--- a/doc/book/en/development/devweb/js.rst Tue Apr 06 10:29:41 2010 +0200
+++ b/doc/book/en/development/devweb/js.rst Tue Apr 06 15:11:51 2010 +0200
@@ -54,12 +54,225 @@
ajax request, otherwise the document itself for standard HTTP
requests.
+Important AJAX APIS
+~~~~~~~~~~~~~~~~~~~
-Overview of what's available
+* `jQuery.fn.loadxhtml` is an important extension to jQuery which
+ allow proper loading and in-place DOM update of xhtml views. It is
+ suitably augmented to trigger necessary events, and process CubicWeb
+ specific elements such as the facet system, fckeditor, etc.
+
+* `asyncRemoteExec` and `remoteExec` are the base building blocks for
+ doing arbitrary async (resp. sync) communications with the server
+
+A simple example with asyncRemoteExec
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+In the python side, we have to extend the BaseController class. The
+@jsonize decorator ensures that the `return value` of the method is
+encoded as JSON data. By construction, the JSonController inputs
+everything in JSON format.
+
+.. sourcecode: python
+
+ from cubicweb.web.views.basecontrollers import JSonController, jsonize
+
+ @monkeypatch(JSonController)
+ @jsonize
+ def js_say_hello(self, name):
+ return u'hello %s' % name
+
+In the javascript side, we do the asynchronous call. Notice how it
+creates a `deferred` object. Proper treatment of the return value or
+error handling has to be done through the addCallback and addErrback
+methods.
+
+.. sourcecode: javascript
+
+ function async_hello(name) {
+ var deferred = asyncRemoteExec('say_hello', name);
+ deferred.addCallback(function (response) {
+ alert(response);
+ });
+ deferred.addErrback(function () {
+ alert('something fishy happened');
+ });
+ }
+
+ function sync_hello(name) {
+ alert( remoteExec('say_hello', name) );
+ }
+
+A simple example with loadxhtml
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Here we are concerned with the retrieval of a specific view to be
+injected in the live DOM. The view will be of course selected
+server-side using an entity eid provided by the client side.
+
+.. sourcecode: python
+
+ from cubicweb import typed_eid
+ from cubicweb.web.views.basecontrollers import JSonController, xhtmlize
+
+ @monkeypatch(JSonController)
+ @xhtmlize
+ def js_frob_status(self, eid, frobname):
+ entity = self._cw.entity_from_eid(typed_eid(eid))
+ return entity.view('frob', name=frobname)
+
+.. sourcecode: javascript
+
+ function update_some_div(divid, eid, frobname) {
+ var params = {fname:'frob_status', eid: eid, frobname:frobname};
+ jQuery('#'+divid).loadxhtml(JSON_BASE_URL, params, 'post');
+ }
+
+In this example, the url argument is the base json url of a cube
+instance (it should contain something like
+`http://myinstance/json?`). The actual JSonController method name is
+encoded in the `params` dictionnary using the `fname` key.
+
+A more real-life example from CubicWeb
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A frequent use case of Web 2 applications is the delayed (or
+on-demand) loading of pieces of the DOM. This is typically achieved
+using some preparation of the initial DOM nodes, jQuery event handling
+and proper use of loadxhtml.
+
+We present here a skeletal version of the mecanism used in CubicWeb
+and available in web/views/tabs.py, in the `LazyViewMixin` class.
+
+.. sourcecode: python
+
+ def lazyview(self, vid, rql=None):
+ """ a lazy version of wview """
+ w = self.w
+ self._cw.add_js('cubicweb.lazy.js')
+ urlparams = {'vid' : vid, 'fname' : 'view'}
+ if rql is not None:
+ urlparams['rql'] = rql
+ w(u'<div id="lazy-%s" cubicweb:loadurl="%s">' % (
+ vid, xml_escape(self._cw.build_url('json', **urlparams))))
+ w(u'</div>')
+ self._cw.add_onload(u"""
+ jQuery('#lazy-%(vid)s').bind('%(event)s', function() {
+ load_now('#lazy-%(vid)s');});"""
+ % {'event': 'load_%s' % vid, 'vid': vid})
+
+This creates a `div` with an specific event associated to it.
+
+The full version deals with:
+
+* optional parameters such as an rql expression, an entity eid, an
+ rset
+
+* the ability to further reload the fragment
+
+* the ability to display a spinning wheel while the fragment is still
+ not loaded
+
+* handling of browsers that do not support ajax (search engines,
+ text-based browsers such as lynx, etc.)
+
+The javascript side is quite simple, due to loadxhtml awesomeness.
+
+.. sourcecode: javascript
+
+ function load_now(eltsel) {
+ var lazydiv = jQuery(eltsel);
+ lazydiv.loadxhtml(lazydiv.attr('cubicweb:loadurl'));
+ }
+
+This is all significantly different of the previous `simple example`
+(albeit this example actually comes from real-life code).
+
+Notice how the `cubicweb:loadurl` is used to convey the url
+information. The base of this url is similar to the global javascript
+JSON_BASE_URL. According to the pattern described earlier,
+the `fname` parameter refers to the standard `js_view` method of the
+JSonController. This method renders an arbitrary view provided a view
+id (or `vid`) is provided, and most likely an rql expression yielding
+a result set against which a proper view instance will be selected.
+
+The `cubicweb:loadurl` is one of the 29 attributes extensions to XHTML
+in a specific cubicweb namespace. It is a means to pass information
+without breaking HTML nor XHTML compliance and without resorting to
+ungodly hacks.
+
+Given all this, it is easy to add a small nevertheless useful feature
+to force the loading of a lazy view (for instance, a very
+computation-intensive web page could be scinded into one fast-loading
+part and a delayed part).
+
+In the server side, a simple call to a javascript function is
+sufficient.
+
+.. sourcecode: python
+
+ def forceview(self, vid):
+ """trigger an event that will force immediate loading of the view
+ on dom readyness
+ """
+ self._cw.add_onload("trigger_load('%s');" % vid)
+
+The browser-side definition follows.
+
+.. sourcecode: javascript
+
+ function trigger_load(divid) {
+ jQuery('#lazy-' + divd).trigger('load_' + divid);
+ }
+
+
+Anatomy of a lodxhtml call
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The loadxhtml extension to jQuery accept many parameters with rich
+semantics. Let us detail these.
+
+* `url` (mandatory) should be a complete url, typically based on the
+ JSonController, but this is not strictly mandatory
+
+* `data` (optional) is a dictionnary of values given to the
+ controller specified through an `url` argument; some keys may have a
+ special meaning depending on the choosen controller (such as `fname`
+ for the JSonController); the `callback` key, if present, must refer
+ to a function to be called at the end of loadxhtml (more on this
+ below)
+
+* `reqtype` (optional) specifies the request method to be used (get or
+ post); if the argument is 'post', then the post method is used,
+ otherwise the get method is used
+
+* `mode` (optional) is one of `replace` (the default) which means the
+ loaded node will replace the current node content, `swap` to replace
+ the current node with the loaded node, and `append` which will
+ append the loaded node to the current node content
+
+
+About the `callback` option:
+
+* it is called with two parameters: the current node, and a list
+ containing the loaded (and post-processed node)
+
+* whenever is returns another function, this function is called in
+ turn with the same parameters as above
+
+This mecanism allows callback chaining.
+
+
+Javascript library: overview
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* jquery.* : jquery and jquery UI library
+* cubicweb.ajax.js : concentrates all ajax related facilities (it
+ extends jQuery with the loahxhtml function, provides a handfull of
+ high-level ajaxy operations like asyncRemoteExec, reloadComponent,
+ replacePageChunk, getDomFromResponse)
+
* cubicweb.python.js : adds a number of practical extension to stdanrd
javascript objects (on Date, Array, String, some list and dictionary
operations), and a pythonesque way to build classes. Defines a
@@ -69,11 +282,6 @@
in various other cubicweb javascript resources (baseuri, progress
cursor handling, popup login box, html2dom function, etc.)
-* cubicweb.ajax.js : concentrates all ajax related facilities (it
- extends jQuery with the loahxhtml function, provides a handfull of
- high-level ajaxy operations like asyncRemoteExec, reloadComponent,
- replacePageChunk, getDomFromResponse)
-
* cubicweb.widgets.js : provides a widget namespace and constructors
and helpers for various widgets (mainly facets and timeline)
@@ -83,5 +291,6 @@
* cubicweb.facets.js : used by the facets mechanism
-xxx massmailing, gmap, fckcwconfig, timeline-bundle, timeline-ext,
-calendar, goa, flotn tazy, tabs, bookmarks
+There is also javascript support for massmailing, gmap (google maps),
+fckcwconfig (fck editor), timeline, calendar, goa (CubicWeb over
+AppEngine), flot (charts drawing), tabs and bookmarks.
--- a/web/views/tabs.py Tue Apr 06 10:29:41 2010 +0200
+++ b/web/views/tabs.py Tue Apr 06 15:11:51 2010 +0200
@@ -32,9 +32,7 @@
def lazyview(self, vid, rql=None, eid=None, rset=None, tabid=None,
reloadable=False, show_spinbox=True, w=None):
- """a lazy version of wview
- first version only support lazy viewing for an entity at a time
- """
+ """ a lazy version of wview """
w = w or self.w
self._cw.add_js('cubicweb.lazy.js')
urlparams = {'vid' : vid, 'fname' : 'view'}