Stream wrappers

If you’ve been writing PHP for a long time, you may have needed to work with local or remote files at some point. The following PHP code is a common way to read a file into a variable that you can do something with:

$contents = '';
$handle = fopen("/local/path/to/file/image.jpg", "rb");
while (!feof($handle)) {
 $contents .= fread($handle, 8192);
}
fclose($handle);

This is pretty straightforward. We get a handle to a local file using fopen() and read 8 KB chunks of the file using fread() until feof() indicates that we’ve reached the end of the file. At that point, we use fclose() to close the handle. The contents of the file are now in the $contents variable.

In addition to local files, we can also access remote ones through fopen() in the exact same way but by specifying the actual remote path instead of the local one we saw before (starting with http(s)://).

Data that we can access this way is streamable, meaning...