OsmApi.py

   1 #-*- coding: utf-8 -*-
   2
   3 ###########################################################################
   4 ##                                                                       ##
   5 ## Copyrights Etienne Chové <chove@crans.org> 2009                       ##
   6 ##                                                                       ##
   7 ## This program is free software: you can redistribute it and/or modify  ##
   8 ## it under the terms of the GNU General Public License as published by  ##
   9 ## the Free Software Foundation, either version 3 of the License, or     ##
  10 ## (at your option) any later version.                                   ##
  11 ##                                                                       ##
  12 ## This program is distributed in the hope that it will be useful,       ##
  13 ## but WITHOUT ANY WARRANTY; without even the implied warranty of        ##
  14 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         ##
  15 ## GNU General Public License for more details.                          ##
  16 ##                                                                       ##
  17 ## You should have received a copy of the GNU General Public License     ##
  18 ## along with this program.  If not, see <http://www.gnu.org/licenses/>. ##
  19 ##                                                                       ##
  20 ###########################################################################
  21
  22 ## HomePage : http://wiki.openstreetmap.org/wiki/PythonOsmApi
  23
  24 ###########################################################################
  25 ## History                                                               ##
  26 ###########################################################################
  27 ## 0.2.9   2009-10-13 automatic changeset management                     ##
  28 ##                    ChangesetUpload implementation                     ##
  29 ## 0.2.8   2009-10-13 *(Create|Update|Delete) use not unique _do method  ##
  30 ## 0.2.7   2009-10-09 implement all missing fonctions except             ##
  31 ##                    ChangesetsGet and GetCapabilities                  ##
  32 ## 0.2.6   2009-10-09 encoding clean-up                                  ##
  33 ## 0.2.5   2009-10-09 implements NodesGet, WaysGet, RelationsGet         ##
  34 ##                               ParseOsm, ParseOsc                      ##
  35 ## 0.2.4   2009-10-06 clean-up                                           ##
  36 ## 0.2.3   2009-09-09 keep http connection alive for multiple request    ##
  37 ##                    (Node|Way|Relation)Get return None when object     ##
  38 ##                    have been deleted (raising error before)           ##
  39 ## 0.2.2   2009-07-13 can identify applications built on top of the lib  ##
  40 ## 0.2.1   2009-05-05 some changes in constructor -- chove@crans.org     ##
  41 ## 0.2     2009-05-01 initial import                                     ##
  42 ###########################################################################
  43
  44 __version__ = '0.2.9'
  45
  46 import httplib, base64, xml.dom.minidom, time
  47
  48 ###########################################################################
  49 ## Main class                                                            ##
  50
  51 class OsmApi:
  52
  53     def __init__(self,
  54         username = None,
  55         password = None,
  56         passwordfile = None,
  57         appid = "",
  58         created_by = "PythonOsmApi/"+__version__,
  59         api = "www.openstreetmap.org",
  60         changesetauto = False,
  61         changesetautotags = {},
  62         changesetautosize = 500):
  63
  64         # Get username
  65         if username:
  66             self._username = username
  67         elif passwordfile:
  68             self._username =  open(passwordfile).readline().split(":")[0].strip()
  69
  70         # Get password
  71         if password:
  72             self._password   = password
  73         elif passwordfile:
  74             for l in open(passwordfile).readlines():
  75                 l = l.strip().split(":")
  76                 if l[0] == self._username:
  77                     self._password = l[1]
  78
  79         # Changest informations
  80         self._changesetauto      = changesetauto      # auto create and close changesets
  81         self._changesetautotags  = changesetautotags  # tags for automatic created changesets
  82         self._changesetautosize  = changesetautosize  # change count for auto changeset
  83         self._changesetautodata  = []                 # data to upload for auto group
  84
  85         # Get API
  86         self._api = api
  87
  88         # Get created_by
  89         if not appid:
  90             self._created_by = created_by
  91         else:
  92             self._created_by = appid + " (" + created_by + ")"
  93
  94         # Initialisation
  95         self._CurrentChangesetId = 0
  96
  97         # Http connection
  98         self._conn = httplib.HTTPConnection(self._api, 80)
  99
 100     def __del__(self):
 101         if self._changesetauto:
 102             self._changesetautoflush(True)
 103         return None
 104
 105     #######################################################################
 106     # Capabilities                                                        #
 107     #######################################################################
 108
 109     def Capabilities(self):
 110         raise NotImplemented
 111
 112     #######################################################################
 113     # Node                                                                #
 114     #######################################################################
 115
 116     def NodeGet(self, NodeId, NodeVersion = -1):
 117         """ Returns NodeData for node #NodeId. """
 118         uri = "/api/0.6/node/"+str(NodeId)
 119         if NodeVersion <> -1: uri += "/"+str(NodeVersion)
 120         data = self._get(uri)
 121         if not data: return data
 122         data = xml.dom.minidom.parseString(data)
 123         data = data.getElementsByTagName("osm")[0].getElementsByTagName("node")[0]
 124         return self._DomParseNode(data)
 125
 126     def NodeCreate(self, NodeData):
 127         """ Creates a node. Returns updated NodeData (without timestamp). """
 128         return self._do("create", "node", NodeData)
 129
 130     def NodeUpdate(self, NodeData):
 131         """ Updates node with NodeData. Returns updated NodeData (without timestamp). """
 132         return self._do("update", "node", NodeData)
 133
 134     def NodeDelete(self, NodeData):
 135         """ Delete node with NodeData. Returns updated NodeData (without timestamp). """
 136         return self._do("delete", "node", NodeData)
 137
 138     def NodeHistory(self, NodeId):
 139         """ Returns dict(NodeVerrsion: NodeData). """
 140         uri = "/api/0.6/node/"+str(NodeId)+"/history"
 141         data = self._get(uri)
 142         data = xml.dom.minidom.parseString(data)
 143         result = {}
 144         for data in data.getElementsByTagName("osm")[0].getElementsByTagName("node"):
 145             data = self._DomParseNode(data)
 146             result[data[u"version"]] = data
 147         return result
 148
 149     def NodeWays(self, NodeId):
 150         """ Returns [WayData, ... ] containing node #NodeId. """
 151         uri = "/api/0.6/node/%d/ways"%NodeId
 152         data = self._get(uri)
 153         data = xml.dom.minidom.parseString(data)
 154         result = []
 155         for data in data.getElementsByTagName("osm")[0].getElementsByTagName("way"):
 156             data = self._DomParseRelation(data)
 157             result.append(data)
 158         return result
 159
 160     def NodeRelations(self, NodeId):
 161         """ Returns [RelationData, ... ] containing node #NodeId. """
 162         uri = "/api/0.6/node/%d/relations"%NodeId
 163         data = self._get(uri)
 164         data = xml.dom.minidom.parseString(data)
 165         result = []
 166         for data in data.getElementsByTagName("osm")[0].getElementsByTagName("relation"):
 167             data = self._DomParseRelation(data)
 168             result.append(data)
 169         return result
 170
 171     def NodesGet(self, NodeIdList):
 172         """ Returns dict(NodeId: NodeData) for each node in NodeIdList """
 173         uri  = "/api/0.6/nodes?nodes=" + ",".join([str(x) for x in NodeIdList])
 174         data = self._get(uri)
 175         data = xml.dom.minidom.parseString(data)
 176         result = {}
 177         for data in data.getElementsByTagName("osm")[0].getElementsByTagName("node"):
 178             data = self._DomParseNode(data)
 179             result[data[u"id"]] = data
 180         return result
 181
 182     #######################################################################
 183     # Way                                                                 #
 184     #######################################################################
 185
 186     def WayGet(self, WayId, WayVersion = -1):
 187         """ Returns WayData for way #WayId. """
 188         uri = "/api/0.6/way/"+str(WayId)
 189         if WayVersion <> -1: uri += "/"+str(WayVersion)
 190         data = self._get(uri)
 191         if not data: return data
 192         data = xml.dom.minidom.parseString(data)
 193         data = data.getElementsByTagName("osm")[0].getElementsByTagName("way")[0]
 194         return self._DomParseWay(data)
 195
 196     def WayCreate(self, WayData):
 197         """ Creates a way. Returns updated WayData (without timestamp). """
 198         return self._do("create", "way", WayData)
 199
 200     def WayUpdate(self, WayData):
 201         """ Updates way with WayData. Returns updated WayData (without timestamp). """
 202         return self._do("update", "way", WayData)
 203
 204     def WayDelete(self, WayData):
 205         """ Delete way with WayData. Returns updated WayData (without timestamp). """
 206         return self._do("delete", "way", WayData)
 207
 208     def WayHistory(self, WayId):
 209         """ Returns dict(WayVerrsion: WayData). """
 210         uri = "/api/0.6/way/"+str(WayId)+"/history"
 211         data = self._get(uri)
 212         data = xml.dom.minidom.parseString(data)
 213         result = {}
 214         for data in data.getElementsByTagName("osm")[0].getElementsByTagName("way"):
 215             data = self._DomParseWay(data)
 216             result[data[u"version"]] = data
 217         return result
 218
 219     def WayRelations(self, WayId):
 220         """ Returns [RelationData, ...] containing way #WayId. """
 221         uri = "/api/0.6/way/%d/relations"%WayId
 222         data = self._get(uri)
 223         data = xml.dom.minidom.parseString(data)
 224         result = []
 225         for data in data.getElementsByTagName("osm")[0].getElementsByTagName("relation"):
 226             data = self._DomParseRelation(data)
 227             result.append(data)
 228         return result
 229
 230     def WayFull(self, WayId):
 231         """ Return full data for way WayId as list of {type: node|way|relation, data: {}}. """
 232         uri = "/api/0.6/way/"+str(WayId)+"/full"
 233         data = self._get(uri)
 234         return self.ParseOsm(data)
 235
 236     def WaysGet(self, WayIdList):
 237         """ Returns dict(WayId: WayData) for each way in WayIdList """
 238         uri = "/api/0.6/ways?ways=" + ",".join([str(x) for x in WayIdList])
 239         data = self._get(uri)
 240         data = xml.dom.minidom.parseString(data)
 241         result = {}
 242         for data in data.getElementsByTagName("osm")[0].getElementsByTagName("way"):
 243             data = self._DomParseWay(data)
 244             result[data[u"id"]] = data
 245         return result
 246
 247     #######################################################################
 248     # Relation                                                            #
 249     #######################################################################
 250
 251     def RelationGet(self, RelationId, RelationVersion = -1):
 252         """ Returns RelationData for relation #RelationId. """
 253         uri = "/api/0.6/relation/"+str(RelationId)
 254         if RelationVersion <> -1: uri += "/"+str(RelationVersion)
 255         data = self._get(uri)
 256         if not data: return data
 257         data = xml.dom.minidom.parseString(data)
 258         data = data.getElementsByTagName("osm")[0].getElementsByTagName("relation")[0]
 259         return self._DomParseRelation(data)
 260
 261     def RelationCreate(self, RelationData):
 262         """ Creates a relation. Returns updated RelationData (without timestamp). """
 263         return self._do("create", "relation", RelationData)
 264
 265     def RelationUpdate(self, RelationData):
 266         """ Updates relation with RelationData. Returns updated RelationData (without timestamp). """
 267         return self._do("update", "relation", RelationData)
 268
 269     def RelationDelete(self, RelationData):
 270         """ Delete relation with RelationData. Returns updated RelationData (without timestamp). """
 271         return self._do("delete", "relation", RelationData)
 272
 273     def RelationHistory(self, RelationId):
 274         """ Returns dict(RelationVerrsion: RelationData). """
 275         uri = "/api/0.6/relation/"+str(RelationId)+"/history"
 276         data = self._get(uri)
 277         data = xml.dom.minidom.parseString(data)
 278         result = {}
 279         for data in data.getElementsByTagName("osm")[0].getElementsByTagName("relation"):
 280             data = self._DomParseRelation(data)
 281             result[data[u"version"]] = data
 282         return result
 283
 284     def RelationRelations(self, RelationId):
 285         """ Returns list of RelationData containing relation #RelationId. """
 286         uri = "/api/0.6/relation/%d/relations"%RelationId
 287         data = self._get(uri)
 288         data = xml.dom.minidom.parseString(data)
 289         result = []
 290         for data in data.getElementsByTagName("osm")[0].getElementsByTagName("relation"):
 291             data = self._DomParseRelation(data)
 292             result.append(data)
 293         return result
 294
 295     def RelationFull(self, RelationId):
 296         """ Return full data for way WayId as list of {type: node|way|relation, data: {}}. """
 297         uri = "/api/0.6/relation/"+str(RelationId)+"/full"
 298         data = self._get(uri)
 299         return self.ParseOsm(data)
 300
 301     def RelationsGet(self, RelationIdList):
 302         """ Returns dict(RelationId: RelationData) for each relation in RelationIdList """
 303         uri = "/api/0.6/relations?relations=" + ",".join([str(x) for x in RelationIdList])
 304         data = self._get(uri)
 305         data = xml.dom.minidom.parseString(data)
 306         result = {}
 307         for data in data.getElementsByTagName("osm")[0].getElementsByTagName("relation"):
 308             data = self._DomParseRelation(data)
 309             result[data[u"id"]] = data
 310         return result
 311
 312     #######################################################################
 313     # Changeset                                                           #
 314     #######################################################################
 315
 316     def ChangesetGet(self, ChangesetId):
 317         """ Returns ChangesetData for changeset #ChangesetId. """
 318         data = self._get("/api/0.6/changeset/"+str(ChangesetId))
 319         data = xml.dom.minidom.parseString(data)
 320         data = data.getElementsByTagName("osm")[0].getElementsByTagName("changeset")[0]
 321         return self._DomParseChangeset(data)
 322
 323     def ChangesetUpdate(self, ChangesetTags = {}):
 324         """ Updates current changeset with ChangesetTags. """
 325         if self._CurrentChangesetId == -1:
 326             raise Exception, "No changeset currently opened"
 327         if u"created_by" not in ChangesetTags:
 328             ChangesetTags[u"created_by"] = self._created_by
 329         result = self._put("/api/0.6/changeset/"+str(self._CurrentChangesetId), self._XmlBuild("changeset", {u"tag": ChangesetTags}))
 330         return self._CurrentChangesetId
 331
 332     def ChangesetCreate(self, ChangesetTags = {}):
 333         """ Opens a changeset. Returns #ChangesetId. """
 334         if self._CurrentChangesetId:
 335             raise Exception, "Changeset alreadey opened"
 336         if u"created_by" not in ChangesetTags:
 337             ChangesetTags[u"created_by"] = self._created_by
 338         result = self._put("/api/0.6/changeset/create", self._XmlBuild("changeset", {u"tag": ChangesetTags}))
 339         self._CurrentChangesetId = int(result)
 340         return self._CurrentChangesetId
 341
 342     def ChangesetClose(self):
 343         """ Closes current changeset. Returns #ChangesetId. """
 344         if not self._CurrentChangesetId:
 345             raise Exception, "No changeset currently opened"
 346         result = self._put("/api/0.6/changeset/"+str(self._CurrentChangesetId)+"/close", u"")
 347         CurrentChangesetId = self._CurrentChangesetId
 348         self._CurrentChangesetId = 0
 349         return CurrentChangesetId
 350
 351     def ChangesetUpload(self, ChangesData):
 352         """ Upload data. ChangesData is a list of dict {type: node|way|relation, action: create|delete|modify, data: {}}. Returns list with updated ids. """
 353         data = ""
 354         data += u"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
 355         data += u"<osmChange version=\"0.6\" generator=\"" + self._created_by + "\">\n"
 356         for change in ChangesData:
 357             data += u"<"+change["action"]+">\n"
 358             change["data"]["changeset"] = self._CurrentChangesetId
 359             data += self._XmlBuild(change["type"], change["data"], False)
 360             data += u"</"+change["action"]+">\n"
 361         data += u"</osmChange>"
 362         data = self._http("POST", "/api/0.6/changeset/"+str(self._CurrentChangesetId)+"/upload", True, data)
 363         data = xml.dom.minidom.parseString(data)
 364         data = data.getElementsByTagName("diffResult")[0]
 365         data = [x for x in data.childNodes if x.nodeType == x.ELEMENT_NODE]
 366         for i in range(len(ChangesData)):
 367             if ChangesData[i]["action"] == "delete":
 368                 ChangesData[i]["data"].pop("version")
 369             else:
 370                 ChangesData[i]["data"]["version"] = int(data[i].getAttribute("new_id"))
 371         return ChangesData
 372
 373     def ChangesetDownload(self, ChangesetId):
 374         """ Download data from a changeset. Returns list of dict {type: node|way|relation, action: create|delete|modify, data: {}}. """
 375         uri = "/api/0.6/changeset/"+str(ChangesetId)+"/download"
 376         data = self._get(uri)
 377         return self.ParseOsc(data)
 378
 379     def ChangesetsGet(self, min_lon=None, min_lat=None, max_lon=None, max_lat=None, userid=None, closed_after=None, created_before=None, only_open=False, only_closed=False):
 380         """ Returns dict(ChangsetId: ChangesetData) matching all criteria. """
 381         raise NotImplemented
 382
 383     #######################################################################
 384     # Other                                                               #
 385     #######################################################################
 386
 387     def Map(self, min_lon, min_lat, max_lon, max_lat):
 388         """ Download data in bounding box. Returns list of dict {type: node|way|relation, data: {}}. """
 389         uri = "/api/0.6/map?bbox=%f,%f,%f,%f"%(min_lon, min_lat, max_lon, max_lat)
 390         data = self._get(uri)
 391         return self.ParseOsm(data)
 392
 393     #######################################################################
 394     # Data parser                                                         #
 395     #######################################################################
 396
 397     def ParseOsm(self, data):
 398         """ Parse osm data. Returns list of dict {type: node|way|relation, data: {}}. """
 399         data = xml.dom.minidom.parseString(data)
 400         data = data.getElementsByTagName("osm")[0]
 401         result = []
 402         for elem in data.childNodes:
 403             if elem.nodeName == u"node":
 404                 result.append({u"type": elem.nodeName, u"data": self._DomParseNode(elem)})
 405             elif elem.nodeName == u"way":
 406                 result.append({u"type": elem.nodeName, u"data": self._DomParseWay(elem)})
 407             elif elem.nodeName == u"relation":
 408                 result.append({u"type": elem.nodeName, u"data": self._DomParseRelation(elem)})
 409         return result
 410
 411     def ParseOsc(self, data):
 412         """ Parse osc data. Returns list of dict {type: node|way|relation, action: create|delete|modify, data: {}}. """
 413         data = xml.dom.minidom.parseString(data)
 414         data = data.getElementsByTagName("osmChange")[0]
 415         result = []
 416         for action in data.childNodes:
 417             if action.nodeName == u"#text": continue
 418             for elem in action.childNodes:
 419                 if elem.nodeName == u"node":
 420                     result.append({u"action":action.nodeName, u"type": elem.nodeName, u"data": self._DomParseNode(elem)})
 421                 elif elem.nodeName == u"way":
 422                     result.append({u"action":action.nodeName, u"type": elem.nodeName, u"data": self._DomParseWay(elem)})
 423                 elif elem.nodeName == u"relation":
 424                     result.append({u"action":action.nodeName, u"type": elem.nodeName, u"data": self._DomParseRelation(elem)})
 425         return result
 426
 427     #######################################################################
 428     # Internal http function                                              #
 429     #######################################################################
 430
 431     def _do(self, action, OsmType, OsmData):
 432         if self._changesetauto:
 433             self._changesetautodata.append({"action":action, "type":OsmType, "data":OsmData})
 434             self._changesetautoflush()
 435             return None
 436         else:
 437             return self._do_manu(action, OsmType, OsmData)
 438
 439     def _do_manu(self, action, OsmType, OsmData):
 440         if not self._CurrentChangesetId:
 441             raise Exception, "You need to open a changeset before uploading data"
 442         if u"timestamp" in OsmData:
 443             OsmData.pop(u"timestamp")
 444         OsmData[u"changeset"] = self._CurrentChangesetId
 445         if action == "create":
 446             if OsmData.get(u"id", -1) > 0:
 447                 raise Exception, "This "+OsmType+" already exists"
 448             result = self._put("/api/0.6/"+OsmType+"/create", self._XmlBuild(OsmType, OsmData))
 449             OsmData[u"id"] = int(result.strip())
 450             OsmData[u"version"] = 1
 451             return OsmData
 452         elif action == "update":
 453             result = self._put("/api/0.6/"+OsmType+"/"+str(OsmData[u"id"]), self._XmlBuild(OsmType, OsmData))
 454             OsmData[u"version"] = int(result.strip())
 455             return OsmData
 456         elif action =="delete":
 457             result = self._delete("/api/0.6/"+OsmType+"/"+str(OsmData[u"id"]), self._XmlBuild(OsmType, OsmData))
 458             OsmData[u"version"] = int(result.strip())
 459             OsmData[u"visible"] = False
 460             return OsmData
 461
 462     def _changesetautoflush(self, force = False):
 463         while (len(self._changesetautodata) >= self._changesetautosize) or (force and self._changesetautodata):
 464             self.ChangesetCreate(self._changesetautotags)
 465             self.ChangesetUpload(self._changesetautodata[:self._changesetautosize])
 466             self._changesetautodata = self._changesetautodata[self._changesetautosize:]
 467             self.ChangesetClose()
 468         return None
 469
 470     def _http_request(self, cmd, path, auth, send):
 471         self._conn.putrequest(cmd, path)
 472         self._conn.putheader('User-Agent', self._created_by)
 473         if auth:
 474             self._conn.putheader('Authorization', 'Basic ' + base64.encodestring(self._username + ':' + self._password).strip())
 475         if send:
 476             self._conn.putheader('Content-Length', len(send))
 477         self._conn.endheaders()
 478         if send:
 479             self._conn.send(send)
 480         response = self._conn.getresponse()
 481         if response.status <> 200:
 482             response.read()
 483             if response.status == 410:
 484                 return None
 485             raise Exception, "API returns unexpected status code "+str(response.status)+" ("+response.reason+")"
 486         return response.read()
 487
 488     def _http(self, cmd, path, auth, send):
 489         i = 0
 490         while True:
 491             i += 1
 492             try:
 493                 return self._http_request(cmd, path, auth, send)
 494             except:
 495                 if i == 5: raise
 496                 if i <> 1: time.sleep(2)
 497                 self._conn = httplib.HTTPConnection(self._api, 80)
 498
 499     def _get(self, path):
 500         return self._http('GET', path, False, None)
 501
 502     def _put(self, path, data):
 503         return self._http('PUT', path, True, data)
 504
 505     def _delete(self, path, data):
 506         return self._http('DELETE', path, True, data)
 507
 508     #######################################################################
 509     # Internal dom function                                               #
 510     #######################################################################
 511
 512     def _DomGetAttributes(self, DomElement):
 513         """ Returns a formated dictionnary of attributes of a DomElement. """
 514         result = {}
 515         for k, v in DomElement.attributes.items():
 516             if k == u"uid"         : v = int(v)
 517             elif k == u"changeset" : v = int(v)
 518             elif k == u"version"   : v = int(v)
 519             elif k == u"id"        : v = int(v)
 520             elif k == u"lat"       : v = float(v)
 521             elif k == u"lon"       : v = float(v)
 522             elif k == u"open"      : v = v=="true"
 523             elif k == u"visible"   : v = v=="true"
 524             elif k == u"ref"       : v = int(v)
 525             result[k] = v
 526         return result
 527
 528     def _DomGetTag(self, DomElement):
 529         """ Returns the dictionnary of tags of a DomElement. """
 530         result = {}
 531         for t in DomElement.getElementsByTagName("tag"):
 532             k = t.attributes["k"].value
 533             v = t.attributes["v"].value
 534             result[k] = v
 535         return result
 536
 537     def _DomGetNd(self, DomElement):
 538         """ Returns the list of nodes of a DomElement. """
 539         result = []
 540         for t in DomElement.getElementsByTagName("nd"):
 541             result.append(int(int(t.attributes["ref"].value)))
 542         return result
 543
 544     def _DomGetMember(self, DomElement):
 545         """ Returns a list of relation members. """
 546         result = []
 547         for m in DomElement.getElementsByTagName("member"):
 548             result.append(self._DomGetAttributes(m))
 549         return result
 550
 551     def _DomParseNode(self, DomElement):
 552         """ Returns NodeData for the node. """
 553         result = self._DomGetAttributes(DomElement)
 554         result[u"tag"] = self._DomGetTag(DomElement)
 555         return result
 556
 557     def _DomParseWay(self, DomElement):
 558         """ Returns WayData for the way. """
 559         result = self._DomGetAttributes(DomElement)
 560         result[u"tag"] = self._DomGetTag(DomElement)
 561         result[u"nd"]  = self._DomGetNd(DomElement)
 562         return result
 563
 564     def _DomParseRelation(self, DomElement):
 565         """ Returns RelationData for the relation. """
 566         result = self._DomGetAttributes(DomElement)
 567         result[u"tag"]    = self._DomGetTag(DomElement)
 568         result[u"member"] = self._DomGetMember(DomElement)
 569         return result
 570
 571     def _DomParseChangeset(self, DomElement):
 572         """ Returns ChangesetData for the changeset. """
 573         result = self._DomGetAttributes(DomElement)
 574         result[u"tag"] = self._DomGetTag(DomElement)
 575         return result
 576
 577     #######################################################################
 578     # Internal xml builder                                                #
 579     #######################################################################
 580
 581     def _XmlBuild(self, ElementType, ElementData, WithHeaders = True):
 582
 583         xml  = u""
 584         if WithHeaders:
 585             xml += u"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
 586             xml += u"<osm version=\"0.6\" generator=\"" + self._created_by + "\">\n"
 587
 588         # <element attr="val">
 589         xml += u"  <" + ElementType
 590         if u"id" in ElementData:
 591             xml += u" id=\"" + str(ElementData[u"id"]) + u"\""
 592         if u"lat" in ElementData:
 593             xml += u" lat=\"" + str(ElementData[u"lat"]) + u"\""
 594         if u"lon" in ElementData:
 595             xml += u" lon=\"" + str(ElementData[u"lon"]) + u"\""
 596         if u"version" in ElementData:
 597             xml += u" version=\"" + str(ElementData[u"version"]) + u"\""
 598         xml += u" visible=\"" + str(ElementData.get(u"visible", True)).lower() + u"\""
 599         if ElementType in [u"node", u"way", u"relation"]:
 600             xml += u" changeset=\"" + str(self._CurrentChangesetId) + u"\""
 601         xml += u">\n"
 602
 603         # <tag... />
 604         for k, v in ElementData.get(u"tag", {}).items():
 605             xml += u"    <tag k=\""+self._XmlEncode(k)+u"\" v=\""+self._XmlEncode(v)+u"\"/>\n"
 606
 607         # <member... />
 608         for member in ElementData.get(u"member", []):
 609             xml += u"    <member type=\""+member[u"type"]+"\" ref=\""+str(member[u"ref"])+u"\" role=\""+self._XmlEncode(member[u"role"])+"\"/>\n"
 610
 611         # <nd... />
 612         for ref in ElementData.get(u"nd", []):
 613             xml += u"    <nd ref=\""+str(ref)+u"\"/>\n"
 614
 615         # </element>
 616         xml += u"  </" + ElementType + u">\n"
 617
 618         if WithHeaders:
 619             xml += u"</osm>\n"
 620
 621         return xml.encode("utf8")
 622
 623     def _XmlEncode(self, text):
 624         return text.replace("&", "&amp;").replace("\"", "&quot;")
 625
 626 ## End of main class                                                     ##
 627 ###########################################################################