Magento Ajax - how to programmatically display custom block from Controller (my HTML content is always blank)

class magento controller block

18,524

I find these things very difficult. I am going to try to answer in two parts:

PART ONE

You may want to try to render the layout in the controller so try this first then read the additional items below:

//file: app/code/local/MyModule/Ajax/controllers/ProductController.php
//class: MyModule_Ajax_ProductController
//function: indexAction()
$this->loadLayout();
$this->renderLayout();

BUT you are making an Ajax module. So you might want to utilise controller methods such as:

//set the response
$this->getResponse()
//->clearHeaders()
->setHeader('Content-Type', 'application/json')
->setBody(json_encode($someReturnObject));
    return;

And if you want to setBody() to a block's HTML then in the controller the code you have posted above is looking good (but see part two below):-

  $this->loadLayout();
  $myBlock = $this->getLayout()->createBlock('ajax/product');
  $myBlock->setTemplate('mymodule_ajax/product.phtml');
  $myHtml =  $myBlock->toHtml(); //also consider $myBlock->renderView();     
  $this->getResponse()
       ->setHeader('Content-Type', 'text/html')
       ->setBody($myHtml);
  return;

And actually even just calling exit(); at the end of indexAction() will flush the PHP output buffer to the browser.

I note that you are making a product controller. Studying the code in the class you are extending may help:

//file: app/code/core/Mage/Catalog/controllers/ProductController.php
//class: Mage_Catalog_ProductController
//function: viewAction()
    public function viewAction()
    {
        // Get initial data from request
        $categoryId = (int) $this->getRequest()->getParam('category', false);
        $productId  = (int) $this->getRequest()->getParam('id');
        $specifyOptions = $this->getRequest()->getParam('options');

        // Prepare helper and params
        $viewHelper = Mage::helper('catalog/product_view');

        $params = new Varien_Object();
        $params->setCategoryId($categoryId);
        $params->setSpecifyOptions($specifyOptions);

        // Render page
        try {
            $viewHelper->prepareAndRender($productId, $this, $params);
        } catch (Exception $e) {
            //...
        }
    }

which might give you some ideas about sending Magento-standard product-related HTML to the browser. You may find the prepareAndRender() helper function more interesting but ultimately it uses $this->renderLayout() to create the output html (here $this is the controller).

PART TWO

I think you need to concentrate on the line in your code:

    echo $this->getLayout()->createBlock('ajax/product')->setTemplate('mymodule_ajax/product.phtml')->toHtml();

and either change it to

    echo $this->getLayout()->createBlock('mymodule_ajax/product')->setTemplate('mymodule_ajax/product.phtml')->toHtml();

or, in your module's config.xml file add something like: (I think this is the answer you need)

<config>
  <global>
        <!-- ... -->

        <blocks>
            <ajax>
                <class>MyModule_Ajax_Block</class>
            </ajax>
        </blocks>

        <!-- ... -->
  </global>
</config>

so that Magento can understand that createBlock('ajax/product') means MyModule_Ajax_Block_Product and not Mage_Ajax_Block_Product.

I also recommend you change MyModule to Mymodule throughout so that there is not a capital letter in the middle. Because

$this->getLayout()->createBlock('mymodule_ajax/product')

well, I don't understand the fine details but generally Magento will make mymodule into Mymodule not MyModule

Does that make sense?

18,524

Author by

Natacha Beaugeais

Updated on June 04, 2022

Comments

Natacha Beaugeais almost 2 years

I am trying to display a block as part of a response to an ajax call. Everything is working except I cannot get the controller to echo the template HTML code.

My module class:

class MyModule_Ajax_ProductController extends Mage_Catalog_ProductController {

    public function indexAction() {

        if ($product = $this->_initProduct()) {

            echo '<div>hello</div>'; //this works

            echo $this->getLayout()->createBlock('ajax/product')->setTemplate('mymodule_ajax/product.phtml')->toHtml();

            //I also tried:
            //$layout = $this->getLayout();
            //$update = $layout->getUpdate();
            //$update->load('ajax_product_index'); 
            //$layout->generateXml();
            //$layout->generateBlocks();
            //$output = $layout->getOutput();
            //echo $output;

        }
    }
}

Inside my template file product.phtml - this HTML never gets shown. (saved to app/design/frontend/default/default/template/mymodule_ajax/product.phtml)

<div>HERE!</div>

My block class:

class MyModule_Ajax_Block_Product extends Mage_Catalog_Block_Product
{
    private $product;

    protected function _construct()
    {
        parent::_construct();
        $this->setTemplate('mymodule_ajax/product.phtml');
    }

    protected function _toHtml() {
        return parent::_toHtml();
    }

    public function setProduct($product) {
        $this->product = $product;
        return $this;
    }

    public function getProduct() {
        return $this->product;
    }

}

My layout/mymodule_ajax.xml

<?xml version="1.0"?>
<layout>

    <ajax_product_index>
        <reference name="root">
            <block type="ajax/project" name="root" output="toHtml" template="mymodule_ajax/product.phtml"/>
        </reference>
    </ajax_product_index>

</layout>

I am assuming that because I am setting up the template programmatically in my block class I shouldn't need the module reference? Removing the reference makes no difference.

I get no PHP errors, the HTML displayed renders

<html>
<head></head>
<body></body>
</html>

I simply can't figure out what I am doing wrong? I'm using Magento CE 1.8.1

Natacha Beaugeais almost 10 years

This all makes sense, yes - thank you so much for all the detail. I am going to go through this now with a fine toothed comb. Hopefully one of your answers help me and saves my sanity... I will get back to you on this soon.
Natacha Beaugeais almost 10 years

THANK YOU. Your detailed answer, explanations etc led me down the path to a resolution. In the end, it was the naming of my block in the code, and the incorrect naming of my template file and folder structure - The system couldn't finding my template but instead of telling me so, it was returning an empty string. This one was super hard to track and debug!!