+
−"""SPARQL integration
+
−
+
−:organization: Logilab
+
−:copyright: 2009 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.
+
−:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
+
−:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
+
−"""
+
−v__docformat__ = "restructuredtext en"
+
−
+
−import rql
+
−from yams import xy
+
−
+
−from lxml import etree
+
−from lxml.builder import E
+
−
+
−from cubicweb.view import StartupView, AnyRsetView
+
−from cubicweb.web import Redirect, form, formfields, formwidgets as fwdgs
+
−from cubicweb.web.views import forms, urlrewrite
+
−try:
+
−    from cubicweb.spa2rql import Sparql2rqlTranslator
+
−except ImportError:
+
−    # fyzz not available (only a recommends)
+
−    Sparql2rqlTranslator = None
+
−
+
−class SparqlForm(forms.FieldsForm):
+
−    id = 'sparql'
+
−    sparql = formfields.StringField(help=_('type here a sparql query'))
+
−    resultvid = formfields.StringField(choices=((_('table'), 'table'),
+
−                                                (_('sparql xml'), 'sparqlxml')),
+
−                                       widget=fwdgs.Radio,
+
−                                       initial='table')
+
−    form_buttons = [fwdgs.SubmitButton()]
+
−    @property
+
−    def action(self):
+
−        return self.req.url()
+
−
+
−
+
−class SparqlFormView(form.FormViewMixIn, StartupView):
+
−    id = 'sparql'
+
−    def call(self):
+
−        form = self.vreg.select('forms', 'sparql', self.req)
+
−        self.w(form.render())
+
−        sparql = self.req.form.get('sparql')
+
−        vid = self.req.form.get('resultvid', 'table')
+
−        if sparql:
+
−            try:
+
−                qinfo = Sparql2rqlTranslator(self.schema).translate(sparql)
+
−            except rql.TypeResolverException, ex:
+
−                self.w(self.req._('can not resolve entity types:') + u' ' + unicode('ex'))
+
−            except UnsupportedQuery:
+
−                self.w(self.req._('we are not yet ready to handle this query'))
+
−            except xy.UnsupportedVocabulary, ex:
+
−                self.w(self.req._('unknown vocabulary:') + u' ' + unicode('ex'))
+
−            if vid == 'sparqlxml':
+
−                url = self.build_url('view', rql=qinfo.finalize(), vid=vid)
+
−                raise Redirect(url)
+
−            rset = self.req.execute(qinfo.finalize())
+
−            self.wview(vid, rset, 'null')
+
−
+
−
+
−## sparql resultset views #####################################################
+
−
+
−YAMS_XMLSCHEMA_MAPPING = {
+
−    'String': 'string',
+
−    'Int': 'integer',
+
−    'Float': 'float',
+
−    'Boolean': 'boolean',
+
−    'Datetime': 'dateTime',
+
−    'Date': 'date',
+
−    'Time': 'time',
+
−    # XXX the following types don't have direct mapping
+
−    'Decimal': 'string',
+
−    'Interval': 'duration',
+
−    'Password': 'string',
+
−    'Bytes': 'base64Binary',
+
−    }
+
−
+
−def xmlschema(yamstype):
+
−    return 'http://www.w3.org/2001/XMLSchema#%s' % YAMS_XMLSCHEMA_MAPPING[yamstype]
+
−
+
−class SparqlResultXmlView(AnyRsetView):
+
−    """The spec can be found here: http://www.w3.org/TR/rdf-sparql-XMLres/
+
−    """
+
−    id = 'sparqlxml'
+
−    content_type = 'application/sparql-results+xml'
+
−    templatable = False
+
−
+
−    def call(self):
+
−        # XXX handle UNION
+
−        rqlst = self.rset.syntax_tree().children[0]
+
−        varnames = [var.name for var in rqlst.selection]
+
−        results = E.results()
+
−        for rowidx in xrange(len(self.rset)):
+
−            result = E.result()
+
−            for colidx, varname in enumerate(varnames):
+
−                result.append(self.cell_binding(rowidx, colidx, varname))
+
−            results.append(result)
+
−        sparql = E.sparql(E.head(*(E.variable(name=name) for name in varnames)),
+
−                          results)
+
−        self.w(u'<?xml version="1.0"?>\n')
+
−        self.w(etree.tostring(sparql, encoding=unicode, pretty_print=True))
+
−
+
−    def cell_binding(self, row, col, varname):
+
−        celltype = self.rset.description[row][col]
+
−        if self.schema.eschema(celltype).final:
+
−            cellcontent = self.view('cell', self.rset, row=row, col=col)
+
−            return E.binding(E.literal(cellcontent,
+
−                                       datatype=xmlschema(celltype)),
+
−                             name=varname)
+
−        else:
+
−            entity = self.entity(row, col)
+
−            return E.binding(E.uri(entity.absolute_url()), name=varname)
+
−
+
−    def set_request_content_type(self):
+
−        """overriden to set the correct filetype and filename"""
+
−        self.req.set_content_type(self.content_type,
+
−                                  filename='sparql.xml',
+
−                                  encoding=self.req.encoding)
+
−
+
−def registration_callback(vreg):
+
−    if Sparql2rqlTranslator is not None:
+
−        vreg.register_all(globals().values(), __name__)