atreyu has asked for the wisdom of the Perl Monks concerning the following question:

Hello,

I am using Perl 5.14.2 and XML::Simple (2.18) to create an XML file from a hash, and I'm having trouble. I can't seem to find the right options to pass to XMLout to create the XML file how I want it. I can modify the way I am creating the hash in the first place, if that is best.

Here's the code: 
#!/usr/bin/perl
use strict;
use warnings;
use XML::Simple qw(:strict);

my $userref = ();
$userref->{0}{'hash'}{'name'} = 'joe';
$userref->{0}{'hash'}{'type'} = 'user';
$userref->{1}{'hash'}{'name'} = 'mary';
$userref->{1}{'hash'}{'type'} = 'user';

my $XmlRef = ();

# loop thru all keys in userref
for my $key(sort keys %$userref){

  # the key name
  my $keyname = 'key'.$key;

  my $cnt = scalar keys %{$XmlRef->{$keyname}{'devices'}};

  my $i=0;
  for my $foo(keys %{$userref->{$key}{'hash'}}){
    $XmlRef->{$keyname}{'devices'}{'dev'.$cnt}{'param'}{$foo}{'content
+'} = [ $userref->{$key}{'hash'}{$foo} ];
    $i+=1;
  }

}

# write XML to file
my $tmpfile = '/tmp/testfile.xml';
my $fh;
open $fh, '>', $tmpfile or die "open($tmpfile): $!\n";
XMLout($XmlRef,
  XMLDecl    => '<?xml version="1.0" encoding="utf-8"?>',
  ContentKey => '-content',
  NoAttr     => 0,
  OutputFile => $fh,
  KeyAttr    => { 'param' => 'id' },
  AttrIndent => 1,
);
close $fh;

[download]

and here's the contents of the generated XML file: 

<?xml version="1.0" encoding="utf-8"?>
<opt>
  <key0>
    <devices>
      <dev0>
        <param id="name">
          <content>joe</content>
        </param>
        <param id="type">
          <content>user</content>
        </param>
      </dev0>
    </devices>
  </key0>
  <key1>
    <devices>
      <dev0>
        <param id="name">
          <content>mary</content>
        </param>
        <param id="type">
          <content>user</content>
        </param>
      </dev0>
    </devices>
  </key1>
</opt>

[download]

however, what i would like is for the "content" key to be removed entirely, e.g.:

<opt>
  <key0>
    <devices>
      <dev0>
        <param id="name">joe</param>
        <param id="type">user</param>
      </dev0>
    </devices>
  </key0>

[download]

if i simply leave off the "content" key when generating the hash, then I lose the ability to make the "id" an attribute of the "param" key. grrr. can anyone help?

Replies are listed 'Best First'.
Re: XMLout and keys/attributes
by sauoq (Abbot) on May 09, 2012 at 15:02 UTC

    Remove the ContentKey option from your call to XMLout and change where you set $XmlRef to the following: 

        $XmlRef->{$keyname}{'devices'}{'dev'.$cnt}{'param'} 
        = [ {$foo => $userref->{$key}{'hash'}{$foo}} ];

    [download]
    Update: No, that's not right... you have two tags, so you have to push them on... Try this: 
      $XmlRef->{$keyname}{'devices'}{'dev'.$cnt}{'param'} = [];
  for my $foo(keys %{$userref->{$key}{'hash'}}) {
    push @{ $XmlRef->{$keyname}{'devices'}{'dev'.$cnt}{'param'} }
         , {id => $foo, content => $userref->{$key}{'hash'}{$foo}} ;
    $i+=1;
  }

    [download]

    Edit: struck out incorrect code.

    -sauoq
    "My two cents aren't worth a dime.";
[reply]
[d/l]
[select]
      Arggg! I just looked at the original code again, and I realized I screwed up the description of the XML. here is the correct $userref example: 
      $userref->{0}{'hash'}{'Name'} = 'joe';
$userref->{0}{'hash'}{'Type'} = 'user';
$userref->{0}{'hash'}{'1Param'} = 'foo';

      [download]
      and here is what I need the XML to look like: 
        <key0>
    <devices>
      <dev0>
        <param id="Name">joe</param>
        <param id="Type">user</param>
        <param id="1Param">foo</param>
      </dev0>
    </devices>
  </key0>

      [download]
      btw, your code suggestion was very close sauoq, care to try again?!
[reply]
[d/l]
[select]
        btw, your code suggestion was very close sauoq, care to try again?!

        I already did. See my update? ;-)

        P.S. It should work with three params as well as two, so your "arrrggg" isn't needed. :-)

        -sauoq
        "My two cents aren't worth a dime.";
[reply]
Re: XMLout and keys/attributes
by tobyink (Canon) on May 09, 2012 at 15:02 UTC

    You are probably best off using something like XML::LibXML. XML::Simple is mostly for people who just want to treat XML as if it were a big hash structure, and don't care about the XML elements, attributes, text nodes, etc.

    Read more... (1111 Bytes)
    perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'
[reply]
[d/l]
      This looks interesting...but I have XML::Simple code everywhere else and I'd like to solve it that way. If I can't though, I'll try your suggestion. Thanks for your response.
[reply]
Re: XMLout and keys/attributes
by Anonymous Monk on May 09, 2012 at 14:48 UTC
    What are you using for XMLin?
[reply]
      I am not using XMLin for anything. What I am trying to do (generate an XML file from a hash/hashref of my own making) has been done elsewhere with no problems. It is just that I am being picky about what is an attribute and what is not that is tripping me up.
[reply]
        I forgot to mention an important point: in the $userref hashref, there will be many values for 'name', and they could start with a number, which is why I want to use them as attributes, and not as keys. example: 
        $userref->{2}{'hash'}{'name'} = '12345';
$userref->{3}{'hash'}{'name'} = '10foo';

        [download]
[reply]
[d/l]

        I am not using XMLin for anything.

        Then I would ditch XMLout ASAP :) seriously

        The way I use XML::Simple, is start with XML I want, then use XMLin to get data I want, then XMLout to get back xml I started with

        If XMLin can't be made into data structure you want, then XMLout can't be made into xml you want

        All that massaging of $userref you do is busywork :)

        So with XML::Rules ( XML::Simple on steriods :) steroids) I might write 

        #!/usr/bin/perl --
use strict; use warnings;
use XML::Rules;
use Data::Dump qw/ dd /;

my $wanted = <<'__XML__';
<?xml version="1.0" encoding="utf-8"?>
<opt>
  <key0>
    <devices>
      <dev0>
        <param id="name">joe</param>
        <param id="type">user</param>
      </dev0>
    </devices>
  </key0>
  <key1>
    <devices>
      <dev0>
        <param id="name">mary</param>
        <param id="type">user</param>
      </dev0>
    </devices>
  </key1>
</opt>
__XML__



use XML::Rules;
my $t = XML::Rules->new(
    qw/ stripspaces 8 /,
    rules => {
      'dev0,devices,key0,key1,opt' => 'no content',
      'param' => 'as array',
    },
);

my $XmlRef  = $t->parse( $wanted );
dd $XmlRef;
print $t->toXML( opt => $XmlRef->{opt}, undef, "  ", );
__END__
{
  opt => {
           key0 => {
                     devices => {
                       dev0 => {
                         param => [
                           { _content => "joe", id => "name" },
                           { _content => "user", id => "type" },
                         ],
                       },
                     },
                   },
           key1 => {
                     devices => {
                       dev0 => {
                         param => [
                           { _content => "mary", id => "name" },
                           { _content => "user", id => "type" },
                         ],
                       },
                     },
                   },
         },
}
<opt>
  <key0>
    <devices>
      <dev0>
        <param id="name">joe</param>
        <param id="type">user</param>
      </dev0>
    </devices>
  </key0>
  <key1>
    <devices>
      <dev0>
        <param id="name">mary</param>
        <param id="type">user</param>
      </dev0>
    </devices>
  </key1>
</opt>

        [download]

        You still get to have a hairy hash, you still get your xml, and you don't spend days trying to make it "Simple"

[reply]
[d/l]

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