How to Fetch a Category Name Using Category ID in Liferay with FreeMarker

In Liferay, categories help organize and classify content, making it easier to manage and retrieve. Often, you might have a category ID and want to fetch its name dynamically in a FreeMarker template. In this guide, we’ll walk you through the steps to achieve this using Liferay’s service locator.

Understanding the Scenario

Let’s say you have a category parameter in the request URL, which represents a category ID. You want to:

1. Retrieve this category ID.
2. Use it to fetch the corresponding category name.
3. Display the category name in the template.

Steps to Implement

Here’s the complete FreeMarker code snippet for achieving this:

<#assign categoryId = ""> 

<#if request.getParameter("category")?has_content> 
    <#assign categoryId = request.getParameter("category")> 
</#if> 

<#if categoryId?has_content> 
    <#-- Use service locator to get AssetCategoryLocalService --> 
    <#assign categoryService = serviceLocator.findService("com.liferay.asset.kernel.service.AssetCategoryLocalService")> 
    
    <#-- Get the AssetCategory object --> 
    <#assign category = categoryService.getAssetCategory(categoryId?number)> 
    
    <#if category??> 
        Category Name: ${category.getTitle(locale)} 
    <#else> 
        Category not found with ID: ${categoryId} 
    </#if> 
</#if>

Code Breakdown

• Fetching the category Parameter:
  • The category ID is retrieved from the request parameter.
  • request.getParameter("category") checks if the parameter exists and assigns its value to categoryId.
• Using the Service Locator:
  • serviceLocator.findService("com.liferay.asset.kernel.service.AssetCategoryLocalService") provides access to the AssetCategoryLocalService class.
• Fetching the Category Object:
  • categoryService.getAssetCategory(categoryId?number) fetches the AssetCategory object corresponding to the provided ID.
• Displaying the Category Name:
  • ${category.getTitle(locale)} retrieves the localized title of the category.
  • If the category ID is invalid or not found, a fallback message is displayed.

Troubleshooting Tips

• serviceLocator Restriction:
  • Ensure serviceLocator is not restricted in Control Panel > System Settings > Template Engines > FreeMarker.
  • If restricted, remove it from the “Restricted Variables” list.
• Invalid Service Path:
  • Verify the correct service path: com.liferay.asset.kernel.service.AssetCategoryLocalService.
• Reindex Categories:
  • If categories are not found, reindex them through Control Panel > Search > Index Actions > Execute Reindex All Indexes.

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