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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 $VERSION = '0.05'; |
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10 | |
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11 | requires 'get_config_from_file'; |
12 | |
13 | has configfile => ( |
14 | is => 'ro', |
15 | isa => File, |
16 | coerce => 1, |
17 | predicate => 'has_configfile', |
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18 | do { try { require MooseX::Getopt; (traits => ['Getopt']) } }, |
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19 | ); |
20 | |
21 | sub new_with_config { |
22 | my ($class, %opts) = @_; |
23 | |
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24 | my $configfile; |
25 | |
26 | if(defined $opts{configfile}) { |
27 | $configfile = $opts{configfile} |
28 | } |
29 | else { |
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30 | # This would only succeed if the consumer had defined a new configfile |
31 | # sub to override the generated reader |
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32 | $configfile = try { $class->configfile }; |
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33 | |
34 | # this is gross, but since a lot of users have swapped in their own |
35 | # default subs, we have to keep calling it rather than calling a |
36 | # builder sub directly - and it might not even be a coderef either |
37 | my $cfmeta = $class->meta->find_attribute_by_name('configfile'); |
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38 | $configfile ||= $cfmeta->default if $cfmeta->has_default; |
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39 | |
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40 | if (ref $configfile eq 'CODE') { |
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41 | $configfile = $configfile->($class); |
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42 | } |
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43 | } |
44 | |
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45 | if (defined $configfile) { |
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46 | my $hash = $class->get_config_from_file($configfile); |
47 | |
48 | no warnings 'uninitialized'; |
49 | croak "get_config_from_file($configfile) did not return a hash (got $hash)" |
50 | unless ref $hash eq 'HASH'; |
51 | |
52 | %opts = (%$hash, %opts); |
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53 | } |
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54 | |
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55 | $class->new(%opts); |
56 | } |
57 | |
58 | no Moose::Role; 1; |
59 | |
60 | __END__ |
61 | |
62 | =pod |
63 | |
64 | =head1 NAME |
65 | |
66 | MooseX::ConfigFromFile - An abstract Moose role for setting attributes from a configfile |
67 | |
68 | =head1 SYNOPSIS |
69 | |
70 | ######## |
71 | ## A real role based on this abstract role: |
72 | ######## |
73 | |
74 | package MooseX::SomeSpecificConfigRole; |
75 | use Moose::Role; |
76 | |
77 | with 'MooseX::ConfigFromFile'; |
78 | |
79 | use Some::ConfigFile::Loader (); |
80 | |
81 | sub get_config_from_file { |
82 | my ($class, $file) = @_; |
83 | |
84 | my $options_hashref = Some::ConfigFile::Loader->load($file); |
85 | |
86 | return $options_hashref; |
87 | } |
88 | |
89 | |
90 | ######## |
91 | ## A class that uses it: |
92 | ######## |
93 | package Foo; |
94 | use Moose; |
95 | with 'MooseX::SomeSpecificConfigRole'; |
96 | |
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97 | # optionally, default the configfile: |
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98 | around configfile => sub { '/tmp/foo.yaml' }; |
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99 | |
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100 | # ... insert your stuff here ... |
101 | |
102 | ######## |
103 | ## A script that uses the class with a configfile |
104 | ######## |
105 | |
106 | my $obj = Foo->new_with_config(configfile => '/etc/foo.yaml', other_opt => 'foo'); |
107 | |
108 | =head1 DESCRIPTION |
109 | |
110 | This is an abstract role which provides an alternate constructor for creating |
111 | objects using parameters passed in from a configuration file. The |
112 | actual implementation of reading the configuration file is left to |
113 | concrete subroles. |
114 | |
115 | It declares an attribute C<configfile> and a class method C<new_with_config>, |
116 | and requires that concrete roles derived from it implement the class method |
117 | C<get_config_from_file>. |
118 | |
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119 | Attributes specified directly as arguments to C<new_with_config> supercede those |
120 | in the configfile. |
121 | |
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122 | L<MooseX::Getopt> knows about this abstract role, and will use it if available |
123 | to load attributes from the file specified by the commandline flag C<--configfile> |
124 | during its normal C<new_with_options>. |
125 | |
126 | =head1 Attributes |
127 | |
128 | =head2 configfile |
129 | |
130 | This is a L<Path::Class::File> object which can be coerced from a regular pathname |
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131 | string. This is the file your attributes are loaded from. You can add a default |
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132 | configfile in the consuming class and it will be honored at the appropriate time |
133 | (note that a simple sub declaration is not sufficient, as there is already a |
134 | sub by that name being added by Moose as the attribute reader) |
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135 | |
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136 | around configfile => sub { '/etc/myapp.yaml' }; |
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137 | |
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138 | Note that you can alternately just provide a C<configfile> method which returns |
139 | the config file when called - this will be used in preference to the default of |
140 | the attribute. |
141 | |
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142 | If you have L<MooseX::Getopt> installed, this attribute will also have the |
143 | C<Getopt> trait supplied, so you can also set the configfile from the |
144 | command line. |
145 | |
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146 | =head1 Class Methods |
147 | |
148 | =head2 new_with_config |
149 | |
150 | This is an alternate constructor, which knows to look for the C<configfile> option |
151 | in its arguments and use that to set attributes. It is much like L<MooseX::Getopts>'s |
152 | C<new_with_options>. Example: |
153 | |
154 | my $foo = SomeClass->new_with_config(configfile => '/etc/foo.yaml'); |
155 | |
156 | Explicit arguments will overide anything set by the configfile. |
157 | |
158 | =head2 get_config_from_file |
159 | |
160 | This class method is not implemented in this role, but it is required of all subroles. |
161 | Its two arguments are the classname and the configfile, and it is expected to return |
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162 | a hashref of arguments to pass to C<new()> which are sourced from the configfile. |
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163 | |
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164 | =head1 COPYRIGHT |
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165 | |
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166 | Copyright (c) - the MooseX::ConfigFromFile "AUTHOR" and "CONTRIBUTORS" as listed below. |
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167 | |
168 | =head1 AUTHOR |
169 | |
170 | Brandon L. Black, E<lt>blblack@gmail.comE<gt> |
171 | |
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172 | =head1 CONTRIBUTORS |
173 | |
174 | =over |
175 | |
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176 | =item Tomas Doran |
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177 | |
178 | =item Karen Etheridge |
179 | |
180 | =item Chris Prather |
181 | |
182 | =item Zbigniew Lukasiak |
183 | |
184 | =back |
185 | |
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186 | =head1 LICENSE |
187 | |
188 | This library is free software; you can redistribute it and/or modify |
189 | it under the same terms as Perl itself. |
190 | |
191 | =cut |