Vazaar Project Blog

New custom timeline widget

Thu, 02 Sep 2010 02:15:14 +0000

Tired of looking for a timeline widget in PyGTK for Vazaar I’ve decided to develop it by myself.

It’s very simple: 1 calendar and 3 treeviews.

The user clicks a day in the calendar and with the selected date Vazaar asks to the database for those resources created that day, the day before and the day after.

Here is a screenshot:

You can find an example in the repository.Similar Posts:

Attached Files:

Vazaar Timeline
A timeline for vazaar showing resources for selected, previous and next day.

posted in GUI by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

How to fix your sqlite database after corruption

Wed, 01 Sep 2010 23:45:00 +0000

If you get something like this:

Traceback (most recent call last):
  File "./bin/vazaar", line 79, in
    Vazaar(options, args)
  File "/home/t00m/dev/trunk/vazaarlib/main.py", line 61, in __init__
    self.store = StoreManager(self)
  File "/home/t00m/dev/trunk/vazaarlib/store.py", line 54, in __init__
    self.__get_graph()
  File "/home/t00m/dev/trunk/vazaarlib/store.py", line 85, in __get_graph
    self.graph.store.open(self.options)
  File "/usr/lib/pymodules/python2.6/rdflib/store/Sleepycat.py", line 77, in open
    index.open(index_name, dbname, dbtype, dbopenflags|db.DB_CREATE, dbmode)

MemoryError: (12, 'Cannot allocate memory -- Lock table is out of available locker entries')

Just go to database directory and delete all files similar to __db.

Reason:
This problem occurs when Vazaar accesses the Berkeley database files, it makes temporary locker entries within the tables while it searches for data. If Vazaar crashes often, this issue will occur much sooner because the locks are never cleared.

Tip found at http://www.linuxmaza.com/system-administration/solved-lock-table-is-out-of-available-locker-entries-yum-install-yum-upgrade-3/Similar Posts:

posted in Python by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

PyGTK XDot Widget

Thu, 19 Aug 2010 15:15:54 +0000

XDot es un magnífico componente para representar grafos interactivos con Python, Graphviz y GTK.

De la web del autor:

xdot.py is an interactive viewer for graphs written in Graphviz’s dot language.

It uses internally the graphviz’s xdot output format as an intermediate format, and PyGTK and Cairo for rendering.
xdot.py can be used either as a standalone application from command line, or as a library embedded in your python application.

Features

Since it doesn’t use bitmaps it is fast and has a small memory footprint.

Arbitrary zoom.

Keyboard/mouse navigation.

Supports events on the nodes with URLs.

Animated jumping between nodes.

Highlights node/edge under mouse.

Este código ilustra como usar el widget en una aplicación. En la mía, genero dinámicamente el código dot según los nodos (recursos) que haya eligido el usuario. En los adjuntos puedes encontrar otro ejemplo mezclando rdflib y xdot:

import gtk # gtk bindings
import xdot # xdot library

class FooXDot(xdot.DotWidget):
def __init__(self, func):
xdot.DotWidget.__init__(self)

# Filters allowed: ‘dot’, ‘neato’, ‘twopi’, ‘circo’, ‘fdp’
self.set_filter(‘circo’)
self.connect(‘clicked’, func)

def display_dot(self):
# Header
dc_head = """digraph Vazaar {\ncharset="UTF-8";\n"""

# Relations
dc_body = """"user1" -> "tennis";\n"""
dc_body = """"user1" -> "basket";\n"""
dc_body += """"user1" -> "soccer";\n"""
dc_body += """"user2" -> "basket";\n"""
dc_body += """"user2" -> "soccer";\n"""
dc_body += """"user3" -> "tennis";\n"""
dc_body += """"user3" -> "soccer";\n"""
dc_body += """"user4" -> "karate";\n"""
dc_body += """"user4" -> "soccer";\n"""
dc_body += """"user4" -> "tennis";\n"""

# Key Nodes
# people
dc_body += """"user1" [URL="%s", url="%s", label="%s", shape="box", \
style="filled", fillcolor="yellow"];\n""" % (‘user1′, ‘user1′, ‘John’)
dc_body += """"user2" [URL="%s", url="%s", label="%s", shape="box", \
style="filled", fillcolor="yellow"];\n""" % (‘user2′, ‘user2′, ‘Steven’)
dc_body += """"user3" [URL="%s", url="%s", label="%s", shape="box", \
style="filled", fillcolor="yellow"];\n""" % (‘user3′, ‘user3′, ‘Paul’)
dc_body += """"user4" [URL="%s", url="%s", label="%s", shape="box", \
style="filled", fillcolor="yellow"];\n""" % (‘user4′, ‘user4′, ‘Thomas’)
# plays
dc_body += """"tennis" [URL="%s", url="%s", label="%s", shape="circle", \
style="filled", fillcolor="green"];\n""" % (‘tennis’, ‘tennis’, ‘Tennis’)
dc_body += """"basket" [URL="%s", url="%s", label="%s", shape="circle", \
style="filled", fillcolor="lightblue"];\n""" % (‘basket’, ‘basket’, ‘Basket’)
dc_body += """"soccer" [URL="%s", url="%s", label="%s", shape="circle", \
style="filled", fillcolor="hotpink"];\n""" % (‘soccer’, ‘soccer’, ‘Soccer’)
dc_body += """"karate" [URL="%s", url="%s", label="%s", shape="circle", \
s tyle="filled", fillcolor="white"];\n""" % (‘karate’, ‘Karate’, ‘Karate’)

# Fotter
dc_footer = "}"

# Join all parts
xdot_code = dc_head + dc_body + dc_footer

# Update widget with the new dot code
self.set_dotcode(xdot_code)

# callback called after user clicks in a node
def on_url_clicked(widget, keynode, event):
print ‘Key Node:’, keynode

if __name__ == ‘__main__’:
# create widget and display dot code
xdot = FooXDot(on_url_clicked)
xdot.display_dot()
xdot.show_all()

# gtk stuff
window = gtk.Window()
window.resize(800, 600)
window.connect(‘destroy’, gtk.main_quit)
window.show_all()

# Embed XDot widget
window.add(xdot)

# Get fun
gtk.main()

Resultado:

XDot widget in action

Código fuente de otro ejemplo: xdot.zipSimilar Posts:

Attached Files:

posted in GUI by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

Question about UTF-8

Wed, 18 Aug 2010 14:56:11 +0000

Sometimes, I’ve noticed that my application doesn’t deal very well with UTF-8 input/output. UTF-8 is mandatory but it’s a headache when you have to spend your time guessing what is wrong and how display the right characteres. I’ve found this function to force encode any text into UTF-8.

keydict = {
‘zwnj’: ”, ‘aring’: ‘\xc3\xa5′, ‘gt’: ‘>’, ‘yen’: ‘\xc2\xa5′,
‘ograve’: ‘\xc3\xb2′, ‘Chi’: ‘\xce\xa7′, ‘delta’: ‘\xce\xb4′,
‘rang’: ‘\xe3\x80\x89′, ‘sup’: ‘\xe2\x8a\x83′,
‘trade’: ‘\xe2\x84\xa2′, ‘ge’: ‘\xe2\x89\xa5′, ‘xi’: ‘\xce\xbe’,
‘upsih’: ‘\xcf\x92′, ‘nbsp’: ”, ‘Atilde’: ‘\xc3\x83′,
‘radic’: ‘\xe2\x88\x9a’, ‘otimes’: ‘\xe2\x8a\x97′,
‘aelig’: ‘\xc3\xa6′, ‘oelig’: ‘\xc5\x93′, ‘equiv’: ‘\xe2\x89\xa1′,
‘ni’: ‘\xe2\x88\x8b’, ‘le’: ‘\xe2\x89\xa4′, ‘auml’: ‘\xc3\xa4′,
‘cup’: ‘\xe2\x88\xaa’, ‘Epsilon’: ‘\xce\x95′, ‘otilde’: ‘\xc3\xb5′,
‘lt’: ‘< ‘, ‘Icirc’: ‘\xc3\x8e’, ‘shy’: ”, ‘Eacute’: ‘\xc3\x89′,
‘ndash’: ‘\xe2\x80\x93′, ‘yacute’: ‘\xc3\xbd’,
‘Prime’: ‘\xe2\x80\xb3′, ‘prime’: ‘\xe2\x80\xb2′, ‘psi’: ‘\xcf\x88′,
‘Kappa’: ‘\xce\x9a’, ‘rsaquo’: ‘\xe2\x80\xba’, ‘Tau’: ‘\xce\xa4′,
‘alefsym’: ‘\xe2\x84\xb5′, ‘ocirc’: ‘\xc3\xb4′, ‘lrm’: ”,
‘zwj’: ”, ‘cedil’: ‘\xc2\xb8′, ‘Ecirc’: ‘\xc3\x8a’,
‘not’: ‘\xc2\xac’, ‘Dagger’: ‘\xe2\x80\xa1′, ‘AElig’: ‘\xc3\x86′,
‘oslash’: ‘\xc3\xb8′, ‘acute’: ‘\xc2\xb4′, ‘lceil’: ‘\xe2\x8c\x88′,
‘iquest’: ‘\xc2\xbf’, ‘uacute’: ‘\xc3\xba’, ‘laquo’: ‘\xc2\xab’,
‘dArr’: ‘\xe2\x87\x93′, ‘rdquo’: ‘\xe2\x80\x9d’,
‘Ntilde’: ‘\xc3\x91′, ‘Igrave’: ‘\xc3\x8c’, ‘nu’: ‘\xce\xbd’,
‘lsquo’: ‘\xe2\x80\x98′, ‘lsaquo’: ‘\xe2\x80\xb9′,
‘sube’: ‘\xe2\x8a\x86′, ‘rarr’: ‘\xe2\x86\x92′,
‘sdot’: ‘\xe2\x8b\x85′, ‘supe’: ‘\xe2\x8a\x87′, ‘Yacute’: ‘\xc3\x9d’,
‘lfloor’: ‘\xe2\x8c\x8a’, ‘lArr’: ‘\xe2\x87\x90′, ‘Auml’: ‘\xc3\x84′,
‘asymp’: ‘\xe2\x89\x88′, ‘Otilde’: ‘\xc3\x95′, ‘szlig’: ‘\xc3\x9f’,
‘clubs’: ‘\xe2\x99\xa3′, ‘agrave’: ‘\xc3\xa0′, ‘Ocirc’: ‘\xc3\x94′,
‘Theta’: ‘\xce\x98′, ‘Pi’: ‘\xce\xa0′, ‘harr’: ‘\xe2\x86\x94′,
‘Scaron’: ‘\xc5\xa0′, ‘frac14′: ‘\xc2\xbc’, ‘egrave’: ‘\xc3\xa8′,
‘sub’: ‘\xe2\x8a\x82′, ‘iexcl’: ‘\xc2\xa1′, ‘frac12′: ‘\xc2\xbd’,
‘ordf’: ‘\xc2\xaa’, ‘rlm’: ”, ‘prop’: ‘\xe2\x88\x9d’,
‘circ’: ‘\xcb\x86′, ‘ntilde’: ‘\xc3\xb1′, ‘apos’: "’",
‘atilde’: ‘\xc3\xa3′, ‘THORN’: ‘\xc3\x9e’, ‘theta’: ‘\xce\xb8′,
‘prod’: ‘\xe2\x88\x8f’, ‘nsub’: ‘\xe2\x8a\x84′,
‘hArr’: ‘\xe2\x87\x94′, ‘rArr’: ‘\xe2\x87\x92′, ‘Oslash’: ‘\xc3\x98′,
‘omicron’: ‘\xce\xbf’, ‘infin’: ‘\xe2\x88\x9e’, ‘yuml’: ‘\xc3\xbf’,
‘Mu’: ‘\xce\x9c’, ‘Psi’: ‘\xce\xa8′, ‘thinsp’: ‘\xe2\x80\x89′,
‘ecirc’: ‘\xc3\xaa’, ‘bdquo’: ‘\xe2\x80\x9e’, ‘Sigma’: ‘\xce\xa3′,
‘kappa’: ‘\xce\xba’, ‘Aring’: ‘\xc3\x85′, ’tilde’: ‘\xcb\x9c’,
‘emsp’: ‘\xe2\x80\x83′, ‘mdash’: ‘\xe2\x80\x94′,
‘uarr’: ‘\xe2\x86\x91′, ‘permil’: ‘\xe2\x80\xb0′, ‘tau’: ‘\xcf\x84′,
‘Ugrave’: ‘\xc3\x99′, ‘fnof’: ‘\xc6\x92′, ‘Agrave’: ‘\xc3\x80′,
‘sup1′: ‘\xc2\xb9′, ‘forall’: ‘\xe2\x88\x80′, ‘eth’: ‘\xc3\xb0′,
‘rceil’: ‘\xe2\x8c\x89′, ‘iuml’: ‘\xc3\xaf’, ‘gamma’: ‘\xce\xb3′,
‘lambda’: ‘\xce\xbb’, ‘reg’: ‘\xc2\xae’, ‘Egrave’: ‘\xc3\x88′,
‘sup3′: ‘\xc2\xb3′, ‘dagger’: ‘\xe2\x80\xa0′, ‘divide’: ‘\xc3\xb7′,
‘Ouml’: ‘\xc3\x96′, ‘image’: ‘\xe2\x84\x91′, ‘hellip’: ‘\xe2\x80\xa6′,
‘igrave’: ‘\xc3\xac’, ‘Yuml’: ‘\xc5\xb8′, ‘Oacute’: ‘\xc3\x93′,
‘pound’: ‘\xc2\xa3′, ‘eacute’: ‘\xc3\xa9′, ‘frasl’: ‘\xe2\x81\x84′,
‘ETH’: ‘\xc3\x90′, ‘lowast’: ‘\xe2\x88\x97′, ‘Nu’: ‘\xce\x9d’,
‘plusmn’: ‘\xc2\xb1′, ‘chi’: ‘\xcf\x87′, ‘sup2′: ‘\xc2\xb2′,
‘frac34′: ‘\xc2\xbe’, ‘Aacute’: ‘\xc3\x81′, ‘cent’: ‘\xc2\xa2′,
‘oline’: ‘\xe2\x80\xbe’, ‘Beta’: ‘\xce\x92′, ‘perp’: ‘\xe2\x8a\xa5′,
‘Delta’: ‘\xce\x94′, ‘loz’: ‘\xe2\x97\x8a’, ‘pi’: ‘\xcf\x80′,
‘iota’: ‘\xce\xb9′, ‘empty’: ‘\xe2\x88\x85′, ‘euml’: ‘\xc3\xab’,
‘brvbar’: ‘\xc2\xa6′, ‘iacute’: ‘\xc3\xad’, ‘para’: ‘\xc2\xb6′,
‘ordm’: ‘\xc2\xba’, ‘epsilon’: ‘\xce\xb5′, ‘uuml’: ‘\xc3\xbc’,
‘OElig’: ‘\xc5\x92′, ‘there4′: ‘\xe2\x88\xb4′,
‘part’: ‘\xe2\x88\x82′, ‘icirc’: ‘\xc3\xae’, ‘bull’: ‘\xe2\x80\xa2′,
‘upsilon’: ‘\xcf\x85′, ‘copy’: ‘\xc2\xa9′, ‘Iuml’: ‘\xc3\x8f’,
‘Lambda’: ‘\xce\x9b’, ‘Xi’: ‘\xce\x9e’, ‘ensp’: ‘\xe2\x80\x82′,
‘ccedil’: ‘\xc3\xa7′, ‘Ucirc’: ‘\xc3\x9b’, ‘cap’: ‘\xe2\x88\xa9′,
‘Upsilon’: ‘\xce\xa5′, ‘mu’: ‘\xce\xbc’, ‘sigmaf’: ‘\xcf\x82′,
‘scaron’: ‘\xc5\xa1′, ‘nabla’: ‘\xe2\x88\x87′,
‘isin’: ‘\xe2\x88\x88′, ‘Zeta’: ‘\xce\x96′, ‘minus’: ‘\xe2\x88\x92′,
‘deg’: ‘\xc2\xb0′, ‘and’: ‘\xe2\x88\xa7′, ‘real’: ‘\xe2\x84\x9c’,
‘ang’: ‘\xe2\x88\xa0′, ‘curren’: ‘\xc2\xa4′, ‘int’: ‘\xe2\x88\xab’,
‘ucirc’: ‘\xc3\xbb’, ‘rfloor’: ‘\xe2\x8c\x8b’, ‘crarr’: ‘\xe2\x86\xb5′,
‘ugrave’: ‘\xc3\xb9′, ‘notin’: ‘\xe2\x88\x89′, ‘exist’: ‘\xe2\x88\x83′,
‘cong’: ‘\xe2\x89\x85′, ‘Uuml’: ‘\xc3\x9c’, ‘oplus’: ‘\xe2\x8a\x95′,
‘times’: ‘\xc3\x97′, ‘Acirc’: ‘\xc3\x82′, ‘piv’: ‘\xcf\x96′,
‘Euml’: ‘\xc3\x8b’, ‘Phi’: ‘\xce\xa6′, ‘raquo’: ‘ \xc2\xbb’,
‘Iacute’: ‘\xc3\x8d’, ‘quot’: ”, ‘Uacute’: ‘\xc3\x9a’,
‘Omicron’: ‘\xce\x9f’, ‘ne’: ‘\xe2\x89\xa0′, ‘Iota’: ‘\xce\x99′,
‘eta’: ‘\xce\xb7′, ‘sbquo’: ‘\xe2\x80\x9a’, ‘Rho’: ‘\xce\xa1′,
‘darr’: ‘\xe2\x86\x93′, ‘Alpha’: ‘\xce\x91′, ‘zeta’: ‘\xce\xb6′,
‘Omega’: ‘\xce\xa9′, ‘acirc’: ‘\xc3\xa2′, ‘sim’: ‘\xe2\x88\xbc’,
‘phi’: ‘\xcf\x86′, ‘diams’: ‘\xe2\x99\xa6′, ‘macr’: ‘\xc2\xaf’,
‘larr’: ‘\xe2\x86\x90′, ‘Ccedil’: ‘\xc3\x87′, ‘aacute’: ‘\xc3\xa1′,
‘uArr’: ‘\xe2\x87\x91′, ‘beta’: ‘\xce\xb2′, ‘Eta’: ‘\xce\x97′,
‘weierp’: ‘\xe2\x84\x98′, ‘rho’: ‘\xcf\x81′, ‘micro’: ‘\xc2\xb5′,
‘alpha’: ‘\xce\xb1′, ‘omega’: ‘\xcf\x89′, ‘middot’: ‘\xc2\xb7′,
‘Gamma’: ‘\xce\x93′, ‘euro’: ‘\xe2\x82\xac’, ‘lang’: ‘\xe3\x80\x88′,
‘spades’: ‘\xe2\x99\xa0′, ‘amp’: ‘and’, ‘rsquo’: ‘\xe2\x80\x99′,
‘uml’: ‘\xc2\xa8′, ‘thorn’: ‘\xc3\xbe’, ‘ouml’: ‘\xc3\xb6′,
‘thetasym’: ‘\xcf\x91′, ‘or’: ‘\xe2\x88\xa8′, ‘Ograve’: ‘\xc3\x92′,
‘sect’: ‘\xc2\xa7′, ‘ldquo’: ‘\xe2\x80\x9c’,
‘hearts’: ‘\xe2\x99\xa5′, ‘sigma’: ‘\xcf\x83′,‘sum’: ‘\xe2\x88\x91′,
‘oacute’: ‘\xc3\xb3′
}

def decode_unicode_references(data):
try:
text = data
pos1 = text.find(‘&’)
pos2 = text.find(‘;’)
if (((pos1 != -1) or (pos2 != -1)) and (pos2 – pos1 < 15)):
entity = text[pos1+1: pos2]
a = text[pos1:pos2+1]
return text.replace(a, keydict[entity])
else:
return data
except:
return data

def str2utf8(data):
data = decode_unicode_references(data)
guess_list=[‘utf-8′,‘iso8859-1′,‘iso8859-2′, \
‘iso8859-15′,‘ascii’]
encoding = ‘iso8859-1′
text = None
string = None
for best_enc in guess_list:
try:
encoding = best_enc
text = data.decode(encoding).encode(‘utf-8′)
break
except Exception, error:
#print "ERROR:", error
pass

return text

How do you deal with UTF-8, python and gtk? Am I doing right? Do you know a better way?

Similar Posts:

posted in Python by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

Reports with Cheetah templates

Mon, 16 Aug 2010 09:32:37 +0000

I’ve found Cheetah template engine very useful to build custom reports. With a very small set of syntactic rules you can mix html and python to generate dynamic content.

This is a small example extracted from my project:

filename default.html:

#import time
#from vazaarlib.i18n import _
#from vazaarlib.utils import fuzzy_date, str2utf8, get_resource_contents
#from vazaarlib.utils import get_beautiful_rtype
#from vazaarlib.namespaces import *
#from vazaarlib.constants import GPATH, LPATH

#set $user_owner_pim_uri = $self.gui.app.cfgmgr.get_value(‘PIMO’, ‘PIM’)
#set $user_owner_uri = $self.gui.ask.get_owner($user_owner_pim_uri)
#set $user_owner_email_uri = $self.gui.ask.get_owner_email($user_owner_uri)
#set $uemail = $self.gui.app.vstore.get_property($user_owner_email_uri)
#set $uowner = $self.gui.app.vstore.get_property($user_owner_uri)
#set $totres = $self.gui.ask.get_total_resources()
#set $typefreq = $self.gui.ask.get_qname_frequency($RDF.type)
#set $medate = time.strftime("%A, %d %b %Y", $time.localtime(time.time()))
#set $metime = time.strftime("%H:%M", $time.localtime(time.time()))
#set $css = $open($GPATH['CSS'] + ‘/default/style.css’, ‘r’).read()

< !DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">

Vazaar
$css
–>

$medate @ $metime

$_("Hi") $uowner, your Knowledge Database has $totres resources

#for $rtype in $typefreq:
#set $title = get_beautiful_rtype($rtype)
#set $freq = $typefreq[$rtype]

#end for

"font-size: 10pt;" cellspacing="3px" cellpadding="3px" width="100%">

id="row">

"border-bottom: 1px solid gray;" align="left">$title	"border-bottom: 0px dotted gray;" align="right">$freq
"border-top: 0px solid black; color: black;" align="right">$_("Total resources: ")	"border-top: 1px solid black; color: black;" align="right">$totres

filename reports.py:

#!/usr/bin/python
# -*- coding: utf-8 -*-
# File: reports.py
# Author: Tomás Vírseda
# License: GPL v3
# Description: Report builder for Vazaar

[…]
from Cheetah.Template import Template

class Report():
def __init__(self, gui):
…
…

def build_starthere_report(self, params):
template = GPATH[‘TEMPLATES’] + ‘/default.html’
report = Template(file=template)
report.css_content = self.css_content
report.author = ‘Tomás Vírseda García’
report.date = ’14/12/2010′
report.params = params

return str(report)
[…]

Check the code at vazaarlib/ui/reports.py in the source project repository.Similar Posts:

posted in Reports by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

Blog info updated

Fri, 13 Aug 2010 22:46:20 +0000

Screenshots for current development version and download info updated.

–
May the cloud be with youSimilar Posts:

posted in News by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

Searching strings

Wed, 21 Jul 2010 10:53:51 +0000

Well, another thing I learnt today: how to search a given string in a RDF graph but matching only Literals:

def by_term(self, search_term):
query = """
SELECT DISTINCT ?rid
WHERE {
?rid ?predicate ?object .
FILTER isLiteral(?object) .
FILTER regex(?object, "%s", "i")
}
ORDER BY ?object
""" % Literal(search_term)
result = run_query(query, self.graph)

return result.selected

The most important here is the operator isLiteral used in the filters.Similar Posts:

posted in SPARQL Queries by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

Vazaar 0.4.8: a new release for testing

Sat, 10 Jul 2010 23:30:19 +0000

Hi,

another version of Vazaar is out for testing. Get it while hot. There are a lot of changes respect older versions. Now, you can manage easily your notes, diary, bookmarks an other resources. Also, you can display them as graph of connected resources or as a list. Resources can be imported/exported to/from other persons.

Don’t hesitate to email me with your comments (kaskaras @ gmail.com). Please, visit my launchpad project page for more info, report bugs, ask questions, etc.

How to get it

Direct link to download
From repository: bzr branch lp:~kaskaras/trunk/vazaar vazaar-readonly
From Pypi (updating)

How to install it

Once unpacked in any arbitrary directory:

Exectute it by running: ./bin/vazaar

Install it system-wide by running: sudo python setup.py install

Similar Posts:

Attached Files:

Vazaar

posted in News by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

What is coming in the next version

Sun, 23 May 2010 16:50:59 +0000

Despite of the fact I don’t post in this weblog most often I think I haven’t wasted my spare time (my current work isn’t related with anything about this, yet). Instead it has been very productive and I am very happy with last results. In the end, I’m starting to see something useful.

Most of time, I’ve been reading more and more about NEPOMUK and playing with SPARQL queries. I have to recognize that it not that simple as I thought in a first moment but I’ll talk about this [intlink id="41" type="category" target="_self"]later[/intlink].

I have something to say about RDFLib: it is wonderful. From time to time I have to deal with some glitches but, most of them, are related to my own code. Anyway I am not using all the potential that this library offers.

Current work:

Vazaar is more stable than before. But (there is always a but) sometimes it crashes with a “segment fault”. This behavior is random and it is related with ‘Website’ resources.
Resources are not added directly to database. Before that, resources are passed to a queue. That means that you can enqueue new resources without waiting to finish the last one. Despite of Vazaar is designed to work with threads sometimes the GUI is blocked. This part is the most difficult and annoying thing that I’ve found. Someone smartest than me should take a look to the code.
By now, it is only possible to create/edit pimo:Notes (it’s finished but needs a deep revision)
“Copy & Paste” mode is working very well. If you copy any text from anywhere from your Desktop it will be added as a note. But Vazaar can recognize if it is more than simple text: if you copy an URL, the text will be added as a Website or if you copy a file from Nautilus the text will be added as a resource depending on its mimetype.
Also, clipboard monitoring can be toggled at any time.
One of the most important features that I want for Vazaar is the possibility of displaying the resources content. Right now, Vazaar is able to display text-based resources (like the source code from a given program), audio, video, images or websites. Other resources like OpenOffice.org documents, compressed files, ISO images, etc. are executed in its own program.
Backup & Restore of your knowledge database. Although it is working very well it is not finished yet.
Basic D-Bus support implemented. Although I haven’t yet decided an API, in the future, others applications will be able to interact with Vazaar to query its database, add resources, etc. …
A basic but extensible plugin system based on hooks is available and working. I have tested it developing smalls plugins which extends the funcionality (send notes to twitter, extend menus, ..). In the future I hope to extend the funcionality of Vazaar by releasing plugins instead of releasing new version of this application.
The SPARQL Editor have been improved: now it groups triples according to its subject.
New icons to describe resources
I’ve developed a new Tag Cloud widget. Websites are analyzed getting their tags (if any). Tags are saved as resources as well.
I’ve started to define the PersonalInformationModel. The Knowledge Database must know who is the owner of (meta)data. This is necessary to share info with other people. Right now it is defined by a set of triples which define a pimo:PersonalInformationModel, which has a pimo:hasOwner. The owner is defined by a nfo:Contact
Another feature that I am trying to handle is related to bug lp:425877 in lauchpad. I’m trying to keep Vazaar window size as small as possible in order to be used in small devices.

Work to be done before releasing the next 0.5 version:

Be able to handle other kinds of resources like: pimo:BlogPost (diary entries), pimo:Topic, pimo:Person and pimo:PersonGroup (nco:Contacts), pimo:Organization, pimo:Project, pimo:Event, pimo:Meeting, tmo:Task, and tmo:TaskGroups, nfo:Bookmark and pimo:Collection
Be able to define relations between resources
Temporal bags: a way to make operations over different resources at the same time. Think in it as virtual collections of resources.
Annotate resources. Any kind of resource can have any number of annotations.
Support for i18n (make Vazaar translatable)

I’ll try to develop all of this along the summer and I hope to have the new version ready for production before next Ubuntu release. Also, I hope to have Debian packages ready to install easily. At the same time, Vazaar be able to be installed from Pypi.

If you are interested in the development of this application (and you are really welcome), take a look to my Launchpad webpage. Check out lp:~kaskaras/vazaar/trunk for last bits (bzr branch lp:~kaskaras/vazaar/trunk)Similar Posts:

posted in News by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

distutils implemented

Sat, 12 Sep 2009 00:48:39 +0000

Finally, I got the way to implement distutils into Vazaar. It lacks support for i18n/gettext but it is in the way. I’ve released a new tarball. You can launch it as developer inside your home with the command ./launch

But if you prefer a wide-system install, you must use the following command:

sudo python2.5 setup.py install

You can find an entry under Applications -> Office -> Vazaar

python 2.6 also works but it throws warnings.

Please, note that you can NOT combine different versions of python because database sqlite formats differs each from other.Similar Posts:

posted in Python by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

Vazaar 0.4 (aka Sacabambaspis) released

Sun, 06 Sep 2009 00:16:05 +0000

Hi everybody,

a new version of vazaar have been released for testing purposes. Although it’s stable you can consider it as proof of concept.

This version is a redesign of the previous one. While the old one was developed in C, the new one is being developed with Python. Also, I’ve been studying a new approach. Instead of work with tags and tagging operations, the new version is powered by the semantic web vision, ideas and tools.

I’d like to highlight RDFLib, a RDF library containing an RDF triple store and RDF/XML parser/serializer which deals with the logic of the application.

Go to the Download page to get it. Check the screenshot page as well.

Development is carried out at Lauchpad.

Now that I understand how a semantic model works I have more and better ideas to implement.

Next version will be released, hopefully, before this year ends.

Enjoy it.Similar Posts:

posted in News by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

Dynamic SPARQL queries and Datatypes

Wed, 26 Aug 2009 09:24:44 +0000

After some headaches I’ve found how to write dynamic SPARQL queries by passing parameters. For example, to query graph about resources collected last hour this code could be a first approach:

#!/usr/bin/env python
# Dynamic query (example code)

from datetime import datetime
import rdflib
from namespaces import XSD

def last_day():
""" get date """
now = datetime.now()
date = now – timedelta(hours=24)

return date

def get_date_filtered_query():
""" build query """
period = last_day()
mydate = Literal(period, datatype=URIRef(XSD))

query = """
PREFIX rdf:
PREFIX nie:
PREFIX nfo:
PREFIX nao:
PREFIX pimo:
PREFIX xsd:
SELECT ?id
WHERE
{
?id rdf:type ?type .
?id nao:created ?date .
FILTER (?type != pimo:Collection) .
FILTER (xsd:dateTime(?date) >= xsd:dateTime("%s")) .
}
ORDER BY DESC(?date)
""" % mydate

return query

# query graph
query = get_date_filtered_query()
result = graph.query(query)

for id in result.selected:
print id

For more information is worth to take a look W3C XML Schema Definition Language (XSD) 1.1 Part 2: Datatypes. A self explained list of XML datatypes:

xsd:anyURI – URI (Uniform Resource Identifier)
xsd:base64Binary – Binary content coded as “base64″
xsd:boolean – Boolean (true or false)
xsd:byte – Signed value of 8 bits
xsd:date – Gregorian calendar date
xsd:dateTime – Instant of time (Gregorian calendar)
xsd:decimal – Decimal numbers
xsd:double – IEEE 64-bit floating-point
xsd:duration – Time durations
xsd:ENTITIES – Whitespace-separated list of unparsed entity references
xsd:ENTITY – Reference to an unparsed entity
xsd:float – IEEE 32-bit floating-point
xsd:gDay – Recurring period of time: monthly day
xsd:gMonth – Recurring period of time: yearly month
xsd:gMonthDay – Recurring period of time: yearly day
xsd:gYear – Period of one year
xsd:gYearMonth – Period of one month
xsd:hexBinary – Binary contents coded in hexadecimal
xsd:ID – Definition of unique identifiers
xsd:IDREF – Definition of references to unique identifiers
xsd:IDREFS – Definition of lists of references to unique identifiers
xsd:int – 32-bit signed integers
xsd:integer – Signed integers of arbitrary length
xsd:language – RFC 1766 language codes
xsd:long – 64-bit signed integers
xsd:Name – XML 1.O name
xsd:NCName – Unqualified names
xsd:negativeInteger – Strictly negative integers of arbitrary length
xsd:NMTOKEN – XML 1.0 name token (NMTOKEN)
xsd:NMTOKENS – List of XML 1.0 name tokens (NMTOKEN)
xsd:nonNegativeInteger – Integers of arbitrary length positive or equal to zero
xsd:nonPositiveInteger – Integers of arbitrary length negative or equal to zero
xsd:normalizedString – Whitespace-replaced strings
xsd:NOTATION – Emulation of the XML 1.0 feature
xsd:positiveInteger – Strictly positive integers of arbitrary length
xsd:QName – Namespaces in XML-qualified names
xsd:short – 32-bit signed integers
xsd:string – Any string
xsd:time – Point in time recurring each day
xsd:token – Whitespace-replaced and collapsed strings
xsd:unsignedByte – Unsigned value of 8 bits
xsd:unsignedInt – Unsigned integer of 32 bits
xsd:unsignedLong – Unsigned integer of 64 bits
xsd:unsignedShort – Unsigned integer of 16 bits

Similar Posts:

posted in SPARQL Queries by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

Querying remote ontologies from integrated SPARQL editor

Sun, 02 Aug 2009 16:28:44 +0000

Checking others parts of the Vazaar GUI, I’ve realized that I can query remote ontologies and vocabularies with a simple SPARQL sentence. In the screenshot you can see how I query for the comments of all NAO entities.

Just for the record, it would be nice to save user queries and integrate them within Vazaar. And, of course, to export result data to a file (eg.: in a CSV file) ready to import to a any spreadsheet program like OpenOffice Calc.Similar Posts:

Attached Files:

Querying remote ontologies
By using the integrated SPARQL editor it is possible to query remote ontologies and vocabularies

posted in SPARQL Queries by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

GUI improvements

Sun, 02 Aug 2009 14:02:17 +0000

After a long weekend coding and trying new design ideas finally I think I got a nice GUI. At least for the StartHere module:

There are still too much glitches in the GUI but I’m trying to fix them as I go. But for now, I feel satisfied. Queries against the model are working as expected.

After clicking in any stats button you get a nice visual for your resources. In next commits, you will be able of choosing one the two kinds of views: ListViews and IconViews. By default, the IconView is preferred.

More ideas are coming like content filtering, properties tagcloud, timeline widget, etc…

At this moment, you can only add new resources by copy&paste operations. An improved dialog for this operation is in the way. Resources can be selected for be deleted. If the selected resource is a collection, all resources which belong to this collection will be deleted. There is no actions popup menu yet but it’s planned.

I’m thinking if a Trash resource is worth. NEPOMUK brings especial classes for this cuestion. I need check twice these. Anyway, it wouldn’t be very difficult.

One of the most important things now is to code common operation for resources: tagging, annotations, relations between them and how to display their content. For example, display text or an image is easy to do but it is not very easy to display websites content. There is not a good browser widget ready to use in PyGTK yet. I put my hope in webkit bindings for Python.Similar Posts:

Attached Files:

Screenshot for Vazaar 0.4b

posted in GUI by Tomás Vírseda Leave A Comment
©2010 Vazaar Project Blog. All Rights Reserved.

About Vazaar 0.4 Beta development

Tue, 09 Jun 2009 16:30:08 +0000

After months of improving my skills with Python and PyGTK and reading documents about semantic web and its integration with Desktops Interfaces (like GNOME or KDE) a lot of improvements have been made in Vazaar. This is an overview of the current state of development.

The presentation layer, the GUI, is more difficult to develop than I’ve ever thought. Althought the concept is simple: given any kind of data, transform them into triples (subject, predicate, object) and operate with them, the time consumed to create an infrastructure around the program has been very high.

As resources can be added at any time, I had to develop a system of queues (qIn and qOut). Furthermore, I had to deal with very high responsiveness times. It’s very annoying when the GUI gets frozen because the kernel is working in other stuff. So I had to implement threads (one thread for the kernel and another thread for the GUI). Along the way, I’ve found a lot of code (see source code in Launchpad) which has helped me to carry on.

In some way, I would like to forget these kind of glitches when I’m developing a Desktop application (not a kernel module). Maybe I’ve learnt something about gtk threads but nothing interesting for this project. Never mind…

I’m still reading some documents and asking about how to create a data model around NEPOMUK. By using the semantic web paradigm things change a lot. There are no database records or tables. Instead there are thousands (or hundreds of thousands) of triples.

But it looks easiest than I thought, at the moment.

Everything is a resource (even collections). A resource has a unique identifier (UUID objects according to RFC 4122). Every resource belong to a unique Nepomuk class. They are a small subset of classes with their properties. Examples of Nepomuk classes are:

nfo:Feed
nfo:Website
nfo:RemoteDataObject
nfo:Image
nfo:Audio
nfo:Clipboard (this class doesn’t belong to NFO but I need it until I find a smart solution for copypaste operations).

As I say before, a collection is a resource. It belongs to the class Collection from PIMO namespace and use the property nie:hasLogicalPart to link resources.

Example of a single resource:

<nfo:Image rdf:about="vazaar://7971c05a-3a69-469e-875c-5ec76b0d0cfb">
    <nao:created>2009-06-09 17:34:51
    <nie:title>comment-icon.png
    <nao:lastModified>2009-06-09 17:34:51
    image
    /home/kaskaras/Documentos/vazaar-export-r303/data/icons/comment-icon.png
    comment-icon
    file
    comment-icon.png
    png
    3269
    /home/kaskaras/Documentos/vazaar-export-r303/data/icons
    png
    image/png

And here and example of a collection:

<pimo:Collection rdf:about="vazaar://9fcea6ca-cc79-4259-baff-6c025319a36e">
    <nao:created>2009-06-09 17:35:13.338280
    <nie:title>/home/kaskaras/Escritorio/screenshots
    <nao:lastModified>2009-06-09 17:35:13.338280
    <nie:hasLogicalPart>
      vazaar://15e820cb-398c-4917-b162-3b6d10cd8054">
        2009-06-09 17:35:13
        Pantallazo.png
        2009-06-09 17:35:13
        image
        /home/kaskaras/Escritorio/screenshots/Pantallazo.png
        Pantallazo
        file
        Pantallazo.png
        png
        188465
        /home/kaskaras/Escritorio/screenshots
        png
        image/png
      
    <nie:hasLogicalPart>
    <nie:hasLogicalPart>
    <nie:hasLogicalPart>
    <nie:hasLogicalPart>

Right now, no problems working with this model. It is simple and I think that powerful. But I haven’t finished of defining the basic core of properties for a given resource (single or collection). Thinking in the future of this application, I would like to expose public resources through a SPARQL End Point so another semantic application will be able to ask it. It shouldn’t be so hard as I’ve seen a couple of python libraries to implement it. But the most important now is to have a solid model which I can work with.

Summing up, this is the result of the of the current code:

Start Here

Make your own SPARQL queries

Basic Import support

Basic Export support

About Vazaar

Syntax Highlighting for your sourcecode-based resources

Basic support for image displaying

It’s a prototype. Don’t expect too much. In the next weeks I’ll try to work in the GUI adding visual improvements and new funcionalities.Similar Posts:

Attached Files:

vazaar-04-about
vazaar-04-export
Serialize database into a RDF file. No compression.
vazaar-04-import
Import a previous database export.
vazaar-04-query
Basic SPARQL editor for advanced users.
vazaar-04-sourceview
by using GtkSourceView python bindings
vazaar-04-starthere
It's the front page of the program where you can view last resources imported, copy pasted resources and collections
vazaar-04-viewimage
Vazaar implements a very basic image viewer
Vazaar RDF Model example
This example shows how Vazaar store data into RDF.

New home for Vazaar

Mon, 08 Jun 2009 22:09:24 +0000

Nine months after my last post, I’ve got a new home for Vazaar.

It lives now at https://launchpad.net/vazaar

I want to use the infrastructure provided by Ubuntu to accelerate the development and subsequent integration into
Ubuntu or Debian repositories.

Hope it be useful for everybody.Similar Posts:

My SVN is gone!

Wed, 03 Sep 2008 17:46:19 +0000

I don’t know what is going on but my svn repository hosted in Dreamhost is gone :-(

patience

Edit Saturday, September 06 2008:

Well, finally, I know what happend. My hosting company deciced to upgrade their 32bits Debian OS to 64bits and it failed. A lot. I haven’t lost anything but the svn is misconfigurated. So I’ve changed my repository to google code.

Please, update your bookmarks. You can access to the repository here:
svn checkout http://vazaar.googlecode.com/svn/trunk/ vazaar-read-only

or check this page:

http://code.google.com/p/vazaar/

Sorry about thatSimilar Posts:

Dublin Core Metadata Glossary

Thu, 28 Feb 2008 01:06:25 +0000

Voy camino de ser el blogger más improductivo de toda la red. Creo que leo más que escribo. Intentaré remediarlo. De momento, os dejo esta perla que me he encontrado:

Dublin Core Metadata Glossary

Final Draft

The Dublin Core Metadata Glossary is a collaborative effort of the User Guide Committee with special thanks to Gail Clement & Pete Winn, whose original glossary was a basis for this version. Terms included in this glossary are based on Dublin Core documents, presentations at DC conferences, and discussions on the DC General listserv. We welcome comments and feedback regarding additions, deletions or changes to the terms and/or definitions found below.For related links, including the guide itself, see this site’s home page.

The glossary was last updated on 02/24/2001

Aunque data del 2001 no me consta que las definiciones cambién de lustro en lustro. Todo un manjar para comprender los conceptos de la web semántica.

Editado (jueves, 28 de febrero de 2008 02:16)

He encontrado el glosario actualizado (23 April 2004) en la propia página de Dublin CoreSimilar Posts:

Revisión: 117. Estado del proyecto

Thu, 14 Feb 2008 13:23:24 +0000

Bueno, después de casi dos meses, puedo decir que he avanzado un poco más. Para no quemarme, aburrirme o morir en el intento voy alternando entre la programación de la interfaz gráfica y el motor de la aplicación.

La parte gráfica de momento es un laboratorio. Me limito a saber leer correctamente los recursos de la base de datos semántica, interpretar lo que me duvuelven las consultas y presentarlo chapuceramente al usuario. Voy a tener que buscar o hacerme bastantes widgets a medida. De momento me he creado una nube basada en una Gtk.Table donde represento los datos y sus frecuencias. Bastante útil, por cierto.

En relación al motor de la aplicación hay tres grandes cambios:

- Para no bloquear la parte gráfica estoy implementando hilos. Deberían llamarse líos.
- He adoptado el uso de colas para todas las peticiones de trabajo.
- Vazaar dispone de un sistema de plugins.

Los hilos es una de las partes más problemáticas y la quiero eliminar en cuanto pueda. Lo natural sería tener un motor que funcione independientemente de la parte gráfica.

La solicitud de trabajos (jobs) se van enconlando y procesando por el DataProvider. Este módulo se encarga de procesar los argumentos y dedcidir de qué tipo de recurso se trata: fichero, directorio, remoto y string. Dependiendo del tipo y el numero de argumentos pasados se llama al módulo Resources donde se construyen colecciones o recursos únicos. Las colecciones albergan dos o más recursos. Uno de los problemas que me ha resuelto la cola es permitir que el usuario pueda trabajar cómodamente mientras se van añadiendo recursos. Por ejemplo, todo lo que corte o pegue quedará automáticamente almacenado como recurso. Automáticamente, el programa se encarga de identificarlo y clasificarlo.

El sistema de plugins era necesario desde un primer momento. Desde que arranca la aplicación hasta que termina hay muchos eventos que atender y muchos recursos que descubrir. Está basado en las setuptools y por medio de ‘capabilities’ el sistema se puede extender. Hasta ahora el sistema de plugins funciona para dar soporte en la extracción de metadatos al módulo Resources y para presentar unas simples estadísticas.

Hoy por hoy el interfaz va unido al motor de la aplicación lo cual no es una buena idea pero de momento no tengo los conocimientos suficientes para montar un servidor de rdf. Lo cual sería una buena idea de cara a montar un servidor público/privado de un repositorio personal o de implentar su compartición vía p2p. Lo dejo para el ToDo.

SPARQL promete como sistema de consulta pero estoy encontrándome con problemas de rendimiento. Rdflib dispone de varios backends para almecanar la información del grafo: en memoria, (des)serializado en n3, rdfxml, etc., en una bbdd SleepyCat con ficheros planos y otro para MySQL. El primero sería impensable pues se comería toda la memoria del sistema. Puedo asegurar que (des)serializando tampoco (aunque de esta manera se aprende a leer e interpretar el propio grafo). El backend de Sleepycat es el que estoy usando ahora y de momento no me está convenciendo. Me parece lento y en la medida de lo posible no pienso aceptar tiempos de respuesta mayores al segundo. Por lo tanto me queda la opción de probar MySQL.

Si quieres ver estas ideas implementadas echa un vistazo al protipo 0.4p1:

svn co http://vazaar-project.org/svn/trunk/devel/0.4p1/ vazaar

Cada día más cerca de sacar algo en claro.

Un saludoSimilar Posts:

Dublin Core

Fri, 07 Dec 2007 17:18:38 +0000

Este es el primero de una serie de artículos sobre Dublin Core (DC) y metadatos. Explicaré un poco la teoría e intentaré mostrar ejemplos prácticos de su uso en Vazaar. Para realizarlo me he ayudado de una traducción al español de DC que he encontrado en RedIris y diversa documentación que he ido encontrando en la web de Dublin Core. Antes de empezar definiendo que es Dublin Core hay que entender que son los metadatos. Por lo tanto,

¿Qué son los metadatos?

Los metadatos se pueden considerar como descripciones que hacemos sobre cualquier clase de recurso que nos ayude a encontrarlo, identificarlo, usarlo, manejarlo, evaluarlo y preservarlo.

¿Cómo se pueden usar los metadatos?

Puedes usarlos para:

descubrir servicios
identificar versiones
marcar la estructura del contenido
manejar documentos
certificar auntenticidad
situar geoespacialmente
control de derechos
indicar estatus
describir procesos

Bases de los metadatos

La unidad básica del metadato es una afirmación
Una afirmación consiste de una propiedad (elemento) y un valor
Todas estas afirmaciones describen los recursos

¿A quién le importa los metadatos?

El término “metadato” tiene sentido en contextos tales como:

El modelado de datos,
la catalogación de libros en bibliotecas
el descubrimeniento de nuevos recursos en internet

Metadatos y Dublin Core

Dublin Core fue diseñado específicamente para proporcionar un vocabulario de características “base”, capaces de proporcionar la información descriptiva básica sobre cualquier recurso, sin que importe el formato de origen, el área de especialización o el origen cultural (extraído de la wikipedia).

Este vocabulario es el resultado de muchos años de búsqueda colaborativa con el objetivo de determinar un conjunto común de propiedades universales que describan cualquier tipo de recurso. El uso de sistemas de clasificación estandarizados hace posible que los metadatos de diferentes colecciones sean combinados y compartidos.

El vocabulario de Dublin Core está formado por elementos. Elementos con nombres descriptivos que pretenden transmitir un significado semántico a los mismos.

Podemos clasificar estos elementos en tres grupos que indican la clase o el ámbito de la información que se guarda en ellos:

1. Elementos relacionados principalmente con el contenido del recurso
2. Elementos relacionados principalmente con el recurso cuando es visto como una propiedad intelectual
3. Elementos relacionados principalmente con la instanciación del recurso

Los 15 elementos del vocabulario de Dublin Core:

	Elemento	Etiqueta	Descripción
1	Título	DC.Title	El nombre dado a un recurso, usualmente por el autor.
2	Autor	DC.Creator	La persona u organización responsable de la creación del contenido intelectual del recurso. Por ejemplo, los autores en el caso de documentos escritos, artistas, fotografos e ilustradoresen el caso de recursos visuales.
3	Claves	DC.Subject	Los tópicos del recurso. Típicamente, Subject expresará las claves o frases que describen el título o el contenido del recurso. Se fomentará el uso de vocabularios controlados y de sistemas de clasificación formales.
4	Descripción	DC.Description	Una descripción textual del recurso, tal como un resumen en el caso de un documento o una descripción del contenidoen el caso de un documento visual.
5	Editor	DC.Publisher	La entidad responsable de hacer que el recurso se encuentre disponible en la red en su formato actual. Por ejemplo la empresa editora, un departamento universitario u otro tipo de organización.
6	Colaboradores	DC.Contributor	Una persona u organizacion que haya tenido una contribución intelectual significativa en la creación del recurso pero cuyas contribuciones son secundarias en comparación a las de las personas u organizaciones especificadas en el elementeo Creator (por ejemplo, editor, ilustrador y traductor).
7	Fecha	DC.Date	Una fecha en la que el recurso se puso a disposición del usuario en su forma actual. Esta fecha no ha de confundirsecon la que pertenece al elemento Coverage, que sería asociada con el recurso solo en la medida en que el contenido intelectualestá de algún modo relacionado con esa fecha.
8	Tipo del Recurso	DC.Type	La categoría del recurso, por ejemplo página personal, romance, poema, minuta, diccionario. Para asegurar la interoperabilidad, Type debería ser seleccionado de entre unalista de valores que actualmente se encuentra bajo desarrollo en un grupo de trabajo.
8	Formato	DC.Format	El formato de datos de un recurso, usado para identificar el software y posiblemente, el hardware que se necesitaría para mostrar el recurso. Para asegurar la interoperabilidad, los valores de Format deberían ser seleccionados de entre una lista de valores que actualmente se encuentra bajo desarrollo en un grupo de trabajo.
10	Identificador	DC.Identifier	Secuencia de caracteres usados para identificar unívocamente un recurso. Ejemplos para recursos en línea pueden ser URLs y URNs (cuando estén implementados). Para otros recursos pueden ser usados otros formatos de identificadores, como por ejemplo ISBN (“International Standard Book Number” – Número Internacional Normalizado para Libros)
11	Fuente	DC.Source	Secuencia de caracteres utilizado para identificar unívocamente un trabajo a partir del cual proviene el recurso actual. Por ejemplo, es posible usar Source con la fecha de 1603 como descripción de una película basada en una obra de Shakespeare, pero es preferible, en ese caso, usar Relation “IsBasedOn” con una referencia a un recurso distinto cuyadescripción contenga el elemento Date con valor 1603.
12	Lengua	DC.Language	Lengua/s del contenido intelectual del recurso. Practicamente el contenido de este campo debería coincidir con los de la RFC 1766 (Tags para la identificación de lenguas, http://ds.internic.net/rfc/rf766.txt ); por ejemplo: en, es, de, fi, ja y zh.
13	Relación	DC.Relation	Un identificador de un segundo recurso y su relación con el recurso actual. Este elemento permite enlazar los recursos relacionados y las descripciones de los recursos.
14	Cobertura	DC.Coverage	La característica de cobertura espacial y/o temporal del contenido intelectual del recurso. La cobertura espacial se refiere a una región física (por ejemplo, sector celestial); uso de coordenadas (por ejemplo, longitud y latitud)o nombres de lugares extraidos de una lista controlada. La cobertura temporal se refiere al contenido del recurso en vez de a cuando fue creado o puesto accesible ya que este último pertenece al elemento Fecha.
15	Derechos	DC.Rights	Una referencia (URL, por ejemplo) para una nota sobre derechos de autor, para un servicio de gestión de derechos o para un servicio que dará información sobre términos y condiciones de acceso a un recurso. Una especificación formal del elemento Rights se encuentra actualmente en discusión y por lo tanto su uso se considera experimental.

Continuará…Similar Posts: