What are the best practices for handling data extraction and manipulation using PHP to avoid violating terms of service of external websites?

When extracting and manipulating data from external websites using PHP, it's important to ensure that you are not violating their terms of service. To avoid this, make sure to read and understand the terms of service of the website you are scraping data from, and only extract data that is publicly available and allowed for scraping. Additionally, consider using APIs provided by the website if available, as this is often the preferred method for accessing their data.

// Example of using cURL to scrape data from a website while respecting their terms of service
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, 'https://www.example.com/data');
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($curl, CURLOPT_USERAGENT, 'Your User Agent Here');
$data = curl_exec($curl);
curl_close($curl);

// Now you can manipulate the $data variable to extract the information you need