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1 | package SQL::Translator::Producer::TT::Base; |
2 | |
3 | # ------------------------------------------------------------------- |
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4 | # $Id$ |
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5 | # ------------------------------------------------------------------- |
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6 | # Copyright (C) 2002-2009 SQLFairy Authors |
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7 | # |
8 | # This program is free software; you can redistribute it and/or |
9 | # modify it under the terms of the GNU General Public License as |
10 | # published by the Free Software Foundation; version 2. |
11 | # |
12 | # This program is distributed in the hope that it will be useful, but |
13 | # WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
15 | # General Public License for more details. |
16 | # |
17 | # You should have received a copy of the GNU General Public License |
18 | # along with this program; if not, write to the Free Software |
19 | # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
20 | # 02111-1307 USA |
21 | # ------------------------------------------------------------------- |
22 | |
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23 | =pod |
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24 | |
25 | =head1 NAME |
26 | |
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27 | SQL::Translator::Producer::TT::Base - TT (Template Toolkit) based Producer base |
28 | class. |
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29 | |
30 | =cut |
31 | |
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32 | use strict; |
33 | |
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34 | use vars qw[ @EXPORT_OK ]; |
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35 | |
36 | use Template; |
37 | use Data::Dumper; |
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38 | use IO::Handle; |
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39 | use Exporter; |
40 | use base qw(Exporter); |
41 | @EXPORT_OK = qw(produce); |
42 | |
43 | use SQL::Translator::Utils 'debug'; |
44 | |
45 | # Hack to convert the produce call into an object. ALL sub-classes need todo |
46 | # this so that the correct class gets created. |
47 | sub produce { |
48 | return __PACKAGE__->new( translator => shift )->run; |
49 | }; |
50 | |
51 | sub new { |
52 | my $proto = shift; |
53 | my $class = ref $proto || $proto; |
54 | my %args = @_; |
55 | |
56 | my $me = bless {}, $class; |
57 | $me->{translator} = delete $args{translator} || die "Need a translator."; |
58 | |
59 | return $me; |
60 | } |
61 | |
62 | sub translator { shift->{translator}; } |
63 | sub schema { shift->{translator}->schema(@_); } |
64 | |
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65 | # Util args access method. |
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66 | # No args - Return hashref (the actual hash in Translator) or hash of args. |
67 | # 1 arg - Return that named args value. |
68 | # Args - List of names. Return values of the given arg names in list context |
69 | # or return as hashref in scalar context. Any names given that don't |
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70 | # exist in the args are returned as undef. |
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71 | sub args { |
72 | my $me = shift; |
73 | |
74 | # No args |
75 | unless (@_) { |
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76 | return wantarray |
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77 | ? %{ $me->{translator}->producer_args } |
78 | : $me->{translator}->producer_args |
79 | ; |
80 | } |
81 | |
82 | # 1 arg. Return the value whatever the context. |
83 | return $me->{translator}->producer_args->{$_[0]} if @_ == 1; |
84 | |
85 | # More args so return values list or hash ref |
86 | my %args = %{ $me->{translator}->producer_args }; |
87 | return wantarray ? @args{@_} : { map { ($_=>$args{$_}) } @_ }; |
88 | } |
89 | |
90 | # Run the produce and return the result. |
91 | sub run { |
92 | my $me = shift; |
93 | my $scma = $me->schema; |
94 | my %args = %{$me->args}; |
95 | my $tmpl = $me->tt_schema or die "No template!"; |
96 | |
97 | debug "Processing template $tmpl\n"; |
98 | my $out; |
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99 | my $tt = Template->new( |
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100 | #DEBUG => $me->translator->debug, |
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101 | ABSOLUTE => 1, # Set so we can use from the command line sensibly |
102 | RELATIVE => 1, # Maybe the cmd line code should set it! Security! |
103 | $me->tt_config, # Hook for sub-classes to add config |
104 | %args, # Allow any TT opts to be passed in the producer_args |
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105 | ) || die "Failed to initialize Template object: ".Template->error; |
106 | |
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107 | $tt->process( $tmpl, { |
108 | $me->tt_default_vars, |
109 | $me->tt_vars, # Sub-class hook for adding vars |
110 | }, \$out ) |
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111 | or die "Error processing template '$tmpl': ".$tt->error; |
112 | |
113 | return $out; |
114 | } |
115 | |
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116 | |
117 | # Sub class hooks |
118 | #----------------------------------------------------------------------------- |
119 | |
120 | sub tt_config { () }; |
121 | |
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122 | sub tt_schema { |
123 | my $me = shift; |
124 | my $class = ref $me; |
125 | |
126 | my $file = $me->args("ttfile"); |
127 | return $file if $file; |
128 | |
129 | no strict 'refs'; |
130 | my $ref = *{"$class\:\:DATA"}{IO}; |
131 | if ( $ref->opened ) { |
132 | local $/ = undef; # Slurp mode |
133 | return \<$ref>; |
134 | } |
135 | |
136 | undef; |
137 | }; |
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138 | |
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139 | sub tt_default_vars { |
140 | my $me = shift; |
141 | return ( |
142 | translator => $me->translator, |
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143 | schema => $me->pre_process_schema($me->translator->schema), |
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144 | ); |
145 | } |
146 | |
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147 | sub pre_process_schema { $_[1] } |
148 | |
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149 | sub tt_vars { () }; |
150 | |
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151 | 1; |
152 | |
153 | # ------------------------------------------------------------------- |
154 | |
155 | =pod |
156 | |
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157 | =head1 SYNOPSIS |
158 | |
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159 | # Create a producer using a template in the __DATA__ section. |
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160 | package SQL::Translator::Producer::Foo; |
161 | |
162 | use base qw/SQL::Translator::Producer::TT::Base/; |
163 | |
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164 | # Convert produce call into a method call on our new class |
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165 | sub produce { return __PACKAGE__->new( translator => shift )->run; }; |
166 | |
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167 | # Configure the Template object. |
168 | sub tt_config { ( INTERPOLATE => 1 ); } |
169 | |
170 | # Extra vars to add to the template |
171 | sub tt_vars { ( foo => "bar" ); } |
172 | |
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173 | # Put template in DATA section (or use file with ttfile producer arg) |
174 | __DATA__ |
175 | Schema |
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176 | |
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177 | Database: [% schema.database %] |
178 | Foo: $foo |
179 | ... |
180 | |
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181 | =head1 DESCRIPTION |
182 | |
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183 | A base class producer designed to be sub-classed to create new TT based |
184 | producers cheaply - by simply giving the template to use and sprinkling in some |
185 | extra template variables and config. |
186 | |
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187 | You can find an introduction to this module in L<SQL::Translator::Manual>. |
188 | |
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189 | The 1st thing the module does is convert the produce sub routine call we get |
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190 | from SQL::Translator into a method call on an object, which we can then |
191 | sub-class. This is done with the following code which needs to appear in B<all> |
192 | sub classes. |
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193 | |
194 | # Convert produce call into an object method call |
195 | sub produce { return __PACKAGE__->new( translator => shift )->run; }; |
196 | |
197 | See L<PRODUCER OBJECT> below for details. |
198 | |
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199 | The upshot of this is we can make new template producers by sub classing this |
200 | base class, adding the above snippet and a template. |
201 | The module also provides a number of hooks into the templating process, |
202 | see L<SUB CLASS HOOKS> for details. |
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203 | |
204 | See the L<SYNOPSIS> above for an example of creating a simple producer using |
205 | a single template stored in the producers DATA section. |
206 | |
207 | =head1 SUB CLASS HOOKS |
208 | |
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209 | Sub-classes can override these methods to control the templating by giving |
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210 | the template source, adding variables and giving config to the Tempate object. |
211 | |
212 | =head2 tt_config |
213 | |
214 | sub tt_config { ( INTERPOLATE => 1 ); } |
215 | |
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216 | Return hash of Template config to add to that given to the L<Template> C<new> |
217 | method. |
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218 | |
219 | =head2 tt_schema |
220 | |
221 | sub tt_schema { "foo.tt"; } |
222 | sub tt_schema { local $/ = undef; \<DATA>; } |
223 | |
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224 | The template to use, return a file name or a scalar ref of TT |
225 | source, or an L<IO::Handle>. See L<Template> for details, as the return from |
226 | this is passed on to it's C<produce> method. |
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227 | |
228 | The default implimentation uses the producer arg C<ttfile> as a filename to read |
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229 | the template from. If the arg isn't there it will look for a C<__DATA__> section |
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230 | in the class, reading it as template source if found. Returns undef if both |
231 | these fail, causing the produce call to fail with a 'no template!' error. |
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232 | |
233 | =head2 tt_vars |
234 | |
235 | sub tt_vars { ( foo => "bar" ); } |
236 | |
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237 | Return hash of template vars to use in the template. Nothing added here |
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238 | by default, but see L<tt_default_vars> for the variables you get for free. |
239 | |
240 | =head2 tt_default_vars |
241 | |
242 | Return a hash-ref of the default vars given to the template. |
243 | You wouldn't normally over-ride this, just inherit the default implimentation, |
244 | to get the C<translator> & C<schema> variables, then over-ride L<tt_vars> to add |
245 | your own. |
246 | |
247 | The current default variables are: |
248 | |
249 | =over 4 |
250 | |
251 | =item schema |
252 | |
253 | The schema to template. |
254 | |
255 | =item translator |
256 | |
257 | The L<SQL::Translator> object. |
258 | |
259 | =back |
260 | |
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261 | =head2 pre_process_schema |
262 | |
263 | WARNING: This method is Experimental so may change! |
264 | |
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265 | Called with the L<SQL::Translator::Schema> object and should return one (it |
266 | doesn't have to be the same one) that will become the C<schema> varibale used |
267 | in the template. |
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268 | |
269 | Gets called from tt_default_vars. |
270 | |
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271 | =head1 PRODUCER OBJECT |
272 | |
273 | The rest of the methods in the class set up a sub-classable producer object. |
274 | You normally just inherit them. |
275 | |
276 | =head2 new |
277 | |
278 | my $tt_producer = TT::Base->new( translator => $translator ); |
279 | |
280 | Construct a new TT Producer object. Takes a single, named arg of the |
281 | L<SQL::Translator> object running the translation. Dies if this is not given. |
282 | |
283 | =head2 translator |
284 | |
285 | Return the L<SQL::Translator> object. |
286 | |
287 | =head2 schema |
288 | |
289 | Return the L<SQL::Translator::Schema> we are translating. This is equivilent |
290 | to C<< $tt_producer->translator->schema >>. |
291 | |
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292 | =head2 run |
293 | |
294 | Called to actually produce the output, calling the sub class hooks. Returns the |
295 | produced text. |
296 | |
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297 | =head2 args |
298 | |
299 | Util wrapper method around C<< TT::Base->translator->producer_args >> for |
300 | (mostley) readonly access to the producer args. How it works depends on the |
301 | number of arguments you give it and the context. |
302 | |
303 | No args - Return hashref (the actual hash in Translator) or hash of args. |
304 | 1 arg - Return value of the arg with the passed name. |
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305 | 2+ args - List of names. In list context returns values of the given arg |
306 | names, returns as a hashref in scalar context. Any names given |
307 | that don't exist in the args are returned as undef. |
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308 | |
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309 | This is still a bit messy but is a handy way to access the producer args when |
310 | you use your own to drive the templating. |
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311 | |
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312 | =head1 SEE ALSO |
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313 | |
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314 | L<perl>, |
315 | L<SQL::Translator>, |
316 | L<Template>. |
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317 | |
318 | =head1 TODO |
319 | |
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320 | - Add support for a sqlf template repository, set as an INCLUDE_PATH, |
321 | so that sub-classes can easily include file based templates using relative |
322 | paths. |
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323 | |
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324 | - Pass in template vars from the producer args and command line. |
325 | |
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326 | - Merge in TT::Table. |
327 | |
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328 | - Hooks to pre-process the schema and post-process the output. |
329 | |
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330 | =head1 AUTHOR |
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331 | |
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332 | Mark Addison E<lt>grommit@users.sourceforge.netE<gt>. |
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333 | |
334 | =cut |