stream_filter_append
resource$stream,
string$filtername,
[int$read_write],
[mixed$params]
): resource
Adds filtername to the list of filters attached to stream.
Parameters
- stream
-
The target stream.
- filtername
-
The filter name.
- read_write
-
By default, stream_filter_append will attach the filter to the read filter chain if the file was opened for reading (i.e. File Mode: r, and/or +). The filter will also be attached to the write filter chain if the file was opened for writing (i.e. File Mode: w, a, and/or +). STREAM_FILTER_READ, STREAM_FILTER_WRITE, and/or STREAM_FILTER_ALL can also be passed to the read_write parameter to override this behavior.
- params
-
This filter will be added with the specified params to the end of the list and will therefore be called last during stream operations. To add a filter to the beginning of the list, use stream_filter_prepend.
Return Values
Returns a resource on success or false on failure. The resource can be used to refer to this filter instance during a call to stream_filter_remove.
false is returned if stream is not a resource or if filtername cannot be located.
Notes
Note:
When using custom (user) filtersstream_filter_register must be called first in order to register the desired user filter to filtername.
Note:
Stream data is read from resources (both local and remote) in chunks, with any unconsumed data kept in internal buffers. When a new filter is appended to a stream, data in the internal buffers is processed through the new filter at that time. This differs from the behavior of stream_filter_prepend.
Note:
When a filter is added for read and write, two instances of the filter are created. stream_filter_append must be called twice with STREAM_FILTER_READ and STREAM_FILTER_WRITE to get both filter resources.