1Merge(3) User Contributed Perl Documentation Merge(3)
2
6 XML::Merge - flexibly merge XML documents
7
9 This documentation refers to version 1.4 of XML::Merge, which was
10 released on Sat Jul 23 14:39:59:48 -0500 2016.
11
13 #!/usr/bin/perl
14 use strict;use warnings;
15 use utf8;use XML::Merge;
16 # create new XML::Merge object from MainFile.xml
18 my $merge_obj= XML::Merge->new('filename' => 'MainFile.xml');
19 # Merge File2Add.xml into MainFile.xml
21 $merge_obj->merge( 'filename' => 'File2Add.xml');
22 # Tidy up the indenting that resulted from the merge
24 $merge_obj->tidy();
25 # Write out changes back to MainFile.xml
27 $merge_obj->write();
28
30 This module inherits from XML::Tidy which in turn inherits from
31 XML::XPath. This ensures that Merge objects' indenting can be tidied up
32 after any merge operation since such modification usually ruins
33 indentation. Polymorphism allows Merge objects to be utilized as normal
34 XML::XPath objects as well.
35 The merging behavior is setup to combine separate XML documents
37 according to certain rules and configurable options. If both documents
38 have root nodes which are elements of the same name, the documents are
39 merged directly. Otherwise, one is merged as a child of the other. An
40 optional XPath location can be specified as the place to perform the
41 merge. If no location is specified, the merge is attempted at the first
42 matching element or is appended as the new last child of the other root
43 if no match is found.
44
46 new()
47 This is the standard Merge object constructor. It can take the same
48 parameters as an XML::XPath object constructor to initialize the
49 primary XML document object (the object which subsequent XML documents
50 will be merged into). These parameters can be any one of:
51 'filename' => 'SomeFile.xml'
53 'xml' => $variable_which_holds_a_bunch_of_XML_data
54 'ioref' => $file_InputOutput_reference
55 'context' => $existing_node_at_specified_context_to_become_new_obj
56 Merge's new() can also accept merge-option parameters to override the
58 default merge behavior. These include:
59 'conflict_resolution_method' => 'main', # main file wins
61 'conflict_resolution_method' => 'merg', # merge file wins
62 # 'last-in_wins' is the same as 'merg'
63 'conflict_resolution_method' => 'warn', # croak conflicts
64 'conflict_resolution_method' => 'test', # just test, 1 if conflict
65 merge()
67 The merge() member function can accept the same XML::XPath constructor
68 options as new() but this time they are for the temporary file which
69 will be merged into the main object. Merge-options from new() can also
70 be specified and they will only impact one particular invokation of
71 merge(). The specified document will be merged into the primary XML
72 document object according to the following default merge rules:
73 1. If both documents share the same root element name, they are merged
75 directly.
76 2. If they don't share root elements but the temporary merge file's
78 root element is found anywhere within the main file, the merge occurs
79 at the match.
80 3. If no root element match is found, the merge document becomes the
82 new last child of the main file's root element.
83 4. Whenever a deeper level is found with an element of the same name in
85 both documents and either it does not contain any distinguishing
86 attributes or it has attributes which are recognized as 'identifier'
87 (id) attributes (by default, for any element, these are attributes
88 named: 'id', 'idx', 'ndx', 'index', 'name', and 'handle'), a
89 corresponding element is searched for to match and merge with.
90 5. Any remaining (non-id) nodes are merged in document order.
92 6. When a conflict arises as non-id attributes or other nodes merge,
94 the specified conflict_resolution_method merge-option is applied (which
95 by default has the main file data persist at the expense of the merging
96 file data).
97 Some of the above rules can be overridden first by the object's merge-
99 options and second by the particular method call's merge-options.
100 Thus, if the default merge-option for conflict resolution is to have
101 the main object win and you use the following constructor:
102 my $merge_obj = XML::Merge->new(
104 'filename' => 'MainFile.xml',
105 'conflict_resolution_method' => 'last-in_wins');
106 ... then any $merge_obj->merge() call would override the default merge
108 behavior by letting the document being merged have priority over the
109 main object's document. However, you could supply additional merge-
110 options in the parameter list of your specific merge() call like:
111 $merge_obj->merge(
113 'filename' => 'File2Add.xml',
114 'conflict_resolution_method' => 'warn');
115 ... to have the latest option override further.
117 The 'test' conflict_resolution_method merge-option does not modify the
119 object at all. It solely returns zero (0) if no conflict was
120 encountered from a temporary attempted merge.
121 It should be used like:
123 for(@files) {
125 if($merge_obj->merge('cres' => 'test', $_)) {
126 croak("Yipes! Conflict with file:$_!\n");
127 } else {
128 $merge_obj->merge($_); # only do it if there are no conflicts
129 }
130 }
131 merge() can also accept another XML::Merge object as a parameter for
133 what to be merged with the main object instead of a filename. An
134 example of this is:
135 $merge_obj->merge($another_merge_obj);
137 Along with the merge options that can be specified in the object
139 constructor, merge() also accepts the following options to specify
140 where to perform the merge relative to:
141 'merge_destination_path' => $main_obj_xpath_location,
143 'merge_source_path' => $merging_obj_xpath_location,
144 unmerge()
146 The unmerge() member function is a shorthand for calling both write()
147 and prune() on a certain XPath location which should be written out to
148 a disk file before being removed from the Merge object. Please see
149 XML::Tidy for documentation of the inherited write() and prune() member
150 functions.
151 This unmerge() process could be the opposite of merge() if no original
153 elements or attributes overlapped and combined but if combining did
154 happen, this would remove original sections of your primary XML
155 document's data from your Merge object so please use this carefully.
156 It is meant to help separate a giant object (probably the result of
157 myriad merge() calls) back into separate useful well-formed XML
158 documents on disk.
159 unmerge() takes a filename and an xpath_location parameter.
161
163 get_object_to_merge()
164 Returns the object which was last merged into the main object.
165 set_object_to_merge()
167 Assigns the object which was last merged into the main object.
168 get_conflict_resolution_method()
170 Returns the underlying merge-option conflict_resolution_method.
171 set_conflict_resolution_method()
173 A new value can be provided as a parameter to be assigned as the
174 XML::Merge object's merge-option.
175 get_id_xpath_list()
177 Returns the underlying id_xpath_list. This is normally just a list of
178 attributes (e.g., '@id', '@idx', '@ndx', '@index', '@name', '@handle')
179 which are unique identifiers for any XML element within merging
180 instance documents. When these attribute names are encountered during a
181 merge(), another element with the same name and attribute value are
182 searched for explicitly in order to align deeper merging and conflict
183 resolution.
184 set_id_xpath_list()
186 A new list can assigned to the XML::Merge object's id_xpath_list.
187 Please note that this list normally contains XPath attributes so they
189 must be preceded by an at-symbol (@) like: '@example_new_id_attribute'.
190
192 Revision history for Perl extension XML::Merge:
193 - 1.4 G7NMEdxm Sat Jul 23 14:39:59:48 -0500 2016
195 * inverted conflict resolution 'test' value since true 1 for conflict
196 makes more sense
197 * renumbered t/*.t
199 * updated Makefile.PL and Build.PL to hopefully fix issue
201 <HTTPS://RT.CPAN.Org/Public/Bug/Display.html?id=29898> (Thanks
202 Kevin.)
203 * removed DBUG printing
205 * removed PT from VERSION to fix issue
207 <HTTPS://RT.CPAN.Org/Public/Bug/Display.html?id=106873> (Thanks
208 ppisar.)
209 * updated license to GPLv3
211 - 1.2.75BAJNl Fri May 11 10:19:23:47 2007
213 * added default id @s: idx, ndx, and index
214 - 1.2.565EgGd Sun Jun 5 14:42:16:39 2005
216 * added use XML::Tidy to make sure exports are available
217 * removed 02prune.t and moved 03keep.t to 02keep.t ... passing tests
219 is good
220 - 1.2.4CCJWiB Sun Dec 12 19:32:44:11 2004
222 * guessing how to fix Darwin test failure @ t/02prune.t first prune()
223 call
224 - 1.0.4CAL5IS Fri Dec 10 21:05:18:28 2004
226 * fixed buggy _recmerge
227 - 1.0.4CAEU0I Fri Dec 10 14:30:00:18 2004
229 * made accessors for _id_xpath_list
230 * made _id_xpath_list take XPath locations instead of elem names (old
232 _idea)
233 * made test _cres (at Marc's request)
235 * made warn _cres croak
237 * made Merge inherit from Tidy (which inherits from XPath)
239 * separated reload(), strip(), tidy(), prune(), and write() into own
241 XML::Tidy module
242 - 1.0.4C2Nf0R Thu Dec 2 23:41:00:27 2004
244 * updated license and prep'd for release
245 - 1.0.4C2BcI2 Thu Dec 2 11:38:18:02 2004
247 * updated reload(), strip(), and tidy() to verify _xpob exists
248 - 1.0.4C1JHOl Wed Dec 1 19:17:24:47 2004
250 * commented out override stuff since it's probably bad form and dumps
251 crap
252 warnings all over tests and causes them to fail... so I guess
253 just
254 uncomment that stuff if you care to preserve PI's and escapes
255 - 1.0.4C1J7gt Wed Dec 1 19:07:42:55 2004
257 * made merge() accept merge_source_xpath and merge_destination_xpath
258 params
259 * made merge() accept other Merge objects
261 * made reload() not clobber basic escapes (by overriding Text
263 toString())
264 * made tidy() not kill processing-instructions (by overriding
266 node_test())
267 * made tidy() not kill comments
269 - 1.0.4BOHGjm Wed Nov 24 17:16:45:48 2004
271 * fixed merge() same elems with diff ids bug
272 - 1.0.4BNBCZL Tue Nov 23 11:12:35:21 2004
274 * rewrote both merge() and _recmerge() _cres stuff since it was
275 buggy before... so hopefully consistently good now
276 - 1.0.4BMJCPm Mon Nov 22 19:12:25:48 2004
278 * fixed merge() for empty elem matching and _cres on text kids
279 - 1.0.4BMGTLF Mon Nov 22 16:29:21:15 2004
281 * separated reload() from strip() so that prune() can call it too
282 - 1.0.4BM0B3x Mon Nov 22 00:11:03:59 2004
284 * fixed tidy() empty elem bug and implemented prune() and unmerge()
285 - 1.0.4BJAZpM Fri Nov 19 10:35:51:22 2004
287 * fixing e() ABSTRACT gen bug
288 - 1.0.4BJAMR6 Fri Nov 19 10:22:27:06 2004
290 * fleshed out POD and members
291 - 1.0.4AIDqmR Mon Oct 18 13:52:48:27 2004
293 * original version
294
296 - add Kevin's multiple _idea option where several element attributes
297 are an ID together, from:
298 <HTTPS://RT.CPAN.Org/Public/Bug/Display.html?id=29897>
299 - make namespaces and attributes stay in order after merge()
300 - make text append merge option
301 - handle comment joins and stamping options
302 - support modification-time conflict resolution method
303 - add _ignr ignore list of merge XPath locations to not merge
304 (pre-prune())
305
307 From the command shell, please run:
308 `perl -MCPAN -e "install XML::Merge"`
310 or uncompress the package and run the standard:
312 `perl Makefile.PL; make; make test; make install`
314 or if you don't have `make` but Module::Build is installed, try:
315 `perl Build.PL; perl Build; perl Build test; perl Build install`
316
318 XML::Merge requires:
319 Carp to allow errors to croak() from calling sub
321 XML::Tidy to use objects derived from XPath to update XML
323
325 Most source code should be Free! Code I have lawful authority over is
326 and shall be! Copyright: (c) 2004-2016, Pip Stuart. Copyleft : This
327 software is licensed under the GNU General Public License
328 (version 3 or later). Please consult
329 <HTTP://GNU.Org/licenses/gpl-3.0.txt>
330 for important information about your freedom. This is Free Software:
331 you
332 are free to change and redistribute it. There is NO WARRANTY, to the
333 extent permitted by law. See <HTTP://FSF.Org> for further
334 information.
335
337 Pip Stuart <Pip@CPAN.Org>
338perl v5.30.1 2020-01-30 Merge(3)