XML::LibXML::Simple is a Exporter
my $xml = ...; # filename, fh, string, or XML::LibXML-node
Imperative:
use XML::LibXML::Simple qw(XMLin); my $data = XMLin $xml, %options;
Or the Object Oriented way:
use XML::LibXML::Simple (); my $xs = XML::LibXML::Simple->new(%options); my $data = $xs->XMLin($xml, %options);
Be warned: this module thinks to be smart. You may very well shoot yourself in the foot with this DWIMmery. Read the whole manual page at least once before you start using it. If your XML is described in a schema or WSDL, then use XML::Compile for maintainable code.
For descriptions of the %options see the ``DETAILS'' section of this manual page.
$data = XMLin('/etc/params.xml', %options);
$data = XMLin('-', %options);
$data = XMLin(undef, ForceArray => 1);
This feature is available for backwards compatibility with XML::Simple, but quite sensitive. You can easily hit the wrong xml file as input. Please do not use it: always use an explicit filename.
$data = XMLin('<opt username="bob" password="flurp" />', %options);
# $fh = IO::File->new('/etc/params.xml') or die;
open my $fh, '<:encoding(utf8)', '/etc/params.xml' or die;
$data = XMLin($fh, %options);
In alphabetic order:
XMLin('<opt one="1">Two</opt>', ContentKey => 'text')
will parse to:
{ one => 1, text => 'Two' }
instead of:
{ one => 1, content => 'Two' }
You can also prefix your selected key name with a '-' character to have "XMLin()" try a little harder to eliminate unnecessary 'content' keys after array folding. For example:
XMLin(
'<opt><item name="one">First</item><item name="two">Second</item></opt>',
KeyAttr => {item => 'name'},
ForceArray => [ 'item' ],
ContentKey => '-content'
)
will parse to:
{
item => {
one => 'First'
two => 'Second'
}
}
rather than this (without the '-'):
{
item => {
one => { content => 'First' }
two => { content => 'Second' }
}
}
<opt>
<name>value</name>
</opt>
would parse to this:
{ name => [ 'value' ] }
instead of this (the default):
{ name => 'value' }
This option is especially useful if the data structure is likely to be written back out as XML and the default behaviour of rolling single nested elements up into attributes is not desirable.
If you are using the array folding feature, you should almost certainly enable this option. If you do not, single nested elements will not be parsed to arrays and therefore will not be candidates for folding to a hash. (Given that the default value of 'KeyAttr' enables array folding, the default value of this option should probably also have been enabled as well).
It is also possible to include compiled regular expressions in the list --any element names which match the pattern will be forced to arrays. If the list contains only a single regex, then it is not necessary to enclose it in an arrayref. Eg:
ForceArray => qr/_list$/
XMLin('<opt><x>text1</x><y a="2">text2</y></opt>', ForceContent => 1)
will parse to:
{
x => { content => 'text1' },
y => { a => 2, content => 'text2' }
}
instead of:
{
x => 'text1',
y => { 'a' => 2, 'content' => 'text2' }
}
<opt>
<searchpath>
<dir>/usr/bin</dir>
<dir>/usr/local/bin</dir>
<dir>/usr/X11/bin</dir>
</searchpath>
</opt>
Would normally be read into a structure like this:
{
searchpath => {
dir => [ '/usr/bin', '/usr/local/bin', '/usr/X11/bin' ]
}
}
But when read in with the appropriate value for 'GroupTags':
my $opt = XMLin($xml, GroupTags => { searchpath => 'dir' });
It will return this simpler structure:
{
searchpath => [ '/usr/bin', '/usr/local/bin', '/usr/X11/bin' ]
}
The grouping element ("<searchpath>" in the example) must not contain any attributes or elements other than the grouped element.
You can specify multiple 'grouping element' to 'grouped element' mappings in the same hashref. If this option is combined with "KeyAttr", the array folding will occur first and then the grouped element names will be eliminated.
When this option is provided, the CODE will be called once the XML DOM tree is ready to get transformed into Perl. Your CODE should return either "undef" (nothing to do) or a HASH which maps values of unique_key (see XML::LibXML::Node method "unique_key" onto CODE references to be called.
Once the translater from XML into Perl reaches a selected node, it will call your routine specific for that node. That triggering node found is the only parameter. When you return "undef", the node will not be found in the final result. You may return any data (even the node itself) which will be included in the final result as is, under the name of the original node.
Example:
my $out = XMLin $file, HookNodes => \&protect_html;
sub protect_html($$)
{ # $obj is the instantated XML::Compile::Simple object
# $xml is a XML::LibXML::Element to get transformed
my ($obj, $xml) = @_;
my %hooks; # collects the table of hooks
# do an xpath search for HTML
my $xpc = XML::LibXML::XPathContext->new($xml);
my @nodes = $xpc->findNodes(...); #XXX
@nodes or return undef;
my $as_text = sub { $_[0]->toString(0) }; # as text
# $as_node = sub { $_[0] }; # as node
# $skip = sub { undef }; # not at all
# the same behavior for all xpath nodes, in this example
$hook{$_->unique_key} = $as_text
for @nodes;
\%hook;
}
$config = XMLin('<config tempdir="/tmp" />', KeepRoot => 1)
You'll be able to reference the tempdir as "$config->{config}->{tempdir}" instead of the default "$config->{tempdir}".
For example, this XML:
<opt>
<user login="grep" fullname="Gary R Epstein" />
<user login="stty" fullname="Simon T Tyson" />
</opt>
would, by default, parse to this:
{
user => [
{ login => 'grep',
fullname => 'Gary R Epstein'
},
{ login => 'stty',
fullname => 'Simon T Tyson'
}
]
}
If the option 'KeyAttr => ``login''' were used to specify that the 'login' attribute is a key, the same XML would parse to:
{
user => {
stty => { fullname => 'Simon T Tyson' },
grep => { fullname => 'Gary R Epstein' }
}
}
The key attribute names should be supplied in an arrayref if there is more than one. "XMLin()" will attempt to match attribute names in the order supplied.
Note 1: The default value for 'KeyAttr' is "['name', 'key', 'id']". If you do not want folding on input or unfolding on output you must setting this option to an empty list to disable the feature.
Note 2: If you wish to use this option, you should also enable the "ForceArray" option. Without 'ForceArray', a single nested element will be rolled up into a scalar rather than an array and therefore will not be folded (since only arrays get folded).
Two further variations are made possible by prefixing a '+' or a '-' character to the attribute name:
The option 'KeyAttr => { user => ``+login'' }' will cause this XML:
<opt>
<user login="grep" fullname="Gary R Epstein" />
<user login="stty" fullname="Simon T Tyson" />
</opt>
to parse to this data structure:
{
user => {
stty => {
fullname => 'Simon T Tyson',
login => 'stty'
},
grep => {
fullname => 'Gary R Epstein',
login => 'grep'
}
}
}
The '+' indicates that the value of the key attribute should be copied rather than moved to the folded hash key.
A '-' prefix would produce this result:
{
user => {
stty => {
fullname => 'Simon T Tyson',
-login => 'stty'
},
grep => {
fullname => 'Gary R Epstein',
-login => 'grep'
}
}
}
Note: you can spell this option with a 'z' if that is more natural for you.
The internally created parser object is configured in safe mode. Read the XML::LibXML::Parser manual about security issues with certain parameter settings. The default is unsafe!
If a filename is provided to "XMLin()" but SearchPath is not defined, the file is assumed to be in the current directory.
If the first parameter to "XMLin()" is undefined, the default SearchPath will contain only the directory in which the script itself is located. Otherwise the default SearchPath will be empty.
<opt>
<colour value="red" />
<size value="XXL" />
</opt>
Setting "ValueAttr => [ 'value' ]" will cause the above XML to parse to:
{
colour => 'red',
size => 'XXL'
}
instead of this (the default):
{
colour => { value => 'red' },
size => { value => 'XXL' }
}
Without this option:
<record xmlns:x="http://xyz"> <x:field1>42</x:field1> </record> <record xmlns:y="http://xyz"> <y:field1>42</y:field1> </record>
translates into
{ 'x:field1' => 42 }
{ 'y:field1' => 42 }
but both source component have exactly the same meaning. When "NsExpand" is used, the result is:
{ '{http://xyz}field1' => 42 }
{ '{http://xyz}field1' => 42 }
Of course, addressing these fields is more work. It is advised to implement it like this:
my $ns = 'http://xyz'; $data->{"{$ns}field1"};
{ field1 => 42 }
{ field1 => 42 }
<opt username="testuser" password="frodo"></opt>
it returns the following data structure:
{
username => 'testuser',
password => 'frodo'
}
The identical result could have been produced with this alternative XML:
<opt username="testuser" password="frodo" />
Or this (although see 'ForceArray' option for variations):
<opt>
<username>testuser</username>
<password>frodo</password>
</opt>
Repeated nested elements are represented as anonymous arrays:
<opt>
<person firstname="Joe" lastname="Smith">
<email>joe@smith.com</email>
<email>jsmith@yahoo.com</email>
</person>
<person firstname="Bob" lastname="Smith">
<email>bob@smith.com</email>
</person>
</opt>
{
person => [
{ email => [ 'joe@smith.com', 'jsmith@yahoo.com' ],
firstname => 'Joe',
lastname => 'Smith'
},
{ email => 'bob@smith.com',
firstname => 'Bob',
lastname => 'Smith'
}
]
}
Nested elements with a recognised key attribute are transformed (folded) from an array into a hash keyed on the value of that attribute (see the "KeyAttr" option):
<opt>
<person key="jsmith" firstname="Joe" lastname="Smith" />
<person key="tsmith" firstname="Tom" lastname="Smith" />
<person key="jbloggs" firstname="Joe" lastname="Bloggs" />
</opt>
{
person => {
jbloggs => {
firstname => 'Joe',
lastname => 'Bloggs'
},
tsmith => {
firstname => 'Tom',
lastname => 'Smith'
},
jsmith => {
firstname => 'Joe',
lastname => 'Smith'
}
}
}
The <anon> tag can be used to form anonymous arrays:
<opt>
<head><anon>Col 1</anon><anon>Col 2</anon><anon>Col 3</anon></head>
<data><anon>R1C1</anon><anon>R1C2</anon><anon>R1C3</anon></data>
<data><anon>R2C1</anon><anon>R2C2</anon><anon>R2C3</anon></data>
<data><anon>R3C1</anon><anon>R3C2</anon><anon>R3C3</anon></data>
</opt>
{
head => [ [ 'Col 1', 'Col 2', 'Col 3' ] ],
data => [ [ 'R1C1', 'R1C2', 'R1C3' ],
[ 'R2C1', 'R2C2', 'R2C3' ],
[ 'R3C1', 'R3C2', 'R3C3' ]
]
}
Anonymous arrays can be nested to arbirtrary levels and as a special case, if the surrounding tags for an XML document contain only an anonymous array the arrayref will be returned directly rather than the usual hashref:
<opt>
<anon><anon>Col 1</anon><anon>Col 2</anon></anon>
<anon><anon>R1C1</anon><anon>R1C2</anon></anon>
<anon><anon>R2C1</anon><anon>R2C2</anon></anon>
</opt>
[
[ 'Col 1', 'Col 2' ],
[ 'R1C1', 'R1C2' ],
[ 'R2C1', 'R2C2' ]
]
Elements which only contain text content will simply be represented as a scalar. Where an element has both attributes and text content, the element will be represented as a hashref with the text content in the 'content' key (see the "ContentKey" option):
<opt>
<one>first</one>
<two attr="value">second</two>
</opt>
{
one => 'first',
two => { attr => 'value', content => 'second' }
}
Mixed content (elements which contain both text content and nested elements) will be not be represented in a useful way - element order and significant whitespace will be lost. If you need to work with mixed content, then XML::Simple is not the right tool for your job - check out the next section.
XML::Simple, the original implementation which interface is followed as closely as possible.
Copyrights of the perl code and the related documentation by 2008-2020 by [Mark Overmeer <markov@cpan.org>]. For other contributors see ChangeLog.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See http://dev.perl.org/licenses/