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David Precious > Dancer-Plugin-SimpleCRUD-0.97 > Dancer::Plugin::SimpleCRUD



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Module Version: 0.97   Source   Latest Release: Dancer-Plugin-SimpleCRUD-1.15


Dancer::Plugin::SimpleCRUD - very simple CRUD (create/read/update/delete)


A plugin for Dancer web applications, to use a few lines of code to create appropriate routes to support creating/editing/deleting/viewing records within a database table. Uses CGI::FormBuilder to generate, process and validate forms, Dancer::Plugin::Database for database interaction and HTML::Table::FromDatabase to display lists of records.

Setting up forms and code to display and edit database records is a very common requirement in web apps; this plugin tries to make something basic trivially easy to set up and use.


The following assumes that you already have a working Dancer app and have put your database connection details in your config.yml to be read by Dancer::Plugin::Database, which this plugin uses in order to obtain a database connection.

    # In your Dancer app,
    use Dancer::Plugin::SimpleCRUD;

    # Simple example:
        record_title => 'Widget',
        prefix => '/widgets',
        db_table => 'widgets',
        editable => 1,

    # The above would create a route to handle C</widgets>, listing all widgets,
    # with options to add/edit entries (linking to C</widgets/add> and
    # C</widgets/edit/:id> respectively) where a form to add a new entry or edit
    # an existing entry will be created.
    # All fields in the database table would be editable.
    # There is also a view route, C</widgets/view/:id>, which shows all the values
    # for the fields of a single database entry.

    # A more in-depth synopsis, using all options (of course, usually you'd only
    # need to use a few of the options where you need to change the default
    # behaviour):

        record_title => 'Team',
        prefix => '/teams',
        db_table => 'team',
        labels => {     # More human-friendly labels for some columns
            venue_id => 'Home Venue',
            name     => 'Team Name', 
        validation => {  # validate values entered for some columns
            division => qr/\d+/,
        input_types => {  # overriding form input type for some columns
            supersecret => 'password',
            lotsoftext' => 'textarea',
        key_column => 'id', # id is default anyway
        editable_columns => [ qw( venue_id name division )    ],
        display_columns  => [ qw( id venue_id name division ) ],
        deleteable => 1,
        editable => 1,
        sortable => 1,
        paginate => 300,
        template => '',
        query_auto_focus => 1,
        downloadable => 1,
        foreign_keys => {
            columnname => {
                table => 'venues',
                key_column => 'id',
                label_column => 'name',
        custom_columns => {
            division_news => {
                raw_column => "division",
                transform  => sub {
                    my $division_name = shift;
                    my $label = "News about $division_name";
                    $division_name =~ s/([^-_.~A-Za-z0-9])/sprintf("%%%02X", ord($1))/seg;
                    my $search = qq{"$division_name"};
                    return "<a href='$search'>$label</a>";
        auth => {
            view => {
                require_login => 1,
            edit => {
                require_role => 1,


This plugin provides a simple_crud keyword, which takes a hash of options as described below, and sets up the appropriate routes to present add/edit/delete options.


The options you can pass to simple_crud are:

record_title (required)

What we're editing, for instance, if you're editing widgets, use 'Widget'. Will be used in form titles (for instance "Add a ...", "Edit ..."), and button labels.

prefix (required)

The prefix for the routes which will be created. Given a prefix of /widgets, then you can go to /widgets/new to create a new Widget, and /widgets/42 to edit the widget with the ID (see keu_column) 42.

Don't confuse this with Dancer's prefix setting, which would be prepended before the prefix you pass to this plugin. For example, if you used:

    prefix '/foo';
        prefix => 'bar',

... then you'd end up with e.g. /foo/bar as the record listing page.

db_table (required)

The name of the database table.

key_column (optional, default: 'id')

Specify which column in the table is the primary key. If not given, defaults to id.

db_connection_name (optional)

We use Dancer::Plugin::Database to obtain database connections. This option allows you to specify the name of a connection defined in the config file to use. See the documentation for Dancer::Plugin::Database for how multiple database configurations work. If this is not supplied or is empty, the default database connection details in your config file will be used - this is often what you want, so unless your app is dealing with multiple DBs, you probably won't need to worry about this option.

labels (optional)

A hashref of field_name => 'Label', if you want to provide more user-friendly labels for some or all fields. As we're using CGI::FormBuilder, it will do a reasonable job of figuring these out for itself usually anyway - for instance, a field named first_name will be shown as First Name.

input_types (optional)

A hashref of field_name => input type, if you want to override the default type of input which would be selected by CGI::FormBuilder or by our DWIMmery (by default, password fields will be used for field names like 'password', 'passwd' etc, and text area inputs will be used for columns with type 'TEXT').

Valid values include anything allowed by HTML, e.g. text, select, textarea, radio, checkbox, password, hidden.


    input_types => {
        first_name => 'text',
        secret     => 'password',
        gender     => 'radio',
validation (optional)

A hashref of field_name => validation criteria which should be passed to CGI::FormBuilder.


    validation => {
        email_address => 'EMAIL',
        age => '/^\d+$/',
message (optional)

A hashref of field_name => messages to show if validation failed.

Default is "Invalid entry".


    message => {
        age   => 'Please enter your age in years',
        email => 'That is not a valid email address',
jsmessage (optional)

A hashref of field_name => message to show when Javascript validation fails.

Default message is "- Invalid entry for the "$fieldname" field". See above for example.

sort_options (optional)

A hashref of field_name => optionspec indicating how select options should be sorted

This is currently a passthrough to CGI::FormBuilder's sortopts. There are several built-in values:

    NAME            Sort option values by name
    NUM             Sort option values numerically
    LABELNAME       Sort option labels by name
    LABELNUM        Sort option labels numerically

See the documentation for "sortopts" in CGI::FormBuilder for more.

acceptable_values (optional)

A hashref of arrayrefs to declare that certain fields can take only a set of acceptable values.


    acceptable_values => {
        gender => ['Male', 'Female'],
        status => [qw(Alive Dead Zombie Unknown)],

You can automatically create option groups (on a field of type select) by specifying the acceptable values in CGI::FormBuilder's [value, label, category] format, like this:

    acceptable_values => {
        gender => ['Male', 'Female'],
        status => [qw(Alive Dead Zombie Unknown)],
        threat_level => [
            [ 'child_puke',   'Regurgitation',       'Child'],
            [ 'child_knee',   'Knee Biter',          'Child'],
            [ 'teen_eye',     'Eye Roll',            'Adolescent'],
            [ 'teen_lip',     'Withering Sarcasm',   'Adolescent'],
            [ 'adult_silent', 'Pointedly Ignore',    'Adult'],
            [ 'adult_freak',  'Become Very Put Out', 'Adult'],

If you are letting FormBuilder choose the field type, you won't see these categories unless you have enough options that it makes the field into a select. If you want to see the categories all the time, you can use the "input_types" option to force your field to be rendered as a select.

default_value (optional)

A hashref of default values to have pre-selected on the add form.


    default_value => {
        gender => 'Female',
        status => 'Unknown',
editable_columns (optional)

Specify an arrayref of fields which the user can edit. By default, this is all columns in the database table, with the exception of the key column.

not_editable_columns (optional)

Specify an arrayref of fields which should not be editable.

required (optional)

Specify an arrayref of fields which must be completed. If this is not provided, DWIMmery based on whether the field is set to allow null values in the database will be used - i.e. if that column can contain null, then it doesn't have to be completed, otherwise, it does.


Specify whether to support deleting records. If set to a true value, a route will be created for /prefix/delete/:id to delete the record with the ID given, and the edit form will have a "Delete $record_title" button.


Specify whether to support editing records. Defaults to true. If set to a false value, it will not be possible to add or edit rows in the table.


Specify whether to support sorting the table. Defaults to false. If set to a true value, column headers will become clickable, allowing the user to sort the output by each column, and with ascending/descending order.


Specify whether to show results in pages (with next/previous buttons). Defaults to undef, meaning all records are shown on one page (not useful for large tables). When defined as a number, only this number of results will be shown.


Specify an arrayref of columns that should show up in the list. Defaults to all.


Specify a template that will be applied to all output. This template must have a "simple_crud" placeholder defined or you won't get any output. This template must be located in your "views" directory.

Any global layout will be applied automatically because this option causes the module to use the template keyword. If you don't use this option, the template keyword is not used, which implies that any before_template_render and after_template_render hooks won't be called.


Specify whether to automatically set input focus to the query input field. Defaults to true. If set to a false value, focus will not be set. The focus is set using a simple inlined javascript.


Specify whether to support downloading the results. Defaults to false. If set to a true value, The results show on the HTML page can be downloaded as CSV/TSV/JSON/XML. The download links will appear at the top of the page.


A hashref to specify columns in the table which are foreign keys; for each one, the value should be a hashref containing the keys table, key_column and label_column.


A hashref to specify custom columns to appear in the list view of an entity. The keys of the hash are custom column names, the values hashrefs specifying a raw_column indicating a column from the table that should be selected to build the custom column from, and transform, a subref to be used as a HTML::Table::FromDatabase callback on the resulting column. If no transform is provided, sub { return shift; } will be used.

If raw_column consists of anything other than letters, numbers, and underscores, it is passed in raw, so you could put something like "NOW()" or "datetime('now')" in there and it should work as expected.


You can require that users be authenticated to view/edit records using the auth option to enable authentication powered by Dancer::Plugin::Auth::Extensible.

You can set different requirements for viewing and editing, for example:

    auth => {
        view => {
            require_login => 1,
        edit => {
            require_role => 'Admin',

The example above means that any logged in user can view records, but only users with the 'Admin' role are able to create/edit/delete records.

Or, to just require login for anything (same requirements for both viewing and editing), you can use the shorthand:

    auth => {
        require_login => 1,

DWIMmery ^

This module tries to do what you'd expect it to do, so you can rock up your web app with as little code and effort as possible, whilst still giving you control to override its decisions wherever you need to.

Field types

CGI::FormBuilder is excellent at working out what kind of field to use by itself, but we give it a little help where needed. For instance, if a field looks like it's supposed to contain a password, we'll have it rendered as a password entry box, rather than a standard text box.

If the column in the database is an ENUM, we'll limit the choices available for this field to the choices defined by the ENUM list. (Unless you've provided a set of acceptable values for this field using the acceptable_values option to simple_crud, in which case what you say goes.)

Hooks ^

add_edit_row (deprecated, use add_edit_row_pre_save)

You can use the same code from your add_edit_row hook in an add_edit_row_pre_save hook. The only modification is that the new hook passes the editable params as a key of the first argument (called params), rather than as the first argument itself. So, if your hook had my $args = shift;, it could just use my $args = shift->{params}; and it should work the same way.

add_edit_row_pre_save, add_edit_row_post_save

These fire right before and after a row is added/edited; a hashref is passed with metadata such as the name of the table (in table_name), the args from the original route setup (args), the table's key column (key_column), and the values of the editable params (params).

In the post-save hook, you are also sent success (the return value of quick_insert or quick_update) telling you if the save was successful, dbh giving you the instance of the handle used to save the entity (so you can access last_insert_id()), and verb (currently either 'create new' or 'update').

For instance, if you were dealing with a users table, you could use the pre_save hook to hash the password before storing it.


David Precious, <>


Alberto Simões (ambs)


Johnathan Barber



Paul Johnson (pjcj)

Rahul Kotamaraju

Michael J South (msouth)

Martijn Lievaart

Josh Rabinowitz


Please report any bugs or feature requests to bug-dancer-plugin-simplecrud at, or through the web interface at I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.


This module is developed on Github:

Bug reports, ideas, suggestions, patches/pull requests all welcome.

Even just a quick "Hey, this is great, thanks" or "This is no good to me because..." is greatly appreciated. It's always good to know if people are using your code, and what they think.


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

    perldoc Dancer::Plugin::SimpleCRUD

You may find help with this module on the main Dancer IRC channel or mailing list - see

You can also look for information at:


Copyright 2010-12 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 for more information.

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