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1 | package SQL::Translator::Producer::TT::Base; |
2 | |
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3 | =pod |
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4 | |
5 | =head1 NAME |
6 | |
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7 | SQL::Translator::Producer::TT::Base - TT (Template Toolkit) based Producer base |
8 | class. |
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9 | |
10 | =cut |
11 | |
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12 | use strict; |
13 | |
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14 | use vars qw[ $VERSION @EXPORT_OK ]; |
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15 | $VERSION = '1.59'; |
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16 | |
17 | use Template; |
18 | use Data::Dumper; |
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19 | use IO::Handle; |
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20 | use Exporter; |
21 | use base qw(Exporter); |
22 | @EXPORT_OK = qw(produce); |
23 | |
24 | use SQL::Translator::Utils 'debug'; |
25 | |
26 | # Hack to convert the produce call into an object. ALL sub-classes need todo |
27 | # this so that the correct class gets created. |
28 | sub produce { |
29 | return __PACKAGE__->new( translator => shift )->run; |
30 | }; |
31 | |
32 | sub new { |
33 | my $proto = shift; |
34 | my $class = ref $proto || $proto; |
35 | my %args = @_; |
36 | |
37 | my $me = bless {}, $class; |
38 | $me->{translator} = delete $args{translator} || die "Need a translator."; |
39 | |
40 | return $me; |
41 | } |
42 | |
43 | sub translator { shift->{translator}; } |
44 | sub schema { shift->{translator}->schema(@_); } |
45 | |
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46 | # Util args access method. |
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47 | # No args - Return hashref (the actual hash in Translator) or hash of args. |
48 | # 1 arg - Return that named args value. |
49 | # Args - List of names. Return values of the given arg names in list context |
50 | # or return as hashref in scalar context. Any names given that don't |
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51 | # exist in the args are returned as undef. |
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52 | sub args { |
53 | my $me = shift; |
54 | |
55 | # No args |
56 | unless (@_) { |
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57 | return wantarray |
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58 | ? %{ $me->{translator}->producer_args } |
59 | : $me->{translator}->producer_args |
60 | ; |
61 | } |
62 | |
63 | # 1 arg. Return the value whatever the context. |
64 | return $me->{translator}->producer_args->{$_[0]} if @_ == 1; |
65 | |
66 | # More args so return values list or hash ref |
67 | my %args = %{ $me->{translator}->producer_args }; |
68 | return wantarray ? @args{@_} : { map { ($_=>$args{$_}) } @_ }; |
69 | } |
70 | |
71 | # Run the produce and return the result. |
72 | sub run { |
73 | my $me = shift; |
74 | my $scma = $me->schema; |
75 | my %args = %{$me->args}; |
76 | my $tmpl = $me->tt_schema or die "No template!"; |
77 | |
78 | debug "Processing template $tmpl\n"; |
79 | my $out; |
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80 | my $tt = Template->new( |
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81 | #DEBUG => $me->translator->debug, |
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82 | ABSOLUTE => 1, # Set so we can use from the command line sensibly |
83 | RELATIVE => 1, # Maybe the cmd line code should set it! Security! |
84 | $me->tt_config, # Hook for sub-classes to add config |
85 | %args, # Allow any TT opts to be passed in the producer_args |
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86 | ) || die "Failed to initialize Template object: ".Template->error; |
87 | |
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88 | $tt->process( $tmpl, { |
89 | $me->tt_default_vars, |
90 | $me->tt_vars, # Sub-class hook for adding vars |
91 | }, \$out ) |
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92 | or die "Error processing template '$tmpl': ".$tt->error; |
93 | |
94 | return $out; |
95 | } |
96 | |
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97 | |
98 | # Sub class hooks |
99 | #----------------------------------------------------------------------------- |
100 | |
101 | sub tt_config { () }; |
102 | |
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103 | sub tt_schema { |
104 | my $me = shift; |
105 | my $class = ref $me; |
106 | |
107 | my $file = $me->args("ttfile"); |
108 | return $file if $file; |
109 | |
110 | no strict 'refs'; |
111 | my $ref = *{"$class\:\:DATA"}{IO}; |
112 | if ( $ref->opened ) { |
113 | local $/ = undef; # Slurp mode |
114 | return \<$ref>; |
115 | } |
116 | |
117 | undef; |
118 | }; |
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119 | |
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120 | sub tt_default_vars { |
121 | my $me = shift; |
122 | return ( |
123 | translator => $me->translator, |
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124 | schema => $me->pre_process_schema($me->translator->schema), |
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125 | ); |
126 | } |
127 | |
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128 | sub pre_process_schema { $_[1] } |
129 | |
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130 | sub tt_vars { () }; |
131 | |
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132 | 1; |
133 | |
134 | # ------------------------------------------------------------------- |
135 | |
136 | =pod |
137 | |
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138 | =head1 SYNOPSIS |
139 | |
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140 | # Create a producer using a template in the __DATA__ section. |
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141 | package SQL::Translator::Producer::Foo; |
142 | |
143 | use base qw/SQL::Translator::Producer::TT::Base/; |
144 | |
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145 | # Convert produce call into a method call on our new class |
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146 | sub produce { return __PACKAGE__->new( translator => shift )->run; }; |
147 | |
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148 | # Configure the Template object. |
149 | sub tt_config { ( INTERPOLATE => 1 ); } |
150 | |
151 | # Extra vars to add to the template |
152 | sub tt_vars { ( foo => "bar" ); } |
153 | |
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154 | # Put template in DATA section (or use file with ttfile producer arg) |
155 | __DATA__ |
156 | Schema |
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157 | |
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158 | Database: [% schema.database %] |
159 | Foo: $foo |
160 | ... |
161 | |
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162 | =head1 DESCRIPTION |
163 | |
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164 | A base class producer designed to be sub-classed to create new TT based |
165 | producers cheaply - by simply giving the template to use and sprinkling in some |
166 | extra template variables and config. |
167 | |
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168 | You can find an introduction to this module in L<SQL::Translator::Manual>. |
169 | |
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170 | The 1st thing the module does is convert the produce sub routine call we get |
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171 | from SQL::Translator into a method call on an object, which we can then |
172 | sub-class. This is done with the following code which needs to appear in B<all> |
173 | sub classes. |
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174 | |
175 | # Convert produce call into an object method call |
176 | sub produce { return __PACKAGE__->new( translator => shift )->run; }; |
177 | |
178 | See L<PRODUCER OBJECT> below for details. |
179 | |
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180 | The upshot of this is we can make new template producers by sub classing this |
181 | base class, adding the above snippet and a template. |
182 | The module also provides a number of hooks into the templating process, |
183 | see L<SUB CLASS HOOKS> for details. |
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184 | |
185 | See the L<SYNOPSIS> above for an example of creating a simple producer using |
186 | a single template stored in the producers DATA section. |
187 | |
188 | =head1 SUB CLASS HOOKS |
189 | |
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190 | Sub-classes can override these methods to control the templating by giving |
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191 | the template source, adding variables and giving config to the Tempate object. |
192 | |
193 | =head2 tt_config |
194 | |
195 | sub tt_config { ( INTERPOLATE => 1 ); } |
196 | |
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197 | Return hash of Template config to add to that given to the L<Template> C<new> |
198 | method. |
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199 | |
200 | =head2 tt_schema |
201 | |
202 | sub tt_schema { "foo.tt"; } |
203 | sub tt_schema { local $/ = undef; \<DATA>; } |
204 | |
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205 | The template to use, return a file name or a scalar ref of TT |
206 | source, or an L<IO::Handle>. See L<Template> for details, as the return from |
207 | this is passed on to it's C<produce> method. |
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208 | |
209 | The default implimentation uses the producer arg C<ttfile> as a filename to read |
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210 | the template from. If the arg isn't there it will look for a C<__DATA__> section |
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211 | in the class, reading it as template source if found. Returns undef if both |
212 | these fail, causing the produce call to fail with a 'no template!' error. |
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213 | |
214 | =head2 tt_vars |
215 | |
216 | sub tt_vars { ( foo => "bar" ); } |
217 | |
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218 | Return hash of template vars to use in the template. Nothing added here |
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219 | by default, but see L<tt_default_vars> for the variables you get for free. |
220 | |
221 | =head2 tt_default_vars |
222 | |
223 | Return a hash-ref of the default vars given to the template. |
224 | You wouldn't normally over-ride this, just inherit the default implimentation, |
225 | to get the C<translator> & C<schema> variables, then over-ride L<tt_vars> to add |
226 | your own. |
227 | |
228 | The current default variables are: |
229 | |
230 | =over 4 |
231 | |
232 | =item schema |
233 | |
234 | The schema to template. |
235 | |
236 | =item translator |
237 | |
238 | The L<SQL::Translator> object. |
239 | |
240 | =back |
241 | |
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242 | =head2 pre_process_schema |
243 | |
244 | WARNING: This method is Experimental so may change! |
245 | |
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246 | Called with the L<SQL::Translator::Schema> object and should return one (it |
247 | doesn't have to be the same one) that will become the C<schema> varibale used |
248 | in the template. |
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249 | |
250 | Gets called from tt_default_vars. |
251 | |
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252 | =head1 PRODUCER OBJECT |
253 | |
254 | The rest of the methods in the class set up a sub-classable producer object. |
255 | You normally just inherit them. |
256 | |
257 | =head2 new |
258 | |
259 | my $tt_producer = TT::Base->new( translator => $translator ); |
260 | |
261 | Construct a new TT Producer object. Takes a single, named arg of the |
262 | L<SQL::Translator> object running the translation. Dies if this is not given. |
263 | |
264 | =head2 translator |
265 | |
266 | Return the L<SQL::Translator> object. |
267 | |
268 | =head2 schema |
269 | |
270 | Return the L<SQL::Translator::Schema> we are translating. This is equivilent |
271 | to C<< $tt_producer->translator->schema >>. |
272 | |
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273 | =head2 run |
274 | |
275 | Called to actually produce the output, calling the sub class hooks. Returns the |
276 | produced text. |
277 | |
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278 | =head2 args |
279 | |
280 | Util wrapper method around C<< TT::Base->translator->producer_args >> for |
281 | (mostley) readonly access to the producer args. How it works depends on the |
282 | number of arguments you give it and the context. |
283 | |
284 | No args - Return hashref (the actual hash in Translator) or hash of args. |
285 | 1 arg - Return value of the arg with the passed name. |
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286 | 2+ args - List of names. In list context returns values of the given arg |
287 | names, returns as a hashref in scalar context. Any names given |
288 | that don't exist in the args are returned as undef. |
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289 | |
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290 | This is still a bit messy but is a handy way to access the producer args when |
291 | you use your own to drive the templating. |
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292 | |
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293 | =head1 SEE ALSO |
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294 | |
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295 | L<perl>, |
296 | L<SQL::Translator>, |
297 | L<Template>. |
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298 | |
299 | =head1 TODO |
300 | |
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301 | - Add support for a sqlf template repository, set as an INCLUDE_PATH, |
302 | so that sub-classes can easily include file based templates using relative |
303 | paths. |
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304 | |
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305 | - Pass in template vars from the producer args and command line. |
306 | |
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307 | - Merge in TT::Table. |
308 | |
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309 | - Hooks to pre-process the schema and post-process the output. |
310 | |
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311 | =head1 AUTHOR |
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312 | |
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313 | Mark Addison E<lt>grommit@users.sourceforge.netE<gt>. |
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314 | |
315 | =cut |