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

Hi wise fellow monks.

In one of my projects, I implemented a subclass of HTTP::Requests to add extra attributes and methods to it. Basically as this: 

package My::HTTPRequest ;
use base qw/HTTP::Request/ ;

sub new{
   my ($class) = shift ;
   my $self = $class->SUPER::new(@_) ;
   $self->{'myA'} = undef ;
   return bless $self, $class ;
}

sub myM{
  my ($self) = @_ ;
  ...
}

...

1;

[download]

Everything is fine appart this problem: I got another module that produce standard HTTP::Requests objects and I want to turn those into my My::HTTPRequests. Basically, what I want to have is this: 


my $httpr = AnotherModule::f() ;
# $httpr is a plain HTTP::Request object

my $ownHttpr = transform($httpr) ;
# $ownHttpr should be an instance of My::HTTPRequest with all the prop
+erties of $httpr .

[download]

According to you, what is the best way to implement the function transform ?

-- Nice photos of naked perl sources here !

Replies are listed 'Best First'.
Re: How to turn an object in my own subclass
by davorg (Chancellor) on Sep 05, 2006 at 10:14 UTC

    As part of your new method, you create a new HTTP::Request object. But in this new scenario, you already have an HTTP::Request object. So why not create a variation of your new method that works with an existing object.

    sub new_from_http_request {
  my ($class) = shift ;
  my $self = $shift ;
  $self->{myA} = undef ;
  return bless $self, $class ;
}

    [download]

    You can then do something like:

    my $httpr = AnotherModule::f() ;
my $ownHttpr =
  My::HTTPRequest->new_from_http_request($httpr);

    [download]

    Alternatively, you could use the same new method and just make it a bit cleverer:

    sub new{
  my ($class) = shift ;
  my $self;

  if (@_) {
    my $self = shift ;
  } else { 
    my $self = $class->SUPER::new(@_) ;
  }
  $self->{'myA'} = undef ;
  return bless $self, $class ;
}

    [download]

    In both cases, the code can probably be improved by using something like UNIVERSAL::isa to ensure that the parameter that you have been passed is actually an HTTP::Request object (or a subclass).

    --
    <http://dave.org.uk>

    "The first rule of Perl club is you do not talk about Perl club."
    -- Chip Salzenberg

[reply]
[d/l]
[select]
      Thx !

      I ended choosing the second solution (the one with the single new method) just after asking the question :)

      Actually, writing down questions often lead you to think about a solution.

      -- Nice photos of naked perl sources here !

[reply]
        Actually, writing down questions often lead you to think about a solution.

        That's why it's good to have a teddy bear (or a stuffed TuX) handy, according to Kernighan and Pike in The practice of programming.

        --
        David Serrano

[reply]
Re: How to turn an object in my own subclass
by jdporter (Paladin) on Sep 05, 2006 at 15:08 UTC
[reply]

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