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1 | package MooseX::ConfigFromFile; |
2 | |
3 | use Moose::Role; |
4 | use MooseX::Types::Path::Class qw( File ); |
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5 | use Try::Tiny qw/ try /; |
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6 | use Carp qw(croak); |
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7 | use namespace::autoclean; |
8 | |
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9 | our $VERSION = '0.03'; |
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10 | |
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11 | requires 'get_config_from_file'; |
12 | |
13 | has configfile => ( |
14 | is => 'ro', |
15 | isa => File, |
16 | coerce => 1, |
17 | predicate => 'has_configfile', |
18 | ); |
19 | |
20 | sub new_with_config { |
21 | my ($class, %opts) = @_; |
22 | |
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23 | my $configfile; |
24 | |
25 | if(defined $opts{configfile}) { |
26 | $configfile = $opts{configfile} |
27 | } |
28 | else { |
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29 | my $cfmeta = $class->meta->find_attribute_by_name('configfile'); |
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30 | $configfile = try { to_File($class->configfile) }; |
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31 | $configfile ||= $cfmeta->default if $cfmeta->has_default; |
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32 | if (ref $configfile eq 'CODE') { |
33 | $configfile = &$configfile($class); |
34 | } |
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35 | } |
36 | |
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37 | if (defined $configfile) { |
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38 | my $hash = $class->get_config_from_file($configfile); |
39 | |
40 | no warnings 'uninitialized'; |
41 | croak "get_config_from_file($configfile) did not return a hash (got $hash)" |
42 | unless ref $hash eq 'HASH'; |
43 | |
44 | %opts = (%$hash, %opts); |
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45 | } |
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46 | |
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47 | $class->new(%opts); |
48 | } |
49 | |
50 | no Moose::Role; 1; |
51 | |
52 | __END__ |
53 | |
54 | =pod |
55 | |
56 | =head1 NAME |
57 | |
58 | MooseX::ConfigFromFile - An abstract Moose role for setting attributes from a configfile |
59 | |
60 | =head1 SYNOPSIS |
61 | |
62 | ######## |
63 | ## A real role based on this abstract role: |
64 | ######## |
65 | |
66 | package MooseX::SomeSpecificConfigRole; |
67 | use Moose::Role; |
68 | |
69 | with 'MooseX::ConfigFromFile'; |
70 | |
71 | use Some::ConfigFile::Loader (); |
72 | |
73 | sub get_config_from_file { |
74 | my ($class, $file) = @_; |
75 | |
76 | my $options_hashref = Some::ConfigFile::Loader->load($file); |
77 | |
78 | return $options_hashref; |
79 | } |
80 | |
81 | |
82 | ######## |
83 | ## A class that uses it: |
84 | ######## |
85 | package Foo; |
86 | use Moose; |
87 | with 'MooseX::SomeSpecificConfigRole'; |
88 | |
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89 | # optionally, default the configfile: |
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90 | sub configfile { '/tmp/foo.yaml' } |
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91 | |
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92 | # ... insert your stuff here ... |
93 | |
94 | ######## |
95 | ## A script that uses the class with a configfile |
96 | ######## |
97 | |
98 | my $obj = Foo->new_with_config(configfile => '/etc/foo.yaml', other_opt => 'foo'); |
99 | |
100 | =head1 DESCRIPTION |
101 | |
102 | This is an abstract role which provides an alternate constructor for creating |
103 | objects using parameters passed in from a configuration file. The |
104 | actual implementation of reading the configuration file is left to |
105 | concrete subroles. |
106 | |
107 | It declares an attribute C<configfile> and a class method C<new_with_config>, |
108 | and requires that concrete roles derived from it implement the class method |
109 | C<get_config_from_file>. |
110 | |
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111 | Attributes specified directly as arguments to C<new_with_config> supercede those |
112 | in the configfile. |
113 | |
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114 | L<MooseX::Getopt> knows about this abstract role, and will use it if available |
115 | to load attributes from the file specified by the commandline flag C<--configfile> |
116 | during its normal C<new_with_options>. |
117 | |
118 | =head1 Attributes |
119 | |
120 | =head2 configfile |
121 | |
122 | This is a L<Path::Class::File> object which can be coerced from a regular pathname |
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123 | string. This is the file your attributes are loaded from. You can add a default |
124 | configfile in the class using the role and it will be honored at the appropriate time: |
125 | |
126 | has +configfile ( default => '/etc/myapp.yaml' ); |
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127 | |
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128 | Note that you can alternately just provide a C<configfile> method which returns |
129 | the config file when called - this will be used in preference to the default of |
130 | the attribute. |
131 | |
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132 | =head1 Class Methods |
133 | |
134 | =head2 new_with_config |
135 | |
136 | This is an alternate constructor, which knows to look for the C<configfile> option |
137 | in its arguments and use that to set attributes. It is much like L<MooseX::Getopts>'s |
138 | C<new_with_options>. Example: |
139 | |
140 | my $foo = SomeClass->new_with_config(configfile => '/etc/foo.yaml'); |
141 | |
142 | Explicit arguments will overide anything set by the configfile. |
143 | |
144 | =head2 get_config_from_file |
145 | |
146 | This class method is not implemented in this role, but it is required of all subroles. |
147 | Its two arguments are the classname and the configfile, and it is expected to return |
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148 | a hashref of arguments to pass to C<new()> which are sourced from the configfile. |
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149 | |
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150 | =head1 COPYRIGHT |
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151 | |
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152 | Copyright (c) 2007 - 2009 the MooseX::ConfigFromFile "AUTHOR" and "CONTRIBUTORS" as listed below. |
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153 | |
154 | =head1 AUTHOR |
155 | |
156 | Brandon L. Black, E<lt>blblack@gmail.comE<gt> |
157 | |
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158 | =head1 CONTRIBUTORS |
159 | |
160 | =over |
161 | |
162 | =item Tomas Doran C<< <bobtfish@bobtfish.net> >> (current maintainer). |
163 | |
164 | =item Karen Etheridge |
165 | |
166 | =item Chris Prather |
167 | |
168 | =item Zbigniew Lukasiak |
169 | |
170 | =back |
171 | |
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172 | =head1 LICENSE |
173 | |
174 | This library is free software; you can redistribute it and/or modify |
175 | it under the same terms as Perl itself. |
176 | |
177 | =cut |