NAME

Catalyst::Plugin::DetachIfNotModified - Short-circuit requests with If-Modified-Since headers

VERSION

version v0.1.0

SYNOPSIS

In your Catalyst class:

  use Catalyst qw/
      DetachIfNotModified
    /;

In a controller method:

  my $item = ...

  $c->detach_if_not_modified_since( $item->timestamp );

  # Do some CPU-intensive stuff or generate response body here.

DESCRIPTION

This plugin will allow your Catalyst app to handle requests with If-Modified-Since headers.

If the content of a web page has not been modified since a given date, you can quickly bail out and avoid generating a web page that you do not need to.

This can improve the performance of your website.

This should be used with Plack::Middleware::ConditionalGET.

METHODS

detach_if_not_modified_since

  $c->detach_if_not_modified_since( $timestamp );

This sets the Last-Modified header in the response to the $timestamp, and checks if the request contains a If-Modified-Since header that not less than the timestamp. If it does, then it will set the response status code to 304 (Not Modified) and detach.

The $timestamp may be a unix epoch, or an object with an epoch method, such as a DateTime object.

CAVEATS

Be careful when aggregating a collection of objects into a single timestamp, e.g. the maximum timestamp from a list. If a member is removed from that collection, then the maximum timestamp won't be affected, and the result is that an outdated web page may be cached by user agents.

SEE ALSO

Catalyst

Catalyst::Plugin::Cache::HTTP::Preempt

Plack::Middleware::ConditionalGET

SOURCE

The development version is on github at https://github.com/robrwo/Catalyst-Plugin-DetachIfNotModified and may be cloned from git://github.com/robrwo/Catalyst-Plugin-DetachIfNotModified.git

BUGS

Please report any bugs or feature requests on the bugtracker website https://github.com/robrwo/Catalyst-Plugin-DetachIfNotModified/issues

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.

AUTHOR

Robert Rothenberg <rrwo@cpan.org>

This module is based on code created for Science Photo Library https://www.sciencephoto.com.

COPYRIGHT AND LICENSE

This software is Copyright (c) 2020 by Robert Rothenberg.

This is free software, licensed under:

  The Artistic License 2.0 (GPL Compatible)

cpanm Catalyst::Plugin::DetachIfNotModified

perl -MCPAN -e shell
install Catalyst::Plugin::DetachIfNotModified