On 18/04/2011 21:55, Rajpreet wrote:
Thanks for your replies. But the above message is jst a sample and the
exact message we get is pretty huge(its a trading sysem message)... I
do have XML Parser installed.. I was trying to format a sample message
using start and a default handler. I do get data in a variable and can
change it, but how do I get the changed XML message in a new file. My
question might be confusing or silly, but thats where I am currently
stuck . I just wrote a dummy script-
#!/usr/bin/perl
use XML::Parser;
use Data::Dumper ;
open(XML, "a.txt") || die("Could not open file XML_FILE !"); ### handler
my $Data =<XML>;
close(XML);
&ReplaceXMLValue($Data,'MOSP_Trader_Code','1111111111111');
sub ReplaceXMLValue
{
my $Data = shift @_;
my $tagName = shift @_;
my $NewValue = shift @_;
my $parser = new XML::Parser ( Handlers => { # Creates our parser
object
Start => \&hdl_start,
Default => \&hdl_default,
});
$parser->parse($Data);
print " \n\n\n Formatted data is - $Data \n\n\n";
}
# The Handlers
sub hdl_start{
my ($p, $elt, %atts) = @_;
return unless $elt eq 'MOSP_Trader_Code'; # We're only interrested in
what's said
$flag=1;
}
sub hdl_default {
my ($p, $data) = @_;
if ($flag == 1)
{
print "Inside default handler \n";
if ($data eq 'CHL')
{
print "chaging data value form CHL to POST\n";
$data ='POST';
print "$data\n";
$flag =0;
}
}
} # End of default_handler
There is a 'Style' option to XML::Parser which, if set to 'Stream', will
cause the symbols in the parsed XML to be normalised and printed to
STDOUT. If appropriately-named subroutines exist, then instead of
sending the symbol to output, the subroutine will be called with the
value in $_.
If there is a procedure called Text(), it will be called each time a
text item in the XML is encountered, and so it could examine the context
and the content of $_ and modify it if necessary before calling print.
The program below uses this technique to perform the transformation that
you have described. Note that the XML::Expat object is passed to Text()
as the first (and only) parameter, and can be used to establish the name
of the current element.
HTH,
Rob
use strict;
use warnings;
use XML::Parser;
ReplaceXMLValue(*DATA, 'MOSP_Trader_Code', 'CHL', 'POST');
sub ReplaceXMLValue {
no warnings 'closure';
my ($fh, $tag_name, $old_value, $new_value) = @_;
my $parser = new XML::Parser(Style => 'Stream');
sub Text {
my $expat = shift;
if ($expat->current_element eq $tag_name) {
s/\A(\s*)\Q$old_value\E(\s*)\z/$1$new_value$2/;
}
print;
};
$parser->parse($fh);
}
__DATA__
<myxml>
<dataset id="1">
<field1>
Field 1 Data
</field1>
<field2>
Field 2 Data
</field2>
<MOSP_Trader_Code>CHL</MOSP_Trader_Code>
<field3>
Data associated with field 3
</field3>
<field4>
Data for field 4
</field4>
</dataset>
</myxml>
**OUTPUT**
<myxml>
<dataset id="1">
<field1>
Field 1 Data
</field1>
<field2>
Field 2 Data
</field2>
<MOSP_Trader_Code>POST</MOSP_Trader_Code>
<field3>
Data associated with field 3
</field3>
<field4>
Data for field 4
</field4>
</dataset>
</myxml>
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