While PHP is capable when it comes to simple file downloads, most real-life applications require additional functionality to handle advanced issues such as form submission, authentication, redirection, and so on. These functions are difficult to facilitate with PHP's built-in functions alone. Therefore, most of this book's examples use PHP/CURL to download files.
The open source cURL project is the product of Swedish developer Daniel Stenberg and a team of developers. The cURL library is available for use with nearly any computer language you can think of. When cURL is used with PHP, it's known as PHP/CURL.
The name cURL is either a blend of the words client and URL or an acronym for the words client URL Request Library—you ...