How to specify the block name in Magento?

Question

This is a basic question, but which drove me sleepless for the past a few days.

I wrote a customized module with a controller, a phtml template and a block class as below: app/code/local/Huahan/HelloWorld/Block Helloworld.php (where Huahan_Helloworld_Block_Helloworld extends Mage_Core_Block_Template) app/code/local/Huahan/HelloWorld/controllers IndexController.php (where indexAction of index controller is defined) app/design/frontend/base/default/template/huahan/helloworld helloworld.phtml (where view is defined) app/design/frontend/base/default/layout helloworld.xml (the filename "helloworld.xml" is specified in etc/config.xml)

I know that every request handling in Magento starts from a controller and its action method.

In the layout helloworld.xml, I specifies the template file in the block tag

<helloworld_index_nihao>
<block type="core/template" name="just_an_arbitary_name" output="toHtml" template="huahan/helloworld/nihao.phtml"/>
</helloworld_index_nihao>
</layout>

So the controller knows which template to use while handling request.

The problem is how I can let Magento know that Huahan_Helloworld_Block_Helloworld is the block class I want it to load before rendering any output?

And if there is any detailed documentation about the Magento xml? I am always frustrated by the complex and arbitrariness of the Magento xml syntax

The version of Magento is ver.1.9.0.1

The config.xml is as below

<?xml version="1.0"?>
<config>
<modules>
<huahan_helloworld>
<version>
0.1.0
</version>
</huahan_helloworld>
</modules>


<frontend>
<routers>
<!-- the <helloworld> tagname appears to be arbitrary, but by
convention is should match the frontName tag below-->
        <helloworld>
                <use>standard</use>
                <args>
                        <module>Huahan_HelloWorld</module>
                        <frontName>helloworld</frontName>
                </args>
        </helloworld>
</routers>

<layout>
        <updates>
                <helloworld>
                        <file>helloworld.xml</file>
                </helloworld>
        </updates>
</layout>
</frontend>

<global>
        <blocks>
                <helloworld>
                        <class>Huahan_Helloworld_block</class>
                </helloworld>
        </blocks>
</global>

</config>

Thanks in advance. I really appreciate that you read it down here.

Mihai Stancu Mihai Stancu · Accepted Answer · 2014-10-01T07:39:42

Block types

The block type attribute is the item which configures what class a block uses. Using a full class-name in the type although possible is discouraged.

The purpose of the class-alias system in Magento is to allow you the flexibility if extending/overwriting core/module functionality in your own modules.

If everyone uses the class-alias you can then replace/override an alias with your own classes and "inject" your behavior instead of the original. It's a form of decoupling code to allow extendability.

Block configs

In your module declaration you already had to specify a block prefix such as:

<blocks>
    <huahan_helloworld>
        <class>Huahan_Helloworld_Block</class>
    </huahan_helloworld>
</blocks>

According to Magento conventions the <class> part should be either huahan_helloworld or helloworld.

Because of these configurations and other Magento conventions your block type should be huahan_helloworld/helloworld or helloworld/helloworld (respectively).

How to specify the block name in Magento?

2 Answers

Block types

Block configs