Provided by: libxml-hash-xs-perl_0.56-1build1_amd64 
NAME
XML::Hash::XS - Simple and fast hash to XML and XML to hash conversion written in C
SYNOPSIS
use XML::Hash::XS;
my $xmlstr = hash2xml \%hash;
hash2xml \%hash, output => $fh;
my $hash = xml2hash $xmlstr;
my $hash = xml2hash \$xmlstr;
my $hash = xml2hash 'test.xml', encoding => 'cp1251';
my $hash = xml2hash $fh;
my $hash = xml2hash *STDIN;
Or OOP way:
use XML::Hash::XS qw();
my $conv = XML::Hash::XS->new(utf8 => 0, encoding => 'utf-8')
my $xmlstr = $conv->hash2xml(\%hash, utf8 => 1);
my $hash = $conv->xml2hash($xmlstr, encoding => 'cp1251');
DESCRIPTION
This module implements simple hash to XML and XML to hash conversion written in C.
During conversion uses minimum of memory, XML or hash is written directly without building
DOM.
Some features are optional and are available with appropriate libraries:
• XML::LibXML library is required in order to build DOM
• ICU or iconv library is required in order to perform charset conversions
FUNCTIONS
hash2xml $hash, [ %options ]
$hash is reference to hash
hash2xml
{
node1 => 'value1',
node2 => [ 'value21', { node22 => 'value22' } ],
node3 => \'value3',
node4 => sub { return 'value4' },
node5 => sub { return { node51 => 'value51' } },
},
canonical => 1,
indent => 2,
;
will convert to:
<?xml version="1.0" encoding="utf-8"?>
<root>
<node1>value1</node1>
<node2>value21</node2>
<node2>
<node22>value22</node22>
</node2>
<node3>value3</node3>
<node4>value4</node4>
<node5>
<node51>value51</node51>
</node5>
</root>
and (use_attr=1):
hash2xml
{
node1 => 'value1',
node2 => [ 'value21', { node22 => 'value22' } ],
node3 => \'value3',
node4 => sub { return 'value4' },
node5 => sub { return { node51 => 'value51' } },
},
use_attr => 1,
canonical => 1,
indent => 2,
;
will convert to:
<?xml version="1.0" encoding="utf-8"?>
<root node1="value1" node3="value3" node4="value4">
<node2>value21</node2>
<node2 node22="value22"/>
<node5 node51="value51"/>
</root>
xml2hash $xml, [ %options ]
$xml may be string, reference to string, file handle or tied file handle:
xml2hash '<root>text</root>';
# output: 'text'
xml2hash '<root a="1" b="2">text</root>';
# output: { a => '1', b => '2', content => 'text' }
open(my $fh, '<', 'test.xml');
xml2hash $fh;
xml2hash *STDIN;
OPTIONS
doc [ => 0 ] # hash2xml
if doc is '1', then returned value is XML::LibXML::Document.
root [ = 'root' ] # hash2xml
Root node name.
version [ = '1.0' ] # hash2xml
XML document version
encoding [ = 'utf-8' ] # hash2xml+xml2hash
XML input/output encoding
indent [ = 0 ] # hash2xml
if indent great than "0", XML output should be indented according to its hierarchic
structure. This value determines the number of spaces.
if indent is "0", XML output will all be on one line.
output [ = undef ] # hash2xml
XML output method
if output is undefined, XML document dumped into string.
if output is FH, XML document writes directly to a filehandle or a stream.
canonical [ = 0 ] # hash2xml
if canonical is "1", converter will be write hashes sorted by key.
if canonical is "0", order of the element will be pseudo-randomly.
use_attr [ = 0 ] # hash2xml
if use_attr is "1", converter will be use the attributes.
if use_attr is "0", converter will be use tags only.
content [ = undef ] # hash2xml+xml2hash
if defined that the key name for the text content(used only if use_attr=1).
force_array => [ = undef ] # xml2hash
This option is similar to "ForceArray" from XML::Simple module:
<https://metacpan.org/pod/XML::Simple#ForceArray-=%3E-1-%23-in-important>.
force_content => [ = 0 ] # xml2hash
This option is similar to "ForceContent" from XML::Simple module:
<https://metacpan.org/pod/XML::Simple#ForceContent-=%3E-1-%23-in-seldom-used>.
merge_text [ = 0 ] # xml2hash
Setting this option to "1" will cause merge adjacent text nodes.
xml_decl [ = 1 ] # hash2xml
if xml_decl is "1", output will start with the XML declaration '<?xml version="1.0"
encoding="utf-8"?>'.
if xml_decl is "0", XML declaration will not be output.
trim [ = 0 ] # hash2xml+xml2hash
Trim leading and trailing whitespace from text nodes.
suppress_empty => [ = 0 ] # xml2hash
This option is similar to "SuppressEmpty" from XMl::Simple module:
<https://metacpan.org/pod/XML::Simple#SuppressEmpty-=%3E-1-%7C-''-%7C-undef-%23-in+out-handy>.
utf8 [ = 1 ] # hash2xml+xml2hash
Turn on utf8 flag for strings if enabled.
max_depth [ = 1024 ] # xml2hash
Maximum recursion depth.
buf_size [ = 4096 ] # hash2xml+xml2hash
Buffer size for reading end encoding data.
keep_root [ = 0 ] # xml2hash
Keep root element.
filter [ = undef ] # xml2hash
Filter nodes matched by pattern and return reference to array of nodes.
Sample:
my $xml = <<'XML';
<root>
<item1>111</item1>
<item2>222</item2>
<item3>333</item3>
</root>
XML
my $nodes = xml2hash($xml, filter => '/root/item1');
# $nodes = [ 111 ]
my $nodes = xml2hash($xml, filter => ['/root/item1', '/root/item2']);
# $nodes = [ 111, 222 ]
my $nodes = xml2hash($xml, filter => qr[/root/item\d$]);
# $nodes = [ 111, 222, 333 ]
It may be used to parse large XML because does not require a lot of memory.
cb [ = undef ] # xml2hash
This option is used in conjunction with "filter" option and defines callback that will
called for each matched node.
Sample:
xml2hash($xml, filter => qr[/root/item\d$], cb => sub {
print $_[0], "\n";
});
# 111
# 222
# 333
method [ = 'NATIVE' ] # hash2xml
experimental support the conversion methods other libraries
if method is 'LX' then conversion result is the same as using XML::Hash::LX library
Note: for 'LX' method following additional options are available:
attr
cdata
text
comm
OBJECT SERIALISATION(hash2xml)
1. When object has a "toString" method
In this case, the <toString> method of object is invoked in scalar context. It must
return a single scalar that can be directly encoded into XML.
Example:
use XML::LibXML;
local $XML::LibXML::skipXMLDeclaration = 1;
my $doc = XML::LibXML->new->parse_string('<foo bar="1"/>');
print hash2xml({ doc => $doc }, indent => 2, xml_decl => 0);
=>
<root>
<doc><foo bar="1"/></doc>
</root>
2. When object has overloaded stringification
In this case, the stringification method of object is invoked and result is directly
encoded into XML.
Example:
package Test {
use overload '""' => sub { shift->stringify }, fallback => 1;
sub new {
my ($class, $str) = @_;
bless { str => $str }, $class;
}
sub stringify {
shift->{str}
}
}
my $obj = Test->new('test string');
print hash2xml({ obj => $obj }, indent => 2, xml_decl => 0);
=>
<root>
<obj>test string</obj>
</root>
3. When object has a "iternext" method ("NATIVE" method only)
In this case, the <iternext> method method will invoke a few times until the return
value is not undefined.
Example:
my $count = 0;
my $o = bless {}, 'Iterator';
*Iterator::iternext = sub { $count++ < 3 ? { count => $count } : undef };
print hash2xml({ item => $o }, use_attr => 1, indent => 2, xml_decl => 0);
=>
<root>
<item count="1"/>
<item count="2"/>
<item count="3"/>
</root>
This can be used to generate a large XML using minimum memory, example with DBI:
my $sth = $dbh->prepare('SELECT * FROM foo WHERE bar=?');
$sth->execute(...);
my $o = bless {}, 'Iterator';
*Iterator::iternext = sub { $sth->fetchrow_hashref() };
open(my $fh, '>', 'data.xml');
hash2xml({ row => $o }, use_attr => 1, indent => 2, xml_decl => 0, output => $fh);
=>
<root>
<row bar="..." ... />
<row bar="..." ... />
...
</root>
BENCHMARK
Performance benchmark in comparison with some popular modules(hash2xml):
Rate XML::Hash XML::Hash::LX XML::Simple XML::Hash::XS
XML::Hash 65.0/s -- -6% -37% -99%
XML::Hash::LX 68.8/s 6% -- -33% -99%
XML::Simple 103/s 58% 49% -- -98%
XML::Hash::XS 4879/s 7404% 6988% 4658% --
Benchmark was done on <http://search.cpan.org/uploads.rdf>
AUTHOR
Yuriy Ustushenko, <yoreek@yahoo.com>
COPYRIGHT AND LICENSE
Copyright (C) 2012-2021 Yuriy Ustushenko
This library is free software; you can redistribute it and/or modify it under the same
terms as Perl itself.