masonpoet

Global Variable mason2 in POET

I'm new to Mason2/POET and I have been using this guide http://search.cpan.org/~jswartz/Poet/lib/Poet/Manual/Tutorial.pod to create my first website.

Now I would like to create a new global variable (example: $User) but then I have no idea or what direction I should take in order to do so since the document doesnt explain about it. Most documents I found were about Apache or mod_perl...

Example of what I'm looking for:

<%augment wrap>
 <html>
  html code goes here
 </html>
</%augment>
<%init>
my $User;
Mason::Interp::allow_globals => [qw($User)];
</%init>
Solution

  • Just read the Poet::Import.

    Simple example:

    # generate app My
poet new my
cd my

    add a class My::Import, e.g.

    vi lib/My/Import.pm

    and add into it

    package My::Import;
use Poet::Moose;
extends 'Poet::Import';

use Types::Path::Tiny qw(Path);

# create some variable
has 'mytemp' => (is => 'ro', isa => Path, coerce => 1, default => '/tmp');

method provide_var_mytemp ($caller) { #your WANTED variable name - add after the "provide_var_"
    return $self->mytemp;
}
1; #happy perl

    e.g. the Poet::Import already importing variables $conf and $env (and also the utility tag :web. So, you just extends the Poet::Import, by adding another "attribute" (your "variable") into it.

    In the above example

    Now, you can use it for example in your components. Edit your comps/index.mc.

    Into the top add

    <%class>
use Poet qw($mytemp);  #your global variable (is a Path::Tiny object to /tmp)
</%class>

    and add following too:

    <h1>My files in the /tmp</h1>
<pre>
% for my $file ($mytemp->children) {
        <% $file %>
% }
</pre>

    The $mytemp using the use Poet qw($mytemp); is imported from your My/Import.pm. (it is read-only, by it's definition - (is => 'ro',...).

    Everything in the Poet/Mason is Moose :), so (of course) you can import rw variable with any isa... etc.

    Just remember, the above is true global and persistent variable. E.g. its content is preserved between requests. In most cases you don't want use such variables, only in few special cases, for example, you want initialise some database handle $dbh (what should be available util the application runs) and such.

    Second, here is also the $m->notes method, but don't over-use it. From the docs:

    The notes() method provides a place to store application data between components - essentially, a hash which persists for the duration of the request.

    Consider storing this kind of data in a read-write attribute of the page component.

    Mostly, it is enough to use simple component attributes, e.g. see for example in the generated default app the usage of the $.title (e.g. $self->title).

    Or you just can pass variables to components as arguments,

    <& somecomp.mc, arg1 => 'some', arg2 => 'other' &>

    and so on...

    Again, every component is:

    :)