/[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 2104 by bh, Fri Mar 12 12:19:15 2004 UTC
# Line 1  Line 1 
1  # Copyright (C) 2001, 2002, 2003 by Intevation GmbH  # Copyright (C) 2001, 2002, 2003, 2004 by Intevation GmbH
2  # Authors:  # Authors:
3  # Jan-Oliver Wagner <[email protected]>  # Jan-Oliver Wagner <[email protected]>
4  # Bernhard Herzog <[email protected]>  # Bernhard Herzog <[email protected]>
# 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                          "http://thuban.intevation.org/dtds/thuban-1.0.0.dtd",
149                          "http://thuban.intevation.org/dtds/thuban-1.1-dev.dtd"):
150              for key, value in dispatchers.items():              for key, value in dispatchers.items():
151                  dispatchers[(xmlns, key)] = value                  dispatchers[(xmlns, key)] = value
152    
153          XMLReader.AddDispatchers(self, dispatchers)          XMLReader.AddDispatchers(self, dispatchers)
154    
155        def Destroy(self):
156            """Clear all instance variables to cut cyclic references.
157    
158            The GC would have collected the loader eventually but it can
159            happen that it doesn't run at all until Thuban is closed (2.3
160            but not 2.2 tries a bit harder and forces a collection when the
161            interpreter terminates)
162            """
163            self.__dict__.clear()
164    
165      def start_session(self, name, qname, attrs):      def start_session(self, name, qname, attrs):
166          self.theSession = Session(self.encode(attrs.get((None, 'title'),          self.theSession = Session(self.encode(attrs.get((None, 'title'),
167                                                          None)))                                                          None)))
# Line 155  class SessionLoader(XMLReader): Line 189  class SessionLoader(XMLReader):
189          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
190          attrs, use that default value as the value in the returned dict.          attrs, use that default value as the value in the returned dict.
191    
192          If a conversion is specified, convert the value before putting          The value is converted before putting it into the returned dict.
193          it into the returned dict. The following conversions are          The following conversions are available:
         available:  
194    
195             'filename' -- The attribute is a filename.             'filename' -- The attribute is a filename.
196    
# Line 173  class SessionLoader(XMLReader): Line 206  class SessionLoader(XMLReader):
206                        defined earlier in the .thuban file. Look it up                        defined earlier in the .thuban file. Look it up
207                        self.idmap. If it's the ID of a shapestore the                        self.idmap. If it's the ID of a shapestore the
208                        value will be the table of the shapestore.                        value will be the table of the shapestore.
209    
210               'idref' -- The attribute is the id of an object defined
211                          earlier in the .thuban file. Look it up self.idmap
212    
213               'ascii' -- The attribute is converted to a bytestring with
214                          ascii encoding.
215    
216               a callable -- The attribute value is passed to the callable
217                             and the return value is used as the converted
218                             value
219    
220            If no conversion is specified for an attribute it is converted
221            with self.encode.
222          """          """
223          normalized = {}          normalized = {}
224    
# Line 182  class SessionLoader(XMLReader): Line 228  class SessionLoader(XMLReader):
228                                  % (element, d.name))                                  % (element, d.name))
229              value = attrs.get(d.fullname, d.default)              value = attrs.get(d.fullname, d.default)
230    
231              if d.conversion == "shapesource":              if d.conversion in ("idref", "shapesource"):
232                  if value in self.idmap:                  if value in self.idmap:
233                      value = self.idmap[value]                      value = self.idmap[value]
234                  else:                  else:
# Line 201  class SessionLoader(XMLReader): Line 247  class SessionLoader(XMLReader):
247              elif d.conversion == "filename":              elif d.conversion == "filename":
248                  value = os.path.abspath(os.path.join(self.GetDirectory(),                  value = os.path.abspath(os.path.join(self.GetDirectory(),
249                                                       value))                                                       value))
250                elif d.conversion == "ascii":
251                    value = value.encode("ascii")
252                elif d.conversion:
253                    # Assume it's a callable
254                    value = d.conversion(value)
255                else:
256                   value = self.encode(value)
257    
258              normalized[d.name] = value              normalized[d.name] = value
259          return normalized          return normalized
260    
261        def start_dbconnection(self, name, qname, attrs):
262            attrs = self.check_attrs(name, attrs,
263                                     [AttrDesc("id", True),
264                                      AttrDesc("dbtype", True),
265                                      AttrDesc("host", False, ""),
266                                      AttrDesc("port", False, ""),
267                                      AttrDesc("user", False, ""),
268                                      AttrDesc("dbname", True)])
269            ID = attrs["id"]
270            dbtype = attrs["dbtype"]
271            if dbtype != "postgis":
272                raise LoadError("dbtype %r not supported" % filetype)
273    
274            del attrs["id"]
275            del attrs["dbtype"]
276    
277            # Try to open the connection and if it fails ask the user for
278            # the correct parameters repeatedly.
279            # FIXME: it would be better not to insist on getting a
280            # connection here. We should handle this more like the raster
281            # images where the layers etc still are created but are not
282            # drawn in case Thuban can't use the data for various reasons
283            while 1:
284                try:
285                    conn = postgisdb.PostGISConnection(**attrs)
286                    break
287                except postgisdb.ConnectionError, val:
288                    if self.db_connection_callback is not None:
289                        attrs = self.db_connection_callback(attrs, str(val))
290                        if attrs is None:
291                            raise LoadCancelled
292                    else:
293                        raise
294    
295            self.idmap[ID] = conn
296            self.theSession.AddDBConnection(conn)
297    
298        def start_dbshapesource(self, name, qname, attrs):
299            attrs = self.check_attrs(name, attrs,
300                                     [AttrDesc("id", True),
301                                      AttrDesc("dbconn", True,
302                                               conversion = "idref"),
303                                      AttrDesc("tablename", True,
304                                               conversion = "ascii"),
305                                      # id_column and geometry_column were
306                                      # newly introduced with thuban-1.1.dtd
307                                      # where they're required.  Since we
308                                      # support the older formats too we
309                                      # have them optional here.
310                                      AttrDesc("id_column", False, "gid",
311                                               conversion = "ascii"),
312                                      AttrDesc("geometry_column", False,
313                                               conversion = "ascii")])
314            # The default value of geometry_column to use when instantiating
315            # the db shapestore is None which we currently can't easily use
316            # in check_attrs
317            geometry_column = attrs["geometry_column"]
318            if not geometry_column:
319                geometry_column = None
320            dbopen = self.theSession.OpenDBShapeStore
321            self.idmap[attrs["id"]] = dbopen(attrs["dbconn"], attrs["tablename"],
322                                             id_column = attrs["id_column"],
323                                             geometry_column=geometry_column)
324    
325      def start_fileshapesource(self, name, qname, attrs):      def start_fileshapesource(self, name, qname, attrs):
326          attrs = self.check_attrs(name, attrs,          attrs = self.check_attrs(name, attrs,
327                                    [AttrDesc("id", True),                                    [AttrDesc("id", True),
# Line 283  class SessionLoader(XMLReader): Line 400  class SessionLoader(XMLReader):
400          self.aMap = None          self.aMap = None
401    
402      def start_projection(self, name, qname, attrs):      def start_projection(self, name, qname, attrs):
403          self.ProjectionName = self.encode(attrs.get((None, 'name'), None))          attrs = self.check_attrs(name, attrs,
404          self.ProjectionParams = [ ]                                   [AttrDesc("name", conversion=self.encode),
405                                      AttrDesc("epsg", default=None,
406                                               conversion=self.encode)])
407            self.projection_name = attrs["name"]
408            self.projection_epsg = attrs["epsg"]
409            self.projection_params = [ ]
410    
411      def end_projection(self, name, qname):      def end_projection(self, name, qname):
412          if self.aLayer is not None:          if self.aLayer is not None:
# Line 295  class SessionLoader(XMLReader): Line 417  class SessionLoader(XMLReader):
417              assert False, "projection tag out of context"              assert False, "projection tag out of context"
418              pass              pass
419    
420          obj.SetProjection(          obj.SetProjection(Projection(self.projection_params,
421              Projection(self.ProjectionParams, self.ProjectionName))                                       self.projection_name,
422                                         epsg = self.projection_epsg))
423    
424      def start_parameter(self, name, qname, attrs):      def start_parameter(self, name, qname, attrs):
425          s = attrs.get((None, 'value'))          s = attrs.get((None, 'value'))
426          s = str(s) # we can't handle unicode in proj          s = str(s) # we can't handle unicode in proj
427          self.ProjectionParams.append(s)          self.projection_params.append(s)
428    
429      def start_layer(self, name, qname, attrs, layer_class = Layer):      def start_layer(self, name, qname, attrs, layer_class = Layer):
430          """Start a layer          """Start a layer
# Line 345  class SessionLoader(XMLReader): Line 468  class SessionLoader(XMLReader):
468          self.aLayer = None          self.aLayer = None
469    
470      def start_classification(self, name, qname, attrs):      def start_classification(self, name, qname, attrs):
471          field = attrs.get((None, 'field'), None)          attrs = self.check_attrs(name, attrs,
472                                     [AttrDesc("field", True),
473                                      AttrDesc("field_type", True)])
474            field = attrs["field"]
475            fieldType = attrs["field_type"]
476    
         fieldType = attrs.get((None, 'field_type'), None)  
477          dbFieldType = self.aLayer.GetFieldType(field)          dbFieldType = self.aLayer.GetFieldType(field)
478    
479          if fieldType != dbFieldType:          if fieldType != dbFieldType:
# Line 437  class SessionLoader(XMLReader): Line 563  class SessionLoader(XMLReader):
563          self.aLayer = self.aMap.LabelLayer()          self.aLayer = self.aMap.LabelLayer()
564    
565      def start_label(self, name, qname, attrs):      def start_label(self, name, qname, attrs):
566          x = float(attrs[(None, 'x')])          attrs = self.check_attrs(name, attrs,
567          y = float(attrs[(None, 'y')])                                   [AttrDesc("x", True, conversion = float),
568          text = self.encode(attrs[(None, 'text')])                                    AttrDesc("y", True, conversion = float),
569          halign = attrs[(None, 'halign')]                                    AttrDesc("text", True),
570          valign = attrs[(None, 'valign')]                                    AttrDesc("halign", True,
571                                               conversion = "ascii"),
572                                      AttrDesc("valign", True,
573                                               conversion = "ascii")])
574            x = attrs['x']
575            y = attrs['y']
576            text = attrs['text']
577            halign = attrs['halign']
578            valign = attrs['valign']
579            if halign not in ("left", "center", "right"):
580                raise LoadError("Unsupported halign value %r" % halign)
581            if valign not in ("top", "center", "bottom"):
582                raise LoadError("Unsupported valign value %r" % valign)
583          self.aLayer.AddLabel(x, y, text, halign = halign, valign = valign)          self.aLayer.AddLabel(x, y, text, halign = halign, valign = valign)
584    
585      def characters(self, chars):      def characters(self, chars):
586          pass          pass
587    
588    
589  def load_session(filename):  def load_session(filename, db_connection_callback = None):
590      """Load a Thuban session from the file object file"""      """Load a Thuban session from the file object file
591    
592      handler = SessionLoader()      The db_connection_callback, if given should be a callable object
593        that can be called like this:
594           db_connection_callback(params, message)
595    
596        where params is a dictionary containing the known connection
597        parameters and message is a string with a message why the connection
598        failed. db_connection_callback should return a new dictionary with
599        corrected and perhaps additional parameters like a password or None
600        to indicate that the user cancelled.
601        """
602        handler = SessionLoader(db_connection_callback)
603      handler.read(filename)      handler.read(filename)
604    
605      session = handler.theSession      session = handler.theSession
606      # Newly loaded session aren't modified      # Newly loaded session aren't modified
607      session.UnsetModified()      session.UnsetModified()
608    
609        handler.Destroy()
610    
611      return session      return session
612    
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