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

multiple apps via a single app.psgi vs. many isolated single apps
by Puneet Kishor 23 Nov '11

23 Nov '11

Inspired by the conversation about deploying multiple apps, and the problems with current Dancer version to dispatch the routes correctly, I have a slightly meta question: What exactly is the advantage of launching multiple apps via a single app.psgi file? Here is my motivation -- I have a multitude of different Dancer apps running on my computer (see http://earth-base.org/apps) The issue I face is that they are all in separate directories, and have different layout files even though they are all identical in appearance and most of their functionality. Just like Dancer.pm itself is installed in one location, and any upgrades to it are available to all my apps, I would also like to abstract the views and css and js. For example, I use the html5 boilerplate from http://html5boilerplate.com/ for all my apps. This means if I want to install the latest build of html5 boilerplate, I have to update it for all my apps. How could I make some of the currently app-specific views to be served from a single location? Would the multiple-apps-via-a-single-app.psgi help here? -- Puneet Kishor

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Dancer - new suggestion - "route namespace"
by Perlover 23 Nov '11

23 Nov '11

Good day! I found a buggy behavior of Dancer with multiply application configuration and routes. Please to see example in current Dancer::Deployment -> Running multiple apps with Plack::Builder [...] builder { mount "/app1" => builder {$app1}; mount "/app2" => builder {$app2}; }; Here 'mount' through Plack::App::URLMap->map will call our $app1 & $app2 BUT /app1 & /app2 will be removed from $request->path_info! Our applications will get a new path_info paths. Imagine a following example: builder { mount "/app1" => builder {$app1}; mount "/app2" => builder { enable "Auth::Basic", authenticator => \&authen_cb; $app2}; }; Here $app2 is protected by Plack::Middleware::Auth::Basic and it has some /admin/* routes (for /app2/admin/... urls) But $app has only one root routes for example as '/' (and may be other routes) Now please to see the source of module Dancer::App, lines 104-106: .... sub find_route_through_apps { my ($class, $request) = @_; for my $app (Dancer::App->current, Dancer::App->applications) { my $route = $app->find_route($request); .... Here we see that searching is going until the target route will be found in all applications! Imagine that we requested the url /app1/admin/... What happens? The $app1 will get path_info as /admin/... after Plack::App::URLMap and Dancer will start a searching in find_route_through_apps and will find a route of $app2! And it will call it code without middleware Auth! And protected and security data will be given for remote user without protection! What is result? The /app1/ URLs will sometimes run app2's routes, the /app2/ URLs will sometimes run a routes of app1 and so on. And in above example we will get a security hole additional... --------------------------------------- What i suggest ? I think Dancer should have: 1) For get & post now we can pass an options hashref before code like this get '/' => {option1 =>..., ...}, sub {} (i see this in code of Dancer but i didn't find it in docs) . I think there should be option 'route_namespace' for example. If it defined it consists a namespace of this route. If not defined it has a namespace defined in route_namespace command (point 2 here) 2) Should be command like 'prefix' but named as 'route_namespace' fro setting up namespace of routes of this application. The prefix option for real pieces in $request->path_info but this route_namespace for virtual because we cannot get a namespace from path_info (only from $request->script_name but i want to make this behavior flexible for 'route_namespace') 3) I think the object Dancer::Request should have a method (getter/setter) route_namespace. Through this method we can setup a namespace of current request for searching of routes. If we set up for example $request->route_namespace('app1') before Dancer->dance($request) (example in Dancer::Deployment -> Running multiple apps with Plack::Builder) for example then the find_route_through_apps should search through all applications all routes BUT with same namespace only. If route_namespace is not defined for current $request a behavior is as now (backward compatible) So after this patches our example in Dancer::Deployment will look like: use Dancer ':syntax'; use Plack::Builder; setting apphandler => 'PSGI'; my $app1 = sub { my $env = shift; local $ENV{DANCER_APPDIR} = '/Users/franck/tmp/app1'; load_app "app1"; # In the app1 module we have command: route_namespace "app1" before routes # May be here we should be able to setup too like: load_app "app1", route_namespace => 'app1'; Dancer::App->set_running_app('app1'); setting appdir => '/Users/franck/tmp/app1'; Dancer::Config->load; my $request = Dancer::Request->new( env => $env )->route_namespace('app1'); # route_namespace as setter returns an instance of Dancer::Request Dancer->dance($request); # Now the Dancer knows in the find_route_through_apps what we want (only routes from "app1" namespace) }; my $app2 = sub { my $env = shift; local $ENV{DANCER_APPDIR} = '/Users/franck/tmp/app2'; load_app "app2"; # In the app2 module we have command: route_namespace "app2" before routes Dancer::App->set_running_app('app2'); setting appdir => '/Users/franck/tmp/app2'; Dancer::Config->load; my $request = Dancer::Request->new( env => $env )->route_namespace('app2'); # route_namespace as setter returns an instance of Dancer::Request; Dancer->dance($request); # Now the Dancer knows in the find_route_through_apps what we want (only routes from "app2" namespace) }; builder { mount "/app1" => builder {$app1}; mount "/app2" => builder { enable "Auth::Basic", authenticator => \&authen_cb; $app2}; }; Your opinions? I can make all this patches in Dancer for devel branch at github But before i want to listen from you some suggestions and opinions Thanks! Perlover

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Re: [Dancer-users] Advent Calendar time again!
by David Precious 21 Nov '11

21 Nov '11

On Monday 21 November 2011 01:08:26 Matthew Vickers wrote: > May I humbly suggest a topic, would someone graciously write an article on > testing a dancer app ? > > I know next to nothing on this topic and selfishly would like to see it in > the advent calendar. We did have a post on last year's advent calendar - "Testing a Dancer application" - http://advent.perldancer.org/2010/6 I'll see whether things have changed sufficiently to warrant an updated version this year :) (If we don't manage to get enough posts together, we might need to nominate a few selected posts from last year for re-publishing, although of course I'd prefer all-fresh content; if we do have to republish some, I'll consider your mention and Sarah's +1 as two votes for republishing this one ;) ) Incidentally, you can see all of last year's posts at: http://advent.perldancer.org/2010/ Cheers Dave P -- David Precious ("bigpresh") http://www.preshweb.co.uk/ "Programming is like sex. One mistake and you have to support it for the rest of your life". (Michael Sinz)

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Dancer vs system()
by Richard Huxton 18 Nov '11

18 Nov '11

Am I missing something obvious here? can't see anything in the list archives / google. my $res = system('/bin/true'); debug "$res / $?"; The above always logs -1 / -1 even though the command runs. I'm acutally using it to run a small external db-updater tool and couldn't figure out how I was getting a failure message from Dancer but the database was updating. Am I being dim here? -- Richard Huxton Archonet Ltd

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Re: [Dancer-users] Sharing config files
by Stephen Fenwick-Paul 15 Nov '11

15 Nov '11

Ta, for the pointers. This does it, if anyone else has similar needs In your conf.yml global_config : "../shared_conf/config.yml" # with relation to appdir and some code to load it: sub includeGlobalConfig { my $self = shift; my ($appdir) = setting('appdir'); # For some reason Mason2 does not like the relative path $appdir =~ s|/bin/..||; my ($gconfig_file) = $appdir . "/" . config->{global_config}; die "Unable to find global config '$gconfig_file'" unless -f $gconfig_file; my ($gconfig) = YAML::LoadFile($gconfig_file); # Merge with default map { config->{$_} = $gconfig->{$_} } keys %{$gconfig}; # If your using Mason2 config->{engines}{mason2}->{data_dir} = $appdir . "/data"; config->{engines}{mason2}->{comp_root} = $appdir . "/views"; config->{engines}{mason2}->{autoextend_request_path} = 0; # Mason2 bug - when not running from server (i.e. test), it looses appdir for views config->{views} = $appdir . "/views"; }; And call it in your app.pm - something like: package MyApp; use Dancer ':syntax'; MyApp::Config->new()->includeGlobalConfig(); get '/index' => { ...... }; On 15 November 2011 10:45, Stephen Fenwick-Paul <stephen(a)activeg.org> wrote: > Thanks, that's the way I will go. > > > On 15 November 2011 10:44, David Precious <davidp(a)preshweb.co.uk> wrote: > >> On Tuesday 15 November 2011 10:42:21 David Precious wrote: >> > In the meantime, you could store your database settings in a separate >> YAML >> > file, then in your apps, load that and put it into the app's config with >> > something a little like: >> > >> > my $db_conf = YAML::LoadFile('database.yml'); >> > config->{plugins}{Database} = $db_conf; >> > >> > That should work :) >> >> And of course that could be even more concise using the from_yaml() >> keyword >> provided by Dancer, e.g.: >> >> config->{plugins}{Database} = from_yaml('database.yml'); >> >> >> -- >> David Precious ("bigpresh") >> http://www.preshweb.co.uk/ >> >> "Programming is like sex. One mistake and you have to support >> it for the rest of your life". (Michael Sinz) >> > >

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Sharing config files
by Stephen Fenwick-Paul 15 Nov '11

15 Nov '11

Hi I have 2 Dancer apps, one a web site and another a RESTful api, both connecting to the same database At the mo they each have their own config.yml, but as so much configuration detail between them is common it would be great to have a central configuration for the common stuff and then a config for the relatively few things unique to the app. Any ideas how achieve such a regime? thanks Stephen

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App responding differently to ajax calls under plackup than Apache - possibly bug
by Stephen Fenwick-Paul 15 Nov '11

15 Nov '11

Hi, I'm moving to plackup because of the well know contamination problem under Dancer when running multiple apps with Plack::Handler::Apache2. My app.psgi is basically a copy of the one in the documentation - ta for that. $ plackup -s Starman --workers=10 -p 5000 -a app.psgi My apache cfg is basically <VirtualHost *:80> ServerName www.app.new ServerAlias app.new DocumentRoot /home/stephen/app <Location /> SetHandler perl-script PerlHandler Plack::Handler::Apache2 PerlSetVar psgi_app /home/stephen/app/bin/app.pl </Location> </VirtualHost> The route: ajax '/locations/box/:nelat/:swlat/:nelng/:swlng' => sub { my ($locs) = Locations->new(); return $locs->search( { mode => 'box' } ); }; is used correctly by apache version, but starman gets: get '/locations/box/:nelat/:swlat/:nelng/:swlng' => sub { set serializer => 'JSON'; my ($locs) = Locations->new(); return $locs->search( { mode => 'box' } ); }; It can not see the ajax route. Examining the starman version's request I see "ajax => 0" because "headers => undef" and that is what Dancer::Request::is_ajax uses to determine whether the call is ajaxed or not. although the starman's version request does contain x_requested_with => "XMLHttpRequest" but it is not within 'headers' so it is not seen by is_ajax. I made this change to Dancer::Request sub is_ajax { my $self = shift; return 1 if (defined $self->{x_requested_with} && ( $self->{x_requested_with} eq "XMLHttpRequest") ); # new return 0 unless defined $self->headers; return 0 unless defined $self->header('X-Requested-With'); return 0 if $self->header('X-Requested-With') ne 'XMLHttpRequest'; return 1; } and it appears to work. Is this a sensible change?

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dancer croaking with a strange error in config.yml
by Puneet Kishor 15 Nov '11

15 Nov '11

This is bizarre. 1 layout: "main" 2 charset: "UTF-8" 3 template: "tiny" 4 5 plugins: 6 Database: 7 driver: 'mysql' 8 database: '***********' 9 host: '127.0.0.1' 10 port: 3306 11 username: '***********' 12 password: '***********' 13 dbi_params: 14 RaiseError: 1 15 AutoCommit: 1 The above config file works just fine on my laptop, but fails on my server with the following message $perl bin/app.pl Use of uninitialized value in numeric gt (>) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 718, <$IN> line 1. Use of uninitialized value in numeric gt (>) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 719, <$IN> line 1. Use of uninitialized value in numeric gt (>) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 719, <$IN> line 1. Use of uninitialized value in numeric ne (!=) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 721, <$IN> line 1. Use of uninitialized value in subtraction (-) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 726, <$IN> line 1. Use of uninitialized value in numeric eq (==) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 361, <$IN> line 1. Use of uninitialized value in numeric eq (==) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 361, <$IN> line 1. Use of uninitialized value in numeric eq (==) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 361, <$IN> line 1. Use of uninitialized value in substitution (s///) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 331, <$IN> line 1. Use of uninitialized value in substitution (s///) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 338, <$IN> line 1. Use of uninitialized value in substitution (s///) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 342, <$IN> line 1. Use of uninitialized value in substitution (s///) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 407, <$IN> line 1. Use of uninitialized value in substitution (s///) at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML/Loader.pm line 407, <$IN> line 1. Unable to parse the configuration file: /Users/punkish/Sites/app/config.yml: YAML Error: Invalid element in map Code: YAML_LOAD_ERR_BAD_MAP_ELEMENT Line: 9 Document: 1 at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/YAML.pm line 36 at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/Dancer/Config.pm line 204 Dancer::Config::load_settings_from_yaml('/Users/punkish/Sites/app/config.yml') called at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/Dancer/Config.pm line 181 Dancer::Config::load('Dancer::Config') called at /Users/punkish/perl5/perlbrew/perls/perl-5.14.1/lib/site_perl/5.14.1/Dancer.pm line 230 Dancer::import('Dancer') called at bin/app.pl line 2 main::BEGIN() called at bin/app.pl line 2 eval {...} called at bin/app.pl line 2 BEGIN failed--compilation aborted at bin/app.pl line 2. Any idea what is going on? Nothing obvious jumps at me. -- Puneet Kishor

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config.yml YAML tabs vs spaces
by Alex Mestiashvili 14 Nov '11

14 Nov '11

Hello , I just started to use Dancer::Plugins::Database and spent some time trying yo figure out why the config from the manual doesn't work for me . The problem ( or a feature ) that YAML doesn't treat tabs as whitespace , and I was getting the following croaks : perl bin/q.pl Unable to parse the configuration file: /home/toor/dancer/MyWeb-App/config.yml: Died at /usr/share/perl5/YAML/Loader.pm line 674, <$IN> line 1. at /usr/share/perl5/Dancer/Config.pm line 204 Dancer::Config::load_settings_from_yaml('/home/toor/dancer/MyWeb-App/config.yml') called at /usr/share/perl5/Dancer/Config.pm line 181 Dancer::Config::load('Dancer::Config') called at /usr/share/perl5/Dancer.pm line 212 Dancer::import('Dancer') called at bin/q.pl line 1 main::BEGIN() called at /usr/share/perl5/Dancer.pm line 1 eval {...} called at /usr/share/perl5/Dancer.pm line 1 BEGIN failed--compilation aborted at bin/q.pl line 1. using spaces solved the problem . So I think that it will be not bad to mention somewhere in the documentation that tabs shouldn't be used in config.yml . Thank you , Alex

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Dancer deployment bugs with Plack::Handler::Apache2
by Assaf Gordon 12 Nov '11

12 Nov '11

Hello, I've deployed two Dancer applications on one apache server using "Plack::Handler::Apache2" (one is the "SimpleCrud" test page mentioned yesterday), and I'm experiencing very strange bugs: It seems the two applications are conflicting, when routes or templates from one application are used by the other. That is, the deployment in Apache is as follows: ========= <Location /labmembers/gordon/simple_crud> SetHandler perl-script PerlHandler Plack::Handler::Apache2 PerlSetVar psgi_app /home/gordon/projects/simple_crud_sortable/bin/app.pl </Location> <VirtualHost *:80> ServerName xxxxx.cshl.edu ServerAlias xxxxx DocumentRoot /var/www/data/xxxxx/ <Location "/"> Order Deny,Allow Deny from all Allow from cshl.edu SetHandler perl-script PerlHandler Plack::Handler::Apache2 PerlSetVar psgi_app /var/www/data/xxxxx/dancer/bin/app.pl </Location> </VirtualHost> ========= And when I browse to the virtual server ( http://xxxxx.cshl.edu ), I most of the times get the correct page, but sometimes I get this error: === '/home/gordon/projects/simple_crud_sortable/views/about/index.tt' is not a regular file at /usr/lib/perl5/site_perl/5.8.8/Dancer.pm line 161 === That is: visiting the new application somehow tries to fetch a template from the "simple_crud" application (probably because a wrong route from "simple_crud" was used). I know it sound strange (or unbelievable?), but it has happened several times (not always, though, so it's hard to pin-point). Additionally, several static files (css/images) sometimes returns HTTP-404 - which I guess is also related to routes mix-up. Also, viewing the "/var/log/httpd/error_log" file, I can see dancer debug messages trying to match rountes from my other application even if I visit "http://cancan.cshl.edu/labmembers/gordon/simple_crud/genes". Has any one encountered such behavior ? Or is no one deploying production application using "Plack::Handler::Apache2" ? Thanks, -gordon

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