Until today, I had a script named "lifestream.pl". This script was triggered via cron once every hour, to fetch various feeds from services I use (like github, identi.ca, ...) and to process the result through a template and dump the result in a HTML file.
Today I was reading Tatsumaki's code and some examples (Social and Subfeedr). Tatsumaki is a "port" tornado (a non blocking server in Python), based on Plack and AnyEvent. I though that using this to replace my old lifestream script would be a good way to test it. Two hours later I have a complete webapp that works (and the code is available here).
The code is really simple: first, I define an handler for my HTTP request. As I have only one things to do (display entries), the handler is really simple:
``` perl
package Lifestream::Handler;
use Moose;
extends 'Tatsumaki::Handler';
sub get {
my $self = shift;
my %params = %{$self->request->params};
$self->render(
'lifestream.html',
{ memes => $self->application->memes($params{page}),
services => $self->application->services
}
);
}
1;
```
For all the get request, 2 methods are called : memes and services. The memes get a list of memes to display on the page. The services get the list of the various services I use (to display them on a sidebar).
Now, as I don't want to have anymore my lifestream.pl script in cron, I will let Tatsumaki do the polling. For this, I add a service to my app, which is just a worker.
``` perl
package Lifestream::Worker;
use Moose;
extends 'Tatsumaki::Service';
use Tatsumaki::HTTPClient;
sub start {
my $self = shift;
my $t;
$t = AE::timer 0, 1800, sub {
scalar $t;
$self->fetch_feeds;
};
}
sub fetch_feeds {
my ($self, $url) = @_;
Tatsumaki::HTTPClient->new->get(
$url,
sub {
#do the fetch and parsing stuff
}
);
}
```
From now, every 60 minutes, feeds will be checked. Tatsumaki::HTTPClient is a HTTP client based on AnyEvent::HTTP.
Let's write the app now
``` perl
package Lifestream;
use Moose;
extends "Tatsumaki::Application";
use Lifestream::Handler;
use Lifestream::Worker;
sub app {
my ($class, %args) = @_;
my $self = $class->new(['/' => 'Lifestream::Handler',]);
$self->config($args{config});
$self->add_service(Lifestream::Worker->new(config => $self->config));
$self;
}
sub memes {
}
sub services {
}
```
The memes and services method called from the handler are defined here. In the app method, I "attch" the "/" path to the handler, and I add the service.
and to launch the app
``` perl
my $app = Lifestream->app(config => LoadFile($config));
require Tatsumaki::Server;
Tatsumaki::Server->new(
port => 9999,
host => 0,
)->run($app);
```
And that's it, I now have a nice webapp, with something like only 200 LOC. I will keep playing with Tatsumaki as I have more ideas (and probably subfeedr too). Thanks to miyagawa for all this code.
