What Filters are Available in PHP?

[N I C K]

Hi friends,
I have done some basic coding programs in PHP programming language. Now I want to know about the filters in PHP. Since I am moving towards the advanced part I think that knowing about filter is essential. So please tell me what are the Filters are Available in PHP? Reply me as early as possible.!!

[Viensterrr]

Every PHP stream contains a small read buffer where it stores blocks of data read from the file system, or other sources to treat them more effectively. As soon as the data is read from the resource into the internal buffer, the data are immediately passed to the filter, even if the PHP application is actually ready for such data. If data is already waiting in the buffer when a filter is added to the stream (appended), these data will be immediately passed to the filter, for the change is transparent. But if you add a filter is prepended, the data will NOT be filtered. They wait until the next block of the resource.

[MELTRONICS]

You should also know about the filters. Each filter does what its name implies and refers to the behavior of the corresponding PHP function. As for filters of channels, the conversion filters are what their name indicates. These filters have been added in PHP 5.0.0. Use this filter to process the data by function str_rot13 (). You can also use this filter to process data through the strtoupper ().

[kyosang]

There are three types of filters available for PHP and those are :

1. Conversion Filters
2. Compression Filters
3. Encryption Filters

This extension filters data by either validating or sanitizing it. This is especially useful when the data source contains unknown (or foreign) data, like user supplied input. For example, this data may come from an HTML form. There are two main types of filtering :

1. validation
2. sanitization.

[Deabelos]

Flags are optionally used with both validation and sanitization to tweak behaviour according to need. For example, passing in FILTER_FLAG_SCHEME_REQUIRED while filtering an URL will require a scheme (like http://) to be present. You don't need any external libraries to build this extension. The filter extension is enabled by default as of PHP 5.2.0. Before this time an experimental PECL extension was used, however, the PECL version is no longer recommended or updated.