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1 | package MooseX::ConfigFromFile; |
2 | |
3 | use Moose::Role; |
4 | use MooseX::Types::Path::Class qw( File ); |
5 | |
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6 | our $VERSION = '0.02'; |
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7 | |
8 | requires 'get_config_from_file'; |
9 | |
10 | has configfile => ( |
11 | is => 'ro', |
12 | isa => File, |
13 | coerce => 1, |
14 | predicate => 'has_configfile', |
15 | ); |
16 | |
17 | sub new_with_config { |
18 | my ($class, %opts) = @_; |
19 | |
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20 | my $configfile; |
21 | |
22 | if(defined $opts{configfile}) { |
23 | $configfile = $opts{configfile} |
24 | } |
25 | else { |
26 | my $cfmeta = $class->meta->get_attribute('configfile'); |
27 | $configfile = $cfmeta->default if $cfmeta->has_default; |
28 | } |
29 | |
30 | if(defined $configfile) { |
31 | %opts = (%{$class->get_config_from_file($configfile)}, %opts); |
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32 | } |
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33 | |
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34 | $class->new(%opts); |
35 | } |
36 | |
37 | no Moose::Role; 1; |
38 | |
39 | __END__ |
40 | |
41 | =pod |
42 | |
43 | =head1 NAME |
44 | |
45 | MooseX::ConfigFromFile - An abstract Moose role for setting attributes from a configfile |
46 | |
47 | =head1 SYNOPSIS |
48 | |
49 | ######## |
50 | ## A real role based on this abstract role: |
51 | ######## |
52 | |
53 | package MooseX::SomeSpecificConfigRole; |
54 | use Moose::Role; |
55 | |
56 | with 'MooseX::ConfigFromFile'; |
57 | |
58 | use Some::ConfigFile::Loader (); |
59 | |
60 | sub get_config_from_file { |
61 | my ($class, $file) = @_; |
62 | |
63 | my $options_hashref = Some::ConfigFile::Loader->load($file); |
64 | |
65 | return $options_hashref; |
66 | } |
67 | |
68 | |
69 | ######## |
70 | ## A class that uses it: |
71 | ######## |
72 | package Foo; |
73 | use Moose; |
74 | with 'MooseX::SomeSpecificConfigRole'; |
75 | |
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76 | # optionally, default the configfile: |
77 | has +configfile ( default => '/tmp/foo.yaml' ); |
78 | |
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79 | # ... insert your stuff here ... |
80 | |
81 | ######## |
82 | ## A script that uses the class with a configfile |
83 | ######## |
84 | |
85 | my $obj = Foo->new_with_config(configfile => '/etc/foo.yaml', other_opt => 'foo'); |
86 | |
87 | =head1 DESCRIPTION |
88 | |
89 | This is an abstract role which provides an alternate constructor for creating |
90 | objects using parameters passed in from a configuration file. The |
91 | actual implementation of reading the configuration file is left to |
92 | concrete subroles. |
93 | |
94 | It declares an attribute C<configfile> and a class method C<new_with_config>, |
95 | and requires that concrete roles derived from it implement the class method |
96 | C<get_config_from_file>. |
97 | |
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98 | Attributes specified directly as arguments to C<new_with_config> supercede those |
99 | in the configfile. |
100 | |
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101 | L<MooseX::Getopt> knows about this abstract role, and will use it if available |
102 | to load attributes from the file specified by the commandline flag C<--configfile> |
103 | during its normal C<new_with_options>. |
104 | |
105 | =head1 Attributes |
106 | |
107 | =head2 configfile |
108 | |
109 | This is a L<Path::Class::File> object which can be coerced from a regular pathname |
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110 | string. This is the file your attributes are loaded from. You can add a default |
111 | configfile in the class using the role and it will be honored at the appropriate time: |
112 | |
113 | has +configfile ( default => '/etc/myapp.yaml' ); |
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114 | |
115 | =head1 Class Methods |
116 | |
117 | =head2 new_with_config |
118 | |
119 | This is an alternate constructor, which knows to look for the C<configfile> option |
120 | in its arguments and use that to set attributes. It is much like L<MooseX::Getopts>'s |
121 | C<new_with_options>. Example: |
122 | |
123 | my $foo = SomeClass->new_with_config(configfile => '/etc/foo.yaml'); |
124 | |
125 | Explicit arguments will overide anything set by the configfile. |
126 | |
127 | =head2 get_config_from_file |
128 | |
129 | This class method is not implemented in this role, but it is required of all subroles. |
130 | Its two arguments are the classname and the configfile, and it is expected to return |
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131 | a hashref of arguments to pass to C<new()> which are sourced from the configfile. |
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132 | |
133 | =head2 meta |
134 | |
135 | The Moose meta stuff, included here because otherwise pod tests fail sometimes |
136 | |
137 | =head1 BUGS |
138 | |
139 | =head1 AUTHOR |
140 | |
141 | Brandon L. Black, E<lt>blblack@gmail.comE<gt> |
142 | |
143 | =head1 LICENSE |
144 | |
145 | This library is free software; you can redistribute it and/or modify |
146 | it under the same terms as Perl itself. |
147 | |
148 | =cut |