Dancer...atabase(3pm)

📦
version 2.17 · 5 versions
, in debian trixie, ubuntu noble, ubuntu resolute, ubuntu stonking

💖 Dancer2::Plugin::Database 💖

okay bestie, so this is the manual page for Dancer2::Plugin::Database (that's Dancer...atabase(3pm) if you saw the fancy truncated header, it's giving mysterious but it's literally just the full name) — User Contributed Perl Documentation, part of the Perl fam. And it's a whole vibe: database connections for your Dancer2 app, but make it ✨effortless✨.

🌸 NAME 🌸

Dancer2::Plugin::Database — easy database connections for Dancer2 applications. that's the whole assignment. easy. connections. slay.

🎀 SYNOPSIS 🎀

use Dancer2;
use Dancer2::Plugin::Database;

# Calling the database keyword will get you a connected database handle:
get '/widget/view/:id' => sub {
    my $sth = database->prepare(
        'select * from widgets where id = ?',
    );
    $sth->execute(params->{id});
    template 'display_widget', { widget => $sth->fetchrow_hashref };
};

# The handle is a Dancer::Plugin::Database::Core::Handle object, which subclasses
# DBI's DBI::db handle and adds a few convenience features, for example:
get '/insert/:name' => sub {
    database->quick_insert('people', { name => params->{name} });
};

get '/users/:id' => sub {
    template 'display_user', {
        person => database->quick_select('users', { id => params->{id} }),
    };
};

dance;

Database connection details are read from your Dancer2 application config — see below. like, the config is the plug, the plugin is the socket, they just fit 🫶

🦋 DESCRIPTION 🦋

It provides an easy way to obtain a connected DBI database handle by simply calling the database keyword inside your Dancer2 application. no boilerplate, no drama, just vibes.

What you get back is a Dancer::Plugin::Database::Core::Handle object, which is a subclass of DBI's DBI::db connection handle object. so it does everything you'd expect to do with DBI, but also adds a few convenience methods on top. See the docs for Dancer::Plugin::Database::Core::Handle for the full deets on those. she's DBI but with extra sparkle 💅

It takes care of making sure the database handle is still connected and valid. If the handle was last asked for more than connection_check_threshold seconds ago, it will check that the connection is still alive — either by using the $dbh->ping method if the DBD driver supports it, or by performing a simple no-op query against the database if not. If the connection has gone away, a new connection will be obtained and returned. This avoids any problems for a long-running script where the connection to the database might go away. iconic behaviour honestly, self-healing connection energy ✨

Care is taken that handles are not shared across processes/threads, so this should be thread-safe with no issues with transactions etc. (Thanks to Matt S Trout for pointing out the previous lack of thread safety. Inspiration was drawn from DBIx::Connector.) shoutout to the legends fr fr 🙌

💅 CONFIGURATION 💅

Connection details will be taken from your Dancer2 application config file, and should be specified as, for example:

plugins:
    Database:
        driver: 'mysql'
        database: 'test'
        host: 'localhost'
        port: 3306
        username: 'myusername'
        password: 'mypassword'
        connection_check_threshold: 10
        dbi_params:
            RaiseError: 1
            AutoCommit: 1
        on_connect_do: ["SET NAMES 'utf8'", "SET CHARACTER SET 'utf8'" ]
        log_queries: 1
        handle_class: 'My::Super::Sexy::Database::Handle'

The connection_check_threshold setting is optional — if not provided, it will default to 30 seconds. If the database keyword was last called more than this number of seconds ago, a quick check will be performed to ensure that we still have a connection to the database, and will reconnect if not. This handles cases where the database handle hasn't been used for a while and the underlying connection has gone away. it's giving "oh you haven't texted in a while, let me check we're still good" 💖

The dbi_params setting is also optional, and if specified, should be settings which can be passed to DBI->connect as its fourth argument; see the DBI documentation for these.

The optional on_connect_do setting is an array of queries which should be performed when a connection is established; if given, each query will be performed using $dbh->do. (If using MySQL, you might want to use this to set SQL_MODE to a suitable value to disable MySQL's built-in free data loss 'features', for example:

on_connect_do: "SET SQL_MODE='TRADITIONAL'"

(If you're not familiar with what I mean, I'm talking about the insane default behaviour of "hmm, this bit of data won't fit the column you're trying to put it in.. hmm, I know, I'll just munge it to fit, and throw a warning afterwards — it's not like you're relying on me to, y'know, store what you ask me to store". See <http://effectivemysql.com/presentation/mysql-idiosyncrasies-that-bite/> for just one illustration. In hindsight, I wish I'd made a sensible sql_mode a default setting, but I don't want to change that now.) truly unhinged default behaviour ngl, like bestie just STORE THE DATA 😭

The optional log_queries setting enables logging of queries generated by the helper functions quick_insert et al in Dancer::Plugin::Database::Core::Handle. If you enable it, generated queries will be logged at 'debug' level.

⚠️ Be aware that they will contain the data you're passing to/from the database, so be careful not to enable this option in production, where you could inadvertently log sensitive information. like, do NOT leave this on in prod, that's a whole privacy situation 🙈

If you prefer, you can also supply a pre-crafted DSN using the dsn setting; in that case, it will be used as-is, and the driver/database/host settings will be ignored. This may be useful if you're using some DBI driver which requires a peculiar DSN. weird DSN? she's got you 🫶

The optional handle_class defines your own class into which database handles should be blessed. This should be a subclass of Dancer::Plugin::Database::Core::Handle (or DBI::db directly, if you just want to skip the extra features). do it your way, main character energy 👑

You will require slightly different options depending on the database engine you're talking to. For instance, for SQLite, you won't need to supply hostname, port etc, but will need to supply database as the name of the SQLite database file:

plugins:
    Database:
        driver: SQLite
        database: 'foo.sqlite'

For Oracle, you may want to pass sid (system ID) to identify a particular database, e.g.:

plugins:
    Database:
        driver: Oracle
        host: localhost
        sid: ABC12

If you have any further connection parameters that need to be appended to the dsn, you can put them in as a hash called dsn_extra. For example, if you're running mysql on a non-standard socket, you could have

plugins:
    Database:
        driver: mysql
        host: localhost
        dsn_extra:
            mysql_socket: /tmp/mysql_staging.sock

🌈 DEFINING MULTIPLE CONNECTIONS 🌈

If you need to connect to multiple databases, this is easy — just list them in your config under connections as shown below:

plugins:
    Database:
        connections:
            foo:
                driver: "SQLite"
                database: "foo.sqlite"
            bar:
                driver: "mysql"
                host: "localhost"
                ....

Then, you can call the database keyword with the name of the database connection you want, for example:

my $foo_dbh = database('foo');
my $bar_dbh = database('bar');

multiple databases?? in THIS economy?? she said yes 💖✨

⭐ RUNTIME CONFIGURATION ⭐

You can pass a hashref to the database() keyword to provide configuration details to override any in the config file at runtime if desired, for instance:

my $dbh = database({ driver => 'SQLite', database => $filename });

(Thanks to Alan Haggai for this feature.) ty bestie 🙏

🧚 AUTOMATIC UTF-8 SUPPORT 🧚

As of version 1.20, if your application is configured to use UTF-8 (you've defined the charset setting in your app config as UTF-8) then support for UTF-8 for the database connection will be enabled, if we know how to do so for the database driver in use.

If you do not want this behaviour, set auto_utf8 to a false value when providing the connection details. no utf8 today? respected, boundaries 💅

🍓 GETTING A DATABASE HANDLE 🍓

Calling database will return a connected database handle; the first time it is called, the plugin will establish a connection to the database, and return a reference to the DBI object. On subsequent calls, the same DBI connection object will be returned, unless it has been found to be no longer usable (the connection has gone away), in which case a fresh connection will be obtained.

If you have declared named connections as described above in 'DEFINING MULTIPLE CONNECTIONS', then calling the database() keyword with the name of the connection as specified in the config file will get you a database handle connected with those details.

You can also pass a hashref of settings if you wish to provide settings at runtime.

🔥 CONVENIENCE FEATURES 🔥

The handle returned by the database keyword is a Dancer::Plugin::Database::Core::Handle object, which subclasses the DBI::db DBI connection handle. This means you can use it just like you'd normally use a DBI handle, but extra convenience methods are provided. same handle, new tricks 💅

There's extensive documentation on these features in Dancer::Plugin::Database::Core::Handle, including using the order_by, limit, columns options to sort / limit results and include only specific columns. sorting, limiting, picking columns — the holy trinity of "I don't want ALL of it" ✨

👑 HOOKS 👑

This plugin uses Dancer2's hooks support to allow you to register code that should execute at given times — for example:

hook 'database_connected' => sub {
    my $dbh = shift;
    # do something with the new DB handle here
};

Currrently defined hook positions are:

  • "database_connected" — Called when a new database connection has been established, after performing any on_connect_do statements, but before the handle is returned. Receives the new database handle as a parameter, so that you can do what you need with it.
  • "database_connection_lost" — Called when the plugin detects that the database connection has gone away. Receives the no-longer usable handle as a parameter, in case you need to extract some information from it (such as which server it was connected to).
  • "database_connection_failed" — Called when an attempt to connect to the database fails. Receives a hashref of connection settings as a parameter, containing the settings the plugin was using to connect (as obtained from the config file).
  • "database_error" — Called when a database error is raised by "DBI". Receives two parameters: the error message being returned by DBI, and the database handle in question.

If you need other hook positions which would be useful to you, please feel free to suggest them! the maintainers are literally listening, go off bestie 🫶

💜 AUTHOR 💜

David Precious, "<davidp@preshweb.co.uk>"

💖 CONTRIBUTING 💖

okay so this module lives on Github and bestie it is right there:

<https://github.com/bigpresh/Dancer-Plugin-Database>

fr fr, go fork the repo and slide those pull requests in, it's giving open source queen energy 👑

also lowkey genius move: watch the repo so you get pinged when stuff updates:

<https://github.com/bigpresh/Dancer-Plugin-Database/toggle_watch>

Feedback and bug reports?? always appreciated, like genuinely. and honestly even just a quick lil mail saying "hey this module is useful to me" would be SO nice — it's nice to know if code is being actively used 🥺💖

🌸 ACKNOWLEDGEMENTS 🌸

shoutout to the whole squad, no cap, every single one of these icons:

  • Igor Bujna
  • Franck Cuny
  • Alan Haggai
  • Christian Sánchez
  • Michael Stiller
  • Martin J Evans
  • Carlos Sosa
  • Matt S Trout
  • Matthew Vickers
  • Christian Walde
  • Alberto Simões
  • James Aitken (LoonyPandora)
  • Mark Allen (mrallen1)
  • Sergiy Borodych (bor)
  • Mario Domgoergen (mdom)
  • Andrey Inishev (inish777)
  • Nick S. Knutov (knutov)
  • Nicolas Franck (nicolasfranck)
  • mscolly

💀 BUGS 💀

found a bug? want a feature? pls pls pls report it to bug-dancer-plugin-database at rt.cpan.org, or just use the web interface like a normal person:

<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Dancer2-Plugin-Database>

the way this works: they get notified, and then you automatically get notified of progress on your bug as changes get made. closed loop, mutual, iconic ✨

🫶 SUPPORT 🫶

you can find the docs for this module with the perldoc command, like so:

perldoc Dancer2::Plugin::Database

and you can also go hunting for info at these fine establishments:

  • RT: CPAN's request tracker

<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Dancer2-Plugin-Database>

  • AnnoCPAN: Annotated CPAN documentation

<http://annocpan.org/dist/Dancer2-Plugin-Database>

  • CPAN Ratings

<http://cpanratings.perl.org/d/Dancer2-Plugin-Database>

  • Search CPAN

<http://search.cpan.org/dist/Dancer2-Plugin-Database/>

and guess what, you can find the author on IRC hanging out in the channel #dancer on <irc.perl.org> 💬

Copyright 2010-2016 David Precious.

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See <http://dev.perl.org/licenses/> for more information.

🌈 SEE ALSO 🌈

  • Dancer::Plugin::Database::Core and Dancer::Plugin::Database::Core::Handle
  • Dancer, Dancer2
  • DBI
  • Dancer::Plugin::SimpleCRUD

and that's a wrap on the whole page bestie 🎀 go forth and query responsibly. this little masterpiece was built with perl v5.36.0, dated 2023-06-13, and lives under the name Dancer...atabase(3pm) — yes that's the truncated name, that's just how the manpage pipeline does it, iykyk 💅 mwah, stan, bye 🦋

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