XML::Smart(3) User Contributed Perl Documentation XML::Smart(3)NAMEXML::Smart - A smart, easy and powerful way to access/create XML
files/data.
DESCRIPTION
This module has an easy way to access/create XML data. It's based on
the HASH tree that is made of the XML data, and enable a dynamic access
to it with the Perl syntax for Hash and Array, without needing to care
if you have a Hash or an Array in the tree. In other words, each point
in the tree work as a Hash and an Array at the same time!
You also have extra resources, like a search for nodes by attribute,
selection of an attribute value in each multiple node, change the
returned format, etc...
The module alson handle automatically binary data (encoding/decoding
to/from base64), CDATA (like contents with <tags>) and Unicode. It can
be used to create XML files, load XML from the Web (just pasting an URL
as a file path) and it has an easy way to send XML data through socket,
just adding the length of the data in the <?xml?> header.
You can use XML::Smart with XML::Parser, or with the 2 standart parsers
of XML::Smart:
XML::Smart::Parser
XML::Smart::HTMLParser.
XML::Smart::HTMLParser can be used to load/parse wild/bad XML data, or
HTML tags.
Tutorial and F.A.Q.
You can find some extra documents about XML::Smart at:
XML::Smart::Tutorial - Tutorial and examples for XML::Smart.
XML::Smart::FAQ - Frequently Asked Questions about XML::Smart.
USAGE
## Create the object and load the file:
my $XML = XML::Smart->new('file.xml') ;
## Force the use of the parser 'XML::Smart::Parser'.
my $XML = XML::Smart->new('file.xml' , 'XML::Smart::Parser') ;
## Get from the web:
my $XML = XML::Smart->new('http://www.perlmonks.org/index.pl?node_id=16046') ;
## Cut the root:
$XML = $XML->cut_root ;
## Or change the root:
$XML = $XML->{hosts} ;
## Get the address [0] of server [0]:
my $srv0_addr0 = $XML->{server}[0]{address}[0] ;
## ...or...
my $srv0_addr0 = $XML->{server}{address} ;
## Get the server where the attibute 'type' eq 'suse':
my $server = $XML->{server}('type','eq','suse') ;
## Get the address again:
my $addr1 = $server->{address}[1] ;
## ...or...
my $addr1 = $XML->{server}('type','eq','suse'){address}[1] ;
## Get all the addresses of a server:
my @addrs = @{$XML->{server}{address}} ;
## ...or...
my @addrs = $XML->{server}{address}('@') ;
## Get a list of types of all the servers:
my @types = $XML->{server}('[@]','type') ;
## Add a new server node:
my $newsrv = {
os => 'Linux' ,
type => 'Mandrake' ,
version => 8.9 ,
address => [qw(192.168.3.201 192.168.3.202)]
} ;
push(@{$XML->{server}} , $newsrv) ;
## Get/rebuild the XML data:
my $xmldata = $XML->data ;
## Save in some file:
$XML->save('newfile.xml') ;
## Send through a socket:
print $socket $XML->data(length => 1) ; ## show the 'length' in the XML header to the
## socket know the amount of data to read.
__DATA__
<?xml version="1.0" encoding="iso-8859-1"?>
<hosts>
<server os="linux" type="redhat" version="8.0">
<address>192.168.0.1</address>
<address>192.168.0.2</address>
</server>
<server os="linux" type="suse" version="7.0">
<address>192.168.1.10</address>
<address>192.168.1.20</address>
</server>
<server address="192.168.2.100" os="linux" type="conectiva" version="9.0"/>
</hosts>
METHODS
new (FILE|DATA|URL , PARSER , OPTIONS)
Create a XML object.
Arguments:
FILE|DATA|URL
The first argument can be:
- XML data as string.
- File path.
- File Handle (GLOB).
- URL (Need LWP::UserAgent).
If not paste, a null XML tree is started, where you should
create your own XML data, than build/save/send it.
PARSER (optional)
Set the XML parser to use. Options:
XML::Parser
XML::Smart::Parser
XML::Smart::HTMLParser
XML::Smart::Parser can only handle basic XML data (not
supported PCDATA, and any header like: ENTITY, NOTATION,
etc...), but is a good choice when you don't want to install
big modules to parse XML, since it comes with the main
module. But it still can handle CDATA and binary data.
** See "PARSING HTML as XML" for XML::Smart::HTMLParser.
Aliases for the options:
SMART|REGEXP => XML::Smart::Parser
HTML => XML::Smart::HTMLParser
Default:
If not set it will look for XML::Parser and load it. If
XML::Parser can't be loaded it will use XML::Smart::Parser,
that actually is a clone of XML::Parser::Lite with some
fixes.
OPTIONS You can force the uper case and lower case for tags (nodes)
and arguments (attributes), and other extra things.
lowtag Make the tags lower case.
lowarg Make the arguments lower case.
upertag Make the tags uper case.
uperarg Make the arguments uper case.
arg_single
Set the value of arguments to 1 when they have a
undef value.
** This option will work only when the XML is
parsed by XML::Smart::HTMLParser, since it accept
arguments without values:
my $xml = new XML::Smart(
'<root><foo arg1="" flag></root>' ,
'XML::Smart::HTMLParser' ,
arg_single => 1 ,
) ;
In this example the option "arg_single" was used,
what will define flag to 1, but arg1 will still
have a null string value ("").
Here's the tree of the example above:
'root' => {
'foo' => {
'flag' => 1,
'arg1' => ''
},
},
use_spaces
Accept contents that have only spaces.
on_start (CODE) *optional
Code/sub to call on start a tag.
** This will be called after XML::Smart parse the
tag, should be used only if you want to change the
tree.
on_char (CODE) *optional
Code/sub to call on content.
** This will be called after XML::Smart parse the
tag, should be used only if you want to change the
tree.
on_end (CODE) *optional
Code/sub to call on end a tag.
** This will be called after XML::Smart parse the
tag, should be used only if you want to change the
tree.
** This options are applied when the XML data is loaded. For
XML generation see data() OPTIONS.
Examples of use:
my $xml_from_url = XML::Smart->new("http://www.perlmonks.org/index.pl?node_id=16046") ;
...
my $xml_from_str = XML::Smart->new(q`<?xml version="1.0" encoding="iso-8859-1" ?>
<root>
<foo arg="xyz"/>
</root>
`) ;
...
my $null_xml = XML::Smart->new() ;
...
my $xml_from_html = XML::Smart->new($html_data , 'html' ,
lowtag => 1 ,
lowarg => 1 ,
on_char => sub {
my ( $tag , $pointer , $pointer_back , $cont) = @_ ;
$pointer->{extra_arg} = 123 ; ## add an extrar argument.
$pointer_back->{$tag}{extra_arg} = 123 ; ## Same, but using the previous pointer.
$$cont .= "\n" ; ## append data to the content.
}
) ;
apply_dtd (DTD , OPTIONS)
Apply the DTD to the XML tree.
DTD can be a source, file, GLOB or URL.
This method is usefull if you need to have the XML generated by data()
formated in a specific DTD, so, elements will be nodes automatically,
attributes will be checked, required elements and attributes will be
created, the element order will be set, etc...
OPTIONS:
no_delete BOOL
If TRUE tells that not defined elements and attributes in the
DTD won't be deleted from the XML tree.
Example of use:
$xml->apply_dtd(q`
<!DOCTYPE cds [
<!ELEMENT cds (album+)>
<!ATTLIST cds
creator CDATA
date CDATA #REQUIRED
type (a|b|c) #REQUIRED "a"
>
<!ELEMENT album (#PCDATA)>
]>
` ,
no_delete => 1 ,
);
args()
Return the arguments names (not nodes).
args_values()
Return the arguments values (not nodes).
back()
Get back one level the pointer in the tree.
** Se base().
base()
Get back to the base of the tree.
Each query to the XML::Smart object return an object pointing to a
different place in the tree (and share the same HASH tree). So, you can
get the main object again (an object that points to the base):
my $srv = $XML->{root}{host}{server} ;
my $addr = $srv->{adress} ;
my $XML2 = $srv->base() ;
$XML2->{root}{hosts}...
content()
Return the content of a node:
## Data:
<foo>my content</foo>
## Access:
my $content = $XML->{foo}->content ;
print "<<$content>>\n" ; ## show: <<my content>>
## or just:
my $content = $XML->{foo} ;
Also can be used with multiple contents:
For this XML data:
<root>
content0
<tag1 arg="1"/>
content1
</root>
Getting all the content:
my $all_content = $XML->{root}->content ;
print "[$all_content]\n" ;
Output:
[
content0
content1
]
Getting in parts:
my @contents = $XML->{root}->content ;
print "[@contents[0]]\n" ;
print "[@contents[1]]\n" ;
Output
[
content0
]
[
content1
]
Setting multiple contents:
$XML->{root}->content(0,"aaaaa") ;
$XML->{root}->content(1,"bbbbb") ;
Output now will be:
[aaaaa]
[bbbbb]
And now the XML data generated will be:
<root>aaaaa<tag1 arg="1"/>bbbbb</root>
copy()
Return a copy of the XML::Smart object (pointing to the base).
** This is good when you want to keep 2 versions of the same XML tree
in the memory, since one object can't change the tree of the other!
cut_root()
Cut the root key:
my $srv = $XML->{rootx}{host}{server} ;
## Or if you don't know the root name:
$XML = $XML->cut_root() ;
my $srv = $XML->{host}{server} ;
** Note that this will cut the root of the pointer in the tree. So, if
you are in some place that have more than one key (multiple roots), the
same object will be retuned without cut anything.
data (OPTIONS)
Return the data of the XML object (rebuilding it).
Options:
nodtd Do not add in the XML content the DTD applied by the method
apply_dtd().
noident If set to true the data isn't idented.
nospace If set to true the data isn't idented and doesn't have space
between the tags (unless the CONTENT have).
lowtag Make the tags lower case.
lowarg Make the arguments lower case.
upertag Make the tags uper case.
uperarg Make the arguments uper case.
length If set true, add the attribute 'length' with the size of the
data to the xml header (<?xml ...?>). This is useful when
you send the data through a socket, since the socket can know
the total amount of data to read.
noheader Do not add the <?xml ...?> header.
nometagen Do not add the meta generator tag: <?meta
generator="XML::Smart" ?>
meta Set the meta tags of the XML document.
Examples:
my $meta = {
build_from => "wxWindows 2.4.0" ,
file => "wx26.htm" ,
} ;
print $XML->data( meta => $meta ) ;
__DATA__
<?meta build_from="wxWindows 2.4.0" file="wx283.htm" ?>
Multiple meta:
my $meta = [
{build_from => "wxWindows 2.4.0" , file => "wx26.htm" } ,
{script => "genxml.pl" , ver => "1.0" } ,
] ;
__DATA__
<?meta build_from="wxWindows 2.4.0" file="wx26.htm" ?>
<?meta script="genxml.pl" ver="1.0" ?>
Or set directly the meta tag:
my $meta = '<?meta foo="bar" ?>' ;
## For multiple:
my $meta = ['<?meta foo="bar" ?>' , '<?meta x="1" ?>'] ;
print $XML->data( meta => $meta ) ;
tree Set the HASH tree to parse. If not set will use the tree of
the XML::Smart object (tree()). ;
wild Accept wild tags and arguments.
** This wont fix wrong keys and tags.
sortall Sort all the tags alphabetically. If not set will keep the
order of the document loaded, or the order of tag creation.
Default: off
data_pointer (OPTIONS)
Make the tree from current point in the XML tree (not from the base as
data()).
Accept the same OPTIONS of the method data().
dump_tree()
Dump the tree of the object using Data::Dumper.
dump_tree_pointer()
Dump the tree of the object, from the pointer, using Data::Dumper.
dump_pointer()
** Same as dump_tree_pointer().
i()
Return the index of the value.
** If the value is from an hash key (not an ARRAY ref) undef is
returned.
is_node()
Return if a key is a node.
key()
Return the key of the value.
If wantarray return the index too: return(KEY , I) ;
nodes()
Return the nodes (objects) in the pointer (keys that aren't arguments).
nodes_keys()
Return the nodes names (not the object) in the pointer (keys that
aren't arguments).
null()
Return true if the XML object has a null tree or if the pointer is in
some place that doesn't exist.
order()
Return the order of the keys. See set_order().
path()
Return the path of the pointer.
Example:
/hosts/server[1]/address[0]
Note that the index is 0 based and 'address' can be an attribute or a
node, what is not compatible with XPath.
** See path_as_xpath().
path_as_xpath()
Return the path of the pointer in the XPath format.
pointer
Return the HASH tree from the pointer.
pointer_ok
Return a copy of the tree of the object, from the pointer, but without
internal keys added by XML::Smart.
root
Return the ROOT name of the XML tree (main key).
** See also key() for sub nodes.
save (FILEPATH , OPTIONS)
Save the XML data inside a file.
Accept the same OPTIONS of the method data().
set_auto
Define the key to be handled automatically. Soo, data() will define
automatically if it's a node, content or attribute.
** This method is useful to remove set_node(), set_cdata() and
set_binary() changes.
set_auto_node
Define the key as a node, and data() will define automatically if it's
CDATA or BINARY.
** This method is useful to remove set_cdata() and set_binary()
changes.
set_binary(BOOL)
Define the node as a BINARY content when TRUE, or force to not handle
it as a BINARY on FALSE.
Example of node handled as BINARY:
<root><foo dt:dt="binary.base64">PGgxPnRlc3QgAzwvaDE+</foo></root>
Original content of foo (the base64 data):
<h1>test \x03</h1>
set_cdata(BOOL)
Define the node as CDATA when TRUE, or force to not handle it as CDATA
on FALSE.
Example of CDATA node:
<root><foo><![CDATA[bla bla bla <tag> bla bla]]></foo></root>
set_node(BOOL)
Set/unset the current key as a node (tag).
** If BOOL is not defined will use TRUE.
set_order(KEYS)
Set the order of the keys (nodes and attributes) in this point.
set_tag
Same as set_node.
tree()
Return the HASH tree of the XML data.
** Note that the real HASH tree is returned here. All the other ways
return an object that works like a HASH/ARRAY through tie.
tree_pointer()
Same as pointer().
tree_ok()
Return a copy of the tree of the object, but without internal keys
added by XML::Smart, like /order and /nodes.
tree_pointer_ok()
Return a copy of the tree of the object, from the pointer, but without
internal keys added by XML::Smart.
xpath() || XPath()
Return a XML::XPath object, based in the XML root in the tree.
## look from the root:
my $data = $XML->XPath->findnodes_as_string('/') ;
** Need XML::XPath installed, but only load when is needed.
xpath_pointer() || XPath_pointer()
Return a XML::XPath object, based in the XML::Smart pointer in the
tree.
## look from this point, soo XPath '/' actually starts at /server/:
my $srvs = $XML->{server} ;
my $data = $srvs->XPath_pointer->findnodes_as_string('/') ;
** Need XML::XPath installed, but only load when is needed.
ACCESS
To access the data you use the object in a way similar to HASH and
ARRAY:
my $XML = XML::Smart->new('file.xml') ;
my $server = $XML->{server} ;
But when you get a key {server}, you are actually accessing the data
through tie(), not directly to the HASH tree inside the object, (This
will fix wrong accesses):
## {server} is a normal key, not an ARRAY ref:
my $server = $XML->{server}[0] ; ## return $XML->{server}
my $server = $XML->{server}[1] ; ## return UNDEF
## {server} has an ARRAY with 2 items:
my $server = $XML->{server} ; ## return $XML->{server}[0]
my $server = $XML->{server}[0] ; ## return $XML->{server}[0]
my $server = $XML->{server}[1] ; ## return $XML->{server}[1]
To get all the values of multiple elements/keys:
## This work having only a string inside {address}, or with an ARRAY ref:
my @addrsses = @{$XML->{server}{address}} ;
Select search
When you don't know the position of the nodes, you can select it by
some attribute value:
my $server = $XML->{server}('type','eq','suse') ; ## return $XML->{server}[1]
Syntax for the select search:
(NAME, CONDITION , VALUE)
NAME The attribute name in the node (tag).
CONDITION Can be
eq ne == != <= >= < >
For REGEX:
=~ !~
## Case insensitive:
=~i !~i
VALUE The value.
For REGEX use like this:
$XML->{server}('type','=~','^s\w+$') ;
Select attributes in multiple nodes:
You can get the list of values of an attribute looking in all multiple
nodes:
## Get all the server types:
my @types = $XML->{server}('[@]','type') ;
Also as:
my @types = $XML->{server}{type}('<@') ;
Without the resource:
my @list ;
my @servers = @{$XML->{server}} ;
foreach my $servers_i ( @servers ) {
push(@list , $servers_i->{type} ) ;
}
Return format
You can change the returned format:
Syntax:
(TYPE)
Where TYPE can be:
$ ## the content.
@ ## an array (list of multiple values).
% ## a hash.
. ## The exact point in the tree, not an object.
$@ ## an array, but with the content, not an objects.
$% ## a hash, but the values are the content, not an object.
## The use of $@ and $% is good if you don't want to keep the object
## reference (and save memory).
@keys ## The keys of the node. note that if you have a key with
## multiple nodes, it will be replicated (this is the
## difference of "keys %{$this->{node}}" ).
<@ ## Return the attribute in the previous node, but looking for
## multiple nodes. Example:
my @names = $this->{method}{wxFrame}{arg}{name}('<@') ;
#### @names = (parent , id , title) ;
<xml> ## Return a XML data from this point.
__DATA__
<method>
<wxFrame return="wxFrame">
<arg name="parent" type="wxWindow" />
<arg name="id" type="wxWindowID" />
<arg name="title" type="wxString" />
</wxFrame>
</method>
Example:
## A servers content
my $name = $XML->{server}{name}('$') ;
## ... or:
my $name = $XML->{server}{name}->content ;
## ... or:
my $name = $XML->{server}{name} ;
$name = "$name" ;
## All the servers
my @servers = $XML->{server}('@') ;
## ... or:
my @servers = @{$XML->{server}} ;
## It still has the object reference:
@servers[0]->{name} ;
## Without the reference:
my @servers = $XML->{server}('$@') ;
## A XML data, same as data_pointer():
my $xml_data = $XML->{server}('<xml>') ;
CONTENT
If a {key} has a content you can access it directly from the variable
or from the method:
my $server = $XML->{server} ;
print "Content: $server\n" ;
## ...or...
print "Content: ". $server->content ."\n" ;
So, if you use the object as a string it works as a string, if you use
as an object it works as an object! ;-P
**See the method content() for more.
CREATING XML DATA
To create XML data is easy, you just use as a normal HASH, but you
don't need to care with multiple nodes, and ARRAY creation/convertion!
## Create a null XML object:
my $XML = XML::Smart->new() ;
## Add a server to the list:
$XML->{server} = {
os => 'Linux' ,
type => 'mandrake' ,
version => 8.9 ,
address => '192.168.3.201' ,
} ;
## The data now:
<server address="192.168.3.201" os="Linux" type="mandrake" version="8.9"/>
## Add a new address to the server. Have an ARRAY creation, convertion
## of the previous key to ARRAY:
$XML->{server}{address}[1] = '192.168.3.202' ;
## The data now:
<server os="Linux" type="mandrake" version="8.9">
<address>192.168.3.201</address>
<address>192.168.3.202</address>
</server>
After create your XML tree you just save it or get the data:
## Get the data:
my $data = $XML->data ;
## Or save it directly:
$XML->save('newfile.xml') ;
## Or send to a socket:
print $socket $XML->data(length => 1) ;
BINARY DATA & CDATA
From version 1.2 XML::Smart can handle binary data and CDATA blocks
automatically.
When parsing, binary data will be detected as:
<code dt:dt="binary.base64">f1NPTUUgQklOQVJZIERBVEE=</code>
Since this is the oficial automatically format for binary data at
XML.com <http://www.xml.com/pub/a/98/07/binary/binary.html>. The
content will be decoded from base64 and saved in the object tree.
CDATA will be parsed as any other content, since CDATA is only a block
that won't be parsed.
When creating XML data, like at $XML->data(), the binary format and
CDATA are detected using this roles:
BINARY:
- If have characters that can't be in XML.
* Characters accepted:
\s \w \d
!"#$%&'()*+,-./:;<=>?@[\]^`{|}~
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
AAAA~AeAaCEEEEeIIIIe‐N~OOOO~OeXOUUUUeYPssaaaa~aeaaaeceeeeeiiiie`n~oooo~oeXouuuueypye
CDATA:
- If have tags: <...>
CONTENT: (<tag>content</tag>)
- If have \r\n\t, or ' and " at the same time.
So, this will be a CDATA content:
<code><![CDATA[
line1
<tag_not_parsed>
line2
]]></code>
If a binary content is detected, it will be converted to base64 and a
dt:dt attribute added in the tag to tell the format.
<code dt:dt="binary.base64">f1NPTUUgQklOQVJZIERBVEE=</code>
UNICODE and ASCII-extended (ISO-8859-1)
XML::Smart support only this 2 encode types, Unicode (UTF-8) and ASCII-
extended (ISO-8859-1), and must be enough. (Note that UTF-8 is only
supported on Perl-5.8+).
When creating XML data, if any UTF-8 character is detected the encoding
attribute in the <?xml ...?> header will be set to UTF-8:
<?xml version="1.0" encoding="utf-8" ?>
<data>A~X</data>
If not, the iso-8859-1 is used:
<?xml version="1.0" encoding="iso-8859-1" ?>
<data>X</data>
When loading XML data with UTF-8, Perl (5.8+) should make all the work
internally.
PARSING HTML as XML, or BAD XML formats
You can use the special parser XML::Smart::HTMLParser to "use" HTML as
XML or not well-formed XML data.
The differences between an normal XML parser and XML::Smart::HTMLParser
are:
- Accept values without quotes:
<foo bar=x>
- Accept any data in the values, including <> and &:
<root><echo sample="echo \"Hello!\">out.txt"></root>
- Accpet URI values without quotes:
<link url=http://www.foo.com/dir/file?query?q=v&x=y target=#_blank>
- Don't need to close the tags adding the '/' before '>':
<root><foo bar="1"></root>
** Note that the parse will try hard to detect the nodes, and where
auto-close or not.
- Don't need to have only one root:
<foo>data</foo><bar>data</bar>
So, XML::Smart::HTMLParser is a willd way to load markuped data (like
HTML), or if you don't want to care with quotes, end tags, etc... when
writing by hand your XML data. So, you can write by hand a bad XML
file, load it with XML::Smart::HTMLParser, and rewrite well saving it
again! ;-P
** Note that <SCRIPT> tags will only parse right if the content is
inside comments <!--...-->, since they can have tags:
<SCRIPT LANGUAGE="JavaScript"><!--
document.writeln("some <tag> in the string");
--></SCRIPT>
ENTITIES
Entities (ENTITY) are handled by the parser. So, if you use XML::Parser
it will do all the job fine. But If you use XML::Smart::Parser or
XML::Smart::HMLParser, only the basic entities (defaults) will be
parsed:
< => The less than sign (<).
> => The greater than sign (>).
& => The ampersand (&).
' => The single quote or apostrophe (').
" => The double quote (").
&#ddd; => An ASCII character or an Unicode character (>255). Where ddd is a decimal.
&#xHHH; => An Unicode character. Where HHH is in hexadecimal.
When creating XML data, already existent Entities won't be changed, and
the characters '<', '&' and '>' will be converted to the appropriated
entity.
** Note that if a content have a <tag>, the characters '<' and '>'
won't be converted to entities, and this content will be inside a CDATA
block.
WHY AND HOW IT WORKS
Every one that have tried to use Perl HASH and ARRAY to access XML
data, like in XML::Simple, have some problems to add new nodes, or to
access the node when the user doesn't know if it's inside an ARRAY, a
HASH or a HASH key. XML::Smart create around it a very dynamic way to
access the data, since at the same time any node/point in the tree can
be a HASH and an ARRAY. You also have other extra resources, like a
search for nodes by attribute:
my $server = $XML->{server}('type','eq','suse') ; ## This syntax is not wrong! ;-)
## Instead of:
my $server = $XML->{server}[1] ;
__DATA__
<hosts>
<server os="linux" type="redhat" version="8.0">
<server os="linux" type="suse" version="7.0">
</hosts>
The idea for this module, came from the problem that exists to access a
complex struture in XML. You just need to know how is this structure,
something that is generally made looking the XML file (what is wrong).
But at the same time is hard to always check (by code) the struture,
before access it. XML is a good and easy format to declare your data,
but to extrac it in a tree way, at least in my opinion, isn't easy. To
fix that, came to my mind a way to access the data with some query
language, like SQL. The first idea was to access using something like:
XML.foo.bar.baz{arg1}
X = XML.foo.bar*
X.baz{arg1}
XML.hosts.server[0]{argx}
And saw that this is very similar to Hashes and Arrays in Perl:
$XML->{foo}{bar}{baz}{arg1} ;
$X = $XML->{foo}{bar} ;
$X->{baz}{arg1} ;
$XML->{hosts}{server}[0]{argx} ;
But the problem of Hash and Array, is not knowing when you have an
Array reference or not. For example, in XML::Simple:
## This is very diffenrent
$XML->{server}{address} ;
## ... of this:
$XML->{server}{address}[0] ;
So, why don't make both ways work? Because you need to make something
crazy!
To create XML::Smart, first I have created the module
Object::MultiType. With it you can have an object that works at the
same time as a HASH, ARRAY, SCALAR, CODE & GLOB. So you can do things
like this with the same object:
$obj = Object::MultiType->new() ;
$obj->{key} ;
$obj->[0] ;
$obj->method ;
@l = @{$obj} ;
%h = %{$obj} ;
&$obj(args) ;
print $obj "send data\n" ;
Seems to be crazy, and can be more if you use tie() inside it, and this
is what XML::Smart does.
For XML::Smart, the access in the Hash and Array way paste through
tie(). In other words, you have a tied HASH and tied ARRAY inside it.
This tied Hash and Array work together, soo you can access a Hash key
as the index 0 of an Array, or access an index 0 as the Hash key:
%hash = (
key => ['a','b','c']
) ;
$hash->{key} ## return $hash{key}[0]
$hash->{key}[0] ## return $hash{key}[0]
$hash->{key}[1] ## return $hash{key}[1]
## Inverse:
%hash = ( key => 'a' ) ;
$hash->{key} ## return $hash{key}
$hash->{key}[0] ## return $hash{key}
$hash->{key}[1] ## return undef
The best thing of this new resource is to avoid wrong access to the
data and warnings when you try to access a Hash having an Array (and
the inverse). Thing that generally make the script die().
Once having an easy access to the data, you can use the same resource
to create data! For example:
## Previous data:
<hosts>
<server address="192.168.2.100" os="linux" type="conectiva" version="9.0"/>
</hosts>
## Now you have {address} as a normal key with a string inside:
$XML->{hosts}{server}{address}
## And to add a new address, the key {address} need to be an ARRAY ref!
## So, XML::Smart make the convertion: ;-P
$XML->{hosts}{server}{address}[1] = '192.168.2.101' ;
## Adding to a list that you don't know the size:
push(@{$XML->{hosts}{server}{address}} , '192.168.2.102') ;
## The data now:
<hosts>
<server os="linux" type="conectiva" version="9.0"/>
<address>192.168.2.100</address>
<address>192.168.2.101</address>
<address>192.168.2.102</address>
</server>
</hosts>
Than after changing your XML tree using the Hash and Array resources
you just get the data remade (through the Hash tree inside the object):
my $xmldata = $XML->data ;
But note that XML::Smart always return an object! Even when you get a
final key. So this actually returns another object, pointhing (inside
it) to the key:
$addr = $XML->{hosts}{server}{address}[0] ;
## Since $addr is an object you can TRY to access more data:
$addr->{foo}{bar} ; ## This doens't make warnings! just return UNDEF.
## But you can use it like a normal SCALAR too:
print "$addr\n" ;
$addr .= ':80' ; ## After this $addr isn't an object any more, just a SCALAR!
TODO
* Finish XPath implementation.
* DTD.
* Implement a better way to declare meta tags.
SEE ALSO
XML::Parser, XML::Parser::Lite, XML::XPath, XML.
Object::MultiType - This is the module that make everything possible,
and was created specially for XML::Smart. ;-P
** See the test.pl script for examples of use.
XML.com <http://www.xml.com>
AUTHOR
Graciliano M. P. <gm@virtuasites.com.br>
I will appreciate any type of feedback (include your opinions and/or
suggestions). ;-P
Enjoy and thanks for who are enjoying this tool and have sent e-mails!
;-P
THANKS
Thanks to Rusty Allen for the extensive tests of CDATA and BINARY
handling of XML::Smart.
Thanks to Ted Haining to point a Perl-5.8.0 bug for tied keys of a
HASH.
Thanks to everybody that have sent ideas, patches or pointed bugs.
COPYRIGHT
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.14.0 2004-10-30 XML::Smart(3)
