NAME

Hustle::Table - Cached general purpose dispatch and routing table

SYNOPSIS

use Hustle::Table;

Create a new table:

my $table=Hustle::Table->new;

Add entry as hash ref:

$table->add( { matcher => qr/regex (match)/, value=> "a value"});

Add entry as array ref (3 elements required):

$table->add( [qr/another/, "another value", undef])

Add entry as flat key value pairs:

    $table->add(matcher=>"jones", value=> sub {"one more"}, type=>"begin");

Add entry as tuple

    $table->add(qr|magic matcher| => "to a value");
    

Set the default entry:

    $table->set_default("default value");

Prepare a dispatcher external cache:

    my %cache;
    my $dispatch = $table->prepare_dispatcher(cache=>\%cache);

Call dispatcher to return the matching entry and any regex captures

my ($entry, $captures)=$dispatch->("thing to match"); 

DESCRIPTION

This module provides a class to construct a routing table and build a high performance dispatcher from it.

A table can have any combination of regex, exact string, begin string end string or numeric matching of entries. The order in which the entries are added defines their precedence. First in, first tested.

In the case of no entries matching the input, a default/fallback entry always matches.

Once all the entries have been added to the table, a dispatcher is prepared/created. The dispatcher is an anonymous subroutine, which tests its argument against the matcher in each entry in the table.

It returns a list containing the first entry that matched, and an anonymous array of any captures from regex matching.

If more entries are required to be added to the table, the dispatcher must be prepared again.

A cache (hash) is used to drastically improve table lookup performance. Entries are automatically added to the cache. However removal of cache entries is up to the user to implement on a application basis.

CREATING A TABLE

Calling the class constructor returns a new table. There are no required arguments:

    my $table=Hustle::Table->new;

In this case, a default catch all entry (an undef value) is added automatically.

If an argument is provided, it is the value used in the default/catch all entry:

    my $table=Hustle::Table->new($default);

ENTRIES

Structure

An entry is an anonymous array containing the following elements:

    [matcher, value, type, default]

• matcher

  matcher can be a regex, a string or a numeric value.

  When matcher is a regex, any captures are returned as the second item when calling the dispatcher

  When matcher is string or numeric value, the last field type specifies how to perform the match. See type below.

  If no type is specified or is undef, the matcher is always treated as a regex

• value

  This is the data you want to retrieve from the table when the matches.

• type

  type is used to adjust how the matcher is interpreted. The possible values are:

      undef   =>      matcher is always treated as a regex
      "begin" =>      matches the begining of input string
      "end"   =>      matches the end of input string
      "exact" =>      string equality
      "numeric" =>    numeric equality
  

  If matcher is a precompiled regex (i.e. qr{}), type is ignored.

  If matcher is a string or number, it is treated as a regex unless type is as above.

• default

  This is a flag indicating if the entry was the default entry

Adding

Entries are added in anonymous hash, anonymous array or flattened format, using the add method.

Anonymous array entries must contain six elements, in the order of:

    $table->add([$matcher, $value, $type]);

Anonymous hashes format only need to specify the matcher and value pairs

    $table->add({matcher=>$matcher, value=>$value, type=>$type});

Single flattened format takes a list directly. It must contain 4 elements

    $table->add(matcher=>$matcher, value=> $value);

Single simple format takes two elements

    $table->add(qr{some matcher}=>$value);

Or add multiple at once using mixed formats together

    $table->add(
            [$matcher, $value, $type],
            {matcher=> $matcher, value=>$value},
            matcher=>$matcher, value=>$value
    );

In any case,matcher and value are the only items which must be defined.

Default Matcher

Each list has a default matcher that will unconditionally match the input. This entry is specified by using undef as the matcher when adding an entry. When set this way only the array format can be used.

To make it more explicit, the it can also be changed via the set_default method.

The default value of the 'default' entry is undef

PREPARING A DISPATCHER

Once all the entries are added to the table, the dispatcher can be constructed by calling prepare_dispatcher:

    my $dispatcher=$table->prepare_dispatcher(%args);

Arguments to this method include:

• cache

  The hash ref to use as the dispatchers cache. Specifying a hash allows external management. If no cache is specified an internal cache is used.

USING A DISPATCHER

The dispatcher is simply a sub, which you call with the input to match against the table entries:

    my ($entry, $captures)=$dispatcher->("input");
    my $value=$entry->[1];

The return from the dispatcher is a list of two elements.

The first is the array reference to the table entry that matched (or the default entry if no match was found). The value associated with the table entry is located in position 1

The second item returned is an anonymous array of any captures due to a matching regex

COMPARISON TO OTHER MODULES

Solid performance compared to other perl routing/dispatch modules. Faster in basic tests then other perl modules:

Smart::Dispatch Router::Simple Router::Boom

If you need even more performance then checkout URI::Router

TODO: make proper benchmark and comparison

AUTHOR

Ruben Westerberg, drclaw@mac.com

COPYRIGHT AND LICENSE

Copyright (C) 2022 by Ruben Westerberg

Licensed under MIT

DISCLAIMER OF WARRANTIES

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.