/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/load.py
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revision 1642 by bh, Mon Aug 25 10:54:31 2003 UTC revision 2004 by bh, Tue Dec 2 13:25:55 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                          "http://thuban.intevation.org/dtds/thuban-1.0rc1.dtd"):
148              for key, value in dispatchers.items():              for key, value in dispatchers.items():
149                  dispatchers[(xmlns, key)] = value                  dispatchers[(xmlns, key)] = value
150    
151          XMLReader.AddDispatchers(self, dispatchers)          XMLReader.AddDispatchers(self, dispatchers)
152    
153        def Destroy(self):
154            """Clear all instance variables to cut cyclic references.
155    
156            The GC would have collected the loader eventually but it can
157            happen that it doesn't run at all until Thuban is closed (2.3
158            but not 2.2 tries a bit harder and forces a collection when the
159            interpreter terminates)
160            """
161            self.__dict__.clear()
162    
163      def start_session(self, name, qname, attrs):      def start_session(self, name, qname, attrs):
164          self.theSession = Session(self.encode(attrs.get((None, 'title'),          self.theSession = Session(self.encode(attrs.get((None, 'title'),
165                                                          None)))                                                          None)))
# Line 155  class SessionLoader(XMLReader): Line 187  class SessionLoader(XMLReader):
187          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
188          attrs, use that default value as the value in the returned dict.          attrs, use that default value as the value in the returned dict.
189    
190          If a conversion is specified, convert the value before putting          The value is converted before putting it into the returned dict.
191          it into the returned dict. The following conversions are          The following conversions are available:
         available:  
192    
193             'filename' -- The attribute is a filename.             'filename' -- The attribute is a filename.
194    
# Line 173  class SessionLoader(XMLReader): Line 204  class SessionLoader(XMLReader):
204                        defined earlier in the .thuban file. Look it up                        defined earlier in the .thuban file. Look it up
205                        self.idmap. If it's the ID of a shapestore the                        self.idmap. If it's the ID of a shapestore the
206                        value will be the table of the shapestore.                        value will be the table of the shapestore.
207    
208               'idref' -- The attribute is the id of an object defined
209                          earlier in the .thuban file. Look it up self.idmap
210    
211               'ascii' -- The attribute is converted to a bytestring with
212                          ascii encoding.
213    
214               a callable -- The attribute value is passed to the callable
215                             and the return value is used as the converted
216                             value
217    
218            If no conversion is specified for an attribute it is converted
219            with self.encode.
220          """          """
221          normalized = {}          normalized = {}
222    
# Line 182  class SessionLoader(XMLReader): Line 226  class SessionLoader(XMLReader):
226                                  % (element, d.name))                                  % (element, d.name))
227              value = attrs.get(d.fullname, d.default)              value = attrs.get(d.fullname, d.default)
228    
229              if d.conversion == "shapesource":              if d.conversion in ("idref", "shapesource"):
230                  if value in self.idmap:                  if value in self.idmap:
231                      value = self.idmap[value]                      value = self.idmap[value]
232                  else:                  else:
# Line 201  class SessionLoader(XMLReader): Line 245  class SessionLoader(XMLReader):
245              elif d.conversion == "filename":              elif d.conversion == "filename":
246                  value = os.path.abspath(os.path.join(self.GetDirectory(),                  value = os.path.abspath(os.path.join(self.GetDirectory(),
247                                                       value))                                                       value))
248                elif d.conversion == "ascii":
249                    value = value.encode("ascii")
250                elif d.conversion:
251                    # Assume it's a callable
252                    value = d.conversion(value)
253                else:
254                   value = self.encode(value)
255    
256              normalized[d.name] = value              normalized[d.name] = value
257          return normalized          return normalized
258    
259        def start_dbconnection(self, name, qname, attrs):
260            attrs = self.check_attrs(name, attrs,
261                                     [AttrDesc("id", True),
262                                      AttrDesc("dbtype", True),
263                                      AttrDesc("host", False, ""),
264                                      AttrDesc("port", False, ""),
265                                      AttrDesc("user", False, ""),
266                                      AttrDesc("dbname", True)])
267            ID = attrs["id"]
268            dbtype = attrs["dbtype"]
269            if dbtype != "postgis":
270                raise LoadError("dbtype %r not supported" % filetype)
271    
272            del attrs["id"]
273            del attrs["dbtype"]
274    
275            # Try to open the connection and if it fails ask the user for
276            # the correct parameters repeatedly.
277            # FIXME: it would be better not to insist on getting a
278            # connection here. We should handle this more like the raster
279            # images where the layers etc still are created but are not
280            # drawn in case Thuban can't use the data for various reasons
281            while 1:
282                try:
283                    conn = postgisdb.PostGISConnection(**attrs)
284                    break
285                except postgisdb.ConnectionError, val:
286                    if self.db_connection_callback is not None:
287                        attrs = self.db_connection_callback(attrs, str(val))
288                        if attrs is None:
289                            raise LoadCancelled
290                    else:
291                        raise
292    
293            self.idmap[ID] = conn
294            self.theSession.AddDBConnection(conn)
295    
296        def start_dbshapesource(self, name, qname, attrs):
297            attrs = self.check_attrs(name, attrs,
298                                     [AttrDesc("id", True),
299                                      AttrDesc("dbconn", True,
300                                               conversion = "idref"),
301                                      AttrDesc("tablename", True,
302                                               conversion = "ascii")])
303            ID = attrs["id"]
304            db = attrs["dbconn"]
305            tablename = attrs["tablename"]
306            self.idmap[ID] = self.theSession.OpenDBShapeStore(db, tablename)
307    
308      def start_fileshapesource(self, name, qname, attrs):      def start_fileshapesource(self, name, qname, attrs):
309          attrs = self.check_attrs(name, attrs,          attrs = self.check_attrs(name, attrs,
310                                    [AttrDesc("id", True),                                    [AttrDesc("id", True),
# Line 283  class SessionLoader(XMLReader): Line 383  class SessionLoader(XMLReader):
383          self.aMap = None          self.aMap = None
384    
385      def start_projection(self, name, qname, attrs):      def start_projection(self, name, qname, attrs):
386          self.ProjectionName = self.encode(attrs.get((None, 'name'), None))          attrs = self.check_attrs(name, attrs,
387          self.ProjectionParams = [ ]                                   [AttrDesc("name", conversion=self.encode),
388                                      AttrDesc("epsg", default=None,
389                                               conversion=self.encode)])
390            self.projection_name = attrs["name"]
391            self.projection_epsg = attrs["epsg"]
392            self.projection_params = [ ]
393    
394      def end_projection(self, name, qname):      def end_projection(self, name, qname):
395          if self.aLayer is not None:          if self.aLayer is not None:
# Line 295  class SessionLoader(XMLReader): Line 400  class SessionLoader(XMLReader):
400              assert False, "projection tag out of context"              assert False, "projection tag out of context"
401              pass              pass
402    
403          obj.SetProjection(          obj.SetProjection(Projection(self.projection_params,
404              Projection(self.ProjectionParams, self.ProjectionName))                                       self.projection_name,
405                                         epsg = self.projection_epsg))
406    
407      def start_parameter(self, name, qname, attrs):      def start_parameter(self, name, qname, attrs):
408          s = attrs.get((None, 'value'))          s = attrs.get((None, 'value'))
409          s = str(s) # we can't handle unicode in proj          s = str(s) # we can't handle unicode in proj
410          self.ProjectionParams.append(s)          self.projection_params.append(s)
411    
412      def start_layer(self, name, qname, attrs, layer_class = Layer):      def start_layer(self, name, qname, attrs, layer_class = Layer):
413          """Start a layer          """Start a layer
# Line 345  class SessionLoader(XMLReader): Line 451  class SessionLoader(XMLReader):
451          self.aLayer = None          self.aLayer = None
452    
453      def start_classification(self, name, qname, attrs):      def start_classification(self, name, qname, attrs):
454          field = attrs.get((None, 'field'), None)          attrs = self.check_attrs(name, attrs,
455                                     [AttrDesc("field", True),
456                                      AttrDesc("field_type", True)])
457            field = attrs["field"]
458            fieldType = attrs["field_type"]
459    
         fieldType = attrs.get((None, 'field_type'), None)  
460          dbFieldType = self.aLayer.GetFieldType(field)          dbFieldType = self.aLayer.GetFieldType(field)
461    
462          if fieldType != dbFieldType:          if fieldType != dbFieldType:
# Line 448  class SessionLoader(XMLReader): Line 557  class SessionLoader(XMLReader):
557          pass          pass
558    
559    
560  def load_session(filename):  def load_session(filename, db_connection_callback = None):
561      """Load a Thuban session from the file object file"""      """Load a Thuban session from the file object file
562    
563      handler = SessionLoader()      The db_connection_callback, if given should be a callable object
564        that can be called like this:
565           db_connection_callback(params, message)
566    
567        where params is a dictionary containing the known connection
568        parameters and message is a string with a message why the connection
569        failed. db_connection_callback should return a new dictionary with
570        corrected and perhaps additional parameters like a password or None
571        to indicate that the user cancelled.
572        """
573        handler = SessionLoader(db_connection_callback)
574      handler.read(filename)      handler.read(filename)
575    
576      session = handler.theSession      session = handler.theSession
577      # Newly loaded session aren't modified      # Newly loaded session aren't modified
578      session.UnsetModified()      session.UnsetModified()
579    
580        handler.Destroy()
581    
582      return session      return session
583    
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