dojo() View Helper
The dojo() view helper is intended to simplify setting up
the Dojo environment, including the following responsibilities:
Specifying either a CDN or a local path to a Dojo
install.Specifying paths to custom Dojo modules.Specifying dojo.require statements.Specifying dijit stylesheet themes to use.Specifying dojo.addOnLoad() events.
The dojo() view helper implementation is an example of a
placeholder implementation. The data set in it persists between view
objects and may be directly echoed from your layout script.
dojo() View Helper Usage Example
For this example, let's assume the developer will be using Dojo from
a local path, will require several dijits, and will be
utilizing the Tundra dijit theme.
On many pages, the developer may not utilize Dojo at all. So, we
will first focus on a view script where Dojo is needed and then on the
layout script, where we will setup some of the Dojo environment and
then render it.
First, we need to tell our view object to use the Dojo view helper
paths. This can be done in your bootstrap or an early-running
plugin; simply grab your view object and execute the following:
addHelperPath('Zend/Dojo/View/Helper/', 'Zend_Dojo_View_Helper');
]]>
Next, the view script. In this case, we're going to specify
that we will be using a FilteringSelect -- which will consume a
custom store based on QueryReadStore, which we'll call
'PairedStore' and store in our 'custom' module.
State:
dojo()->enable()
->setDjConfigOption('parseOnLoad', true)
->registerModulePath('custom', '../custom/')
->requireModule('dijit.form.FilteringSelect')
->requireModule('custom.PairedStore'); ?>
]]>
In our layout script, we'll then check to see if Dojo is enabled,
and, if so, we'll do some more general configuration and assemble
it:
doctype() ?>
headTitle() ?>
headMeta() ?>
headLink() ?>
headStyle() ?>
dojo()->isEnabled()){
$this->dojo()->setLocalPath('/js/dojo/dojo.js')
->addStyleSheetModule('dijit.themes.tundra');
echo $this->dojo();
}
?>
headScript() ?>
layout()->content ?>
inlineScript() ?>
]]>
At this point, you only need to ensure that your files are in the
correct locations and that you've created the end point action for
your FilteringSelect!
Programmatic and Declarative Usage of Dojo
Dojo allows both declarative and
programmatic usage of many of its features.
Declarative usage uses standard HTML elements
with non-standard attributes that are parsed when the page is
loaded. While this is a powerful and simple syntax to utilize, for
many developers this can cause issues with page validation.
Programmatic usage allows the developer to
decorate existing elements by pulling them by ID or CSS selectors
and passing them to the appropriate object constructors in Dojo.
Because no non-standard HTML attributes are used, pages continue to
validate.
In practice, both use cases allow for graceful degradation when
javascript is disabled or the various Dojo script resources are
unreachable. To promote standards and document validation,
Zend Framework uses programmatic usage by default; the various view
helpers will generate javascript and push it to the
dojo() view helper for inclusion when rendered.
Developers using this technique may also wish to explore the option
of writing their own programmatic decoration of the page. One
benefit would be the ability to specify handlers for dijit events.
To allow this, as well as the ability to use declarative syntax,
there are a number of static methods available to set this behavior
globally.
Specifying Declarative and Programmatic Dojo Usage
To specify declarative usage, simply call the static
setUseDeclarative() method:
If you decide instead to use programmatic usage, call the static
setUseProgrammatic() method:
Finally, if you want to create your own programmatic rules, you
should specify programmatic usage, but pass in the value '-1';
in this situation, no javascript for decorating any dijits used
will be created.
Themes
Dojo allows the creation of themes for its dijits (widgets). You may
select one by passing in a module path:
dojo()->addStylesheetModule('dijit.themes.tundra');
]]>
The module path is discovered by using the character '.' as a
directory separator and using the last value in the list as the name
of the CSS file in that theme directory to use; in the example
above, Dojo will look for the theme in
'dijit/themes/tundra/tundra.css'.
When using a theme, it is important to remember to pass the theme
class to, at the least, a container surrounding any dijits you are
using; the most common use case is to pass it in the body:
]]>Using Layers (Custom Builds)
By default, when you use a dojo.require statement, dojo will make a
request back to the server to grab the appropriate javascript file.
If you have many dijits in place, this results in many requests to
the server -- which is not optimal.
Dojo's answer to this is to provide the ability to create
custom builds. Builds do several things:
Groups required files into layers; a layer
lumps all required files into a single JS file. (Hence the name
of this section.)
"Interns" non-javascript files used by dijits (typically,
template files). These are also grouped in the same JS file as
the layer.
Passes the file through ShrinkSafe, which strips whitespace and
comments, as well as shortens variable names.
Some files can not be layered, but the build process will create a
special release directory with the layer file and all other files.
This allows you to have a slimmed-down distribution customized for
your site or application needs.
To use a layer, the dojo() view helper has a
addLayer() method for adding paths to required layers:
dojo()->addLayer('/js/foo/foo.js');
]]>
For more information on creating custom builds, please refer
to the Dojo build documentation.
Methods Available
The dojo() view helper always returns an instance of
the dojo placeholder container. That container object has the
following methods available:
setView(Zend_View_Interface $view): set
a view instance in the container.enable(): explicitly enable Dojo
integration.disable(): disable Dojo
integration.isEnabled(): determine whether or not
Dojo integration is enabled.requireModule($module): setup a
dojo.require statement.getModules(): determine what modules
have been required.registerModulePath($module, $path):
register a custom Dojo module path.getModulePaths(): get list of
registered module paths.addLayer($path): add a layer (custom
build) path to use.getLayers(): get a list of all
registered layer paths (custom builds).removeLayer($path): remove the layer
that matches $path from the list of registered
layers (custom builds).setCdnBase($url): set the base URL for
a CDN; typically, one of the
Zend_Dojo::CDN_BASE_AOL or
Zend_Dojo::CDN_BASE_GOOGLE, but it only needs
to be the URL string prior to the version number.getCdnBase(): retrieve the base CDN url
to utilize.setCdnVersion($version = null): set
which version of Dojo to utilize from the CDN.getCdnVersion(): retrieve what
version of Dojo from the CDN will be used.setCdnDojoPath($path): set the relative
path to the dojo.js or dojo.xd.js file on a CDN; typically,
one of the Zend_Dojo::CDN_DOJO_PATH_AOL or
Zend_Dojo::CDN_DOJO_PATH_GOOGLE, but it only
needs to be the path string following the version
number.getCdnDojoPath(): retrieve the last
path segment of the CDN url pointing to the dojo.js
file.useCdn(): tell the container to
utilize the CDN; implicitly enables integration.setLocalPath($path): tell the container
the path to a local Dojo install (should be a path relative
to the server, and contain the dojo.js file itself);
implicitly enables integration.getLocalPath(): determine what local
path to Dojo is being used.useLocalPath(): is the integration
utilizing a Dojo local path?setDjConfig(array $config): set
dojo/dijit configuration values (expects assoc
array).setDjConfigOption($option, $value): set
a single dojo/dijit configuration value.getDjConfig(): get all dojo/dijit
configuration values.getDjConfigOption($option, $default =
null): get a single dojo/dijit configuration
value.addStylesheetModule($module): add a
stylesheet based on a module theme.getStylesheetModules(): get stylesheets
registered as module themes.addStylesheet($path): add a local
stylesheet for use with Dojo.getStylesheets(): get local Dojo
stylesheets.addOnLoad($spec, $function = null): add
a lambda for dojo.onLoad to call. If one argument is passed,
it is assumed to be either a function name or a javascript
closure. If two arguments are passed, the first is assumed
to be the name of an object instance variable and the second
either a method name in that object or a closure to utilize
with that object.prependOnLoad($spec, $function = null):
exactly like addOnLoad(), excepts prepends to
beginning of onLoad stack.getOnLoadActions(): retrieve all
dojo.onLoad actions registered with the container. This will
be an array of arrays.onLoadCaptureStart($obj = null):
capture data to be used as a lambda for dojo.onLoad(). If
$obj is provided, the captured JS code will be considered a
closure to use with that Javascript object.onLoadCaptureEnd($obj = null): finish
capturing data for use with dojo.onLoad().javascriptCaptureStart():
capture arbitrary javascript to be included with Dojo JS
(onLoad, require, etc. statements).javascriptCaptureEnd(): finish
capturing javascript.__toString(): cast the container to a
string; renders all HTML style and script elements.