/[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 2551 by jonathan, Thu Jan 27 14:19:41 2005 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]>
5  # Jonathan Coles <[email protected]>  # Jonathan Coles <[email protected]>
6    # Frank Koormann <[email protected]>
7  #  #
8  # This program is free software under the GPL (>=v2)  # This program is free software under the GPL (>=v2)
9  # Read the file COPYING coming with GRASS for details.  # Read the file COPYING coming with GRASS for details.
# Line 38  from Thuban.Model.data import DerivedSha Line 39  from Thuban.Model.data import DerivedSha
39  from Thuban.Model.table import DBFTable  from Thuban.Model.table import DBFTable
40  from Thuban.Model.transientdb import TransientJoinedTable  from Thuban.Model.transientdb import TransientJoinedTable
41    
42    from Thuban.Model.xmlreader import XMLReader
43    import resource
44    
45    import postgisdb
46    
47  class LoadError(Exception):  class LoadError(Exception):
     pass  
48    
49  from Thuban.Model.xmlreader import XMLReader      """Exception raised when the thuban file is corrupted
50  import resource  
51        Not all cases of corrupted thuban files will lead to this exception
52        but those that are found by checks in the loading code itself are.
53        """
54    
55    
56    class LoadCancelled(Exception):
57    
58        """Exception raised to indicate that loading was interrupted by the user"""
59    
60    
61  def parse_color(color):  def parse_color(color):
62      """Return the color object for the string color.      """Return the color object for the string color.
# Line 87  class AttrDesc: Line 101  class AttrDesc:
101    
102  class SessionLoader(XMLReader):  class SessionLoader(XMLReader):
103    
104      def __init__(self):      def __init__(self, db_connection_callback = None,
105                           shapefile_callback = None):
106          """Inititialize the Sax handler."""          """Inititialize the Sax handler."""
107          XMLReader.__init__(self)          XMLReader.__init__(self)
108    
109            self.db_connection_callback = db_connection_callback
110            self.shapefile_callback = shapefile_callback
111          self.theSession = None          self.theSession = None
112          self.aMap = None          self.aMap = None
113          self.aLayer = None          self.aLayer = None
# Line 101  class SessionLoader(XMLReader): Line 118  class SessionLoader(XMLReader):
118    
119          dispatchers = {          dispatchers = {
120              'session'       : ("start_session",        "end_session"),              'session'       : ("start_session",        "end_session"),
121    
122                'dbconnection': ("start_dbconnection", None),
123    
124                'dbshapesource': ("start_dbshapesource", None),
125              'fileshapesource': ("start_fileshapesource", None),              'fileshapesource': ("start_fileshapesource", None),
126              'derivedshapesource': ("start_derivedshapesource", None),              'derivedshapesource': ("start_derivedshapesource", None),
127              'filetable': ("start_filetable", None),              'filetable': ("start_filetable", None),
# Line 122  class SessionLoader(XMLReader): Line 143  class SessionLoader(XMLReader):
143    
144          # 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
145          for xmlns in ("http://thuban.intevation.org/dtds/thuban-0.8.dtd",          for xmlns in ("http://thuban.intevation.org/dtds/thuban-0.8.dtd",
146                        "http://thuban.intevation.org/dtds/thuban-0.9-dev.dtd"):                        "http://thuban.intevation.org/dtds/thuban-0.9-dev.dtd",
147                          "http://thuban.intevation.org/dtds/thuban-0.9.dtd",
148                          "http://thuban.intevation.org/dtds/thuban-1.0-dev.dtd",
149                          "http://thuban.intevation.org/dtds/thuban-1.0rc1.dtd",
150                          "http://thuban.intevation.org/dtds/thuban-1.0.0.dtd",
151                          "http://thuban.intevation.org/dtds/thuban-1.1-dev.dtd"):
152              for key, value in dispatchers.items():              for key, value in dispatchers.items():
153                  dispatchers[(xmlns, key)] = value                  dispatchers[(xmlns, key)] = value
154    
155          XMLReader.AddDispatchers(self, dispatchers)          XMLReader.AddDispatchers(self, dispatchers)
156    
157        def Destroy(self):
158            """Clear all instance variables to cut cyclic references.
159    
160            The GC would have collected the loader eventually but it can
161            happen that it doesn't run at all until Thuban is closed (2.3
162            but not 2.2 tries a bit harder and forces a collection when the
163            interpreter terminates)
164            """
165            self.__dict__.clear()
166    
167      def start_session(self, name, qname, attrs):      def start_session(self, name, qname, attrs):
168          self.theSession = Session(self.encode(attrs.get((None, 'title'),          self.theSession = Session(self.encode(attrs.get((None, 'title'),
169                                                          None)))                                                          None)))
# Line 155  class SessionLoader(XMLReader): Line 191  class SessionLoader(XMLReader):
191          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
192          attrs, use that default value as the value in the returned dict.          attrs, use that default value as the value in the returned dict.
193    
194          If a conversion is specified, convert the value before putting          The value is converted before putting it into the returned dict.
195          it into the returned dict. The following conversions are          The following conversions are available:
         available:  
196    
197             'filename' -- The attribute is a filename.             'filename' -- The attribute is a filename.
198    
# Line 173  class SessionLoader(XMLReader): Line 208  class SessionLoader(XMLReader):
208                        defined earlier in the .thuban file. Look it up                        defined earlier in the .thuban file. Look it up
209                        self.idmap. If it's the ID of a shapestore the                        self.idmap. If it's the ID of a shapestore the
210                        value will be the table of the shapestore.                        value will be the table of the shapestore.
211    
212               'idref' -- The attribute is the id of an object defined
213                          earlier in the .thuban file. Look it up self.idmap
214    
215               'ascii' -- The attribute is converted to a bytestring with
216                          ascii encoding.
217    
218               a callable -- The attribute value is passed to the callable
219                             and the return value is used as the converted
220                             value
221    
222            If no conversion is specified for an attribute it is converted
223            with self.encode.
224          """          """
225          normalized = {}          normalized = {}
226    
# Line 182  class SessionLoader(XMLReader): Line 230  class SessionLoader(XMLReader):
230                                  % (element, d.name))                                  % (element, d.name))
231              value = attrs.get(d.fullname, d.default)              value = attrs.get(d.fullname, d.default)
232    
233              if d.conversion == "shapesource":              if d.conversion in ("idref", "shapesource"):
234                  if value in self.idmap:                  if value in self.idmap:
235                      value = self.idmap[value]                      value = self.idmap[value]
236                  else:                  else:
# Line 201  class SessionLoader(XMLReader): Line 249  class SessionLoader(XMLReader):
249              elif d.conversion == "filename":              elif d.conversion == "filename":
250                  value = os.path.abspath(os.path.join(self.GetDirectory(),                  value = os.path.abspath(os.path.join(self.GetDirectory(),
251                                                       value))                                                       value))
252                elif d.conversion == "ascii":
253                    value = value.encode("ascii")
254                elif d.conversion:
255                    # Assume it's a callable
256                    value = d.conversion(value)
257                else:
258                   value = self.encode(value)
259    
260              normalized[d.name] = value              normalized[d.name] = value
261          return normalized          return normalized
262    
263        def open_shapefile(self, filename):
264            """Open shapefile, with alternative path handling.
265            
266               If a shapefile cannot be opened and an IOError is raised, check for
267               an alternative. This alternative can be specified interactively by
268               the user or taken from a list of (potential) locations, depending on
269               the callback implementation.
270                
271               The alternative is rechecked. If taken from a list the user
272               has to confirm the alternative.
273            """
274    
275            # Flag if the alternative path was specified interactively / from list.
276            from_list = 0
277            while 1:
278                try:
279                    store = self.theSession.OpenShapefile(filename)
280                    if from_list:
281                        # A valid path has been guessed from a list
282                        # Let the user confirm - or select an alternative.
283                        filename, from_list = self.shapefile_callback(
284                                                filename, "check")
285                        if filename is None:
286                            # Selection cancelled
287                            raise LoadCancelled
288                        elif store.FileName() == filename:
289                            # Proposed file has been accepted
290                            break
291                        else:
292                            # the filename has been changed, try the new file
293                            pass
294                    else:
295                        break
296                except IOError:
297                    if self.shapefile_callback is not None:
298                        filename, from_list = self.shapefile_callback(
299                                                filename,
300                                                mode = "search",
301                                                second_try = from_list)
302                        if filename is None:
303                            raise LoadCancelled
304                    else:
305                        raise
306            return store
307    
308        def start_dbconnection(self, name, qname, attrs):
309            attrs = self.check_attrs(name, attrs,
310                                     [AttrDesc("id", True),
311                                      AttrDesc("dbtype", True),
312                                      AttrDesc("host", False, ""),
313                                      AttrDesc("port", False, ""),
314                                      AttrDesc("user", False, ""),
315                                      AttrDesc("dbname", True)])
316            ID = attrs["id"]
317            dbtype = attrs["dbtype"]
318            if dbtype != "postgis":
319                raise LoadError("dbtype %r not supported" % filetype)
320    
321            del attrs["id"]
322            del attrs["dbtype"]
323    
324            # Try to open the connection and if it fails ask the user for
325            # the correct parameters repeatedly.
326            # FIXME: it would be better not to insist on getting a
327            # connection here. We should handle this more like the raster
328            # images where the layers etc still are created but are not
329            # drawn in case Thuban can't use the data for various reasons
330            while 1:
331                try:
332                    conn = postgisdb.PostGISConnection(**attrs)
333                    break
334                except postgisdb.ConnectionError, val:
335                    if self.db_connection_callback is not None:
336                        attrs = self.db_connection_callback(attrs, str(val))
337                        if attrs is None:
338                            raise LoadCancelled
339                    else:
340                        raise
341    
342            self.idmap[ID] = conn
343            self.theSession.AddDBConnection(conn)
344    
345        def start_dbshapesource(self, name, qname, attrs):
346            attrs = self.check_attrs(name, attrs,
347                                     [AttrDesc("id", True),
348                                      AttrDesc("dbconn", True,
349                                               conversion = "idref"),
350                                      AttrDesc("tablename", True,
351                                               conversion = "ascii"),
352                                      # id_column and geometry_column were
353                                      # newly introduced with thuban-1.1.dtd
354                                      # where they're required.  Since we
355                                      # support the older formats too we
356                                      # have them optional here.
357                                      AttrDesc("id_column", False, "gid",
358                                               conversion = "ascii"),
359                                      AttrDesc("geometry_column", False,
360                                               conversion = "ascii")])
361            # The default value of geometry_column to use when instantiating
362            # the db shapestore is None which we currently can't easily use
363            # in check_attrs
364            geometry_column = attrs["geometry_column"]
365            if not geometry_column:
366                geometry_column = None
367            dbopen = self.theSession.OpenDBShapeStore
368            self.idmap[attrs["id"]] = dbopen(attrs["dbconn"], attrs["tablename"],
369                                             id_column = attrs["id_column"],
370                                             geometry_column=geometry_column)
371    
372      def start_fileshapesource(self, name, qname, attrs):      def start_fileshapesource(self, name, qname, attrs):
373          attrs = self.check_attrs(name, attrs,          attrs = self.check_attrs(name, attrs,
374                                    [AttrDesc("id", True),                                    [AttrDesc("id", True),
# Line 216  class SessionLoader(XMLReader): Line 380  class SessionLoader(XMLReader):
380          filetype = attrs["filetype"]          filetype = attrs["filetype"]
381          if filetype != "shapefile":          if filetype != "shapefile":
382              raise LoadError("shapesource filetype %r not supported" % filetype)              raise LoadError("shapesource filetype %r not supported" % filetype)
383          self.idmap[ID] = self.theSession.OpenShapefile(filename)          self.idmap[ID] = self.open_shapefile(filename)
384    
385      def start_derivedshapesource(self, name, qname, attrs):      def start_derivedshapesource(self, name, qname, attrs):
386          attrs = self.check_attrs(name, attrs,          attrs = self.check_attrs(name, attrs,
# Line 283  class SessionLoader(XMLReader): Line 447  class SessionLoader(XMLReader):
447          self.aMap = None          self.aMap = None
448    
449      def start_projection(self, name, qname, attrs):      def start_projection(self, name, qname, attrs):
450          self.ProjectionName = self.encode(attrs.get((None, 'name'), None))          attrs = self.check_attrs(name, attrs,
451          self.ProjectionParams = [ ]                                   [AttrDesc("name", conversion=self.encode),
452                                      AttrDesc("epsg", default=None,
453                                               conversion=self.encode)])
454            self.projection_name = attrs["name"]
455            self.projection_epsg = attrs["epsg"]
456            self.projection_params = [ ]
457    
458      def end_projection(self, name, qname):      def end_projection(self, name, qname):
459          if self.aLayer is not None:          if self.aLayer is not None:
# Line 295  class SessionLoader(XMLReader): Line 464  class SessionLoader(XMLReader):
464              assert False, "projection tag out of context"              assert False, "projection tag out of context"
465              pass              pass
466    
467          obj.SetProjection(          obj.SetProjection(Projection(self.projection_params,
468              Projection(self.ProjectionParams, self.ProjectionName))                                       self.projection_name,
469                                         epsg = self.projection_epsg))
470    
471      def start_parameter(self, name, qname, attrs):      def start_parameter(self, name, qname, attrs):
472          s = attrs.get((None, 'value'))          s = attrs.get((None, 'value'))
473          s = str(s) # we can't handle unicode in proj          s = str(s) # we can't handle unicode in proj
474          self.ProjectionParams.append(s)          self.projection_params.append(s)
475    
476      def start_layer(self, name, qname, attrs, layer_class = Layer):      def start_layer(self, name, qname, attrs, layer_class = Layer):
477          """Start a layer          """Start a layer
# Line 321  class SessionLoader(XMLReader): Line 491  class SessionLoader(XMLReader):
491          if attrs.has_key((None, "shapestore")):          if attrs.has_key((None, "shapestore")):
492              store = self.idmap[attrs[(None, "shapestore")]]              store = self.idmap[attrs[(None, "shapestore")]]
493          else:          else:
494              store = self.theSession.OpenShapefile(filename)              store = self.open_shapefile(filename)
495    
496          self.aLayer = layer_class(title, store,          self.aLayer = layer_class(title, store,
497                                    fill = fill, stroke = stroke,                                    fill = fill, stroke = stroke,
498                                    lineWidth = stroke_width,                                    lineWidth = stroke_width,
# Line 337  class SessionLoader(XMLReader): Line 508  class SessionLoader(XMLReader):
508          filename = os.path.join(self.GetDirectory(), filename)          filename = os.path.join(self.GetDirectory(), filename)
509          filename = self.encode(filename)          filename = self.encode(filename)
510          visible  = self.encode(attrs.get((None, 'visible'), "true")) != "false"          visible  = self.encode(attrs.get((None, 'visible'), "true")) != "false"
511            useMask = self.encode(attrs.get((None, 'use_mask'), "false")) != "false"
512    
513          self.aLayer = layer_class(title, filename, visible = visible)          self.aLayer = layer_class(title, filename, visible = visible)
514    
515            self.aLayer.SetUseMask(useMask)
516    
517      def end_rasterlayer(self, name, qname):      def end_rasterlayer(self, name, qname):
518          self.aMap.AddLayer(self.aLayer)          self.aMap.AddLayer(self.aLayer)
519          self.aLayer = None          self.aLayer = None
520    
521      def start_classification(self, name, qname, attrs):      def start_classification(self, name, qname, attrs):
522          field = attrs.get((None, 'field'), None)          attrs = self.check_attrs(name, attrs,
523                                     [AttrDesc("field", True),
524                                      AttrDesc("field_type", True)])
525            field = attrs["field"]
526            fieldType = attrs["field_type"]
527    
         fieldType = attrs.get((None, 'field_type'), None)  
528          dbFieldType = self.aLayer.GetFieldType(field)          dbFieldType = self.aLayer.GetFieldType(field)
529    
530          if fieldType != dbFieldType:          if fieldType != dbFieldType:
# Line 428  class SessionLoader(XMLReader): Line 605  class SessionLoader(XMLReader):
605              parse_color(attrs.get((None, 'stroke'), "None")))              parse_color(attrs.get((None, 'stroke'), "None")))
606          self.cl_prop.SetLineWidth(          self.cl_prop.SetLineWidth(
607              int(attrs.get((None, 'stroke_width'), "0")))              int(attrs.get((None, 'stroke_width'), "0")))
608            self.cl_prop.SetSize(int(attrs.get((None, 'size'), "5")))
609          self.cl_prop.SetFill(parse_color(attrs.get((None, 'fill'), "None")))          self.cl_prop.SetFill(parse_color(attrs.get((None, 'fill'), "None")))
610    
611      def end_cldata(self, name, qname):      def end_cldata(self, name, qname):
# Line 437  class SessionLoader(XMLReader): Line 615  class SessionLoader(XMLReader):
615          self.aLayer = self.aMap.LabelLayer()          self.aLayer = self.aMap.LabelLayer()
616    
617      def start_label(self, name, qname, attrs):      def start_label(self, name, qname, attrs):
618          x = float(attrs[(None, 'x')])          attrs = self.check_attrs(name, attrs,
619          y = float(attrs[(None, 'y')])                                   [AttrDesc("x", True, conversion = float),
620          text = self.encode(attrs[(None, 'text')])                                    AttrDesc("y", True, conversion = float),
621          halign = attrs[(None, 'halign')]                                    AttrDesc("text", True),
622          valign = attrs[(None, 'valign')]                                    AttrDesc("halign", True,
623                                               conversion = "ascii"),
624                                      AttrDesc("valign", True,
625                                               conversion = "ascii")])
626            x = attrs['x']
627            y = attrs['y']
628            text = attrs['text']
629            halign = attrs['halign']
630            valign = attrs['valign']
631            if halign not in ("left", "center", "right"):
632                raise LoadError("Unsupported halign value %r" % halign)
633            if valign not in ("top", "center", "bottom"):
634                raise LoadError("Unsupported valign value %r" % valign)
635          self.aLayer.AddLabel(x, y, text, halign = halign, valign = valign)          self.aLayer.AddLabel(x, y, text, halign = halign, valign = valign)
636    
637      def characters(self, chars):      def characters(self, chars):
638          pass          pass
639    
640    
641  def load_session(filename):  def load_session(filename, db_connection_callback = None,
642      """Load a Thuban session from the file object file"""                             shapefile_callback = None):
643        """Load a Thuban session from the file object file
644      handler = SessionLoader()  
645        The db_connection_callback, if given should be a callable object
646        that can be called like this:
647           db_connection_callback(params, message)
648    
649        where params is a dictionary containing the known connection
650        parameters and message is a string with a message why the connection
651        failed. db_connection_callback should return a new dictionary with
652        corrected and perhaps additional parameters like a password or None
653        to indicate that the user cancelled.
654        """
655        handler = SessionLoader(db_connection_callback, shapefile_callback)
656      handler.read(filename)      handler.read(filename)
657    
658      session = handler.theSession      session = handler.theSession
659      # Newly loaded session aren't modified      # Newly loaded session aren't modified
660      session.UnsetModified()      session.UnsetModified()
661    
662        handler.Destroy()
663    
664      return session      return session
665    
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