rel="canonical" attribute in OpenCart pagination and sorting

This modifier adds a tag to sorting and pagination pages in OpenCart, preventing duplicate content and improving SEO. This helps search engines correctly index product pages and prevents duplicate content from appearing in search results.

How does the modifier work?

• Determines whether the page parameter is present in the URL.
  • If there is limit or page > 1, then this is a sorting or pagination page.
• Generates a URL without pagination parameters
  • Checks whether http or https protocol is used.
  • Removes all parameters after ?, leaving only the base URL.
  • If the URL ends with /, removes that slash.
• Adds rel="canonical" to the page's head
  • Inserts a <link rel="canonical"> tag after <base href="..."> in the header file.
  • If there is no limit or page parameter or it is equal to 1, the tag is not added.

Why is this necessary?

Google may perceive paginated pages ( page=2, page=3, etc.) as duplicate content, which negatively impacts SEO. This modifier tells search engines that the canonical version of a page is the first page of product listings, articles, and other elements. This tool automatically manages canonical links, improving the relevance of pages in search results.