Provided by: libdancer-perl_1.3521+dfsg-1_all 
NAME
Dancer - lightweight yet powerful web application framework
VERSION
version 1.3521
SYNOPSIS
#!/usr/bin/perl
use Dancer;
get '/hello/:name' => sub {
return "Why, hello there " . param('name');
};
dance;
The above is a basic but functional web app created with Dancer. If you want to see more
examples and get up and running quickly, check out the Dancer::Introduction and the
Dancer::Cookbook. For examples on deploying your Dancer applications, see
Dancer::Deployment.
DESCRIPTION
Dancer is a web application framework designed to be as effortless as possible for the
developer, taking care of the boring bits as easily as possible, yet staying out of your
way and letting you get on with writing your code.
Dancer aims to provide the simplest way for writing web applications, and offers the
flexibility to scale between a very simple lightweight web service consisting of a few
lines of code in a single file, all the way up to a more complex fully-fledged web
application with session support, templates for views and layouts, etc.
If you don't want to write CGI scripts by hand, and find Catalyst too big or cumbersome
for your project, Dancer is what you need.
Dancer has few pre-requisites, so your Dancer webapps will be easy to deploy.
Dancer apps can be used with an embedded web server (great for easy testing), and can run
under PSGI/Plack for easy deployment in a variety of webserver environments.
MORE DOCUMENTATION
This documentation describes all the exported symbols of Dancer. If you want a quick start
guide to discover the framework, you should look at Dancer::Introduction, or
Dancer::Tutorial to learn by example.
If you want to have specific examples of code for real-life problems, see the
Dancer::Cookbook.
If you want to see configuration examples of different deployment solutions involving
Dancer and Plack, see Dancer::Deployment.
You can find out more about the many useful plugins available for Dancer in
Dancer::Plugins.
DANCER 2
This is the original version of Dancer, which is now in maintenance mode. This means that
it will not receive significant new features, but will continue to receive bugfixes and
security fixes. However, no "end of life" date has been set, and it is expected that this
version of Dancer will continue to receive bugfixes and security fixes for quite some time
yet.
However, you should consider migrating to Dancer2 instead when you can, and are advised to
use Dancer2 for newly-started apps.
Dancer2 is mostly backwards compatible, but has been re-written from the ground up to be
more maintainable and extensible, and is the future of Dancer.
Dancer2::Manual::Migration covers the changes you should be aware of when migrating an
existing Dancer 1 powered app to Dancer 2.
EXPORTS
By default, "use Dancer" exports all the functions below plus sets up your app. You can
control the exporting through the normal Exporter mechanism. For example:
# Just export the route controllers
use Dancer qw(get post put patch del);
# Export everything but pass to avoid clashing with Test::More
use Test::More;
use Dancer qw(!pass);
Please note that the utf8 and strict pragmas are exported by this module.
By default, the warnings pragma will also be exported, meaning your app/script will be
running under "use warnings". If you do not want this, set the global_warnings setting to
a false value.
There are also some special tags to control exports and behaviour.
:moose
This will export everything except functions which clash with Moose. Currently these are
"after" and "before".
:syntax
This tells Dancer to just export symbols and not set up your app. This is most useful for
writing Dancer code outside of your main route handler.
:tests
This will export everything except functions which clash with commonly used testing
modules. Currently these are "pass".
It can be combined with other export pragmas. For example, while testing...
use Test::More;
use Dancer qw(:syntax :tests);
# Test::Most also exports "set" and "any"
use Test::Most;
use Dancer qw(:syntax :tests !set !any);
# Alternatively, if you want to use Dancer's set and any...
use Test::Most qw(!set !any);
use Dancer qw(:syntax :tests);
:script
This will export all the keywords, load the configuration, and will not try to parse
command-line arguments via Dancer::GetOpt.
This is useful when you want to use your Dancer application from a script.
use MyApp;
use Dancer ':script';
MyApp::schema('DBSchema')->deploy();
Note that using ":script" will disable command-line parsing for all subsequent
invocations of "use Dancer" (such that you don't have to use ":script" for each and every
module to make sure the command-line arguments don't get stolen by Dancer).
!keyword
If you want to simply prevent Dancer from exporting specific keywords (perhaps you plan to
implement them yourself in a different way, or you don't plan to use them and they clash
with another module you're loading), you can simply exclude them:
use Dancer qw(!session);
The above would import all keywords as normal, with the exception of "session".
FUNCTIONS
after
Deprecated - see the "after" hook.
any
Defines a route for multiple HTTP methods at once:
any ['get', 'post'] => '/myaction' => sub {
# code
};
Or even, a route handler that would match any HTTP methods:
any '/myaction' => sub {
# code
};
before
Deprecated - see the "before" hook.
before_template
Deprecated - see the "before_template" hook.
cookies
Accesses cookies values, it returns a HashRef of Dancer::Cookie objects:
get '/some_action' => sub {
my $cookie = cookies->{name};
return $cookie->value;
};
In the case you have stored something other than a Scalar in your cookie:
get '/some_action' => sub {
my $cookie = cookies->{oauth};
my %values = $cookie->value;
return ($values{token}, $values{token_secret});
};
cookie
Accesses a cookie value (or sets it). Note that this method will eventually be preferred
over "set_cookie".
cookie lang => "fr-FR"; # set a cookie and return its value
cookie lang => "fr-FR", expires => "2 hours"; # extra cookie info
cookie "lang" # return a cookie value
If your cookie value is a key/value URI string, like
token=ABC&user=foo
"cookie" will only return the first part ("token=ABC") if called in scalar context. Use
list context to fetch them all:
my @values = cookie "name";
Note that if the client has sent more than one cookie with the same value, the one
returned will be the last one seen. This should only happen if you have set multiple
cookies with the same name but different paths. So, don't do that.
config
Accesses the configuration of the application:
get '/appname' => sub {
return "This is " . config->{appname};
};
content_type
Sets the content-type rendered, for the current route handler:
get '/cat/:txtfile' => sub {
content_type 'text/plain';
# here we can dump the contents of param('txtfile')
};
You can use abbreviations for content types. For instance:
get '/svg/:id' => sub {
content_type 'svg';
# here we can dump the image with id param('id')
};
Note that if you want to change the default content-type for every route, you have to
change the "content_type" setting instead.
dance
Alias for the "start" keyword.
dancer_version
Returns the version of Dancer. If you need the major version, do something like:
int(dancer_version);
debug
Logs a message of debug level:
debug "This is a debug message";
See Dancer::Logger for details on how to configure where log messages go.
dirname
Returns the dirname of the path given:
my $dir = dirname($some_path);
engine
Given a namespace, returns the current engine object
my $template_engine = engine 'template';
my $html = $template_engine->apply_renderer(...);
$template_engine->apply_layout($html);
error
Logs a message of error level:
error "This is an error message";
See Dancer::Logger for details on how to configure where log messages go.
false
Constant that returns a false value (0).
forward
Runs an internal redirect of the current request to another request. This helps you avoid
having to redirect the user using HTTP and set another request to your application.
It effectively lets you chain routes together in a clean manner.
get '/demo/articles/:article_id' => sub {
# you'll have to implement this next sub yourself :)
change_the_main_database_to_demo();
forward "/articles/" . params->{article_id};
};
In the above example, the users that reach /demo/articles/30 will actually reach
/articles/30 but we've changed the database to demo before.
This is pretty cool because it lets us retain our paths and offer a demo database by
merely going to /demo/....
You'll notice that in the example we didn't indicate whether it was GET or POST. That is
because "forward" chains the same type of route the user reached. If it was a GET, it will
remain a GET (but if you do need to change the method, you can do so; read on below for
details.)
WARNING : using forward will not preserve session data set on the forwarding rule.
WARNING : Issuing a forward immediately exits the current route, and perform the forward.
Thus, any code after a forward is ignored, until the end of the route. e.g.
get '/foo/:article_id' => sub {
if ($condition) {
forward "/articles/" . params->{article_id};
# The following code is never executed
do_stuff();
}
more_stuff();
};
So it's not necessary anymore to use "return" with forward.
Note that forward doesn't parse GET arguments. So, you can't use something like:
return forward '/home?authorized=1';
But "forward" supports an optional HashRef with parameters to be added to the actual
parameters:
return forward '/home', { authorized => 1 };
Finally, you can add some more options to the forward method, in a third argument, also as
a HashRef. That option is currently only used to change the method of your request. Use
with caution.
return forward '/home', { auth => 1 }, { method => 'POST' };
from_dumper ($structure)
Deserializes a Data::Dumper structure.
from_json ($structure, \%options)
Deserializes a JSON structure. Can receive optional arguments. Those arguments are valid
JSON arguments to change the behaviour of the default "JSON::from_json" function.
Compatibility notice: "from_json" changed in 1.3002 to take a hashref as options, instead
of a hash.
from_yaml ($structure)
Deserializes a YAML structure.
from_xml ($structure, %options)
Deserializes a XML structure. Can receive optional arguments. These arguments are valid
XML::Simple arguments to change the behaviour of the default "XML::Simple::XMLin"
function.
get
Defines a route for HTTP GET requests to the given path:
get '/' => sub {
return "Hello world";
}
Note that a route to match HEAD requests is automatically created as well.
halt
Sets a response object with the content given.
When used as a return value from a filter, this breaks the execution flow and renders the
response immediately:
hook before sub {
if ($some_condition) {
halt("Unauthorized");
# This code is not executed :
do_stuff();
}
};
get '/' => sub {
"hello there";
};
WARNING : Issuing a halt immediately exits the current route, and perform the halt. Thus,
any code after a halt is ignored, until the end of the route. So it's not necessary
anymore to use "return" with halt.
headers
Adds custom headers to responses:
get '/send/headers', sub {
headers 'X-Foo' => 'bar', X-Bar => 'foo';
}
header
adds a custom header to response:
get '/send/header', sub {
header 'x-my-header' => 'shazam!';
}
Note that it will overwrite the old value of the header, if any. To avoid that, see
"push_header".
push_header
Do the same as "header", but allow for multiple headers with the same name.
get '/send/header', sub {
push_header 'x-my-header' => '1';
push_header 'x-my-header' => '2';
will result in two headers "x-my-header" in the response
}
hook
Adds a hook at some position. For example :
hook before_serializer => sub {
my $response = shift;
$response->content->{generated_at} = localtime();
};
There can be multiple hooks assigned to a given position, and each will be executed in
order. Note that all hooks are always called, even if they are defined in a different
package loaded via "load_app".
(For details on how to register new hooks from within plugins, see Dancer::Hook.)
Supported before hooks (in order of execution):
before_deserializer
This hook receives no arguments.
hook before_deserializer => sub {
...
};
before_file_render
This hook receives as argument the path of the file to render.
hook before_file_render => sub {
my $path = shift;
...
};
before_error_init
This hook receives as argument a Dancer::Error object.
hook before_error_init => sub {
my $error = shift;
...
};
before_error_render
This hook receives as argument a Dancer::Error object.
hook before_error_render => sub {
my $error = shift;
};
before
This hook receives one argument, the route being executed (a Dancer::Route object).
hook before => sub {
my $route_handler = shift;
...
};
it is equivalent to the deprecated
before sub {
...
};
before_template_render
This is an alias to 'before_template'.
This hook receives as argument a HashRef containing the tokens that will be passed to
the template. You can use it to add more tokens, or delete some specific token.
hook before_template_render => sub {
my $tokens = shift;
delete $tokens->{user};
$tokens->{time} = localtime;
};
is equivalent to
hook before_template => sub {
my $tokens = shift;
delete $tokens->{user};
$tokens->{time} = localtime;
};
before_layout_render
This hook receives two arguments. The first one is a HashRef containing the tokens.
The second is a ScalarRef representing the content of the template.
hook before_layout_render => sub {
my ($tokens, $html_ref) = @_;
...
};
before_serializer
This hook receives as argument a Dancer::Response object.
hook before_serializer => sub {
my $response = shift;
$response->content->{start_time} = time();
};
Supported after hooks (in order of execution):
after_deserializer
This hook receives no arguments.
hook after_deserializer => sub {
...
};
after_file_render
This hook receives as argument a Dancer::Response object.
hook after_file_render => sub {
my $response = shift;
};
after_template_render
This hook receives as argument a ScalarRef representing the content generated by the
template.
hook after_template_render => sub {
my $html_ref = shift;
};
after_layout_render
This hook receives as argument a ScalarRef representing the content generated by the
layout
hook after_layout_render => sub {
my $html_ref = shift;
};
after
This is an alias for "after".
This hook runs after a request has been processed, but before the response is sent.
It receives a Dancer::Response object, which it can modify if it needs to make changes
to the response which is about to be sent.
hook after => sub {
my $response = shift;
};
This is equivalent to the deprecated
after sub {
my $response = shift;
};
after_error_render
This hook receives as argument a Dancer::Response object.
hook after_error_render => sub {
my $response = shift;
};
on_handler_exception
This hook is called when an exception has been caught, at the handler level, just
before creating and rendering Dancer::Error. This hook receives as argument a
Dancer::Exception object.
hook on_handler_exception => sub {
my $exception = shift;
};
on_reset_state
This hook is called when global state is reset to process a new request. It receives
a boolean value that indicates whether the reset was called as part of a forwarded
request.
hook on_reset_state => sub {
my $is_forward = shift;
};
on_route_exception
This hook is called when an exception has been caught, at the route level, just before
rethrowing it higher. This hook receives the exception as argument. It can be a
Dancer::Exception, or a string, or whatever was used to "die".
hook on_route_exception => sub {
my $exception = shift;
};
info
Logs a message of info level:
info "This is a info message";
See Dancer::Logger for details on how to configure where log messages go.
layout
This method is deprecated. Use "set":
set layout => 'user';
logger
Deprecated. Use "<set logger => 'console'"> to change current logger engine.
load
Loads one or more perl scripts in the current application's namespace. Syntactic sugar
around Perl's "require":
load 'UserActions.pl', 'AdminActions.pl';
load_app
Loads a Dancer package. This method sets the libdir to the current "./lib" directory:
# if we have lib/Webapp.pm, we can load it like:
load_app 'Webapp';
# or with options
load_app 'Forum', prefix => '/forum', settings => {foo => 'bar'};
Note that the package loaded using load_app must import Dancer with the ":syntax" option.
To load multiple apps repeat load_app:
load_app 'one';
load_app 'two';
The old way of loading multiple apps in one go (load_app 'one', 'two';) is deprecated.
mime
Shortcut to access the instance object of Dancer::MIME. You should read the Dancer::MIME
documentation for full details, but the most commonly-used methods are summarized below:
# set a new mime type
mime->add_type( foo => 'text/foo' );
# set a mime type alias
mime->add_alias( f => 'foo' );
# get mime type for an alias
my $m = mime->for_name( 'f' );
# get mime type for a file (based on extension)
my $m = mime->for_file( "foo.bar" );
# get current defined default mime type
my $d = mime->default;
# set the default mime type using config.yml
# or using the set keyword
set default_mime_type => 'text/plain';
params
This method should be called from a route handler. It's an alias for the Dancer::Request
params accessor. In list context it returns a list of key/value pair of all defined
parameters. In scalar context it returns a hash reference instead. Check "param" below to
access quickly to a single parameter value.
param
This method should be called from a route handler. This method is an accessor to the
parameters hash table.
post '/login' => sub {
my $username = param "user";
my $password = param "pass";
# ...
}
param_array
This method should be called from a route handler. Like param, but always returns the
parameter value or values as a list. Returns the number of values in scalar context.
# if request is '/tickets?tag=open&tag=closed&order=desc'...
get '/tickets' => sub {
my @tags = param_array 'tag'; # ( 'open', 'closed' )
my $tags = param 'tag'; # array ref
my @order = param_array 'order'; # ( 'desc' )
my $order = param 'order'; # 'desc'
};
pass
This method should be called from a route handler. Tells Dancer to pass the processing of
the request to the next matching route.
WARNING : Issuing a pass immediately exits the current route, and performs the pass. Thus,
any code after a pass is ignored until the end of the route. So it's not necessary any
more to use "return" with pass.
get '/some/route' => sub {
if (...) {
# we want to let the next matching route handler process this one
pass(...);
# This code will be ignored
do_stuff();
}
};
patch
Defines a route for HTTP PATCH requests to the given URL:
patch '/resource' => sub { ... };
("PATCH" is a relatively new and not-yet-common HTTP verb, which is intended to work as a
"partial-PUT", transferring just the changes; please see
<http://tools.ietf.org/html/rfc5789|RFC5789> for further details.)
Please be aware that, if you run your app in standalone mode, "PATCH" requests will not
reach your app unless you have a new version of HTTP::Server::Simple which accepts "PATCH"
as a valid verb. The current version at time of writing, 0.44, does not. A pull request
has been submitted to add this support, which you can find at:
<https://github.com/bestpractical/http-server-simple/pull/1>
path
Concatenates multiple paths together, without worrying about the underlying operating
system:
my $path = path(dirname($0), 'lib', 'File.pm');
It also normalizes (cleans) the path aesthetically. It does not verify the path exists.
post
Defines a route for HTTP POST requests to the given URL:
post '/' => sub {
return "Hello world";
}
prefix
Defines a prefix for each route handler, like this:
prefix '/home';
From here, any route handler is defined to /home/*:
get '/page1' => sub {}; # will match '/home/page1'
You can unset the prefix value:
prefix undef;
get '/page1' => sub {}; will match /page1
For a safer alternative you can use lexical prefix like this:
prefix '/home' => sub {
## Prefix is set to '/home' here
get ...;
get ...;
};
## prefix reset to the previous version here
This makes it possible to nest prefixes:
prefix '/home' => sub {
## some routes
prefix '/private' => sub {
## here we are under /home/private...
## some more routes
};
## back to /home
};
## back to the root
Notice: once you have a prefix set, do not add a caret to the regex:
prefix '/foo';
get qr{^/bar} => sub { ... } # BAD BAD BAD
get qr{/bar} => sub { ... } # Good!
del
Defines a route for HTTP DELETE requests to the given URL:
del '/resource' => sub { ... };
options
Defines a route for HTTP OPTIONS requests to the given URL:
options '/resource' => sub { ... };
put
Defines a route for HTTP PUT requests to the given URL:
put '/resource' => sub { ... };
redirect
Generates an HTTP redirect (302). You can either redirect to a completely different site
or within the application:
get '/twitter', sub {
redirect 'http://twitter.com/me';
};
You can also force Dancer to return a specific 300-ish HTTP response code:
get '/old/:resource', sub {
redirect '/new/'.params->{resource}, 301;
};
It is important to note that issuing a redirect by itself does not exit and redirect
immediately. Redirection is deferred until after the current route or filter has been
processed. To exit and redirect immediately, use the return function, e.g.
get '/restricted', sub {
return redirect '/login' if accessDenied();
return 'Welcome to the restricted section';
};
render_with_layout
Allows a handler to provide plain HTML (or other content), but have it rendered within the
layout still.
This method is DEPRECATED, and will be removed soon. Instead, you should be using the
"engine" keyword:
get '/foo' => sub {
# Do something which generates HTML directly (maybe using
# HTML::Table::FromDatabase or something)
my $content = ...;
# get the template engine
my $template_engine = engine 'template';
# apply the layout (not the renderer), and return the result
$template_engine->apply_layout($content)
};
It works very similarly to "template" in that you can pass tokens to be used in the
layout, and/or options to control the way the layout is rendered. For instance, to use a
custom layout:
render_with_layout $content, {}, { layout => 'layoutname' };
request
Returns a Dancer::Request object representing the current request.
See the Dancer::Request documentation for the methods you can call, for example:
request->referer; # value of the HTTP referer header
request->remote_address; # user's IP address
request->user_agent; # User-Agent header value
send_error
Returns an HTTP error. By default the HTTP code returned is 500:
get '/photo/:id' => sub {
if (...) {
send_error("Not allowed", 403);
} else {
# return content
}
}
WARNING : Issuing a send_error immediately exits the current route, and perform the
send_error. Thus, any code after a send_error is ignored, until the end of the route. So
it's not necessary anymore to use "return" with send_error.
get '/some/route' => sub {
if (...) {
# we want to let the next matching route handler process this one
send_error(..);
# This code will be ignored
do_stuff();
}
};
send_file
Lets the current route handler send a file to the client. Note that the path of the file
must be relative to the public directory unless you use the "system_path" option (see
below).
get '/download/:file' => sub {
send_file(params->{file});
}
WARNING : Issuing a send_file immediately exits the current route, and performs the
send_file. Thus, any code after a send_file is ignored until the end of the route. So
it's not necessary any more to use "return" with send_file.
get '/some/route' => sub {
if (...) {
# we want to let the next matching route handler process this one
send_file(...);
# This code will be ignored
do_stuff();
}
};
Send file supports streaming possibility using PSGI streaming. The server should support
it but normal streaming is supported on most, if not all.
get '/download/:file' => sub {
send_file( params->{file}, streaming => 1 );
}
You can control what happens using callbacks.
First, "around_content" allows you to get the writer object and the chunk of content read,
and then decide what to do with each chunk:
get '/download/:file' => sub {
send_file(
params->{file},
streaming => 1,
callbacks => {
around_content => sub {
my ( $writer, $chunk ) = @_;
$writer->write("* $chunk");
},
},
);
}
You can use "around" to all get all the content (whether a filehandle if it's a regular
file or a full string if it's a scalar ref) and decide what to do with it:
get '/download/:file' => sub {
send_file(
params->{file},
streaming => 1,
callbacks => {
around => sub {
my ( $writer, $content ) = @_;
# we know it's a text file, so we'll just stream
# line by line
while ( my $line = <$content> ) {
$writer->write($line);
}
},
},
);
}
Or you could use "override" to control the entire streaming callback request:
get '/download/:file' => sub {
send_file(
params->{file},
streaming => 1,
callbacks => {
override => sub {
my ( $respond, $response ) = @_;
my $writer = $respond->( [ $newstatus, $newheaders ] );
$writer->write("some line");
},
},
);
}
You can also set the number of bytes that will be read at a time (default being 42K bytes)
using "bytes":
get '/download/:file' => sub {
send_file(
params->{file},
streaming => 1,
bytes => 524288, # 512K
);
};
The content-type will be set depending on the current MIME types definition (see "mime" if
you want to define your own).
If your filename does not have an extension, or you need to force a specific mime type,
you can pass it to "send_file" as follows:
send_file(params->{file}, content_type => 'image/png');
Also, you can use your aliases or file extension names on "content_type", like this:
send_file(params->{file}, content_type => 'png');
For files outside your public folder, you can use the "system_path" switch. Just bear in
mind that its use needs caution as it can be dangerous.
send_file('/etc/passwd', system_path => 1);
If you have your data in a scalar variable, "send_file" can be useful as well. Pass a
reference to that scalar, and "send_file" will behave as if there were a file with that
contents:
send_file( \$data, content_type => 'image/png' );
Note that Dancer is unable to guess the content type from the data contents. Therefore you
might need to set the "content_type" properly. For this kind of usage an attribute named
"filename" can be useful. It is used as the Content-Disposition header, to hint the
browser about the filename it should use.
send_file( \$data, content_type => 'image/png'
filename => 'onion.png' );
set
Defines a setting:
set something => 'value';
You can set more than one value at once:
set something => 'value', otherthing => 'othervalue';
setting
Returns the value of a given setting:
setting('something'); # 'value'
set_cookie
Creates or updates cookie values:
get '/some_action' => sub {
set_cookie name => 'value',
expires => (time + 3600),
domain => '.foo.com';
};
In the example above, only 'name' and 'value' are mandatory.
You can also store more complex structure in your cookies:
get '/some_auth' => sub {
set_cookie oauth => {
token => $twitter->request_token,
token_secret => $twitter->secret_token,
...
};
};
You can't store more complex structure than this. All keys in the HashRef should be
Scalars; storing references will not work.
See Dancer::Cookie for further options when creating your cookie.
Note that this method will be eventually deprecated in favor of the new "cookie" method.
session
Provides access to all data stored in the user's session (if any).
It can also be used as a setter to store data in the session:
# getter example
get '/user' => sub {
if (session('user')) {
return "Hello, ".session('user')->name;
}
};
# setter example
post '/user/login' => sub {
...
if ($logged_in) {
session user => $user;
}
...
};
You may also need to clear a session:
# destroy session
get '/logout' => sub {
...
session->destroy;
...
};
If you need to fetch the session ID being used for any reason:
my $id = session->id;
In order to be able to use sessions, first you need to enable session support in one of
the configuration files. A quick way to do it is to add
session: "YAML"
to config.yml.
For more details, see Dancer::Session.
splat
Returns the list of captures made from a route handler with a route pattern which includes
wildcards:
get '/file/*.*' => sub {
my ($file, $extension) = splat;
...
};
There is also the extensive splat (A.K.A. "megasplat"), which allows extensive greedier
matching, available using two asterisks. The additional path is broken down and returned
as an ArrayRef:
get '/entry/*/tags/**' => sub {
my ( $entry_id, $tags ) = splat;
my @tags = @{$tags};
};
This helps with chained actions:
get '/team/*/**' => sub {
my ($team) = splat;
var team => $team;
pass;
};
prefix '/team/*';
get '/player/*' => sub {
my ($player) = splat;
# etc...
};
get '/score' => sub {
return score_for( vars->{'team'} );
};
start
Starts the application or the standalone server (depending on the deployment choices).
This keyword should be called at the very end of the script, once all routes are defined.
At this point, Dancer takes over control.
status
Changes the status code provided by an action. By default, an action will produce an
"HTTP 200 OK" status code, meaning everything is OK:
get '/download/:file' => {
if (! -f params->{file}) {
status 'not_found';
return "File does not exist, unable to download";
}
# serving the file...
};
In that example Dancer will notice that the status has changed, and will render the
response accordingly.
The status keyword receives either a numeric status code or its name in lower case, with
underscores as a separator for blanks. See the list in "HTTP CODES" in Dancer::HTTP.
template
Returns the response of processing the given template with the given parameters (and
optional settings), wrapping it in the default or specified layout too, if layouts are in
use.
An example of a route handler which returns the result of using template to build a
response with the current template engine:
get '/' => sub {
...
return template 'some_view', { token => 'value'};
};
Note that "template" simply returns the content, so when you use it in a route handler, if
execution of the route handler should stop at that point, make sure you use 'return' to
ensure your route handler returns the content.
Since template just returns the result of rendering the template, you can also use it to
perform other templating tasks, e.g. generating emails:
post '/some/route' => sub {
if (...) {
email {
to => 'someone@example.com',
from => 'foo@example.com',
subject => 'Hello there',
msg => template('emails/foo', { name => params->{name} }),
};
return template 'message_sent';
} else {
return template 'error';
}
};
Compatibility notice: "template" was changed in version 1.3090 to immediately interrupt
execution of a route handler and return the content, as it's typically used at the end of
a route handler to return content. However, this caused issues for some people who were
using "template" to generate emails etc, rather than accessing the template engine
directly, so this change has been reverted in 1.3091.
The first parameter should be a template available in the views directory, the second one
(optional) is a HashRef of tokens to interpolate, and the third (again optional) is a
HashRef of options.
For example, to disable the layout for a specific request:
get '/' => sub {
template 'index', {}, { layout => undef };
};
Or to request a specific layout, of course:
get '/user' => sub {
template 'user', {}, { layout => 'user' };
};
Some tokens are automatically added to your template ("perl_version", "dancer_version",
"settings", "request", "params", "vars" and, if you have sessions enabled, "session").
Check Dancer::Template::Abstract for further details.
to_dumper ($structure)
Serializes a structure with Data::Dumper.
to_json ($structure, \%options)
Serializes a structure to JSON. Can receive optional arguments. Thoses arguments are valid
JSON arguments to change the behaviour of the default "JSON::to_json" function.
Compatibility notice: "to_json" changed in 1.3002 to take a hashref as options, instead of
a hash.
to_yaml ($structure)
Serializes a structure to YAML.
to_xml ($structure, %options)
Serializes a structure to XML. Can receive optional arguments. Thoses arguments are valid
XML::Simple arguments to change the behaviour of the default "XML::Simple::XMLout"
function.
true
Constant that returns a true value (1).
upload
Provides access to file uploads. Any uploaded file is accessible as a
Dancer::Request::Upload object. You can access all parsed uploads via:
post '/some/route' => sub {
my $file = upload('file_input_foo');
# file is a Dancer::Request::Upload object
};
If you named multiple inputs of type "file" with the same name, the upload keyword will
return an Array of Dancer::Request::Upload objects:
post '/some/route' => sub {
my ($file1, $file2) = upload('files_input');
# $file1 and $file2 are Dancer::Request::Upload objects
};
You can also access the raw HashRef of parsed uploads via the current request object:
post '/some/route' => sub {
my $all_uploads = request->uploads;
# $all_uploads->{'file_input_foo'} is a Dancer::Request::Upload object
# $all_uploads->{'files_input'} is an ArrayRef of Dancer::Request::Upload objects
};
Note that you can also access the filename of the upload received via the params keyword:
post '/some/route' => sub {
# params->{'files_input'} is the filename of the file uploaded
};
See Dancer::Request::Upload for details about the interface provided.
uri_for
Returns a fully-qualified URI for the given path:
get '/' => sub {
redirect uri_for('/path');
# can be something like: http://localhost:3000/path
};
Querystring parameters can be provided by passing a hashref as a second param, and URL-
encoding can be disabled via a third parameter:
uri_for('/path', { foo => 'bar' }, 1);
# would return e.g. http://localhost:3000/path?foo=bar
captures
Returns a reference to a copy of "%+", if there are named captures in the route Regexp.
Named captures are a feature of Perl 5.10, and are not supported in earlier versions:
get qr{
/ (?<object> user | ticket | comment )
/ (?<action> delete | find )
/ (?<id> \d+ )
/?$
}x
, sub {
my $value_for = captures;
"i don't want to $$value_for{action} the $$value_for{object} $$value_for{id} !"
};
var
Provides an accessor for variables shared between filters and route handlers. Given a
key/value pair, it sets a variable:
hook before sub {
var foo => 42;
};
Later, route handlers and other filters will be able to read that variable:
get '/path' => sub {
my $foo = var 'foo';
...
};
vars
Returns the HashRef of all shared variables set during the filter/route chain with the
"var" keyword:
get '/path' => sub {
if (vars->{foo} eq 42) {
...
}
};
warning
Logs a warning message through the current logger engine:
warning "This is a warning";
See Dancer::Logger for details on how to configure where log messages go.
AUTHOR
This module has been written by Alexis Sukrieh <sukria@cpan.org> and others, see the
AUTHORS file that comes with this distribution for details.
SOURCE CODE
The source code for this module is hosted on GitHub
<https://github.com/PerlDancer/Dancer>. Feel free to fork the repository and submit pull
requests! (See Dancer::Development for details on how to contribute).
Also, why not watch the repo <https://github.com/PerlDancer/Dancer/toggle_watch> to keep
up to date with the latest upcoming changes?
GETTING HELP / CONTRIBUTING
The Dancer development team can be found on #dancer on irc.perl.org:
<irc://irc.perl.org/dancer>
If you don't have an IRC client installed/configured, there is a simple web chat client at
<http://www.perldancer.org/irc> for you.
There is also a Dancer users mailing list available. Subscribe at:
<http://lists.preshweb.co.uk/mailman/listinfo/dancer-users>
If you'd like to contribute to the Dancer project, please see
<http://www.perldancer.org/contribute> for all the ways you can help!
DEPENDENCIES
The following modules are mandatory (Dancer cannot run without them):
HTTP::Server::Simple::PSGI
HTTP::Tiny
MIME::Types
URI
The following modules are optional:
JSON : needed to use JSON serializer
Plack : in order to use PSGI
Template : in order to use TT for rendering views
XML::Simple and <XML:SAX> or <XML:Parser> for XML serialization
YAML : needed for configuration file support
SEE ALSO
Main Dancer web site: <http://perldancer.org/>.
The concept behind this module comes from the Sinatra ruby project, see
<http://www.sinatrarb.com/> for details.
AUTHOR
Dancer Core Developers
COPYRIGHT AND LICENSE
This software is copyright (c) 2010 by Alexis Sukrieh.
This is free software; you can redistribute it and/or modify it under the same terms as
the Perl 5 programming language system itself.