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URL Based Apache Directives

Published: February 27, 2017

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Recently, I was working through an issue where I wanted to conditionally increase PHP’s memory limit based on the request URL. Rather than building that logic into the application, handling via Apache directives seemed like a cleaner approach. Here I’ll outline how I achieved this.

Overriding Inline onclick Attributes With Event Capturing

Published: February 16, 2017

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Recently, I needed to override a <button>’s inline onclick attribute. I was writing a plugin for Magento, which, for better or worse, makes heavy use on inline onclick attributes. If you run a Google search you’ll see that the canonical answer looks something like this…

document.getElementById('my-id').onclick = myOnClick;

For most uses cases this work fine. However, there is a caveat that should accompany this answer. It doesn’t work for elements that are dynamically added to the document.

But never fear, there’s another approach that can be used to override inline onclick attributes that works with dynamically added elements. And that approach, my friends, is called event capturing.

Digging Into Magento 2's Partial Reindexing Implementation

Published: February 13, 2017

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Partial reindexing was only a thing in Enterprise Edition of Magento 1. In Magento 2, however, it’s part of Community Edition. While the overall architecture is pretty much the same, as with all of Magento 2, the code is very different. In this post I’ll dig through Magento 2’s core code to investigate the implementation.

NOTE This post is based on the Magento 2.1.4 code base.

Magento's REQUEST_PATH FPC Tag

Published: February 6, 2017

When Magento saves data to cache, it has the option to add “tags” to the data it is saving. This feature, which is built into Zend Framework 1, is particularly useful as it allows the application easily invalidate all data associated with a particular tag.

For example, when the name of a product changes, all pages on which that product was displayed can be invalidated by passing the appropriate tag to the cache instance’s clean method. If the product with entity_id 1 had changed, cleaning all cache data would look like this…

Enterprise_PageCache_Model_Cache::getCacheInstance()
    ->clean('CATALOG_PRODUCT_1');

One tag that Magento’s Enterprise_PageCache module makes uses of is the REQUEST_PATH tag. In this post, we’ll first explore how Magento uses this tag out-of-box. Then, we’ll take a look at how we can take advantage of this tag.

Mage::getStoreConfig() in tight loops

Published: February 2, 2017

Recently, while doing some profiling of an uncached category page, I noticed something funny…A sizable amount of time being spent on Mage::getStoreConfig().

Digging in, I saw that it was coming from the navigation module. It contained a function called getAllFilterableOptionsAsHash, which builds a map of URL keys (using it’s own logic) to Magento attribute option IDs. It looks something like this (abbreviated for simplicity’s sake)…

public function getAllFilterableOptionsAsHash()
{
    $hash = array();

    $attributes = $this->getFilterableAttributes();

    $options = $this->getAllOptions();

    foreach ($attributes as $a) {
        $hash[$a->getAttributeCode()] = array();
        foreach ($options as $o){
            if (o['attribute_id'] == $a->getId()) {
                $key = $this->createKey($o['url_alias']);
                $key .= Mage::getStoreConfig('module/part/special_char');
                $hash[$code][$key] = $o['option_id'];
            }
        }
    }

    return $hash;
}

In this case getAllFilterableAttributes will return all attributes that are filterable and getAllOptions will return all options for filterable attributes. On the site in question there were 18 filterable attributes with ~4250 options.

Based on the code above, this means Mage::getStoreConfig('module/part/special_char'); will be called ~4250 times. I began to wonder what the benefit might be of caching the value in an temporary value, rather than calling Mage::getStoreConfig over and over. Here, I’ll share the results of my investigation…

How Partial Reindexing Schedule Impacts Page Cache Hit Rate

Published: January 30, 2017

One factor that impacts your Magento site’s full page cache hit rate is your partial reindexing schedule. By partial reindexing, I mean execution of the enterprise_refresh_index job, which runs when the Magento cron is executed in “always” mode.

Let’s take a closer look at the interplay between partial reindexing and full page cache hit rate.