Search engine bots (sometimes called spiders or crawlers) are computer programs(bots) that crawl the web pages. In other words, they visit webpages, find links to further pages, and visit them. Often they map content that they find to use later for search purposes (indexing). They also help developers diagnose issues with their websites.
PHP doesn’t have any built-in function to detect search engine bots. However, the following function can be used for this purpose.
This function compares the PHP user agent with a list of common spiders from search engines, more than 180 bots, spiders and crawlers.
When ‘Googlebot’ is given as input, the function returns true(1) as the provided input is the name of a search engine bot.