/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/load.py
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revision 1408 by frank, Mon Jul 14 09:38:29 2003 UTC revision 1970 by bh, Mon Nov 24 18:36:00 2003 UTC
# Line 38  from Thuban.Model.data import DerivedSha Line 38  from Thuban.Model.data import DerivedSha
38  from Thuban.Model.table import DBFTable  from Thuban.Model.table import DBFTable
39  from Thuban.Model.transientdb import TransientJoinedTable  from Thuban.Model.transientdb import TransientJoinedTable
40    
41    from Thuban.Model.xmlreader import XMLReader
42    import resource
43    
44    import postgisdb
45    
46  class LoadError(Exception):  class LoadError(Exception):
     pass  
47    
48  from Thuban.Model.xmlreader import XMLReader      """Exception raised when the thuban file is corrupted
49  import resource  
50        Not all cases of corrupted thuban files will lead to this exception
51        but those that are found by checks in the loading code itself are.
52        """
53    
54    
55    class LoadCancelled(Exception):
56    
57        """Exception raised to indicate that loading was interrupted by the user"""
58    
59    
60  def parse_color(color):  def parse_color(color):
61      """Return the color object for the string color.      """Return the color object for the string color.
# Line 87  class AttrDesc: Line 100  class AttrDesc:
100    
101  class SessionLoader(XMLReader):  class SessionLoader(XMLReader):
102    
103      def __init__(self):      def __init__(self, db_connection_callback = None):
104          """Inititialize the Sax handler."""          """Inititialize the Sax handler."""
105          XMLReader.__init__(self)          XMLReader.__init__(self)
106    
107            self.db_connection_callback = db_connection_callback
108    
109          self.theSession = None          self.theSession = None
110          self.aMap = None          self.aMap = None
111          self.aLayer = None          self.aLayer = None
# Line 101  class SessionLoader(XMLReader): Line 116  class SessionLoader(XMLReader):
116    
117          dispatchers = {          dispatchers = {
118              'session'       : ("start_session",        "end_session"),              'session'       : ("start_session",        "end_session"),
119    
120                'dbconnection': ("start_dbconnection", None),
121    
122                'dbshapesource': ("start_dbshapesource", None),
123              'fileshapesource': ("start_fileshapesource", None),              'fileshapesource': ("start_fileshapesource", None),
124              'derivedshapesource': ("start_derivedshapesource", None),              'derivedshapesource': ("start_derivedshapesource", None),
125              'filetable': ("start_filetable", None),              'filetable': ("start_filetable", None),
# Line 122  class SessionLoader(XMLReader): Line 141  class SessionLoader(XMLReader):
141    
142          # all dispatchers should be used for the 0.8 and 0.9 namespaces too          # all dispatchers should be used for the 0.8 and 0.9 namespaces too
143          for xmlns in ("http://thuban.intevation.org/dtds/thuban-0.8.dtd",          for xmlns in ("http://thuban.intevation.org/dtds/thuban-0.8.dtd",
144                        "http://thuban.intevation.org/dtds/thuban-0.9-dev.dtd"):                        "http://thuban.intevation.org/dtds/thuban-0.9-dev.dtd",
145                          "http://thuban.intevation.org/dtds/thuban-0.9.dtd",
146                          "http://thuban.intevation.org/dtds/thuban-1.0-dev.dtd"):
147              for key, value in dispatchers.items():              for key, value in dispatchers.items():
148                  dispatchers[(xmlns, key)] = value                  dispatchers[(xmlns, key)] = value
149    
150          XMLReader.AddDispatchers(self, dispatchers)          XMLReader.AddDispatchers(self, dispatchers)
151    
152        def Destroy(self):
153            """Clear all instance variables to cut cyclic references.
154    
155            The GC would have collected the loader eventually but it can
156            happen that it doesn't run at all until Thuban is closed (2.3
157            but not 2.2 tries a bit harder and forces a collection when the
158            interpreter terminates)
159            """
160            self.__dict__.clear()
161    
162      def start_session(self, name, qname, attrs):      def start_session(self, name, qname, attrs):
163          self.theSession = Session(self.encode(attrs.get((None, 'title'),          self.theSession = Session(self.encode(attrs.get((None, 'title'),
164                                                          None)))                                                          None)))
# Line 155  class SessionLoader(XMLReader): Line 186  class SessionLoader(XMLReader):
186          If the attribute has a default value and it is not present in          If the attribute has a default value and it is not present in
187          attrs, use that default value as the value in the returned dict.          attrs, use that default value as the value in the returned dict.
188    
189          If a conversion is specified, convert the value before putting          The value is converted before putting it into the returned dict.
190          it into the returned dict. The following conversions are          The following conversions are available:
         available:  
191    
192             'filename' -- The attribute is a filename.             'filename' -- The attribute is a filename.
193    
# Line 173  class SessionLoader(XMLReader): Line 203  class SessionLoader(XMLReader):
203                        defined earlier in the .thuban file. Look it up                        defined earlier in the .thuban file. Look it up
204                        self.idmap. If it's the ID of a shapestore the                        self.idmap. If it's the ID of a shapestore the
205                        value will be the table of the shapestore.                        value will be the table of the shapestore.
206    
207               'idref' -- The attribute is the id of an object defined
208                          earlier in the .thuban file. Look it up self.idmap
209    
210               'ascii' -- The attribute is converted to a bytestring with
211                          ascii encoding.
212    
213               a callable -- The attribute value is passed to the callable
214                             and the return value is used as the converted
215                             value
216    
217            If no conversion is specified for an attribute it is converted
218            with self.encode.
219          """          """
220          normalized = {}          normalized = {}
221    
222          for d in descr:          for d in descr:
223              if d.required and not attrs.has_key(d.fullname):              if d.required and not attrs.has_key(d.fullname):
224                  pass                  raise LoadError("Element %s requires an attribute %r"
225              #raise LoadError("Element %s requires an attribute %r"                                  % (element, d.name))
             #                    % (element, d.name))  
226              value = attrs.get(d.fullname, d.default)              value = attrs.get(d.fullname, d.default)
227    
228              if d.conversion == "shapesource":              if d.conversion in ("idref", "shapesource"):
229                  if value in self.idmap:                  if value in self.idmap:
230                      value = self.idmap[value]                      value = self.idmap[value]
231                  else:                  else:
# Line 202  class SessionLoader(XMLReader): Line 244  class SessionLoader(XMLReader):
244              elif d.conversion == "filename":              elif d.conversion == "filename":
245                  value = os.path.abspath(os.path.join(self.GetDirectory(),                  value = os.path.abspath(os.path.join(self.GetDirectory(),
246                                                       value))                                                       value))
247                elif d.conversion == "ascii":
248                    value = value.encode("ascii")
249                elif d.conversion:
250                    # Assume it's a callable
251                    value = d.conversion(value)
252                else:
253                   value = self.encode(value)
254    
255              normalized[d.name] = value              normalized[d.name] = value
256          return normalized          return normalized
257    
258        def start_dbconnection(self, name, qname, attrs):
259            attrs = self.check_attrs(name, attrs,
260                                     [AttrDesc("id", True),
261                                      AttrDesc("dbtype", True),
262                                      AttrDesc("host", False, ""),
263                                      AttrDesc("port", False, ""),
264                                      AttrDesc("user", False, ""),
265                                      AttrDesc("dbname", True)])
266            ID = attrs["id"]
267            dbtype = attrs["dbtype"]
268            if dbtype != "postgis":
269                raise LoadError("dbtype %r not supported" % filetype)
270    
271            del attrs["id"]
272            del attrs["dbtype"]
273    
274            # Try to open the connection and if it fails ask the user for
275            # the correct parameters repeatedly.
276            # FIXME: it would be better not to insist on getting a
277            # connection here. We should handle this more like the raster
278            # images where the layers etc still are created but are not
279            # drawn in case Thuban can't use the data for various reasons
280            while 1:
281                try:
282                    conn = postgisdb.PostGISConnection(**attrs)
283                    break
284                except postgisdb.ConnectionError, val:
285                    if self.db_connection_callback is not None:
286                        attrs = self.db_connection_callback(attrs, str(val))
287                        if attrs is None:
288                            raise LoadCancelled
289                    else:
290                        raise
291    
292            self.idmap[ID] = conn
293            self.theSession.AddDBConnection(conn)
294    
295        def start_dbshapesource(self, name, qname, attrs):
296            attrs = self.check_attrs(name, attrs,
297                                     [AttrDesc("id", True),
298                                      AttrDesc("dbconn", True,
299                                               conversion = "idref"),
300                                      AttrDesc("tablename", True,
301                                               conversion = "ascii")])
302            ID = attrs["id"]
303            db = attrs["dbconn"]
304            tablename = attrs["tablename"]
305            self.idmap[ID] = self.theSession.OpenDBShapeStore(db, tablename)
306    
307      def start_fileshapesource(self, name, qname, attrs):      def start_fileshapesource(self, name, qname, attrs):
308          attrs = self.check_attrs(name, attrs,          attrs = self.check_attrs(name, attrs,
309                                    [AttrDesc("id", True),                                    [AttrDesc("id", True),
# Line 284  class SessionLoader(XMLReader): Line 382  class SessionLoader(XMLReader):
382          self.aMap = None          self.aMap = None
383    
384      def start_projection(self, name, qname, attrs):      def start_projection(self, name, qname, attrs):
385          self.ProjectionName = self.encode(attrs.get((None, 'name'), None))          attrs = self.check_attrs(name, attrs,
386          self.ProjectionParams = [ ]                                   [AttrDesc("name", conversion=self.encode),
387                                      AttrDesc("epsg", default=None,
388                                               conversion=self.encode)])
389            self.projection_name = attrs["name"]
390            self.projection_epsg = attrs["epsg"]
391            self.projection_params = [ ]
392    
393      def end_projection(self, name, qname):      def end_projection(self, name, qname):
394          if self.aLayer is not None:          if self.aLayer is not None:
# Line 296  class SessionLoader(XMLReader): Line 399  class SessionLoader(XMLReader):
399              assert False, "projection tag out of context"              assert False, "projection tag out of context"
400              pass              pass
401    
402          obj.SetProjection(          obj.SetProjection(Projection(self.projection_params,
403              Projection(self.ProjectionParams, self.ProjectionName))                                       self.projection_name,
404                                         epsg = self.projection_epsg))
405    
406      def start_parameter(self, name, qname, attrs):      def start_parameter(self, name, qname, attrs):
407          s = attrs.get((None, 'value'))          s = attrs.get((None, 'value'))
408          s = str(s) # we can't handle unicode in proj          s = str(s) # we can't handle unicode in proj
409          self.ProjectionParams.append(s)          self.projection_params.append(s)
410    
411      def start_layer(self, name, qname, attrs, layer_class = Layer):      def start_layer(self, name, qname, attrs, layer_class = Layer):
412          """Start a layer          """Start a layer
# Line 346  class SessionLoader(XMLReader): Line 450  class SessionLoader(XMLReader):
450          self.aLayer = None          self.aLayer = None
451    
452      def start_classification(self, name, qname, attrs):      def start_classification(self, name, qname, attrs):
453          field = attrs.get((None, 'field'), None)          attrs = self.check_attrs(name, attrs,
454                                     [AttrDesc("field", True),
455                                      AttrDesc("field_type", True)])
456            field = attrs["field"]
457            fieldType = attrs["field_type"]
458    
         fieldType = attrs.get((None, 'field_type'), None)  
459          dbFieldType = self.aLayer.GetFieldType(field)          dbFieldType = self.aLayer.GetFieldType(field)
460    
461          if fieldType != dbFieldType:          if fieldType != dbFieldType:
# Line 363  class SessionLoader(XMLReader): Line 470  class SessionLoader(XMLReader):
470          elif fieldType == FIELDTYPE_DOUBLE:          elif fieldType == FIELDTYPE_DOUBLE:
471              self.conv = float              self.conv = float
472    
473          self.aLayer.GetClassification().SetFieldInfo(field, fieldType)          self.aLayer.SetClassificationColumn(field)
474    
475      def end_classification(self, name, qname):      def end_classification(self, name, qname):
476          pass          pass
# Line 381  class SessionLoader(XMLReader): Line 488  class SessionLoader(XMLReader):
488      def start_clpoint(self, name, qname, attrs):      def start_clpoint(self, name, qname, attrs):
489          attrib_value = attrs.get((None, 'value'), "0")          attrib_value = attrs.get((None, 'value'), "0")
490    
491          value = self.conv(attrib_value)          field = self.aLayer.GetClassificationColumn()
492            if self.aLayer.GetFieldType(field) == FIELDTYPE_STRING:
493                value = self.encode(attrib_value)
494            else:
495                value = self.conv(attrib_value)
496          self.cl_group = ClassGroupSingleton(value)          self.cl_group = ClassGroupSingleton(value)
497          self.cl_group.SetLabel(self.encode(attrs.get((None, 'label'), "")))          self.cl_group.SetLabel(self.encode(attrs.get((None, 'label'), "")))
498          self.cl_prop = ClassGroupProperties()          self.cl_prop = ClassGroupProperties()
# Line 446  class SessionLoader(XMLReader): Line 556  class SessionLoader(XMLReader):
556          pass          pass
557    
558    
559  def load_session(filename):  def load_session(filename, db_connection_callback = None):
560      """Load a Thuban session from the file object file"""      """Load a Thuban session from the file object file
561    
562      handler = SessionLoader()      The db_connection_callback, if given should be a callable object
563        that can be called like this:
564           db_connection_callback(params, message)
565    
566        where params is a dictionary containing the known connection
567        parameters and message is a string with a message why the connection
568        failed. db_connection_callback should return a new dictionary with
569        corrected and perhaps additional parameters like a password or None
570        to indicate that the user cancelled.
571        """
572        handler = SessionLoader(db_connection_callback)
573      handler.read(filename)      handler.read(filename)
574    
575      session = handler.theSession      session = handler.theSession
576      # Newly loaded session aren't modified      # Newly loaded session aren't modified
577      session.UnsetModified()      session.UnsetModified()
578    
579        handler.Destroy()
580    
581      return session      return session
582    
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