July 2011 - dancer-users - lists.preshweb.co.uk

dancer script doesn't work in strawberry perl on windows
by Charlie Gonzalez 31 Jul '11

31 Jul '11

Hi, When attempting to create a Dancer project, the dancer script doesn't create a project directory and instead displays the help page. C:\Users\cgonzalez\Desktop>dancer -a Addressit Usage: dancer [options] -a <appname> Options: -h, --help : print what you are currently reading -a, --application : the name of your application -p, --path : the path where to create your application (current directory if not specified) -x, --no-check : don't check for the latest version of Dancer (checking version implies internet connection) -v, --version : print the version of dancer being used Please advise. -- Charlie Gonzalez (E) itcharlie(a)gmail.com http://itcharlie.blogspot.com/ https://github.com/itcharlie

2 3

Current State of Dancer::Script
by Carlos Ivan Sosa 29 Jul '11

29 Jul '11

I wrote a post of the status of Dancer::Script, which is basically most of my work for GSoC this year. I haven't finished, but I'm more than done with what was needed. Well, enough of description of what the post is about. You can read more about it in my current post of the current state of my work. http://log.gnusosa.net/code/gsoc/dancer-script-state My intention with these post is to get the core team to check it, and see if it can be merged to Dancer's repo in github. Franck Cuny, rebased my work, so my current repo is up-to-date with Sukria's Dancer repo.

2 1

+1 Dancer on MetaCPAN.org
by sawyer x 29 Jul '11

29 Jul '11

Hey all, you can now login to MetaCPAN.org with your PAUSEID, Github, Facebook or Twitter. It takes 3 seconds altogether. Once logged in, you can +1 distributions to notify you like them and/or you think they're helpful/cool/worthwhile/fluffy! Feel free (and please do) +1 Dancer dist! Have a great weekend, S.

3 3

Dancing Corona?
by Chip Salzenberg 29 Jul '11

29 Jul '11

Corona uses Coro, which is a style of Perl threading that has much to recommend it. However, code not designed for it may not function well. In particular, global state is a danger. Given that Dancer uses global state implicitly in such functions as param(), can it even in theory work with Corona? Has anyone tried? Perspiring minds want to know.

2 1

security release 1.3071
by Alexis Sukrieh 28 Jul '11

28 Jul '11

Hello fellow Dancers. We've been notified about a security issue that affects Dancer 1.3070. Indeed, since 1.3070, it was possible to abuse the static file serving feature to obtain files from a directory immediately above the directory configured to serve static files from. This issue has been reported by Vladimir Lettiev and fixed by David Precious. Note that we've added more tests in the suite to make sure this issue cannot come back in future releases. I've published a security release yesterday: 1.3071 which provides the very patch needed to solve the issue. Also be aware that the diff between 1.3070 and 1.3071 is minimal, it only provides the security fix: http://search.cpan.org/diff?from=Dancer-1.3070&to=Dancer-1.3071 We strongly advice you to upgrade to 1.3071 if you're running under 1.3070 in production. http://search.cpan.org/CPAN/authors/id/S/SU/SUKRIA/Dancer-1.3071.tar.gz Thanks for your trust, and happy dancing. -- Alexis Sukrieh -+- Hackers gonna hack! “The problem with quotes on the Internet is that you can't always be sure of their authenticity.” -- Abraham Lincoln http://sukria.net http://twitter.com/sukria

1 0

Confused on error reporting
by Stephen Fenwick-Paul 25 Jul '11

25 Jul '11

Hi all, I've done some reading on how RESTful apps should respond to errors, but I'm getting confused on how Dancer handles this for me. My simple app: package Test; use Dancer ':syntax'; use Dancer::Plugin::Ajax; # Case 1: Just a normal web page with layout get '/error.html' => sub { eval { die "HTML die"; } or do { send_error("HTML: You made a mistake", 400); }; }; # Case 2: A json call get '/error.json' => sub { set serializer => 'JSON'; eval { die "JSON die"; } or do { send_error("JSON: You made a mistake", 400); }; }; # Case 3: HTML being return from an ajax call, thus no layout ajax '/error.html' => sub { eval { die "AJAX die"; } or do { send_error("AJAX: You made a mistake", 400); }; }; With the environment set to development, each of these responds as I expect. Case 1 gives me a full backtrace, case 2 gives me a a json with just the error message, and case 3 again give me a full backtrace, Now moving to the production environment. I get $ curl http://127.0.0.1:3000/error.html <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html> <head> <title>Error 400</title> <link rel="stylesheet" href="/css/style.css" /> <meta http-equiv="Content-type" content="text/html; charset=utf-8" /> </head> <body> <h1>Error 400</h1> <div id="content"> <h2>Unable to process your query</h2>The page you requested is not available </div> <div id="footer"> Powered by <a href="http://perldancer.org/">Dancer</a> 1.3060 </div> </body> Which is OK, but where is the meaningful message to the user gone? $ curl http://127.0.0.1:3000/error.json "An internal error occured" Again, not very useful. $ curl -H 'X-Requested-With: XMLHttpRequest' http://127.0.0.1:3000/error.html "An internal error occured" I need to send something more than this back to the client. What am I doing wrong? If I declare my own error template: set error_template => 'error'; Then, again, in development every thing is as expected, but in production I get "An internal error occured" in all 3 cases. My production,yml is the standard one. Thanks for any insights. Stephen P.S. occured should be occurred

4 4

ajax progress update
by Mr. Puneet Kishor 24 Jul '11

24 Jul '11

On certain client action, my app is firing several, concurrent, ajax requests fielded by difference Dancer servers. Some requests are completed quickly, others take a long time. Since they are asynchronous, there is little feedback for the user who might start fidgeting around thereby firing more ajax requests inadvertently. Two things -- One, how can I ignore or reject the extra requests that are a result of fidgety behavior? I realize this is a not a Dancer-specific question per se, but, one, you guys are likely to have some helpful suggestions, and two, I want to have a fall-back on the server side also -- if Dancer is busy with a request from a client, is there a way to ignore further requests from the same client until at least the first one is complete? Two, this is more Dancer-specific, I guess -- once Dancer starts a process, how can I send periodic updates on that process back to the browser to power an ajax-y progress bar? My intent is to show a little floating div with a progress bar for each of the processes that were fired by the client. Puneet.

3 2

Browser String not available when run with plackup
by Gurunandan Bhat 20 Jul '11

20 Jul '11

Hi, I want to find the Browser string something that is available with $ENV{HTTP_USER_AGENT} when I run a Da*ncer app with teh default backend. However when I run the app with plackup (plackup -s Starman app.pl) $ENV{HTTP_USER_AGENT} is undefined. Is there a way I can get to this value that does not depend on how I run the Dancer application? Thank you. *

2 3

many dancer apps with Starman (part 3)
by Mr. Puneet Kishor 19 Jul '11

19 Jul '11

In part 1 [http://www.backup-manager.org/pipermail/dancer-users/2011-July/001614.html] I dipped my toes into powering many apps on the same computer using Starman. I had a few errors, and the solutions, that I documented. I also received a very helpful reply from Pedro Melo [http://www.backup-manager.org/pipermail/dancer-users/2011-July/001617.html] suggesting that instead of one script for all the apps, I should fire up separate Starman processes for each app. In part 2 [http://www.backup-manager.org/pipermail/dancer-users/2011-July/001616.html] I described a more generic scenario that would cover most of the circumstances I could dream of at the moment at my work. In part 3, [http://www.backup-manager.org/pipermail/dancer-users/2011-July/001633.html] I described that I was getting a cryptic error from Plack::Builder complaining that there was an "Error while loading foo.psgi: Paths need to start with / at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/Plack/Builder.pm line 89." Now, taking Perdo Melo's advice, I am just launching separate Starman processes directly calling the `dancer -a` generated /path/to/webapp/bin/app.pl with $plackup -E production -D -s Starman --workers=10 -p 5000 -a path/to/webapp/bin/app.pl I change the port number for each app to match the apache proxy settings. So, here I ask the following: the above is working, but is rapidly going to become cumbersome in three regards -- 1. It will become tricky keeping track of the port numbers for each app, and make sure they match between what has been set in httpd.conf (for proxy purposes) and what has been used to call in the `plackup` command; 2. It will become very cumbersome shutting off or restarting one or more Starman app because I would have to find out the parent process of each app, and kill that in order to kill all the child workers; and 3. If I have 10 or 20 apps on the same server, with 10 Starman workers for each app, I would have 100 or 200 perl processes running on my computer even if my apps are really low traffic. I tried setting the number of workers to 2 or 2, but found that the server started dropping connections. Is having so many perl processes running not problematic?

8 18

Dancer::plugin:ajax & config:load
by Stephen Fenwick-Paul 18 Jul '11

18 Jul '11

Hi, V. simple app: package MyApp; use Dancer ':syntax'; use Dancer::Plugin::Ajax; ajax '/hellox/:name' => sub { template 'hello'; }; true; Produces: $ curl -H 'X-Requested-With: XMLHttpRequest' http://www.myapp.new/hellox/fred *<p>This is hello</p>* * * Which is to be expected. But: package MyApp; use Dancer ':syntax'; use Dancer::Plugin::Ajax; ajax '/hellox/:name' => sub { * Dancer::Config::setting('appdir',$ENV{ROOT});* * Dancer::Config::load();* template 'hello'; }; true; $ curl -H 'X-Requested-With: XMLHttpRequest' http://www.myapp.new/hellox/fred Produces: *<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"* *"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">* *<html xmlns="http://www.w3.org/1999/xhtml">* *<head></head>* *<body>* * * *<p>This is hello</p>* * * *</body>* *</html>* So, running *Dancer::Config::load() *stops Plugin::Ajax working. This may seems a strange thing to do, but for me the load() was deep in a module that some times runs outside of Dancer but picks up stuff from the Dancer config. Handling the ajax call manually (as per the the Cookbox) there are no problems with using load(). Stephen

2 5