Path::Dispatcher(3) flexible and extensible dispatch


use Path::Dispatcher;
my $dispatcher = Path::Dispatcher->new;
regex => qr{^/(foo)/},
block => sub { warn shift->pos(1); },
tokens => ['ticket', 'delete', qr/^\d+$/],
delimiter => '/',
block => sub { delete_ticket(shift->pos(3)) },
my $dispatch = $dispatcher->dispatch("/foo/bar");
die "404" unless $dispatch->has_matches;


We really like Jifty::Dispatcher and wanted to use it for Prophet's command line.

The basic operation is that of dispatch. Dispatch takes a path and a list of rules, and it returns a list of matches. From there you can ``run'' the rules that matched. These phases are distinct so that, if you need to, you can inspect which rules were matched without ever running their codeblocks.

Tab completion support is also available (see in particular ``How can I configure tab completion for shells?'' in Path::Dispatcher::Cookbook) for the dispatchers you write.

Each rule may take a variety of different forms (which I think justifies the ``flexible'' adjective in the module's description). Some of the rule types are:

Matches the path against a regular expression.
Match one of a set of strings.
Execute a coderef to determine whether the path matches the rule. So you can do anything you like. Though writing a domain-specific rule (see below) will enable better introspection and encoding intent.
Use another Path::Dispatcher to match the path. This facilitates both extending dispatchers (a bit like subclassing) and delegating to plugins.

Since Path::Dispatcher is designed with good object-oriented programming practices, you can also write your own domain-specific rule classes (which earns it the ``extensible'' adjective). For example, in Prophet, we have a custom rule for matching, and tab completing, record IDs.

You may want to use Path::Dispatcher::Declarative which gives you some sugar inspired by Jifty::Dispatcher.



A list of Path::Dispatcher::Rule objects.



Adds a Path::Dispatcher::Rule to the end of this dispatcher's rule set.

dispatch path -> dispatch

Takes a string (the path) and returns a Path::Dispatcher::Dispatch object representing a list of matches (Path::Dispatcher::Match objects).

run path, args

Dispatches on the path and then invokes the "run" method on the Path::Dispatcher::Dispatch object, for when you don't need to inspect the dispatch.

The args are passed down directly into each rule codeblock. No other args are given to the codeblock.

complete path -> strings

Given a path, consult each rule for possible completions for the path. This is intended for tab completion. You can use it with Term::ReadLine like so:

    $term->Attribs->{completion_function} = sub {
        my ($last_word, $line, $start) = @_;
        my @matches = map { s/^.* //; $_ } $dispatcher->complete($line);
        return @matches;

This API is experimental and subject to change. In particular I think I want to return an object that resembles Path::Dispatcher::Dispatch.


Shawn M Moore, "<sartak at>"


Copyright 2008-2011 Best Practical Solutions.

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