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The streamWrapper class

(PHP 4 >= 4.3.2, PHP 5)

简介

Allows you to implement your own protocol handlers and streams for use with all the other filesystem functions (such as fopen() , fread() etc.).

Note:

This is NOT a real class, only a prototype of how a class defining its own protocol should be.

Note:

Implementing the methods in other ways then described here can lead to undefined behaviour.

An instance of this class is initialized as soon as a stream function tries to access the protocol it is associated with.

类摘要

streamWrapper {

public resource $context ;

__construct ( void )

__destruct ( void )

public bool dir_closedir ( void )

public bool dir_opendir ( string $path , int $options )

public string dir_readdir ( void )

public bool dir_rewinddir ( void )

public bool mkdir ( string $path , int $mode , int $options )

public bool rename ( string $path_from , string $path_to )

public bool rmdir ( string $path , int $options )

public resource stream_cast ( int $cast_as )

public void stream_close ( void )

public bool stream_eof ( void )

public bool stream_flush ( void )

public bool stream_lock ( int $operation )

public bool stream_metadata ( string $path , int $option , mixed $value )

public bool stream_open ( string $path , string $mode , int $options , string &$opened_path )

public string stream_read ( int $count )

public bool stream_seek ( int $offset , int $whence = SEEK_SET )

public bool stream_set_option ( int $option , int $arg1 , int $arg2 )

public array stream_stat ( void )

public int stream_tell ( void )

public bool stream_truncate ( int $new_size )

public int stream_write ( string $data )

public bool unlink ( string $path )

public array url_stat ( string $path , int $flags )

}

属性

resource context

The current context, or NULL if no context was passed to the caller function.

Use the stream_context_get_options() to parse the context.

Note:

This property must be public so PHP can populate it with the actual context resource.

更新日志

版本	说明
5.0.0	Added the context property.

参见

Example class registered as stream wrapper
stream_wrapper_register()
stream_wrapper_unregister()
stream_wrapper_restore()

streamWrapper::__construct — Constructs a new stream wrapper
streamWrapper::__destruct — Destructs an existing stream wrapper
streamWrapper::dir_closedir — Close directory handle
streamWrapper::dir_opendir — Open directory handle
streamWrapper::dir_readdir — Read entry from directory handle
streamWrapper::dir_rewinddir — Rewind directory handle
streamWrapper::mkdir — Create a directory
streamWrapper::rename — Renames a file or directory
streamWrapper::rmdir — Removes a directory
streamWrapper::stream_cast — Retrieve the underlaying resource
streamWrapper::stream_close — Close a resource
streamWrapper::stream_eof — Tests for end-of-file on a file pointer
streamWrapper::stream_flush — Flushes the output
streamWrapper::stream_lock — Advisory file locking
streamWrapper::stream_metadata — Change stream options
streamWrapper::stream_open — Opens file or URL
streamWrapper::stream_read — Read from stream
streamWrapper::stream_seek — Seeks to specific location in a stream
streamWrapper::stream_set_option — Change stream options
streamWrapper::stream_stat — Retrieve information about a file resource
streamWrapper::stream_tell — Retrieve the current position of a stream
streamWrapper::stream_truncate — Truncate stream
streamWrapper::stream_write — Write to stream
streamWrapper::unlink — Delete a file
streamWrapper::url_stat — Retrieve information about a file

用户评论:

[#1] Anonymous [2011-09-21 12:02:36]

Here is a very simple stream wrapper which calls your callback function for reads:

<?php class CallbackUrl { const WRAPPER_NAME = 'callback'; public $context; private $_cb; private $_eof = false; private static $_isRegistered = false; public static function getContext($cb) { if (!self::$_isRegistered) { stream_wrapper_register(self::WRAPPER_NAME, get_class()); self::$_isRegistered = true; } if (!is_callable($cb)) return false; return stream_context_create(array(self::WRAPPER_NAME => array('cb' => $cb))); } public function stream_open($path, $mode, $options, &$opened_path) { if (!preg_match('/^r[bt]?$/', $mode) || !$this->context) return false; $opt = stream_context_get_options($this->context); if (!is_array($opt[self::WRAPPER_NAME]) || !isset($opt[self::WRAPPER_NAME]['cb']) || !is_callable($opt[self::WRAPPER_NAME]['cb'])) return false; $this->_cb = $opt[self::WRAPPER_NAME]['cb']; return true; } public function stream_read($count) { if ($this->_eof || !$count) return ''; if (($s = call_user_func($this->_cb, $count)) == '') $this->_eof = true; return $s; } public function stream_eof() { return $this->_eof; } } class Test { private $_s; public function __construct($s) { $this->_s = $s; } public function read($count) { return fread($this->_s, $count); } } $t = new Test(fopen('/etc/services', 'r')); $fd = fopen('callback://', 'r', false, CallbackUrl::getContext(array($t, 'read'))); while(($buf = fread($fd, 128)) != '') { print $buf; } ?>

[#2] isaac dot z dot no dot foster at spam dot gmail dot please dot com [2010-10-22 09:12:57]

It's worth noting that the interface defined by yannick at gmail should not always be implemented by a stream wrapper class, as several of the methods should not be implemented if the class has no use for them (as per the manual).

Specifically, mkdir, rename, rmdir, and unlink are methods that "should not be defined" if the wrapper has no use for them. The consequence is that the appropriate error message will not be returned.

If the interface is implemented, you won't have the flexibility to not implement those methods.

Not trying to be academic, but it was useful for me.

[#3] yannick dot battail at gmail dot com [2009-07-17 02:38:09]

a php interface for wrapper

<?php interface WrapperInterface { //public $context; public function __construct(); public function dir_closedir(); public function dir_opendir($path , $options); public function dir_readdir(); public function dir_rewinddir(); public function mkdir($path , $mode , $options); public function rename($path_from , $path_to); public function rmdir($path , $options); public function stream_cast($cast_as); public function stream_close(); public function stream_eof(); public function stream_flush(); public function stream_lock($operation); public function stream_open($path , $mode , $options , &$opened_path); public function stream_read($count); public function stream_seek($offset , $whence = SEEK_SET); public function stream_set_option($option , $arg1 , $arg2); public function stream_stat(); public function stream_tell(); public function stream_write($data); public function unlink($path); public function url_stat($path , $flags); } ?>

The streamWrapper class

简介

类摘要

属性

更新日志

参见

Table of Contents

用户评论: