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Tue May 13 07:00:33 2003 UTC (21 years, 1 month ago) by joko
Branch: MAIN
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1 joko 1.1 =pod
2    
3    
4     =head1 NAME
5    
6     Data::Storage - Interface for accessing various Storage implementations for Perl in an independent way
7    
8    
9     =head1 AIMS
10    
11     - should encapsulate Tangram, DBI, DBD::CSV and LWP:: to access them in an unordinary (more convenient) way ;)
12     - introduce a generic layered structure, refactor *SUBLAYER*-stuff, make (e.g.) this possible:
13     Perl Data::Storage[DBD::CSV] -> Perl LWP:: -> Internet HTTP/FTP/* -> Host Daemon -> csv-file
14     - provide generic synchronization mechanisms across arbitrary/multiple storages based on ident/checksum
15     maybe it's possible to have schema-, structural- and semantical modifications synchronized???
16    
17    
18     =head1 SYNOPSIS
19    
20 joko 1.2 =head2 ACCESS
21 joko 1.1
22 joko 1.2 # connect to LDAP
23     my $ldapLocator = Data::Storage::Locator->new(
24     ldap => {
25     type => "NetLDAP",
26     dsn => "ldap:host=192.168.10.150;binddn='cn=root, o=netfrag.org, c=de';pass=secret",
27     basedn => "o=netfrag.org, c=de",
28     want_transactions => 0,
29     syncable => 1,
30     },
31     );
32     my $ldapStorage = Data::Storage->new($ldapLocator);
33     $ldapStorage->connect();
34    
35     # connect to MAPI
36     my $mapiLocator = Data::Storage::Locator->new(
37     outlook => {
38     type => "MAPI",
39     showProfileChooser => $self->{config}->get("mapi_showProfileChooser"),
40     ProfileName => $self->{config}->get("mapi_ProfileName"),
41     ProfilePass => $self->{config}->get("mapi_ProfilePass"),
42     syncable => 1,
43     },
44     );
45     my $mapiStorage = Data::Storage->new($mapiLocator);
46     $mapiStorage->connect();
47 joko 1.1
48    
49 joko 1.2 =head2 SYNCHRONIZATION
50    
51     This functionality is (in the meanwhile) provided by the Data::Transfer::Sync module.
52 joko 1.1
53 joko 1.2 =head3 proposal V1
54 joko 1.1
55     my $nodemapping = {
56     'LangText' => 'langtexts.csv',
57     'Currency' => 'currencies.csv',
58     'Country' => 'countries.csv',
59     };
60    
61     my $propmapping = {
62     'LangText' => [
63     [ 'source:lcountrykey' => 'target:country' ],
64     [ 'source:lkey' => 'target:key' ],
65     [ 'source:lvalue' => 'target:text' ],
66     ],
67     'Currency' => [
68     [ 'source:ckey' => 'target:key' ],
69     [ 'source:cname' => 'target:text' ],
70     ],
71     'Country' => [
72     [ 'source:ckey' => 'target:key' ],
73     [ 'source:cname' => 'target:text' ],
74     ],
75     };
76    
77     s ub syncResource {
78    
79     my $self = shift;
80     my $node_source = shift;
81     my $mode = shift;
82     my $opts = shift;
83    
84     $mode ||= '';
85     $opts->{erase} ||= 0;
86    
87     $logger->info( __PACKAGE__ . "->syncResource( node_source $node_source mode $mode erase $opts->{erase} )");
88    
89     # resolve metadata for syncing requested resource
90     my $node_target = $nodemapping->{$node_source};
91     my $mapping = $propmapping->{$node_source};
92    
93     if (!$node_target || !$mapping) {
94     # loggger.... "no target, sorry!"
95     print "error while resolving resource metadata", "\n";
96     return;
97     }
98    
99     if ($opts->{erase}) {
100     $self->_erase_all($node_source);
101     }
102    
103     # create new sync object
104     my $sync = Data::Transfer::Sync->new(
105     storages => {
106 joko 1.2 L => $self->{storage}->{backend},
107     R => $self->{storage}->{resources},
108 joko 1.1 },
109     id_authorities => [qw( L ) ],
110     checksum_authorities => [qw( L ) ],
111     write_protected => [qw( R ) ],
112     verbose => 1,
113     );
114    
115     # sync
116     # todo: filter!?
117     $sync->syncNodes( {
118     direction => $mode, # | +PUSH | +PULL | -FULL | +IMPORT | -EXPORT
119     method => 'checksum', # | -timestamp | -manual
120     source => "L:$node_source",
121     source_ident => 'storage_method:id',
122     source_exclude => [qw( id cs )],
123     target => "R:$node_target",
124     target_ident => 'property:oid',
125     mapping => $mapping,
126     } );
127    
128     }
129 joko 1.2
130     =head3 proposal V2
131    
132     # create a new synchronization object
133     my $sync = Data::Transfer::Sync->new( 'sync_version' => $sync_version, __parent => $self );
134    
135     # configure the synchronization-object
136     $sync->configure(
137     source => {
138     storage => {
139     handle => $mapiStorage,
140     #isIdentAuthority => 1,
141     #isChecksumAuthority => 1,
142     #writeProtected => 1,
143     },
144     },
145     target => {
146     storage => {
147     handle => $ldapStorage,
148     #idAuthority => 1,
149     #isChecksumAuthority => 1,
150     #isWriteProtected => 0,
151     },
152     },
153     verbose => 1,
154     );
155 joko 1.1
156    
157     =head2 NOTE
158    
159     This module heavily relies on DBI and Tangram, but adds a lot of additional bugs and quirks.
160     Please look at their documentation and/or this code for additional information.
161    
162    
163     =head1 REQUIREMENTS
164    
165     For full functionality:
166     DBI from CPAN
167     DBD::mysql from CPAN
168     Tangram 2.04 from CPAN (hmmm, 2.04 won't do in some cases)
169     Tangram 2.05 from http://... (2.05 seems okay but there are also additional patches from our side)
170     Class::Tangram from CPAN
171     DBD::CSV from CPAN
172     MySQL::Diff from http://adamspiers.org/computing/mysqldiff/
173     ... and all their dependencies
174    
175    
176     =head1 DESCRIPTION
177    
178     =head2 Data::Storage
179    
180     Data::Storage is a module for accessing various "data structures / kinds of structured data" stored inside
181     various "data containers".
182     We tried to use the AdapterPattern to implement a wrapper-layer around known CPAN modules.
183     (e.g. DBI, Tangram, XML::Simple)
184     References:
185     - http://c2.com/cgi/wiki?AdapterPattern
186     - http://home.earthlink.net/~huston2/dp/adapter.html
187    
188     =head2 Why?
189    
190     You will get a better code-structure (not bad for later maintenance) in growing Perl code projects,
191     especially when using multiple database connections at the same time.
192     You will be able to switch between different _kinds_ of implementations used for storing data.
193     Your code will use the very same API to access these storage layers.
194     ... implementation has to be changed for now
195     Maybe you will be able to switch "on-the-fly" without changing any bits in code in the future....
196     ... but that's not the focus
197    
198     =head2 What else?
199    
200     Having this, we were able to do implement a generic data synchronization module more easy,
201     please look at Data::Transfer.
202    
203    
204     =head1 AUTHORS / COPYRIGHT
205    
206     The Data::Storage module is Copyright (c) 2002 Andreas Motl.
207     All rights reserved.
208     You may distribute it under the terms of either the GNU General Public
209     License or the Artistic License, as specified in the Perl README file.
210    
211    
212     =head1 ACKNOWLEDGEMENTS
213    
214     Larry Wall for Perl, Tim Bunce for DBI, Jean-Louis Leroy for Tangram and Set::Object,
215     Sam Vilain for Class::Tangram, Jochen Wiedmann and Jeff Zucker for DBD::CSV & Co.,
216     Adam Spiers for MySQL::Diff and all contributors.
217    
218    
219     =head1 SUPPORT / WARRANTY
220    
221     Data::Storage is free software. IT COMES WITHOUT WARRANTY OF ANY KIND.
222    
223    
224     =head1 TODO
225    
226 joko 1.3 o interface with Jeff Zucker's AnyData:: modules, e.g. AnyData::Storage::RAM
227     o what about DBD::RAM? (DBD::RAM - a DBI driver for files and data structures)
228     o use DBD::Proxy!
229     o what about DBIx::AnyDBD?
230     o enhance schema information:
231     - DBIx::SystemCatalog
232     - DBIx::SystemCatalog::MSSQL?
233     - Data::Reporter
234    
235 joko 1.1
236     =head2 BUGS
237    
238     "DBI-Error [Tangram]: DBD::mysql::st execute failed: Unknown column 't1.requestdump' in 'field list'"
239    
240     ... occours when operating on object-attributes not introduced yet:
241     this should be detected and appended/replaced through:
242     "Schema-Error detected, maybe (just) an inconsistency.
243     Please check if your declaration in schema-module "a" matches structure in database "b" or try to run"
244     db_setup.pl --dbkey=import --action=deploy
245    
246    
247     Compare schema (structure diff) with database ...
248    
249     ... when issuing "db_setup.pl --dbkey=import --action=deploy"
250     on a database with an already deployed schema, use an additional "--update" then
251     to lift the schema inside the database to the current declared schema.
252     You will have to approve removals and changes on field-level while
253     new objects and new fields are introduced silently without any interaction needed.
254     In future versions there may be additional options to control silent processing of
255     removals and changes.
256     See this CRUD-table applying to the actions occouring on Classes and Class variables when deploying schemas,
257     don't mix this up with CRUD-actions on Objects, these are already handled by (e.g.) Tangram itself.
258     Classes:
259     C create -> yes, handled automatically
260     R retrieve -> no, not subject of this aspect since it is about deployment only
261     U update -> yes, automatically for Class meta-attributes, yes/no for Class variables (look at the rules down here)
262     D delete -> yes, just by user-interaction
263     Class variables:
264     C create -> yes, handled automatically
265     R retrieve -> no, not subject of this aspect since it is about deployment only
266     U update -> yes, just by user-interaction; maybe automatically if it can be determined that data wouldn't be lost
267     D delete -> yes, just by user-interaction
268    
269     It's all about not to be able to loose data simply while this is in pre-alpha stage.
270     And loosing data by being able to modify and redeploy schemas easily is definitely quite easy.
271    
272     As we can see, creations of Classes and new Class variables is handled
273     automatically and this is believed to be the most common case under normal circumstances.
274    
275    
276     =head2 FEATURES
277    
278     - Get this stuff together with UML (Unified Modeling Language) and/or standards from ODMG.
279     - Make it possible to load/save schemas in XMI (XML Metadata Interchange),
280     which seems to be most commonly used today, perhaps handle objects with OIFML.
281     Integrate/bundle this with a web-/html-based UML modeling tool or
282     some other interesting stuff like the "Co-operative UML Editor" from Uni Darmstadt. (web-/java-based)
283     - Enable Round Trip Engineering. Keep code and diagrams in sync. Don't annoy/bother the programmers.
284     - Add support for some more handlers/locators to be able to
285     access the following standards/protocols/interfaces/programs/apis transparently:
286     + DBD::CSV (via Data::Storage::Handler::DBI)
287     (-) Text::CSV, XML::CSV, XML::Excel
288     - MAPI
289     - LDAP
290     - DAV (look at PerlDAV: http://www.webdav.org/perldav/)
291     - Mbox (use formail for seperating/splitting entries/nodes)
292     - Cyrus (cyrdeliver - what about cyrretrieve (export)???)
293     - use File::DiffTree, use File::Compare
294     - Hibernate
295     - "Win32::UserAccountDb"
296     - "*nix::UserAccountDb"
297     - .wab - files (Windows Address Book)
298     - .pst - files (Outlook Post Storage?)
299     - XML (e.g. via XML::Simple?)
300     - Move to t3, look at InCASE
301     - some kind of security layer for methods/objects
302     - acls (stored via tangram/ldap?) for functions, methods and objects (entity- & data!?)
303     - where are the hooks needed then?
304     - is Data::Storage & Co. okay, or do we have to touch the innards of DBI and/or Tangram?
305     - an attempt to start could be:
306     - 'sub getACLByObjectId($id, $context)'
307     - 'sub getACLByMethodname($id, $context)'
308     - 'sub getACLByName($id, $context)'
309     ( would require a kinda registry to look up these very names pointing to arbitrary locations (code, data, ...) )
310     - add more hooks and various levels
311     - better integrate introduced 'getObjectByGuid'-mechanism from Data::Storage::Handler::Tangram
312    
313    
314     =head3 LINKS / REFERENCES
315    
316     Specs:
317     UML 1.3 Spec: http://cgi.omg.org/cgi-bin/doc?ad/99-06-08.pdf
318     XMI 1.1 Spec: http://cgi.omg.org/cgi-bin/doc?ad/99-10-02.pdf
319     XMI 2.0 Spec: http://cgi.omg.org/docs/ad/01-06-12.pdf
320     ODMG: http://odmg.org/
321     OIFML: http://odmg.org/library/readingroom/oifml.pdf
322    
323     CASE Tools:
324     Rational Rose (commercial): http://www.rational.com/products/rose/
325     Together (commercial): http://www.oi.com/products/controlcenter/index.jsp
326     InCASE - Tangram-based Universal Object Editor
327     Sybase PowerDesigner: http://www.sybase.com/powerdesigner
328    
329     UML Editors:
330     Fujaba (free, university): http://www.fujaba.de/
331     ArgoUML (free): http://argouml.tigris.org/
332     Poseidon (commercial): http://www.gentleware.com/products/poseidonDE.php3
333     Co-operative UML Editor (research): http://www.darmstadt.gmd.de/concert/activities/internal/umledit.html
334     Metamill (commercial): http://www.metamill.com/
335     Violet (university, research, education): http://www.horstmann.com/violet/
336     PyUt (free): http://pyut.sourceforge.net/
337     (Dia (free): http://www.lysator.liu.se/~alla/dia/)
338     UMLet (free, university): http://www.swt.tuwien.ac.at/umlet/index.html
339     Voodoo (free): http://voodoo.sourceforge.net/
340     Umbrello UML Modeller: http://uml.sourceforge.net/
341    
342     UML Tools:
343     http://www.objectsbydesign.com/tools/umltools_byPrice.html
344    
345     Further readings:
346     http://www.google.com/search?q=web+based+uml+editor&hl=en&lr=&ie=UTF-8&oe=UTF-8&start=10&sa=N
347     http://www.fernuni-hagen.de/DVT/Aktuelles/01FHHeidelberg.pdf
348     http://www.enhyper.com/src/documentation/
349     http://cis.cs.tu-berlin.de/Dokumente/Diplomarbeiten/2001/skinner.pdf
350     http://citeseer.nj.nec.com/vilain00diagrammatic.html
351     http://archive.devx.com/uml/articles/Smith01/Smith01-3.asp
352    
353    
354     =cut
355    

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