This post is not a class on categories, but I’m going to take some tips so you do not create unnecessary frontend codes, redoing native functions that the system already offers.

So it’s very important that you get to know the system well before you start creating modules and functions that already exist.

Backend Settings

When you access a category, there are dozens of information that can be configured, thus excluding the need to create codes to check (if it is category X do this, if category Y changes it).

Things that can be done by backend:

- Remove the category from the navigation menu but keep active in the system;
- Leave each category a color (by changing the design);
- Include custom blocks (like banners);
- Change the order of display of the products in the listing;
- Add (or remove) dynamic blocks (such as cart or newsletter) from the template;
- Add an image to the category (normal and miniature);
- Customize SEO indidivually (by category);

Of course you can do other things as well, but these are some that you can configure without having to insert a single line of code in the template.

Modifying other elements

Let’s assume that you want to modify a very specific element of the page when accessing a particular category. (it is difficult to set a good example, since almost everything can be done by the backend).

When you access a category, the system registers in the initialization of this category some information, as you can see in:

app > code > core > Mage > Catalog > controllers > CategoryController.php

Within the method _initCatagory() the code that registers the variable has information about the category:

Mage::register('current_category', $category);

Then in your template you can retrieve this information with the code:

Mage::registry('current_category')->getName();

This code can be useful when you need to match several conditions at the same time, for example: if the category is X, and the cart is with Y products, and the customer is from the W group, Then the page should have Z.

Other information you could get from the registry:

- getDescription();
- getName();
- getUrlPath();
...I counted 33 available attributes...

On non-category pages, this code does not work (return null ).

And when you do not have a register?

But not all pages have a register at the start of the class. So how can we retrieve the category of products in the homepage listing?

Let’s see an example, so open the phtml file responsible for loading your product listing – if you do not know which file you are using, read the post: Debug in Frontend.

If you do not know how to list products on the homepage read the post: Featured Products On the Home page. In this example I will use the new.phtml file that is located at:

app > design > frontend > base > default > template > catalog > product > new.phtml

Remember to not change files in base/default, always make a copy to default/default or your template/theme custom.

In this case we will use the association between products and categories (which is N to N). And while the code runs product by product to display on the screen, we will take to recover the category of each product listed.

/* loads all categories to which this product belongs */
$cats = Mage::getModel('catalog/product')->load($_product->getId())->getCategoryIds();
/* Loads the category name by entering the category id q was loaded by the product */
echo Mage::getModel('catalog/category')->load($cats[1])->getName();

Just add this php code inside the foreach, just below the product name and you will see the result.

So with the above code you have a starting point for many variations, you can play the category name in a variable to make comparisons and make presentation decisions according to the category.

A product can be associated with several categories, so getCategoryIds() returns an array of objects, and it’s up to you to decide which category you want to load.

Success!