/[cvs]/nfo/perl/libs/Data/Storage.pod
ViewVC logotype

Annotation of /nfo/perl/libs/Data/Storage.pod

Parent Directory Parent Directory | Revision Log Revision Log


Revision 1.2 - (hide annotations)
Tue Feb 11 10:31:09 2003 UTC (21 years, 4 months ago) by joko
Branch: MAIN
Changes since 1.1: +58 -19 lines
+ updated

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    
227     =head2 BUGS
228    
229     "DBI-Error [Tangram]: DBD::mysql::st execute failed: Unknown column 't1.requestdump' in 'field list'"
230    
231     ... occours when operating on object-attributes not introduced yet:
232     this should be detected and appended/replaced through:
233     "Schema-Error detected, maybe (just) an inconsistency.
234     Please check if your declaration in schema-module "a" matches structure in database "b" or try to run"
235     db_setup.pl --dbkey=import --action=deploy
236    
237    
238     Compare schema (structure diff) with database ...
239    
240     ... when issuing "db_setup.pl --dbkey=import --action=deploy"
241     on a database with an already deployed schema, use an additional "--update" then
242     to lift the schema inside the database to the current declared schema.
243     You will have to approve removals and changes on field-level while
244     new objects and new fields are introduced silently without any interaction needed.
245     In future versions there may be additional options to control silent processing of
246     removals and changes.
247     See this CRUD-table applying to the actions occouring on Classes and Class variables when deploying schemas,
248     don't mix this up with CRUD-actions on Objects, these are already handled by (e.g.) Tangram itself.
249     Classes:
250     C create -> yes, handled automatically
251     R retrieve -> no, not subject of this aspect since it is about deployment only
252     U update -> yes, automatically for Class meta-attributes, yes/no for Class variables (look at the rules down here)
253     D delete -> yes, just by user-interaction
254     Class variables:
255     C create -> yes, handled automatically
256     R retrieve -> no, not subject of this aspect since it is about deployment only
257     U update -> yes, just by user-interaction; maybe automatically if it can be determined that data wouldn't be lost
258     D delete -> yes, just by user-interaction
259    
260     It's all about not to be able to loose data simply while this is in pre-alpha stage.
261     And loosing data by being able to modify and redeploy schemas easily is definitely quite easy.
262    
263     As we can see, creations of Classes and new Class variables is handled
264     automatically and this is believed to be the most common case under normal circumstances.
265    
266    
267     =head2 FEATURES
268    
269     - Get this stuff together with UML (Unified Modeling Language) and/or standards from ODMG.
270     - Make it possible to load/save schemas in XMI (XML Metadata Interchange),
271     which seems to be most commonly used today, perhaps handle objects with OIFML.
272     Integrate/bundle this with a web-/html-based UML modeling tool or
273     some other interesting stuff like the "Co-operative UML Editor" from Uni Darmstadt. (web-/java-based)
274     - Enable Round Trip Engineering. Keep code and diagrams in sync. Don't annoy/bother the programmers.
275     - Add support for some more handlers/locators to be able to
276     access the following standards/protocols/interfaces/programs/apis transparently:
277     + DBD::CSV (via Data::Storage::Handler::DBI)
278     (-) Text::CSV, XML::CSV, XML::Excel
279     - MAPI
280     - LDAP
281     - DAV (look at PerlDAV: http://www.webdav.org/perldav/)
282     - Mbox (use formail for seperating/splitting entries/nodes)
283     - Cyrus (cyrdeliver - what about cyrretrieve (export)???)
284     - use File::DiffTree, use File::Compare
285     - Hibernate
286     - "Win32::UserAccountDb"
287     - "*nix::UserAccountDb"
288     - .wab - files (Windows Address Book)
289     - .pst - files (Outlook Post Storage?)
290     - XML (e.g. via XML::Simple?)
291     - Move to t3, look at InCASE
292     - some kind of security layer for methods/objects
293     - acls (stored via tangram/ldap?) for functions, methods and objects (entity- & data!?)
294     - where are the hooks needed then?
295     - is Data::Storage & Co. okay, or do we have to touch the innards of DBI and/or Tangram?
296     - an attempt to start could be:
297     - 'sub getACLByObjectId($id, $context)'
298     - 'sub getACLByMethodname($id, $context)'
299     - 'sub getACLByName($id, $context)'
300     ( would require a kinda registry to look up these very names pointing to arbitrary locations (code, data, ...) )
301     - add more hooks and various levels
302     - better integrate introduced 'getObjectByGuid'-mechanism from Data::Storage::Handler::Tangram
303    
304    
305     =head3 LINKS / REFERENCES
306    
307     Specs:
308     UML 1.3 Spec: http://cgi.omg.org/cgi-bin/doc?ad/99-06-08.pdf
309     XMI 1.1 Spec: http://cgi.omg.org/cgi-bin/doc?ad/99-10-02.pdf
310     XMI 2.0 Spec: http://cgi.omg.org/docs/ad/01-06-12.pdf
311     ODMG: http://odmg.org/
312     OIFML: http://odmg.org/library/readingroom/oifml.pdf
313    
314     CASE Tools:
315     Rational Rose (commercial): http://www.rational.com/products/rose/
316     Together (commercial): http://www.oi.com/products/controlcenter/index.jsp
317     InCASE - Tangram-based Universal Object Editor
318     Sybase PowerDesigner: http://www.sybase.com/powerdesigner
319    
320     UML Editors:
321     Fujaba (free, university): http://www.fujaba.de/
322     ArgoUML (free): http://argouml.tigris.org/
323     Poseidon (commercial): http://www.gentleware.com/products/poseidonDE.php3
324     Co-operative UML Editor (research): http://www.darmstadt.gmd.de/concert/activities/internal/umledit.html
325     Metamill (commercial): http://www.metamill.com/
326     Violet (university, research, education): http://www.horstmann.com/violet/
327     PyUt (free): http://pyut.sourceforge.net/
328     (Dia (free): http://www.lysator.liu.se/~alla/dia/)
329     UMLet (free, university): http://www.swt.tuwien.ac.at/umlet/index.html
330     Voodoo (free): http://voodoo.sourceforge.net/
331     Umbrello UML Modeller: http://uml.sourceforge.net/
332    
333     UML Tools:
334     http://www.objectsbydesign.com/tools/umltools_byPrice.html
335    
336     Further readings:
337     http://www.google.com/search?q=web+based+uml+editor&hl=en&lr=&ie=UTF-8&oe=UTF-8&start=10&sa=N
338     http://www.fernuni-hagen.de/DVT/Aktuelles/01FHHeidelberg.pdf
339     http://www.enhyper.com/src/documentation/
340     http://cis.cs.tu-berlin.de/Dokumente/Diplomarbeiten/2001/skinner.pdf
341     http://citeseer.nj.nec.com/vilain00diagrammatic.html
342     http://archive.devx.com/uml/articles/Smith01/Smith01-3.asp
343    
344    
345     =cut
346    

MailToCvsAdmin">MailToCvsAdmin
ViewVC Help
Powered by ViewVC 1.1.26 RSS 2.0 feed