The streamWrapper class

    (PHP 4 >= 4.3.2, PHP 5, PHP 7, PHP 8)

    Introduction

    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 than 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.

    Class synopsis

    class streamWrapper {
    /* Properties */
    public resource $context;
    /* Methods */
    public __construct()
    public dir_closedir(): bool
    public dir_opendir(string $path, int $options): bool
    public dir_readdir(): string
    public dir_rewinddir(): bool
    public mkdir(string $path, int $mode, int $options): bool
    public rename(string $path_from, string $path_to): bool
    public rmdir(string $path, int $options): bool
    public stream_cast(int $cast_as): resource
    public stream_close(): void
    public stream_eof(): bool
    public stream_flush(): bool
    public stream_lock(int $operation): bool
    public stream_metadata(string $path, int $option, mixed $value): bool
    public stream_open(
        string $path,
        string $mode,
        int $options,
        ?string &$opened_path
    ): bool
    public stream_read(int $count): string|false
    public stream_seek(int $offset, int $whence = SEEK_SET): bool
    public stream_set_option(int $option, int $arg1, int $arg2): bool
    public stream_stat(): array|false
    public stream_tell(): int
    public stream_truncate(int $new_size): bool
    public stream_write(string $data): int
    public unlink(string $path): bool
    public url_stat(string $path, int $flags): array|false
    public __destruct()
    }

    Properties

    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.

    See Also

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    User Contributed Notes 4 notes

    up
    14
    isaac dot z dot no dot foster at spam dot gmail dot please dot com
    14 years ago
    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.
    up
    1
    info at ensostudio dot ru
    4 years ago
    THIS METHODS NOT REQUIRED, you can implement only part of their: directories, files, etc.
    For example, "glob://" support minimal syntax, glob() more powerful, you can replace/extend native wrapper: check options in table https://www.php.net/manual/ru/wrappers.glob , you need create wrapper only with 'dir_...dir' methods. For more info, see https://www.php.net/manual/en/class.globiterator.php#125220
    up
    2
    Anonymous
    13 years ago
    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;
    }
    ?>
    up
    2
    yannick dot battail at gmail dot com
    15 years ago
    a php interface for wrapper

    <?php
    interface WrapperInterface
    {
    /**
    * resource context
    *
    * @var resource
    */
    //public $context;

    /**
    * constructor
    *
    */
    public function __construct();

    /**
    *
    *
    * @return bool
    */
    public function dir_closedir();

    /**
    * Enter description here...
    *
    * @param string $path
    * @param int $options
    * @return bool
    */
    public function dir_opendir($path , $options);

    /**
    * Enter description here...
    *
    * @return string
    */
    public function dir_readdir();

    /**
    * Enter description here...
    *
    * @return bool
    */
    public function dir_rewinddir();

    /**
    * Enter description here...
    *
    * @param string $path
    * @param int $mode
    * @param int $options
    * @return bool
    */
    public function mkdir($path , $mode , $options);

    /**
    * Enter description here...
    *
    * @param string $path_from
    * @param string $path_to
    * @return bool
    */
    public function rename($path_from , $path_to);

    /**
    * Enter description here...
    *
    * @param string $path
    * @param int $options
    * @return bool
    */
    public function rmdir($path , $options);

    /**
    * Enter description here...
    *
    * @param int $cast_as
    * @return resource
    */
    public function stream_cast($cast_as);

    /**
    * Enter description here...
    *
    */
    public function stream_close();

    /**
    * Enter description here...
    *
    * @return bool
    */
    public function stream_eof();

    /**
    * Enter description here...
    *
    * @return bool
    */
    public function stream_flush();

    /**
    * Enter description here...
    *
    * @param mode $operation
    * @return bool
    */
    public function stream_lock($operation);

    /**
    * Enter description here...
    *
    * @param string $path
    * @param string $mode
    * @param int $options
    * @param string &$opened_path
    * @return bool
    */
    public function stream_open($path , $mode , $options , &$opened_path);

    /**
    * Enter description here...
    *
    * @param int $count
    * @return string
    */
    public function stream_read($count);

    /**
    * Enter description here...
    *
    * @param int $offset
    * @param int $whence = SEEK_SET
    * @return bool
    */
    public function stream_seek($offset , $whence = SEEK_SET);

    /**
    * Enter description here...
    *
    * @param int $option
    * @param int $arg1
    * @param int $arg2
    * @return bool
    */
    public function stream_set_option($option , $arg1 , $arg2);

    /**
    * Enter description here...
    *
    * @return array
    */
    public function stream_stat();

    /**
    * Enter description here...
    *
    * @return int
    */
    public function stream_tell();

    /**
    * Enter description here...
    *
    * @param string $data
    * @return int
    */
    public function stream_write($data);

    /**
    * Enter description here...
    *
    * @param string $path
    * @return bool
    */
    public function unlink($path);

    /**
    * Enter description here...
    *
    * @param string $path
    * @param int $flags
    * @return array
    */
    public function url_stat($path , $flags);
    }

    ?>
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