What are the best practices for handling redirects and cookies in PHP when accessing external data?

When accessing external data in PHP, it is important to handle redirects and cookies properly to ensure a smooth data retrieval process. To handle redirects, you can use the `curl` library in PHP which allows you to follow redirects automatically. For handling cookies, you can use the `CURLOPT_COOKIEFILE` and `CURLOPT_COOKIEJAR` options in `curl` to store and send cookies between requests.

// Initialize a cURL session
$ch = curl_init();

// Set the URL to fetch data from
curl_setopt($ch, CURLOPT_URL, 'https://example.com/data');

// Follow redirects automatically
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);

// Enable cookie handling
curl_setopt($ch, CURLOPT_COOKIEFILE, 'cookie.txt');
curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookie.txt');

// Execute the cURL session
$response = curl_exec($ch);

// Close the cURL session
curl_close($ch);

// Process the response data
echo $response;