Provided by: libdancer2-perl_0.205002+dfsg-2_all 

NAME
Dancer2::Config - Configure Dancer2 to suit your needs
VERSION
version 0.205002
DESCRIPTION
The Dancer2 configuration (as implemented by Dancer2::Core::Role::ConfigReader) handles reading and
changing the configuration of your Dancer2 apps. This document describes how to manipulate Dancer2's
configuration settings (through code or by file), and to document the various settings that are available
in Dancer2.
MANIPULATING SETTINGS VIA CODE
You can change a setting with the keyword "set":
use Dancer2;
# changing default settings
set port => 8080;
set content_type => 'text/plain';
set startup_info => 0;
MANIPULATING SETTINGS VIA CONFIGURATION FILES
There's nothing wrong with using "set" to configure your application. In fact you might have some great
reasons for doing so. For greater flexibility, ease of deployment, etc., you should also consider
extracting those settings into a configuration file.
Configuration file path and file names
Dancer2 will first look for the file config.EXT (where EXT is the type of configuration file you are
using; e.g. ini or json or yml) in the root directory of your application. This is considered your global
Dancer2 config file. If you do not care to have separate settings for production and development
environments (not a recommended practice!), then this file is all you need.
Next, Dancer2 will look for a file called config_local.EXT. This file is typically useful for deployment-
specific configuration that should not be checked into source control. For instance, database credentials
could be stored in this file. Any settings in this file are merged into the existing configuration such
that those with the same name in your global configuration file will take precedence over those settings
in the global file.
Next, Dancer2 will look in the environments directory for a configuration file specific to the platform
you are deploying to (production.EXT or development.EXT, for example). Again, the configuration from the
environment is merged with the existing configuration with the deployment config taking precedence.
Finally, Dancer2 will look in the environments directory for a local configuration for the specific
platform you are deploying to (e.g. prodcution_local.EXT or development_local.EXT) The configuration in
this file is merged as before.
Much like config_local.EXT, this file would be useful for environment- specific configuration that would
not be checked into source control. For instance, when developing an application that talks to multiple
services, each developer could have their own URLs to those services stored within their
environments/development_local.yaml file.
Note, if there is no config.EXT, Dancer2 will not look for a config_local.EXT. The same is true for the
local environment configuration.
Supported configuration file formats
Dancer2 supports any configuration file format that is supported by Config::Any. At the time of this
writing, that includes YAML (.yml and .yaml), JSON (.jsn and .json), INI (.ini), Apache-style
configurations (.cnf and .conf), XML (.xml), and Perl-style hashes (.pl and .perl).
Dancer2 iterates over these file extensions in the order provided by Config::Any and loads any config
files that it finds with later configuration information overriding earlier config information. To
restrict which file extension Dancer2 looks for, you may set the "DANCER_CONFIG_EXT" envinroment variable
to a specific extension and Dancer2 will only look for config files with that extension.
Make sure you pick the appropriate extension for your configuration file name, as Dancer2 guesses the
type of format based on the file extension.
Sample configuration files
Note: Not all possibilities are covered here, only the most common options.
If you prefer YAML, a sample YAML based config file might look like this:
appname: "Hello"
charset: "UTF-8"
auto_page: 1
session: "YAML"
serializer: "JSON"
plugins:
DBIC:
default:
dsn: dbi:SQLite:db/mydata.db
schema_class: Hello::Schema
If JSON is more your thing, your file might look more like this:
{
"appname": "Hello",
"charset": "UTF-8",
"auto_page": "1",
"session": "YAML",
"serializer": "JSON",
"plugins": {
"DBIC": {
"default": {
"dsn": "dbi:SQLite:db/mydata.db",
"schema_class": "Hello::Schema"
}
}
}
}
If you like Apache configuration files, try something similar to:
appname = Hello
charset = UTF-8
auto_page = 1
session = YAML
serializer = JSON
<plugins>
<DBIC>
<default>
dsn = dbi =SQLite =db/mydata.db
schema_class = Hello = =Schema
</default>
</DBIC>
</plugins>
INI-style files are deliberately simplistic and not recommended for use in your Dancer2 applications.
SUPPORTED SETTINGS
Run mode and listening interface/port
server (string)
The IP address that the Dancer2 app should bind to. Default is 0.0.0.0, i.e. bind to all available
interfaces.
port (int)
The port Dancer2 will listen to.
Default value is 3000. This setting can be changed on the command-line with the --port switch.
behind_proxy (boolean)
If set to true, Dancer2 will look to "X-Forwarded-Protocol" and "X-Forwarded-host" when constructing URLs
(for example, when using "redirect" or "host"). This is useful if your application is behind a proxy.
Note: If either of these are missing, the values of the proxy server will be used instead. For example,
if the client sends a HTTP/1.0 request to a proxy that is hosted locally, then "host" will return the
value "localhost". In a similar vein, if the client makes a secure connection to the proxy, but the proxy
does not pass "X-Forwarded-Protocol", then "base" will return "http://...". For these reasons, it is
recommended that the values are hard-configured in the proxy if possible. For Apache this would be:
RequestHeader set X_FORWARDED_PROTO "https"
RequestHeader set X_FORWARDED_HOST "www.example.com"
Content type / character set
content_type (string)
The default content type of outgoing content. Default value is 'text/html'.
charset (string)
This setting has multiple effects:
• It sets the default charset of outgoing content. "charset=" item will be added to Content-Type
response header.
• It makes Unicode bodies in HTTP responses of "text/*" types to be encoded to this charset.
• It also indicates to Dancer2 in which charset the static files and templates are encoded.
• If you're using Dancer2::Plugin::Database, UTF-8 support will automatically be enabled for your
database - see "AUTOMATIC UTF-8 SUPPORT" in Dancer2::Plugin::Database
Default value is empty which means don't do anything. HTTP responses without charset will be interpreted
as ISO-8859-1 by most clients.
You can cancel any charset processing by specifying your own charset in Content-Type header or by
ensuring that response body leaves your handler without Unicode flag set (by encoding it into some 8bit
charset, for example).
Also, since automatically serialized JSON responses have "application/json" Content-Type, you should
always encode them by hand.
default_mime_type (string)
Dancer2's Dancer2::Core::MIME module uses "application/data" as a default mime type. This setting lets
the user change it. For example, if you have a lot of files being served in the public folder that do not
have an extension, and are text files, set the "default_mime_type" to "text/plain".
File / directory locations
environment (string)
This is the name of the environment that should be used. Standard Dancer2 applications have a
"environments" folder with specific configuration files for different environments (usually development
and production environments). They specify different kind of error reporting, deployment details, etc.
These files are read after the generic "config.yml" configuration file.
The running environment can be set with:
set environment => "production";
Note that this variable is also used as a default value if other values are not defined.
appdir (directory)
This is the path where your application will live. It's where Dancer2 will look by default for your
config files, templates and static content.
It is typically set by "use Dancer2" to use the same directory as your script.
public_dir (directory)
This is the directory, where static files are stored. Any existing file in that directory will be served
as a static file, before matching any route.
See also static_handler.
Default: "$appdir/public".
static_handler (boolean)
This setting have to be declared and set to true if you modify standard "public_dir" location.
Default: true if $ENV{DANCER_PUBLIC} is set or "public_dir" is set to "$appdir/public".
views (directory)
This is the directory where your templates and layouts live. It's the "view" part of MVC (model, view,
controller).
Default: "$appdir/views".
Templating & layouts
template
Allows you to configure which template engine should be used. For instance, to use Template Toolkit, add
the following to "config.yml":
template: template_toolkit
layout (string)
The name of the layout to use when rendering view. Dancer2 will look for a matching template in the
directory "$views/layouts".
Your can override the default layout using the third argument of the "template" keyword. Check "Dancer2"
manpage for details.
layout_dir (string)
A relative path where the layouts reside inside the "views" directory.
layout_dir: actual_layouts
Default: layouts.
Logging, debugging and error handling
strict_config (boolean, default: false)
If true, "config" will return an object instead of a hash reference. See Dancer2::Config::Object for more
information.
startup_info (boolean)
If set to true, prints a banner at the server start with information such as versions and the environment
(or "dancefloor").
Conforms to the environment variable "DANCER_STARTUP_INFO".
traces (boolean)
If set to true, Dancer2 will display full stack traces when a warning or a die occurs. (Internally sets
Carp::Verbose). Default to false.
no_server_tokens (boolean)
If set to true, Dancer2 will not add an "X-Powered-By" header and also append the Dancer2 version to the
"Server" header. Default to false - adding.
You can also use the environment variable "DANCER_NO_SERVER_TOKENS".
logger (enum)
Select which logger to use. For example, to write to log files with Dancer2::Logger::File:
logger: File
Or to direct log messages to the console from which you started your Dancer2 app with
Dancer2::Logger::Console:
logger: Console
Loggers are configured with a corresponding "Logger engine" section, as shown below.
session (enum)
This setting lets you enable a session engine for your web application. By default, sessions are disabled
in Dancer2, you must choose a session engine to use them.
Sessions are configured with a corresponding "Session engine" section, as shown below.
show_errors (boolean)
If set to true, Dancer2 will render a detailed debug screen whenever an error is caught. If set to false,
Dancer2 will render the default error page, using "$public/$error_code.html" if it exists,
"$views/$error_code.tt" or the template specified by the "error_template" setting.
The error screen attempts to sanitise sensitive looking information (passwords / card numbers in the
request, etc) but you still should not have show_errors enabled whilst in production, as there is still a
risk of divulging details.
error_template (template path)
This setting lets you specify a template to be used in case of runtime error. At the present moment the
template (as well as "$views/$error_code.tt" templates) can use four variables:
title
The error title.
content
The error specific content (if any).
status
The HTTP status code throwing that error.
exception
The stringified exception (e.g. $@) if any.
Keep in mind that 'content' and 'exception' can vary depending on the problem.
For example:
A 404 has an empty 'exception' and 'content' contains the URI that was not found. Unless you do the 404
yourself via "send_error("You chose ... poorly!", 404);", then 'content' is 'You chose ... poorly!'.
A 500 because of, say, dividing 0 by 0 will have an empty 'content' and 'exception like 'Illegal division
by zero at ...'.
A 401 from "send_error("You can not know the secret until you sign in grasshopper!", 401);" will have an
empty 'exception' and 'content' will contain 'You can not know the secret until you sign in
grasshopper!'.
Logger engine
The logger must be configured in a separate "engines" section, like so:
logger: Console
engines:
logger:
Console:
log_level: core
All loggers support the configuration options below. See documentation for a particular logger for other
supported options.
log_level
This option tells which log messages should be actually logged. Possible values are core, info, debug,
warning or error.
core : all messages are logged, including some from Dancer2 itself
debug : all messages are logged
info : only info, warning and error messages are logged
warning : only warning and error messages are logged
error : only error messages are logged
During development, you'll probably want to use "debug" to see your own debug messages, and "core" if you
need to see what Dancer2 is doing. In production, you'll likely want "error" or "warning" only, for
less-chatty logs.
Session engine
The session engine is configured in the "engines" section.
session: Simple
engines:
session:
Simple:
cookie_name: dance.set
cookie_duration: '24 hours'
is_secure: 1
is_http_only: 1
See Dancer2::Core::Role::SessionFactory for more detailed documentation for these options, or the
particular session engine for other supported options.
cookie_name
The name of the cookie to store the session ID in. Defaults to "dancer.session". This can be overridden
by certain session engines.
cookie_domain
The domain of the cookie. By default there is no domain defined for the cookie.
cookie_path
The path of the cookie. By default there is no path defined for the cookie.
cookie_duration
The session expiry time in seconds, or as e.g. "2 hours" (see "expires" in Dancer2::Core::Cookie. By
default, there is no specific expiry time.
is_secure
The user's session ID is stored in a cookie. If the "is_secure" setting is set to a true value, the
cookie will be marked as secure, meaning it should only be sent over HTTPS connections.
is_http_only
This setting defaults to 1 and instructs the session cookie to be created with the "HttpOnly" option
active, meaning that JavaScript will not be able to access to its value.
auto_page (boolean)
For simple pages where you're not doing anything dynamic, but still want to use the template engine to
provide headers etc, you can use the auto_page feature to avoid the need to create a route for each page.
With "auto_page" enabled, if the requested path does not match any specific route, Dancer2 will check in
the views directory for a matching template, and use it to satisfy the request if found.
Simply enable auto_page in your config:
auto_page: 1
Then, if you request "/foo/bar", Dancer2 will look in the views dir for "/foo/bar.tt".
Dancer2 will honor your "before_template_render" code, and all default variables. They will be accessible
and interpolated on automatic served pages.
dsl_class
For complex applications that require extended DSL keywords or other functionality the DSL class used can
be specified at import time or in the config settings.
dsl_class: 'My::DSL'
This is the same as specifying
use Dancer2 dsl => 'My::DSL'
in your module. dsl_class defaults to Dancer2::Core::DSL if not specified
Environment variables
DANCER_CONFDIR
Sets the configuration directory.
This correlates to the "confdir" config option.
DANCER_ENVDIR
Sets the environment directory.
This correlates to the "envdir" config option.
PLACK_ENV
Sets the given environment. This can be overridden by "DANCER_ENVIRONMENT".
DANCER_ENVIRONMENT
Sets the given environment. This takes higher precedence over "PLACK_ENV".
If neither "PLACK_ENV" or "DANCER_ENVIRONMENT" is set, the environment defaults to development.
DANCER_APPHANDLER
The "DANCER_APPHANDLER" configuration controls what the "dance" keyword does.
If is set to "PSGI" (which will automatically be set if "PLACK_ENV" is set), "dance" will return the PSGI
application coderef.
Otherwise (which is the default is - "Standalone"), it runs the Plack standalone server with the
application.
DANCER_PORT
Sets the port which will be used by the development server (if not run by plackup).
DANCER_SERVER
Sets the host the development server will be used by the development server (if not run by plackup).
Note: this might change in the future.
DANCER_STARTUP_INFO
Controls whether to display start up info.
DANCER_NO_SERVER_TOKENS
Controls whether to display the server tokens.
DANCER_PUBLIC
Sets the public directory location.
DANCER_TRACES
Sets the tracing flag which sets Carp's $Verbose flag.
DANCER_VIEWS
Sets the views (templates) directory.
DANCER_LOGGER
Sets the logger engine.
DANCER_CHARSET
Sets the default charset.
DANCER_CONTENT_TYPE
Sets the default content type.
If not set, defaults to text/html.
SEE ALSO
Dancer2
AUTHOR
Dancer Core Developers
COPYRIGHT AND LICENSE
This software is copyright (c) 2017 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.
perl v5.26.1 2017-12-05 Dancer2::Config(3pm)