What are the common pitfalls when dealing with character encoding in PHP, especially with external data sources like RSS feeds?

When dealing with character encoding in PHP, especially with external data sources like RSS feeds, a common pitfall is mismatched character encodings leading to garbled or incorrectly displayed text. To solve this issue, it is important to consistently use the correct character encoding throughout your PHP code and when interacting with external data sources. One way to handle this is by using functions like `mb_convert_encoding()` to convert the character encoding of the data to match the encoding used in your PHP script.

// Fetch RSS feed data
$rss_feed = file_get_contents('https://example.com/rss-feed');

// Convert character encoding to UTF-8
$rss_feed_utf8 = mb_convert_encoding($rss_feed, 'UTF-8', 'auto');

// Now you can process the RSS feed data with the correct character encoding
// For example, display the feed content
echo $rss_feed_utf8;