/ 
Dancer-Plugin-Database-1.41
River stage one • 7 direct dependents • 9 total dependents
/ Dancer::Plugin::Database

NAME

Dancer::Plugin::Database - easy database connections for Dancer applications

SYNOPSIS

use Dancer;
use Dancer::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::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 Dancer application config - see below.

DESCRIPTION

Provides an easy way to obtain a connected DBI database handle by simply calling the database keyword within your Dancer application

Returns a Dancer::Plugin::Database::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. See the documentation for Dancer::Plugin::Database::Handle for full details of those.

Takes care of ensuring that 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, using either the $dbh->ping method if the DBD driver supports it, or 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.

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.)

CONFIGURATION

Connection details will be taken from your Dancer 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

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.

The dbi_params setting is also optional, and if specified, should be settings which can be passed to DBI->connect as its third 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.

The optional log_queries setting enables logging of queries generated by the helper functions quick_insert et al in Dancer::Plugin::Database::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.

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.

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');

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.)

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.

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 (quick_select, quick_update, quick_insert, quick_delete)

The handle returned by the database keyword is a Dancer::Plugin::Database::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, as documented in the POD for Dancer::Plugin::Database::Handle.

Examples:

# Quickly fetch the (first) row whose ID is 42 as a hashref:
my $row = database->quick_select($table_name, { id => 42 });

# Fetch all badgers as an array of hashrefs:
my @badgers = database->quick_select('animals', { genus => 'Mellivora' });

# Update the row where the 'id' column is '42', setting the 'foo' column to
# 'Bar':
database->quick_update($table_name, { id => 42 }, { foo => 'Bar' });

# Insert a new row, using a named connection (see above)
database('connectionname')->quick_insert($table_name, { foo => 'Bar' });

# Delete the row with id 42:
database->quick_delete($table_name, { id => 42 });

# Fetch all rows from a table (since version 1.30):
database->quick_select($table_name, {});

AUTHOR

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

CONTRIBUTING

This module is developed on Github at:

http://github.com/bigpresh/Dancer-Plugin-Database

Feel free to fork the repo and submit pull requests! Also, it makes sense to watch the repo on GitHub for updates.

Feedback and bug reports are always appreciated. Even a quick mail to let me know the module is useful to you would be very nice - it's nice to know if code is being actively used.

ACKNOWLEDGEMENTS

Igor Bujna

Franck Cuny

Alan Haggai

Christian Sánchez

Michael Stiller

Martin J Evans

Carlos Sosa

Matt S Trout

Matthew Vickers

Christian Walde

BUGS

Please report any bugs or feature requests to bug-dancer-plugin-database at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Dancer-Plugin-Database. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc Dancer::Plugin::Database

You can also look for information at:

You can find the author on IRC in the channel #dancer on <irc.perl.org>.

LICENSE AND COPYRIGHT

Copyright 2010-11 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

DBI

1 POD Error

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Around line 473:

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