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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 $VERSION = '0.02'; |
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7 | |
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8 | use Carp qw(croak); |
9 | |
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10 | requires 'get_config_from_file'; |
11 | |
12 | has configfile => ( |
13 | is => 'ro', |
14 | isa => File, |
15 | coerce => 1, |
16 | predicate => 'has_configfile', |
17 | ); |
18 | |
19 | sub new_with_config { |
20 | my ($class, %opts) = @_; |
21 | |
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22 | my $configfile; |
23 | |
24 | if(defined $opts{configfile}) { |
25 | $configfile = $opts{configfile} |
26 | } |
27 | else { |
28 | my $cfmeta = $class->meta->get_attribute('configfile'); |
29 | $configfile = $cfmeta->default if $cfmeta->has_default; |
30 | } |
31 | |
32 | if(defined $configfile) { |
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33 | my $hash = $class->get_config_from_file($configfile); |
34 | |
35 | no warnings 'uninitialized'; |
36 | croak "get_config_from_file($configfile) did not return a hash (got $hash)" |
37 | unless ref $hash eq 'HASH'; |
38 | |
39 | %opts = (%$hash, %opts); |
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40 | } |
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41 | |
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42 | $class->new(%opts); |
43 | } |
44 | |
45 | no Moose::Role; 1; |
46 | |
47 | __END__ |
48 | |
49 | =pod |
50 | |
51 | =head1 NAME |
52 | |
53 | MooseX::ConfigFromFile - An abstract Moose role for setting attributes from a configfile |
54 | |
55 | =head1 SYNOPSIS |
56 | |
57 | ######## |
58 | ## A real role based on this abstract role: |
59 | ######## |
60 | |
61 | package MooseX::SomeSpecificConfigRole; |
62 | use Moose::Role; |
63 | |
64 | with 'MooseX::ConfigFromFile'; |
65 | |
66 | use Some::ConfigFile::Loader (); |
67 | |
68 | sub get_config_from_file { |
69 | my ($class, $file) = @_; |
70 | |
71 | my $options_hashref = Some::ConfigFile::Loader->load($file); |
72 | |
73 | return $options_hashref; |
74 | } |
75 | |
76 | |
77 | ######## |
78 | ## A class that uses it: |
79 | ######## |
80 | package Foo; |
81 | use Moose; |
82 | with 'MooseX::SomeSpecificConfigRole'; |
83 | |
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84 | # optionally, default the configfile: |
85 | has +configfile ( default => '/tmp/foo.yaml' ); |
86 | |
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87 | # ... insert your stuff here ... |
88 | |
89 | ######## |
90 | ## A script that uses the class with a configfile |
91 | ######## |
92 | |
93 | my $obj = Foo->new_with_config(configfile => '/etc/foo.yaml', other_opt => 'foo'); |
94 | |
95 | =head1 DESCRIPTION |
96 | |
97 | This is an abstract role which provides an alternate constructor for creating |
98 | objects using parameters passed in from a configuration file. The |
99 | actual implementation of reading the configuration file is left to |
100 | concrete subroles. |
101 | |
102 | It declares an attribute C<configfile> and a class method C<new_with_config>, |
103 | and requires that concrete roles derived from it implement the class method |
104 | C<get_config_from_file>. |
105 | |
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106 | Attributes specified directly as arguments to C<new_with_config> supercede those |
107 | in the configfile. |
108 | |
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109 | L<MooseX::Getopt> knows about this abstract role, and will use it if available |
110 | to load attributes from the file specified by the commandline flag C<--configfile> |
111 | during its normal C<new_with_options>. |
112 | |
113 | =head1 Attributes |
114 | |
115 | =head2 configfile |
116 | |
117 | This is a L<Path::Class::File> object which can be coerced from a regular pathname |
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118 | string. This is the file your attributes are loaded from. You can add a default |
119 | configfile in the class using the role and it will be honored at the appropriate time: |
120 | |
121 | has +configfile ( default => '/etc/myapp.yaml' ); |
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122 | |
123 | =head1 Class Methods |
124 | |
125 | =head2 new_with_config |
126 | |
127 | This is an alternate constructor, which knows to look for the C<configfile> option |
128 | in its arguments and use that to set attributes. It is much like L<MooseX::Getopts>'s |
129 | C<new_with_options>. Example: |
130 | |
131 | my $foo = SomeClass->new_with_config(configfile => '/etc/foo.yaml'); |
132 | |
133 | Explicit arguments will overide anything set by the configfile. |
134 | |
135 | =head2 get_config_from_file |
136 | |
137 | This class method is not implemented in this role, but it is required of all subroles. |
138 | Its two arguments are the classname and the configfile, and it is expected to return |
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139 | a hashref of arguments to pass to C<new()> which are sourced from the configfile. |
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140 | |
141 | =head2 meta |
142 | |
143 | The Moose meta stuff, included here because otherwise pod tests fail sometimes |
144 | |
145 | =head1 BUGS |
146 | |
147 | =head1 AUTHOR |
148 | |
149 | Brandon L. Black, E<lt>blblack@gmail.comE<gt> |
150 | |
151 | =head1 LICENSE |
152 | |
153 | This library is free software; you can redistribute it and/or modify |
154 | it under the same terms as Perl itself. |
155 | |
156 | =cut |