NAME¶
XML::SAX::Pipeline - Manage a linear pipeline of SAX processors
VERSION¶
version 0.46
SYNOPSIS¶
use XML::SAX::Machines qw( Pipeline ); ## Most common way
use XML::Fitler::Foo;
my $m = Pipeline(
XML::Filter::Foo->new, ## Create it manually
"XML::Filter::Bar", ## Or let Pipeline load & create it
"XML::Filter::Baz",
{
## Normal options
Handler => $h,
}
);
## To choose the default parser automatically if XML::Filter::Foo
## does not implement a parse_file method, just pretend the Pipeline
## is a parser:
$m->parse_file( "blah" );
## To feed the pipeline from an upstream processor, treat it like
## any other SAX filter:
my $p = Some::SAX::Generator->new( Handler => $m );
## To read a file or the output from a subprocess:
my $m = Pipeline( "<infile.txt" );
my $m = Pipeline( "spew_xml |" );
## To send output to a file handle, file, or process:
my $m = Pipeline( ..., \*STDOUT );
my $m = Pipeline( ..., ">outfile.txt" );
my $m = Pipeline( ..., "| xmllint --format -" );
DESCRIPTION¶
An XML::SAX::Pipeline is a linear sequence SAX processors. Events passed to the
pipeline are received by the "Intake" end of the pipeline and the
last filter to process events in the pipeline passes the events out the
"Exhaust" to the filter set as the pipeline's handler:
+-----------------------------------------------------------+
| An XML:SAX::Pipeline |
| Intake |
| +---------+ +---------+ +---------+ Exhaust |
--+-->| Stage_0 |--->| Stage_1 |-->...-->| Stage_N |----------+----->
| +---------+ +---------+ +---------+ |
+-----------------------------------------------------------+
As with all SAX machines, a pipeline can also create an ad hoc parser (using
XML::SAX::ParserFactory) if you ask it to parse something and the first SAX
processer in the pipeline can't handle a parse request:
+-------------------------------------------------------+
| An XML:SAX::Pipeline |
| Intake |
| +--------+ +---------+ +---------+ Exhaust |
| | Parser |-->| Stage_0 |-->...-->| Stage_N |----------+----->
| +--------+ +---------+ +---------+ |
+-------------------------------------------------------+
or if you specify an input file like so:
my $m = Pipeline(qw(
<input_file.xml
XML::Filter::Bar
XML::Filter::Baz
));
Pipelines (and machines) can also create ad hoc XML::SAX::Writer instances when
you specify an output file handle (as shown in the SYNOPSIS) or an output
file:
my $m = Pipeline(qw(
XML::Filter::Bar
XML::Filter::Baz
>output_file.xml
));
And, thanks to Perl's magic open (see perlopentut), you can read and write from
processes:
my $m = Pipeline(
"gen_xml.pl |",
"XML::Filter::Bar",
"XML::Filter::Baz",
"| consume_xml.pl",
);
This can be used with an XML::SAX::Tap to place a handy debugging tap in a
pipeline (or other machine):
my $m = Pipeline(
"<input_file.xml"
"XML::Filter::Bar",
Tap( "| xmllint --format -" ),
"XML::Filter::Baz",
">output_file.xml",
);
NAME¶
XML::SAX::Pipeline - Manage a linear pipeline of SAX processors
METHODS¶
See XML::SAX::Machine for most of the methods.
- new
-
my $pipeline = XML::SAX::Pipeline->new( @processors, \%options );
Creates a pipeline and links all of the given processors together. Longhand
for Pipeline().
AUTHOR¶
Barrie Slaymaker <barries@slaysys.com>
COPYRIGHT¶
Copyright 2002, Barrie Slaymaker, All Rights Reserved.
You may use this module under the terms of the Artistic, GNU Public, or BSD
licenses, your choice.
AUTHORS¶
- •
- Barry Slaymaker
- •
- Chris Prather <chris@prather.org>
COPYRIGHT AND LICENSE¶
This software is copyright (c) 2013 by Barry Slaymaker.
This is free software; you can redistribute it and/or modify it under the same
terms as the Perl 5 programming language system itself.