diff -r 76ab3c71aff2 -r c67bcee93248 doc/book/en/devweb/js.rst --- a/doc/book/en/devweb/js.rst Mon Jul 06 17:39:35 2015 +0200 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,394 +0,0 @@ -.. -*- coding: utf-8 -*- - -Javascript ----------- - -*CubicWeb* uses quite a bit of javascript in its user interface and -ships with jquery (1.3.x) and parts of the jquery UI library, plus a -number of homegrown files and also other third party libraries. - -All javascript files are stored in cubicweb/web/data/. There are -around thirty js files there. In a cube it goes to data/. - -Obviously one does not want javascript pieces to be loaded all at -once, hence the framework provides a number of mechanisms and -conventions to deal with javascript resources. - -Conventions -~~~~~~~~~~~ - -It is good practice to name cube specific js files after the name of -the cube, like this : 'cube.mycube.js', so as to avoid name clashes. - -.. XXX external_resources variable (which needs love) - -Server-side Javascript API -~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Javascript resources are typically loaded on demand, from views. The -request object (available as self._cw from most application objects, -for instance views and entities objects) has a few methods to do that: - -* `add_js(self, jsfiles, localfile=True)` which takes a sequence of - javascript files and writes proper entries into the HTML header - section. The localfile parameter allows to declare resources which - are not from web/data (for instance, residing on a content delivery - network). - -* `add_onload(self, jscode)` which adds one raw javascript code - snippet inline in the html headers. This is quite useful for setting - up early jQuery(document).ready(...) initialisations. - -Javascript events -~~~~~~~~~~~~~~~~~ - -* ``server-response``: this event is triggered on HTTP responses (both - standard and ajax). The two following extra parameters are passed - to callbacks : - - - ``ajax``: a boolean that says if the reponse was issued by an - ajax request - - - ``node``: the DOM node returned by the server in case of an - ajax request, otherwise the document itself for standard HTTP - requests. - -Important javascript AJAX APIS -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -* `asyncRemoteExec` and `remoteExec` are the base building blocks for - doing arbitrary async (resp. sync) communications with the server - -* `reloadComponent` is a convenience function to replace a DOM node - with server supplied content coming from a specific registry (this - is quite handy to refresh the content of some boxes for instances) - -* `jQuery.fn.loadxhtml` is an important extension to jQuery which - allows 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. - - -A simple example with asyncRemoteExec -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -On the python side, we have to define an -:class:`cubicweb.web.views.ajaxcontroller.AjaxFunction` object. The -simplest way to do that is to use the -:func:`cubicweb.web.views.ajaxcontroller.ajaxfunc` decorator (for more -details on this, refer to :ref:`ajax`). - -.. sourcecode: python - - from cubicweb.web.views.ajaxcontroller import ajaxfunc - - # serialize output to json to get it back easily on the javascript side - @ajaxfunc(output_type='json') - def js_say_hello(self, name): - return u'hello %s' % name - -On 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 asyncHello(name) { - var deferred = asyncRemoteExec('say_hello', name); - deferred.addCallback(function (response) { - alert(response); - }); - deferred.addErrback(function (error) { - alert('something fishy happened'); - }); - } - - function syncHello(name) { - alert( remoteExec('say_hello', name) ); - } - -Anatomy of a reloadComponent call -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -`reloadComponent` allows to dynamically replace some DOM node with new -elements. It has the following signature: - -* `compid` (mandatory) is the name of the component to be reloaded - -* `rql` (optional) will be used to generate a result set given as - argument to the selected component - -* `registry` (optional) defaults to 'components' but can be any other - valid registry name - -* `nodeid` (optional) defaults to compid + 'Component' but can be any - explicitly specified DOM node id - -* `extraargs` (optional) should be a dictionary of values that will be - given to the cell_call method of the component - -A simple reloadComponent example -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -The server side implementation of `reloadComponent` is the -:func:`cubicweb.web.views.ajaxcontroller.component` *AjaxFunction* appobject. - -The following function implements a two-steps method to delete a -standard bookmark and refresh the UI, while keeping the UI responsive. - -.. sourcecode:: javascript - - function removeBookmark(beid) { - d = asyncRemoteExec('delete_bookmark', beid); - d.addCallback(function(boxcontent) { - reloadComponent('bookmarks_box', '', 'boxes', 'bookmarks_box'); - document.location.hash = '#header'; - updateMessage(_("bookmark has been removed")); - }); - } - -`reloadComponent` is called with the id of the bookmark box as -argument, no rql expression (because the bookmarks display is actually -independant of any dataset context), a reference to the 'boxes' -registry (which hosts all left, right and contextual boxes) and -finally an explicit 'bookmarks_box' nodeid argument that stipulates -the target DOM node. - -Anatomy of a loadxhtml call -~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -`jQuery.fn.loadxhtml` is an important extension to jQuery which allows -proper loading and in-place DOM update of xhtml views. The existing -`jQuery.load`_ function does not handle xhtml, hence the addition. The -API of loadxhtml is roughly similar to that of `jQuery.load`_. - -.. _`jQuery.load`: http://api.jquery.com/load/ - - -* `url` (mandatory) should be a complete url (typically referencing - the :class:`cubicweb.web.views.ajaxcontroller.AjaxController`, - but this is not strictly mandatory) - -* `data` (optional) is a dictionary 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 it returns another function, this function is called in - turn with the same parameters as above - -This mechanism allows callback chaining. - - -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.web.views.ajaxcontroller import ajaxfunc - - @ajaxfunc(output_type='xhtml') - def frob_status(self, eid, frobname): - entity = self._cw.entity_from_eid(eid) - return entity.view('frob', name=frobname) - -.. sourcecode:: javascript - - function updateSomeDiv(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/ajax?`). The actual AjaxController method name is -encoded in the `params` dictionary using the `fname` key. - -A more real-life example -~~~~~~~~~~~~~~~~~~~~~~~~ - -A frequent need of Web 2 applications is the delayed (or demand -driven) 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'