, my background image is in a :file:`background.jpg` file
+in the cube's :file:`data` directory, but there are still some things to explain
+to newcomers here:
+
+* The :meth:`call` method is there the main access point of the view. It's called by
+ the view's :meth:`render` method. It is not the only access point for a view, but
+ this will be detailed later.
+
+* Calling `self.w` writes something to the output stream. Except for binary views
+ (which do not generate text), it *must* be passed an Unicode string.
+
+* The proper way to get a file in :file:`data` directory is to use the `datadir_url`
+ attribute of the incoming request (e.g. `self._cw`).
+
+I won't explain again the :func:`registration_callback` stuff, you should understand it
+now! If not, go back to previous posts in the series :)
+
+Fine. Now all I've to do is to add a bit of CSS to get it to behave nicely (which
+is not the case at all for now). I'll put all this in a :file:`cubes.sytweb.css`
+file, stored as usual in our :file:`data` directory:
+
+.. sourcecode:: css
+
+
+ /* fixed full screen background image
+ * as explained on http://webdesign.about.com/od/css3/f/blfaqbgsize.htm
+ *
+ * syt update: set z-index=0 on the img instead of z-index=1 on div#page & co to
+ * avoid pb with the user actions menu
+ */
+ img#bg-image {
+ position: fixed;
+ top: 0;
+ left: 0;
+ width: 100%;
+ height: 100%;
+ z-index: 0;
+ }
+
+ div#page, table#header, div#footer {
+ background: transparent;
+ position: relative;
+ }
+
+ /* add some space around the logo
+ */
+ img#logo {
+ padding: 5px 15px 0px 15px;
+ }
+
+ /* more dark font for metadata to have a chance to see them with the background
+ * image
+ */
+ div.metadata {
+ color: black;
+ }
+
+You can see here stuff explained in the cited page, with only a slight modification
+explained in the comments, plus some additional rules to make things somewhat cleaner:
+
+* a bit of padding around the logo
+
+* darker metadata which appears by default below the content (the white frame in the page)
+
+To get this CSS file used everywhere in the site, I have to modify the :file:`uiprops.py` file
+introduced above:
+
+.. sourcecode:: python
+
+ STYLESHEETS = sheet['STYLESHEETS'] + [data('cubes.sytweb.css')]
+
+.. Note::
+ `sheet` is another predefined variable containing values defined by
+ already process `:file:`uiprops.py`` file, notably the CubicWeb's one.
+
+Here we simply want our CSS in addition to CubicWeb's base CSS files, so we
+redefine the `STYLESHEETS` variable to existing CSS (accessed through the `sheet`
+variable) with our one added. I could also have done:
+
+.. sourcecode:: python
+
+ sheet['STYLESHEETS'].append(data('cubes.sytweb.css'))
+
+But this is less interesting since we don't see the overriding mechanism...
+
+At this point, the site should start looking good, the background image being
+resized to fit the screen.
+
+.. image:: ../../images/tutos-photowebsite_background-image.png
+
+The final touch: let's customize CubicWeb's CSS to get less orange... By simply adding
+
+.. sourcecode:: python
+
+ contextualBoxTitleBg = incontextBoxTitleBg = '#AAAAAA'
+
+and reloading the page we've just seen, we know have a nice greyed box instead of
+the orange one:
+
+.. image:: ../../images/tutos-photowebsite_grey-box.png
+
+This is because CubicWeb's CSS include some variables which are
+expanded by values defined in uiprops file. In our case we controlled the
+properties of the CSS `background` property of boxes with CSS class
+`contextualBoxTitleBg` and `incontextBoxTitleBg`.
+
+
+Step 2: configuring boxes
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Boxes present to the user some ways to use the application. Let's first do a few
+user interface tweaks in our :file:`views.py` file:
+
+.. sourcecode:: python
+
+ from cubicweb.predicates import none_rset
+ from cubicweb.web.views import bookmark
+ from cubes.zone import views as zone
+ from cubes.tag import views as tag
+
+ # change bookmarks box selector so it's only displayed on startup views
+ bookmark.BookmarksBox.__select__ = bookmark.BookmarksBox.__select__ & none_rset()
+ # move zone box to the left instead of in the context frame and tweak its order
+ zone.ZoneBox.context = 'left'
+ zone.ZoneBox.order = 100
+ # move tags box to the left instead of in the context frame and tweak its order
+ tag.TagsBox.context = 'left'
+ tag.TagsBox.order = 102
+ # hide similarity box, not interested
+ tag.SimilarityBox.visible = False
+
+The idea is to move all boxes in the left column, so we get more space for the
+photos. Now, serious things: I want a box similar to the tags box but to handle
+the `Person displayed_on File` relation. We can do this simply by adding a
+:class:`AjaxEditRelationCtxComponent` subclass to our views, as below:
+
+.. sourcecode:: python
+
+ from logilab.common.decorators import monkeypatch
+ from cubicweb import ValidationError
+ from cubicweb.web.views import uicfg, component
+ from cubicweb.web.views import basecontrollers
+
+ # hide displayed_on relation using uicfg since it will be displayed by the box below
+ uicfg.primaryview_section.tag_object_of(('*', 'displayed_on', '*'), 'hidden')
+
+ class PersonBox(component.AjaxEditRelationCtxComponent):
+ __regid__ = 'sytweb.displayed-on-box'
+ # box position
+ order = 101
+ context = 'left'
+ # define relation to be handled
+ rtype = 'displayed_on'
+ role = 'object'
+ target_etype = 'Person'
+ # messages
+ added_msg = _('person has been added')
+ removed_msg = _('person has been removed')
+ # bind to js_* methods of the json controller
+ fname_vocabulary = 'unrelated_persons'
+ fname_validate = 'link_to_person'
+ fname_remove = 'unlink_person'
+
+
+ @monkeypatch(basecontrollers.JSonController)
+ @basecontrollers.jsonize
+ def js_unrelated_persons(self, eid):
+ """return tag unrelated to an entity"""
+ rql = "Any F + ' ' + S WHERE P surname S, P firstname F, X eid %(x)s, NOT P displayed_on X"
+ return [name for (name,) in self._cw.execute(rql, {'x' : eid})]
+
+
+ @monkeypatch(basecontrollers.JSonController)
+ def js_link_to_person(self, eid, people):
+ req = self._cw
+ for name in people:
+ name = name.strip().title()
+ if not name:
+ continue
+ try:
+ firstname, surname = name.split(None, 1)
+ except:
+ raise ValidationError(eid, {('displayed_on', 'object'): 'provide <first name> <surname>'})
+ rset = req.execute('Person P WHERE '
+ 'P firstname %(firstname)s, P surname %(surname)s',
+ locals())
+ if rset:
+ person = rset.get_entity(0, 0)
+ else:
+ person = req.create_entity('Person', firstname=firstname,
+ surname=surname)
+ req.execute('SET P displayed_on X WHERE '
+ 'P eid %(p)s, X eid %(x)s, NOT P displayed_on X',
+ {'p': person.eid, 'x' : eid})
+
+ @monkeypatch(basecontrollers.JSonController)
+ def js_unlink_person(self, eid, personeid):
+ self._cw.execute('DELETE P displayed_on X WHERE P eid %(p)s, X eid %(x)s',
+ {'p': personeid, 'x': eid})
+
+
+You basically subclass to configure with some class attributes. The `fname_*`
+attributes give the name of methods that should be defined on the json control to
+make the AJAX part of the widget work: one to get the vocabulary, one to add a
+relation and another to delete a relation. These methods must start by a `js_`
+prefix and are added to the controller using the `@monkeypatch` decorator. In my
+case, the most complicated method is the one which adds a relation, since it
+tries to see if the person already exists, and else automatically create it,
+assuming the user entered "firstname surname".
+
+Let's see how it looks like on a file primary view:
+
+.. image:: ../../images/tutos-photowebsite_boxes.png
+
+Great, it's now as easy for me to link my pictures to people than to tag them.
+Also, visitors get a consistent display of these two pieces of information.
+
+.. Note::
+ The ui component system has been refactored in `CubicWeb 3.10`_, which also
+ introduced the :class:`AjaxEditRelationCtxComponent` class.
+
+
+Step 3: configuring facets
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The last feature we'll add today is facet configuration. If you access to the
+'/file' url, you'll see a set of 'facets' appearing in the left column. Facets
+provide an intuitive way to build a query incrementally, by proposing to the user
+various way to restrict the result set. For instance CubicWeb proposes a facet to
+restrict based on who created an entity; the tag cube proposes a facet to
+restrict based on tags; the zoe cube a facet to restrict based on geographical
+location, and so on. In that gist, I want to propose a facet to restrict based on
+the people displayed on the picture. To do so, there are various classes in the
+:mod:`cubicweb.web.facet` module which simply have to be configured using class
+attributes as we've done for the box. In our case, we'll define a subclass of
+:class:`RelationFacet`.
+
+.. Note::
+
+ Since that's ui stuff, we'll continue to add code below to our
+ :file:`views.py` file. Though we begin to have a lot of various code their, so
+ it's may be a good time to split our views module into submodules of a `view`
+ package. In our case of a simple application (glue) cube, we could start using
+ for instance the layout below: ::
+
+ views/__init__.py # uicfg configuration, facets
+ views/layout.py # header/footer/background stuff
+ views/components.py # boxes, adapters
+ views/pages.py # index view, 404 view
+
+.. sourcecode:: python
+
+ from cubicweb.web import facet
+
+ class DisplayedOnFacet(facet.RelationFacet):
+ __regid__ = 'displayed_on-facet'
+ # relation to be displayed
+ rtype = 'displayed_on'
+ role = 'object'
+ # view to use to display persons
+ label_vid = 'combobox'
+
+Let's say we also want to filter according to the `visibility` attribute. This is
+even simpler as we just have to derive from the :class:`AttributeFacet` class:
+
+.. sourcecode:: python
+
+ class VisibilityFacet(facet.AttributeFacet):
+ __regid__ = 'visibility-facet'
+ rtype = 'visibility'
+
+Now if I search for some pictures on my site, I get the following facets available:
+
+.. image:: ../../images/tutos-photowebsite_facets.png
+
+.. Note::
+
+ By default a facet must be applyable to every entity in the result set and
+ provide at leat two elements of vocabulary to be displayed (for instance you
+ won't see the `created_by` facet if the same user has created all
+ entities). This may explain why you don't see yours...
+
+
+Conclusion
+~~~~~~~~~~
+
+We started to see the power behind the infrastructure provided by the
+framework, both on the pure ui (CSS, Javascript) side and on the Python side
+(high level generic classes for components, including boxes and facets). We now
+have, with a few lines of code, a full-featured web site with a personalized look.
+
+Of course we'll probably want more as time goes, but we can now
+concentrate on making good pictures, publishing albums and sharing them with
+friends...
+
+
+
+.. _`CubicWeb 3.10`: http://www.cubicweb.org/blogentry/1330518
+.. _`here`: http://webdesign.about.com/od/css3/f/blfaqbgsize.htm