Drupal 7 Module Development

Chapter 11
In some cases you may not need some of this functionality provided by the interface.
For instance, in our example, we are only reading photos from Twitpic without
offering the ability to write data anywhere, so functions like stream_write()
and stream_mkdir() don't apply. In these cases we simply return FALSE.
For the full implementation details of
DrupalStreamWrapperInterface, refer to http://api.drupal.
org/api/drupal/includes--stream_wrappers.inc/7. You may
also want to refer to PHP's prototype stream wrapper class at http://
php.net/manual/en/streamwrapper.stream-open.php.
DrupalStreamWrapperInterface is quite extensive, with over 20 functions to be
defined by the implementing classes. Every stream wrapper should implement each
of PHP's file handling functions. As mentioned earlier, many of these simply return
FALSE. Others simply pass through to matching PHP functionality. (stream_eof()
simply calls and returns the results of feof($handle).)
Since the class is so large, you may want to put it into a separate file to improve
readability and maintainability of your code. You can do this by creating a new file
in your module's directory, and adding it to the files[] array in your module.info
file as shown:
files[] = twitpicstreamwrapper.inc
In order to keep things simple, we will only discuss the most noteworthy parts of the
class shown in the following code. The full code listing can be downloaded from the
Packt website.
/**
* Twitpic Stream Wrapper
*
* This class provides a complete stream wrapper implementation.
*/
class TwitPicStreamWrapper implements DrupalStreamWrapperInterface {
/**
* Instance URI as scheme://target.
*/
protected $uri;
/**
* A generic resource handle.
*/
public $handle = NULL;
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