# HG changeset patch
# User Adrien Di Mascio <Adrien.DiMascio@logilab.fr>
# Date 1248280947 -7200
# Node ID 70f85df651a5dfccda87e2fdcd4c6a1518581f8f
# Parent  f6757021018fe41c6f042f4734d4d3ca01c660aa
simple implementation of sparql XML resultset view

diff -r f6757021018f -r 70f85df651a5 web/views/sparql.py
--- a/web/views/sparql.py	Wed Jul 22 18:35:21 2009 +0200
+++ b/web/views/sparql.py	Wed Jul 22 18:42:27 2009 +0200
@@ -5,10 +5,15 @@
 :contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
 :license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
 """
+__docformat__ = "restructuredtext en"
+
 import rql
 from yams import xy
 
-from cubicweb.view import StartupView
+from lxml import etree
+from lxml.builder import E
+
+from cubicweb.view import StartupView, AnyRsetView
 from cubicweb.web import form, formfields, formwidgets as fwdgs
 from cubicweb.web.views import forms, urlrewrite
 from cubicweb.spa2rql import Sparql2rqlTranslator
@@ -41,3 +46,57 @@
             except xy.UnsupportedVocabulary, ex:
                 self.w(self.req._('unknown vocabulary:') + u' ' + unicode('ex'))
             self.wview('table', 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 = 'sparql'
+    content_type = 'application/sparql-results+xml'
+    templatable = False
+    # XXX use accept-headers-selectors to choose among the sparql result views
+
+    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))
+
+    def cell_binding(self, row, col, varname):
+        celltype = self.rset.description[row][col]
+        if self.schema.eschema(celltype).is_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)