August 2010 - dancer-users - lists.preshweb.co.uk

idiom for programming the Perl OO way with Dancer
by P Kishor 03 Aug '10

03 Aug '10

The following would hopefully be a welcome change from my usual "I can't deploy" emails ;-). I am looking for the right idiom(s) for programming correctly with Dancer. Right now, my dance.pm looks a mess package dance; use Dancer ':syntax'; # bunch of modules ##################### use Tie::File; use Tie::File::AsHash; use URI::Escape; use lib '/Users/punkish/Library/Perl'; use Markdown 'markdown'; my $markdown_opts = {url_prefix => '/', url_pattern => '-'}; # end bunch of modules ################# our $VERSION = '0.1'; get '/*?' => sub { my ($p) = splat; my $page_name = $p ? $p : config->{default_page}; if ( $page_name =~ /slideshow/ ) { template 'album.tt', {..}; } elsif ($page_name =~ /maps/ { template 'map.tt', {..}; } elsif ($page_name =~ /something_else/ { template 'something_else.tt', {..}; } else { template 'default.tt', {..}; } }; sub slideshow { .. } sub maps { .. } sub something_else { .. } The above is just the beginning. All those subs and methods not only make for a very long dance.pm, they also clash syntactically with Dancer's magic "get '/' => sub {}" idiom. Now, in the world of CGI::Application, I would actually sub-class CGI::Application, add my custom methods and junk to it, and then sub-class that custom instance into my application instance which would then be clean. Yes, I know, I am sweeping the crap under the carpet, but at least the carpet it clean. Is there something like that I can do with Dancer? Can I create a sub-class of Dancer, add my custom stuff to it, and then create application instances with it and program with it the Perl OO way? Has someone written a tute on that? :-) -- Puneet Kishor http://www.punkish.org Carbon Model http://carbonmodel.org Charter Member, Open Source Geospatial Foundation http://www.osgeo.org Science Commons Fellow, http://sciencecommons.org/about/whoweare/kishor Nelson Institute, UW-Madison http://www.nelson.wisc.edu ----------------------------------------------------------------------- Assertions are politics; backing up assertions with evidence is science =======================================================================

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deploying via Apache
by P Kishor 03 Aug '10

03 Aug '10

I have discovered that if I type the following in my application directory "~/Sites/dance" perl -MPlack::Runner -e"Plack::Runner->run('app.psgi')" the application runs fine. Its starts up with the prompt HTTP::Server::PSGI: Accepting connections at http://0:5000/ and I am able to see my web site at http://localhost:5000/ However, the same command invoked via dance/public/dispatch.cgi results in Error while loading /Users/punkish/Sites/dance/app.psgi: unable to load application dance : Can't locate dance.pm in @INC (@INC contains: /Users/punkish/Sites/dance/public/lib So, obviously, in spite of what the docs say, somewhere Dancer is being instructed to look for 'lib' in my application's public folder, but is failing to do so. On the other hand, Plack::Runner('app.psgi') is happily able to run without being told anything special about 'public' I am going to give this another few hours and then basically give up on Dancer and move back to CGI::Application or explore mojo. Dancer is a beautiful framework, but the grief in getting beyond the basics is just not worth it. It would be very sad and ironic if this is all because of something extremely obvious that I am overlooking. Hoping I can resolve this soon. -- Puneet Kishor http://www.punkish.org Carbon Model http://carbonmodel.org Charter Member, Open Source Geospatial Foundation http://www.osgeo.org Science Commons Fellow, http://sciencecommons.org/about/whoweare/kishor Nelson Institute, UW-Madison http://www.nelson.wisc.edu ----------------------------------------------------------------------- Assertions are politics; backing up assertions with evidence is science =======================================================================

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get template command to ignore layout
by David Holden 03 Aug '10

03 Aug '10

Hello, I was wondering is it possible to get the template command to ignore the layout, e.g. here I want it to use the layout template 'index' => $tt2_ds; but here template 'table_result' => $tt2_ds; I want it to just return the template contents alone, i.e. not wrapped by the layout - for an ajax response. Thanks, Dave.

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Dancer deployment still confusing, difficult and a non-starter
by P Kishor 02 Aug '10

02 Aug '10

First, the perldancer.org domain was out for several days and emails to dancer-users mailing would bounce back ("rejected by recipient domain"). A conversation on IRC channel revealed that the DNS server was down, but nothing could be done about it until Sukrieh returned from a vacation. Would it be possible to not have such a single point of failure or blocking in the canonical, root domain of the web framework please? It gives the impression that the project has been abandoned. Nevertheless, while I am able to very quickly download, install and even create a basic dancer app, its deployment still remains a mystery to me. First, I will describe my working scenario in the hope that there might others with the same scenario, and then I will list what all I attempted and failed. I apologize for this email's length, but my hope is that it will lead to clearer and easier deployment notes with Dancer. I develop on my MacBook with Perl 5.12.1 installed under /usr/local/bin. My web projects live under ~/Sites, and are served by Apache2 running from /usr/local/apache2 (all custom installations). Any custom Perl libraries I develop go under ~/Library/Perl, and are available to all my web projects. I try to mimic the conditions on the actual production server as much as possible. One such server is a Mac OS X server, so its layout is almost identical to my MacBook, but another is a shared web host, most likely some variant of Linux. On that I get an html docs folder in my home folder, but I don't get access to tinkering with Apache which does all the serving. I can, for the most part, request custom Perl module installations, and I can use .htaccess files. Since these applications eventually get served from their own domain names, I try to not develop using http://localhost/app1 and http://localhost/app2. Doing so confuses me with regards to relative URLs and makes for a bit trickier development. Instead, I use virtual hosts with Apache, and I add the name of the virtual host to my /etc/hosts file. This allows me to get to my apps via http://app1.local and http://app2.local and so on. This way, when I eventually put the app in production, all I have to do is change the the host name from app1.local to app1.org and so on. While developing, I don't really worry about speed, so I just use cgi scripts with Apache... no persistent environment here. In fact, while on the Xserve I can install any persistent environment, on the shared web server I may not even have access to a persistent environment at all. So, I have to develop using the least common denominator, and then deploy with the best possible tools. Also, whatever deployment I choose, it is most likely to be Apache based. While it may not be the fastest, Apache is tried and tested, is available by default on whichever server I choose, and is even required by other projects. Now, on to deployment. The docs at Dancer::Deployment say that deploying http://localhost/dance/dispatch.cgi 500 Internal Server Error - Wrong http://localhost/dance/dispatch.cgi/ 200 OK - Right The above give me a generic Apache 404 error script not found or unable to stat: /Users/punkish/Sites/dance/dispatch.cgi File does not exist: /Users/punkish/Sites/dance/missing.html Actually, both of the above are wrong. It should really be http://localhost/myapp/public/dispatch.cgi/ But, then I get the following errors in Apache logs Unable to open /Users/punkish/Sites/dance/logs/development.log for writing, unable to log at /usr/local/lib/perl5/site_perl/5.12.1/Dancer/Logger/File.pm line 32, <DATA> line 16. Unable to open /Users/punkish/Sites/dance/logs/development.log for writing, unable to log at /usr/local/lib/perl5/site_perl/5.12.1/Dancer/Logger/File.pm line 32. Error while loading /Users/punkish/Sites/dance/app.psgi: unable to load application dance : Can't locate dance.pm in @INC (@INC contains: /Users/punkish/Sites/dance/public/lib /usr/local/lib/perl5/site_perl/5.12.1/darwin-2level /usr/local/lib/perl5/site_perl/5.12.1 /usr/local/lib/perl5/5.12.1/darwin-2level /usr/local/lib/perl5/5.12.1 /usr/local/lib/perl5/site_perl .) at (eval 60) line 2. BEGIN failed--compilation aborted at (eval 60) line 2. Premature end of script headers: dispatch.cgi File does not exist: /Users/punkish/Sites/dance/favicon.ico, referer: http://dance.local/public/dispatch.cgi/ File does not exist: /Users/punkish/Sites/dance/missing.html, referer: http://dance.local/public/dispatch.cgi/ I can fix the errors re. not being able to open development.log for writing by changing permissions on it chmod -R 777 logs but, the Dancer script that creates the logs folder should have set the permissions correctly automatically so Apache can write to it. Nevertheless, the other error is more serious... app.psgi is unable to load application dance because it can't locate dance.pm in @INC. If you see above, @INC contains 'dance/public/lib', but 'lib' is actually sitting one level above under 'dance'. So, I move 'lib' down to 'dance/public'. But, now I get a dancer 404, and the following errors in Apache logs File does not exist: /Users/punkish/Sites/dance/css, referer: http://dance.local/public/dispatch.cgi/ File does not exist: /Users/punkish/Sites/dance/missing.html, referer: http://dance.local/public/dispatch.cgi/ File does not exist: /Users/punkish/Sites/dance/favicon.ico, referer: http://dance.local/public/dispatch.cgi/ File does not exist: /Users/punkish/Sites/dance/missing.html, referer: http://dance.local/public/dispatch.cgi/ So, the interesting thing is, now I am getting the 404 via the dancer 404 template. So, dancer is running, and responding, but it is unable to grok the route. Plus, all the paths in the template are now wrong. Now what do I do? -- Puneet Kishor http://www.punkish.org Carbon Model http://carbonmodel.org Charter Member, Open Source Geospatial Foundation http://www.osgeo.org Science Commons Fellow, http://sciencecommons.org/about/whoweare/kishor Nelson Institute, UW-Madison http://www.nelson.wisc.edu ----------------------------------------------------------------------- Assertions are politics; backing up assertions with evidence is science =======================================================================

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