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

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.

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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. *

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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?

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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

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mysterious behavior putting Dancer app in production on Starman
by Mr. Puneet Kishor 17 Jul '11

17 Jul '11

Check out the following [http://teststrata.geology.wisc.edu/macromap] It should be working -- it should show a Google map backdrop with a bunch of polygons and a few points. As you pan and zoom, polys and points for the new viewport should be retrieved. The polys and points are retrieved via ajax from [http://teststrata.geology.wisc.edu/mstrat/] that is serving them from a MySQL db as a REST service. Both apps are Dancer based, and are running on Starman using the following invocation $ plackup -p <port> -E production -s Starman -w 10 -a bin/app.pl The first app (macromap) also has the -D switch added to the above plackup command so plackup runs in the background as a daemon (or a faceless app, or whatever is the correct terminology). Here is the interesting thing -- if I add the -D switch to the second app as well, it fails to return the polys and the points. It fails with the error {"error":"Warning caught during route execution: DBD::mysql::st fetchall_arrayref failed: fetch() without execute() at <path/to>/macrostrat.pm line 79.\n"} The offending lines are 71> my $sql = qq{ 72> .. 73> 74> 75> }; 76> 77> my $sth = $dbh->prepare($sql); 78> $sth->execute(); 79> my $res = $sth->fetchall_arrayref({}); The above could be just correlation rather than causal, but it definitely seems to be a pattern. First, this is bizarre, and why so? And, two... this is totally bogus... how can execute() not take place above? Perl doesn't have a habit of jumping over lines, does it? Absolutely mystified in Madison. Puneet.

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testing ajax
by Stephen Fenwick-Paul 17 Jul '11

17 Jul '11

Hi How to you approach testing ajax calls? If I had: use Dancer::Plugin::Ajax; ajax '/somedata.json' => sub { return { data => "hello" }; }; The tests: route_exists [ 'GET' => '/somedata.json'], 'a route handler is defined for /somedata'; response_status_is ['GET' => '/somedata.json'], 200, 'response status is 200 for /somedata'; give: 1..2 ok 1 not ok 2 - response status is 200 for / # Failed test 'response status is 200 for /' # at t/003_api_route.t line 10. # got: '404' # expected: '200' # Looks like you failed 1 test of 2. So how do I construct the response_status_is to be: X-Requested-With: XMLHttpRequest And secondly the route_exists call would also match: get '/somedata.json' => sub { return { data => "hello" }; }; so how do I distinguish between a GET and an AJAX call with a route_exists? Thanks for any pointers.

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New plugin
by Oleg A. Mamontov 15 Jul '11

15 Jul '11

Hi. I have recently uploaded the new Dancer plugin for common task of images thumbnails creation: http://search.cpan.org/~lonerr/Dancer-Plugin-Thumbnail It's probably offtopic for this list, but i hope to get some constructive criticism or new ideas from experienced Dancer developers. I would appreciate any comments! -- Cheers, Oleg A. Mamontov mailto: oleg(a)mamontov.net jabber: lonerr(a)charla.mamontov.net icq uin: 79-521-617 cell: +7-903-798-1352

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Re: [Dancer-users] cross domain ajax to dancer app
by Alex Kalderimis 13 Jul '11

13 Jul '11

That is exactly right. In this context the server is the whole stack, including your webapp, which is solely responsible for getting the content right. Dancer makes writing webapps easier, but it doesn't do everything. Perhaps this is a good area for a plugin or some sugar though... Alex ----- sent from my phone - please excuse any brevity ----- Reply message ----- From: "Mr. Puneet Kishor" <punk.kish(a)gmail.com> To: "Mr. Puneet Kishor" <punk.kish(a)gmail.com> Cc: "Alex Kalderimis" <alex(a)flymine.org>, "Dancer Users" <dancer-users(a)perldancer.org> Subject: [Dancer-users] cross domain ajax to dancer app Date: Wed, Jul 13, 2011 4:43 am On Jul 12, 2011, at 10:13 PM, "Mr. Puneet Kishor" <punk.kish(a)gmail.com> wrote: > On Jul 12, 2011, at 4:50 PM, "Alex Kalderimis" <alex(a)flymine.org> wrote: > >> Remember that jsonp requests must return their data wrapped in the function callback to work. If not, the json will be evaluated, but do nothing, as it is in void context (so to speak). Dancer does not do this for you - you will need to read the callback parameter yourself. On more research, I think I understand better what you are suggesting. I don't have access to my server ritnow, but I am guessing I would have to do something like follows >> get '/poly.:format' => sub { >> my $poly = params->{'BBOX'}; get '/poly.:format' => sub { my $poly = params->{'BBOX'}; + my $callback = params->{'callback'}; my $res = recs_within_poly($poly); + $res = $callback . '(' . $res . ')'; return $res; } Does the above make sense? >> > > > I kind of follow what you are saying, but I am not sure what I am supposed to do. From my side (the client side), I am specifying that it is a JSONP request, and I am even specifying the callback param. From what I understand, as you state above, the server is supposed to send back the JSON stream wrapped in the function callback. Let me read that again -- the server is supposed to do the above. Dancer is the responding server, and it is not doing so, as you confirm above. So, how do I read the callback param myself? > > I checked Firebug as well as the Safari web developer... The JSON object is clealy returned, but the jQuery Ajax call's success method is never triggered. Instead, its error method is triggered. > > Suggestions? > > Many thanks in advance. > > >> Alex. >> >> ----- >> sent from my phone - please excuse any brevity >> >> ----- Reply message ----- >> From: "Mr. Puneet Kishor" <punk.kish(a)gmail.com> >> To: "dancer-users" <dancer-users(a)perldancer.org> >> Subject: [Dancer-users] cross domain ajax to dancer app >> Date: Tue, Jul 12, 2011 10:30 pm >> >> >> I am trying to send an ajax GET request from one dancer app (powered by Starman on one port) to another dancer app (powered by Starman on another port). I am using jQuery like so >> >> $.ajax({ >> "url": url, >> "data": data, >> "type": "GET", >> "dataType": "jsonp", >> "jsonpCallback": function(res) { >> .. do something with res .. >> } >> }); >> >> I can see the result come back from the second dancer app in Safari web inspector. It looks like a JSON stream, but it doesn't trigger the jsonpCallback. The web inspector complains that "Resource interpreted as script but transferred with MIME type application/json." I am wondering if there is something in the second dancer app (the one that returns the result) which is setting a wrong header that is causing the callback to not be tripped. The code in the second dancer app looks like so >> >> use Dancer::Plugin::REST; >> prepare_serializer_for_format; >> >> use DBI; >> >> >> get '/poly.:format' => sub { >> my $poly = params->{'BBOX'}; >> >> my $res = recs_within_poly($poly); >> return $res; >> }; >> >> By the way, seems like if I use Dancer::Plugin::REST, I can't use Dancer::Plugin::Ajax, or can I? Changing the above route to `ajax '../ => sub {};` gives an error that the route was not found. >> >> >> _______________________________________________ >> Dancer-users mailing list >> Dancer-users(a)perldancer.org >> http://www.backup-manager.org/cgi-bin/listinfo/dancer-users

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Re: [Dancer-users] cross domain ajax to dancer app
by Alex Kalderimis 13 Jul '11

13 Jul '11

Remember that jsonp requests must return their data wrapped in the function callback to work. If not, the json will be evaluated, but do nothing, as it is in void context (so to speak). Dancer does not do this for you - you will need to read the callback parameter yourself. Alex. ----- sent from my phone - please excuse any brevity ----- Reply message ----- From: "Mr. Puneet Kishor" <punk.kish(a)gmail.com> To: "dancer-users" <dancer-users(a)perldancer.org> Subject: [Dancer-users] cross domain ajax to dancer app Date: Tue, Jul 12, 2011 10:30 pm I am trying to send an ajax GET request from one dancer app (powered by Starman on one port) to another dancer app (powered by Starman on another port). I am using jQuery like so $.ajax({ "url": url, "data": data, "type": "GET", "dataType": "jsonp", "jsonpCallback": function(res) { .. do something with res .. } }); I can see the result come back from the second dancer app in Safari web inspector. It looks like a JSON stream, but it doesn't trigger the jsonpCallback. The web inspector complains that "Resource interpreted as script but transferred with MIME type application/json." I am wondering if there is something in the second dancer app (the one that returns the result) which is setting a wrong header that is causing the callback to not be tripped. The code in the second dancer app looks like so use Dancer::Plugin::REST; prepare_serializer_for_format; use DBI; get '/poly.:format' => sub { my $poly = params->{'BBOX'}; my $res = recs_within_poly($poly); return $res; }; By the way, seems like if I use Dancer::Plugin::REST, I can't use Dancer::Plugin::Ajax, or can I? Changing the above route to `ajax '../ => sub {};` gives an error that the route was not found. _______________________________________________ Dancer-users mailing list Dancer-users(a)perldancer.org http://www.backup-manager.org/cgi-bin/listinfo/dancer-users

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cross domain ajax to dancer app
by Mr. Puneet Kishor 12 Jul '11

12 Jul '11

I am trying to send an ajax GET request from one dancer app (powered by Starman on one port) to another dancer app (powered by Starman on another port). I am using jQuery like so $.ajax({ "url": url, "data": data, "type": "GET", "dataType": "jsonp", "jsonpCallback": function(res) { .. do something with res .. } }); I can see the result come back from the second dancer app in Safari web inspector. It looks like a JSON stream, but it doesn't trigger the jsonpCallback. The web inspector complains that "Resource interpreted as script but transferred with MIME type application/json." I am wondering if there is something in the second dancer app (the one that returns the result) which is setting a wrong header that is causing the callback to not be tripped. The code in the second dancer app looks like so use Dancer::Plugin::REST; prepare_serializer_for_format; use DBI; get '/poly.:format' => sub { my $poly = params->{'BBOX'}; my $res = recs_within_poly($poly); return $res; }; By the way, seems like if I use Dancer::Plugin::REST, I can't use Dancer::Plugin::Ajax, or can I? Changing the above route to `ajax '../ => sub {};` gives an error that the route was not found.

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