Yancy::Util - Utilities for Yancy


version 1.088


    use Yancy::Util qw( load_backend );
    my $be = load_backend( 'memory://localhost', $schema );

    use Yancy::Util qw( curry );
    my $helper = curry( \&_helper_sub, @args );

    use Yancy::Util qw( currym );
    my $sub = currym( $object, 'method_name', @args );

    use Yancy::Util qw( match );
    if ( match( $where, $item ) ) {
        say 'Matched!';

    use Yancy::Util qw( fill_brackets );
    my $value = fill_brackets( $template, $item );


This module contains utility functions for Yancy.



    my $backend = load_backend( $backend_url, $schema );
    my $backend = load_backend( { $backend_name => $arg }, $schema );
    my $backend = load_backend( $db_object, $schema );

Get a Yancy backend from the given backend URL, or from a hash reference with a backend name and optional argument. The $schema hash is the configured JSON schema for this backend.

A backend URL should begin with a name followed by a colon. The first letter of the name will be capitalized, and used to build a class name in the Yancy::Backend namespace.

The $backend_name should be the name of a module in the Yancy::Backend namespace. The $arg is handled by the backend module. Read your backend module's documentation for details.

The $db_object can be one of: Mojo::Pg, Mojo::mysql, Mojo::SQLite, or a subclass of DBIx::Class::Schema. The appropriate backend object will be created.

See "Database Backend" in Yancy::Guides::Schema for information about backend URLs and Yancy::Backend for more information about backend objects.


    my $curried_sub = curry( $sub, @args );

Return a new subref that, when called, will call the passed-in subref with the passed-in @args first.

For example:

    my $add = sub {
        my ( $lop, $rop ) = @_;
        return $lop + $rop;
    my $add_four = curry( $add, 4 );
    say $add_four->( 1 ); # 5
    say $add_four->( 2 ); # 6
    say $add_four->( 3 ); # 7

This is more-accurately called partial application, but curry is shorter.


    my $curried_sub = currym( $obj, $method, @args );

Return a subref that, when called, will call given $method on the given $obj with any passed-in @args first.

See "curry" for an example.


    my $subschema = copy_inline_refs( $schema, '/user' );


a "source" JSON schema (will not be mutated)
a JSON Pointer into the source schema, from which to be copied

will return another, copied standalone JSON schema, with any $ref either copied in, or if previously encountered, with a $ref to the new location.


    my $bool = match( $where, $item );

Test if the given $item matches the given SQL::Abstract $where data structure. See "WHERE CLAUSES" in SQL::Abstract for the full syntax.

Not all of SQL::Abstract's syntax is supported yet, so patches are welcome.


    my $ordered_array = order_by( $order_by, $unordered_array );

Order the given arrayref by the given SQL::Abstract order-by clause.


    my $string = fill_brackets( $template, $item );

This routine will fill in the given template string with the values from the given $item hashref. The template contains field names within curly braces. Values in the $item hashref will be escaped with "xml_escape" in Mojo::Util.

    my $item = {
        name => 'Doug Bell',
        email => '',
        quote => 'I <3 Perl',

    # Doug Bell <>
    fill_brackets( '{name} <{email}>', $item );

    # I &lt;3 Perl
    fill_brackets( '{quote}', $item );


    my $bool = is_type( $schema->{properties}{myprop}{type}, 'boolean' );

Returns true if the given JSON schema type value (which can be a string or an array of strings) contains the given value, allowing the given type for the property.

    # true
    is_type( 'boolean', 'boolean' );
    is_type( [qw( boolean null )], 'boolean' );
    # false
    is_type( 'string', 'boolean' );
    is_type( [qw( string null )], 'boolean' );


    my $bool = is_format( $schema->{properties}{myprop}{format}, 'date-time' );

Returns true if the given JSON schema format value (a string) is the given value.

    # true
    is_format( 'date-time', 'date-time' );
    # false
    is_format( 'email', 'date-time' );


    derp "This feature is deprecated in file '%s'", $file;

Print out a deprecation message as a warning. A message will only be printed once for each set of arguments from each caller.


    my $json_validator = json_validator( $schema );

Build a JSON::Validator object for the given schema, adding all the necessary attributes.




Doug Bell <>


This software is copyright (c) 2021 by Doug Bell.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.