NAME
POE::Filter::XML - A POE Filter for parsing XML
SYSNOPSIS
use POE::Filter::XML;
my $filter = POE::Filter::XML->new();
my $wheel = POE::Wheel:ReadWrite->new(
Filter => $filter,
InputEvent => 'input_event',
);
DESCRIPTION
POE::Filter::XML provides POE with a completely encapsulated XML parsing
strategy for POE::Wheels that will be dealing with XML streams.
The parser is XML::LibXML
Default, the Filter will spit out POE::Filter::XML::Nodes because that
is what the default XML::SAX compliant Handler produces from the stream
it is given. You are of course encouraged to override the default
Handler for your own purposes if you feel POE::Filter::XML::Node to be
inadequate.
Also, Filter requires POE::Filter::XML::Nodes for put(). If you are
wanting to send raw XML, it is recommened that you subclass the Filter
and override put()
PUBLIC METHODS
Since POE::Filter::XML follows the POE::Filter API look to POE::Filter
for documentation. Deviations from Filter API will be covered here.
new()
new() accepts a total of four(4) named arguments that are all
optional: (1) 'BUFFER': a string that is XML waiting to be parsed
(i.e. xml received from the wheel before the Filter was
instantiated), (2) 'CALLBACK': a coderef to be executed upon a
parsing error, (3) 'HANDLER': a XML::SAX compliant Handler, or (4)
'NOTSTREAMING': boolean telling the filter to not process incoming
XML as a stream but as single documents.
If no options are specified, then a default coderef containing a
simple Carp::confess is generated, a new instance of
POE::Filter::XML::Handler is used, and activated in streaming mode.
reset()
reset() is an internal method that gets called when either a
stream_start(1) POE::Filter::XML::Node gets placed into the filter
via put(), or when a stream_end(1) POE::Filter::XML::Node is pulled
out of the queue of finished Nodes via get_one(). This facilitates
automagical behavior when using the Filter within the XMPP protocol
that requires many new stream initiations. This method is also
called after every document when not in streaming mode. Useful for
handling XMLRPC processing.
This method really should never be called outside of the Filter, but
it is documented here in case the Filter is used outside of the POE
context.
Internally reset() gets another parser, calls reset() on the stored
handler and then deletes any data in the buffer.
callback()
callback() is an internal accessor to the coderef used when a
parsing error occurs. If you want to place stateful nformation into
a closure that gets executed when a parsering error happens, this is
the method to use.
BUGS AND NOTES
The underlying parser was switched to XML::LibXML.
Also note that the PXF::Nodes returned are now subclassed from
LibXML::Element and that the underlying API for Nodes has changed
completely with out ANY compatibility at all. This was done for
performance reasons, and also to gain XPath capabilities on the nodes
returned.
Meta filtering was removed. No one was using it and the increased level
of indirection was a posible source of performance issues.
put() now requires POE::Filter::XML::Nodes. Raw XML text can no longer
be put() into the stream without subclassing the Filter and overriding
put().
reset() semantics were properly worked out to now be automagical and
consistent. Thanks Eric Waters (ewaters@uarc.com).
A new argument was added to the constructor to allow for multiple single
document processing instead of one coherent stream. This allows for
inbound XMLRPC requests to be properly parsed automagically without
manually touching the reset() method on the Filter.
Arguments passed to new() must be in name/value pairs (ie. 'BUFFER' =>
"stuff")
AUTHOR
Copyright (c) 2003 - 2009 Nicholas Perez. Released and distributed under
the GPL.