DZone Snippets: Beutelevision's Code Snippets

Create an RFC822 compliant date in Perl

beutelevision (Thomas Beutel) — Fri, 08 Jul 2005 04:41:10 GMT



use Date::Manip qw(ParseDate UnixDate);



# Create an RFC822 compliant date (current time)

my $rfc822_format = "%a, %d %b %Y %H:%M %Z";

my $today         = ParseDate("Now");



my $rfc822_date   = UnixDate($today,$rfc822_format);

Cheap XML append in Perl

beutelevision (Thomas Beutel) — Fri, 01 Jul 2005 01:19:52 GMT

Here is a really cheap way in Perl to append an XML fragment to an existing XML doc. It appends it just before the last closing tag. Note that there is no validation or well-formedness checking. Use at your own risk. That said, it can be handy if you know that your XML is going to be OK.

#!/usr/bin/perl



sub xappend(\$$) { ${$_[0]} =~ s/(<\/[^>]+>\s*)$/$_[1]$1/s }



$a = "foo";

xappend($a,"bar");



print $a; # prints foobar

Easy Substitution Oneliner

beutelevision (Thomas Beutel) — Fri, 06 May 2005 23:45:54 GMT

Suppose you have a bunch of files where you need to make the same substitution. This oneliner will make the substitution and keep the old version in backups. This is particularly handy for configuration files.



perl -p -i.bak -e 's:oldtext:newtext:g' *.conf

From database records to XML

beutelevision (Thomas Beutel) — Sat, 16 Apr 2005 14:57:13 GMT

Here is a quick way to convert database records to XML using XML::Simple.



#!/usr/bin/perl



use warnings;

use strict;

use XML::Simple;

use DBI;



my $dbh = DBI->connect('DBI:mysql:MYDATABASE','user','password')

  or die DBI->errstr;



# Get an array of hashes

my $recs = $dbh->selectall_arrayref('SELECT * FROM contents',{ Columns => {} });



# Convert to XML where each hash element becomes an XML element

my $xml = XMLout( {record => $recs}, NoAttr => 1 );



print $xml;



$dbh->disconnect;

For a table with fields named "id", "entry", and "modified", the output would be:





  

    1

    1932 - 1939

    2005-04-15 22:24:44

  

  

    2

    Yet another entry

    2005-04-15 22:25:00

  

  

    3

    More stuff here

    2005-04-15 22:25:13

Post XML using curl

beutelevision (Thomas Beutel) — Sat, 16 Apr 2005 09:42:57 GMT

You can use curl on the command line to do a POST to an endpoint.

echo 'Some content.' | curl -X POST -H 'Content-type: text/xml' -d @- http://example.com/restapi

This is handy for adding web services to applications that do not do web services but can do command lines--FileMaker for example.

Convert HTML entities

beutelevision (Thomas Beutel) — Fri, 15 Apr 2005 00:05:00 GMT

Include this to convert those ampersands and angle brackets to proper entities. It can help with XML too but remember there are lots of other entities that need converting.



use HTML::Entities;



...



$html = encode_entities($string, '<>&"');

XSLT Alternating Colors for HTML Table Rows

beutelevision (Thomas Beutel) — Tue, 12 Apr 2005 01:18:46 GMT

This attaches a style attribute to the tr tag, but only on every other tag.







  

    background-color:#dddddd

Oneliner - Print a File as Hex

beutelevision (Thomas Beutel) — Sat, 09 Apr 2005 06:09:27 GMT



perl -ne '@a=split"";for(@a){printf"%02x ",ord;print"\n"unless++$c % 20}' sample.txt

Expand Numerical Ranges

beutelevision (Thomas Beutel) — Sat, 09 Apr 2005 05:57:27 GMT

This rather long winded Perl subroutine returns an array of numbers expanded from a list such as 34,35,36,42-56,98-150. There are plenty of other ways to do this (eval comes to mind).



 sub expand {                                                              

  my $range = shift;            

  my @result; 

$range =~ s/[^\d\-\,]//gs; #remove extraneous characters

 my @items = split(/,/,$range);    

  foreach (@items){                 

    m/^\d+$/ and push(@result,$_) and next;  my ($start,$finish) = split /-/;   push(@result,($start .. $finish)) if $start < $finish;                    

  }                                 

  return @result;                        

 }

Read a File with any Line Ending

beutelevision (Thomas Beutel) — Sat, 09 Apr 2005 05:49:20 GMT

Here is a quick way in Perl to read lines from a file regardless of whether it is Unix, Mac, or DOS.



my @lines = split(/\012\015?|\015\012?/,(join '',));