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

flow control
by Maurice Mengel 25 Aug '10

25 Aug '10

Hi all, am I the only one who struggles with this? Maurice package dancer_test; use Dancer ':syntax'; our $VERSION = '0.1'; get '/1' => sub { #You put all the code here, #collect all the output and then just return it #via template or as html etc. return "I wanna hold your hand"; #works }; get '/2' => sub { #you don't even have to write a return "I wanna hold your hand"; #works too #let's call it a "magic return" since there is no return #seems to be a feature of perl not of dancer }; get '/3' => sub { #works only as long as you don't have anything after the return value "I wanna hold your hand"; #does NOT work my $i; }; get '/4' => sub { #sometimes Dancer displays the last variable (magic return) my $out="I wanna hold your hand"; }; get '/5' => sub { #return values from a sub five(); #I find this one a bit spooky }; sub five{ #this outputs the content of $out although no return anywhere #so we might call it "magic return in a sub" my $out="I wanna hold your hand"; } get '/6' => sub { six(); #returns 1 for success, not the content of $out }; sub six{ #this outputs the content of $out although no return anywhere my $out="I wanna hold your hand"; debug "I get here of course"; } get '/7' => sub { seven(); }; sub seven { #this seems more proper than six my $out="I wanna hold your hand"; return $out; debug "I never get here of course"; } get '/8' => sub { eight(); # does not output anything eight(); # does output once #I find this one a bit unintuitive }; sub eight{ #same as no. 5 my $out="I wanna hold your hand"; } get '/81' => sub { eight(); # does not output anything eight(); # does not output anything debug "Does output a one for success"; #I find this one a bit unintuitive }; get '/9' => sub { #if you actually want the return value twice in your output my $r=nine(); $r.=nine(); }; sub nine { #I consider this good style return "testing seven"; } get '/10' => sub { #works just as 9 my $r=ten(); $r.=ten(); }; sub ten { #as 9 but with magic return value "testing seven"; } get '/11' => sub { #i want to stop if any errors are returned eleven_one(); #does not display anything eleven_two(); #displays "I don't ever want to get here"; }; sub eleven_zero{} sub eleven_one{ #do this and that #if I encounter an error #if I don't encounter an error I return #nothing like in eleven_zero my $error="code 101"; return $error; } sub eleven_two{ return "I don't ever want to get here"; } get '/11b' => sub { #result is as in 11 eleven_three(); #does not display anything eleven_two(); #displays "I don't ever want to get here"; }; sub eleven_three{ #Dancer keyword halt does not work in this sub return halt "I don't ever want to get here"; #halt works only in a filter like before } get '/11c' => sub { #result is different from 11, but never returns eleven_two even if first #one returns nothing (see 11d) return eleven_one(); #displays "code 101" eleven_two(); #never gets there }; get '/11d' => sub { #result is different from 11 return eleven_zero(); #returns nothing eleven_two(); #never gets there }; get '/11e' => sub { #gets to eleven_two only if no error returned from eleven_one #see 11f my $ret=eleven_one(); return $ret if $ret; $ret=eleven_two(); return $ret if $ret; }; get '/11f' => sub { #gets to eleven_two only if no error returned from eleven_zero my $ret=eleven_zero(); return $ret if $ret; $ret=eleven_two(); return "I do want to get here now" if $ret; }; get '/11g' => sub { #returns emptys string my $ret=eleven_zero(); return $ret; $ret=eleven_two(); return "I do want to get here now"; }; #how does it look if we use OO? true;

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deployment and performance
by Maurice Mengel 25 Aug '10

25 Aug '10

Hi again, if i cut my big xml to a16th of the original size, I have an acceptable speed using DancingAppl.pl for development. Is there any chance by improving speed enough by proper deployment to get it working with full xml? In Dancer::Deployment various deployment strategies are described, but the text doesn't say very much about performance. Thanks! Maurice

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setting up an alias in Apache2 fails when using Plack::Handler::Apache2
by P Kishor 25 Aug '10

25 Aug '10

This is driving me nuts... not really a Dancer question, but since my only experience with PSGI is via Dancer, here goes. I have the following set-up with Apache2 vhost <VirtualHost *:80> ServerName foo.org ServerAlias www.foo.org DocumentRoot "/Users/punkish/Sites/foo" Alias /lib "/Users/punkish/Sites/lib" <Directory "/Users/punkish/Sites/foo"> AllowOverride None Order allow,deny Allow from all </Directory> <Directory "/Users/punkish/Sites/lib"> AllowOverride None Order allow,deny Allow from all </Directory> <Location /> SetHandler perl-script PerlHandler Plack::Handler::Apache2 PerlSetVar psgi_app /Users/punkish/Sites/foo/app.psgi </Location> ErrorLog "/Users/punkish/Logs/foo.org-error_log" CustomLog "/Users/punkish/Logs/foo.org-access_log" common </VirtualHost> Everything works well, except for the /lib alias. If I have the Location handler calling the app via Plack::Handler::Apache2, http://foo.org/lib or http://foo.org/lib/ both throw a 404. -- 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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Dancer::Session::SQLite
by P Kishor 24 Aug '10

24 Aug '10

Using Dancer::Session::YAML and Dancer::Session::Storable as templates, I created a Dancer::Session::SQLite module. I put it in /usr/local/lib/perl5/site_perl/5.12.1/Dancer/Session/SQLite.pm and set session => 'SQLite'. Yet, I get an error saying 'Error while loading /Users/punkish/Sites/lca/app.psgi: unknown session engine 'SQLite', perhaps you need to install Dancer::Session::SQLite? at /usr/local/lib/perl5/site_perl/5.12.1/Dancer/Engine.pm' What am I doing wrong? -- Puneet Kishor

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timeout
by Maurice Mengel 24 Aug '10

24 Aug '10

Hi, I am processing an xml document which is too big, respectively, I am processing it too slow. Anyways, at some point I get a timeout. Now I am trying to understand 'who' causes the timeout. Does Dancer do something in this respect? Is there something like php's max_execution_time? Or maybe there is none of it on the server side and the timeout comes from the client? Thanks for enlightenment in advance. Maurice

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Debugging with Dancer
by Peter Gordon 24 Aug '10

24 Aug '10

When debugging a web app, I find it much easier if I can run the app like this: perl -d myApp.pl color=red name=apple where the parameters are given on the command line, or within a file. Can someone suggest the best/easiest way to do this with Dancer. Thanks, Peter

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complex data structures in config.yml
by P Kishor 24 Aug '10

24 Aug '10

I am trying to unsuccessfully move a couple of complex data structures to config.yml For example, I have the following in my Perl script @models = ( {id => 1, name => "Low carbon", palette => "black_blue", year => 1900}, {id => 2, name => "Low nitrogen", palette => "red_green", year => 1900}, {id => 3, name => "High water", palette => "yellow_red", year => 1900} ); As far as I can tell, I can convert it to YAML like so models: - model_id: 1 name: "Low carbon" palette: "black_blue" start_year: 1900 - model_id: 2 name: "Low nitrogen" palette: "red_green" start_year: 1900 - model_id: 3 name: "High water" palette: "yellow_red" start_year: 1900 and then, in my Dancer code, I should be able to do my @models = config->{models}; or at least my $models = config->{models}; (I am not sure if I should get an array or an arrayref). In any case, I get the following error Error while loading /Users/punkish/Sites/app/app.psgi: YAML Error: Stream does not end with newline character\n Code: YAML_PARSE_ERR_NO_FINAL_NEWLINE\n Needless to say, I do have a final newline, so the error is misleading. What am I doing wrong? What can I do right? -- 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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Danceer 1.1807 uploaded to CPAN
by Alexis Sukrieh 23 Aug '10

23 Aug '10

Hey perl dancers! I'm very glad to announce that a new stable release has just been uploaded to CPAN. The tarball should be available from your CPAN client in a couple of hours. In the meanwhile you can grab a snapshot here: http://github.com/sukria/Dancer/tarball/v1.1807 This is a huge step that has been done since 1.1805 and I'm sure you'll enjoy a lot all the new stuff: http://github.com/sukria/Dancer/blob/v1.1807/CHANGES Although bugs can still happen, this release has been heavily tested, with two development releases preceeding it (1.1806_01 and 1.1806_02). I really want to thank all the people involved with this release (as time goes more and more people contribute to the project, and nothing could make me happier). A special thank and lots of beers go to Franck Cuny who did a huge amount of work for this release, in many fields (PSGI compliance, bug fixing, test enhancements, documentation reviews and many more). My informant also told me he's been working on Websocket suppport but hush! this is another (upcoming) story ;) Enjoy your dances. -- Alexis

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websockets
by Naveed Massjouni 22 Aug '10

22 Aug '10

I think it would be awesome if Dancer supported websockets http://en.wikipedia.org/wiki/WebSockets. Has anyone started working on this? Lets do it. Who's with me? :) -Naveed

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Re: [Dancer-users] documentation github wiki
by Maurice Mengel 21 Aug '10

21 Aug '10

Hi all, I am new to dancer, don't know too much about webapps, but like his/her or simply its (?) elegance and simplicity (from the user perspective). There were recently some complaints referring to quality of documentation recently on this list. A bit exaggerated, but not completely without reason, in my opinion. I noticed that there are different bits and pieces of documentation on a number of different places: mainly cpan, github, perldancer.org. I tried to change documentation page on github wiki to point to the various resources instead of repeating old hats once again yesterday. Now another suggestion for the github wiki: I suggest to use the github wiki to collaboratively improve the docs. It's not really anything new. Anybody can write to this list with suggestions or file issues on github with suggestions to improve documentation, but maybe a wiki is a little friendlier for people like me who are no full-time developers. I imagine that good passages could be taken over in the pod section if developers like it. In the worst case this effort will end before much has happened, but no harm done. If there is positive feedback I would start a wiki version of the cookbook on github wiki and try to improve that as I learn. What's your opinion? best Maurice

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