app/models/relation.rb

   1 class Relation < ActiveRecord::Base
   2   require 'xml/libxml'
   3
   4   set_table_name 'current_relations'
   5
   6   belongs_to :user
   7
   8   has_many :old_relations, :foreign_key => 'id', :order => 'version'
   9
  10   has_many :relation_members, :foreign_key => 'id'
  11   has_many :relation_tags, :foreign_key => 'id'
  12
  13   has_many :containing_relation_members, :class_name => "RelationMember", :as => :member
  14   has_many :containing_relations, :class_name => "Relation", :through => :containing_relation_members, :source => :relation, :extend => ObjectFinder
  15
  16   def self.from_xml(xml, create=false)
  17     begin
  18       p = XML::Parser.new
  19       p.string = xml
  20       doc = p.parse
  21
  22       doc.find('//osm/relation').each do |pt|
  23         return Relation.from_xml_node(pt, create)
  24       end
  25     rescue
  26       return nil
  27     end
  28   end
  29
  30   def self.from_xml_node(pt, create=false)
  31     relation = Relation.new
  32
  33     if !create and pt['id'] != '0'
  34       relation.id = pt['id'].to_i
  35     end
  36
  37     relation.version = pt['version']
  38
  39     if create
  40       relation.timestamp = Time.now
  41       relation.visible = true
  42     else
  43       if pt['timestamp']
  44         relation.timestamp = Time.parse(pt['timestamp'])
  45       end
  46     end
  47
  48     pt.find('tag').each do |tag|
  49       relation.add_tag_keyval(tag['k'], tag['v'])
  50     end
  51
  52     pt.find('member').each do |member|
  53       relation.add_member(member['type'], member['ref'], member['role'])
  54     end
  55
  56     return relation
  57   end
  58
  59   def to_xml
  60     doc = OSM::API.new.get_xml_doc
  61     doc.root << to_xml_node()
  62     return doc
  63   end
  64
  65   def to_xml_node(user_display_name_cache = nil)
  66     el1 = XML::Node.new 'relation'
  67     el1['id'] = self.id.to_s
  68     el1['visible'] = self.visible.to_s
  69     el1['timestamp'] = self.timestamp.xmlschema
  70     el1['version'] = self.version.to_s
  71
  72     user_display_name_cache = {} if user_display_name_cache.nil?
  73
  74     if user_display_name_cache and user_display_name_cache.key?(self.user_id)
  75       # use the cache if available
  76     elsif self.user.data_public?
  77       user_display_name_cache[self.user_id] = self.user.display_name
  78     else
  79       user_display_name_cache[self.user_id] = nil
  80     end
  81
  82     el1['user'] = user_display_name_cache[self.user_id] unless user_display_name_cache[self.user_id].nil?
  83
  84     self.relation_members.each do |member|
  85       p=0
  86       #if visible_members
  87       #  # if there is a list of visible members then use that to weed out deleted segments
  88       #  if visible_members[member.member_type][member.member_id]
  89       #    p=1
  90       #  end
  91       #else
  92         # otherwise, manually go to the db to check things
  93         if member.member.visible?
  94           p=1
  95         end
  96       #end
  97       if p
  98         e = XML::Node.new 'member'
  99         e['type'] = member.member_type
 100         e['ref'] = member.member_id.to_s
 101         e['role'] = member.member_role
 102         el1 << e
 103        end
 104     end
 105
 106     self.relation_tags.each do |tag|
 107       e = XML::Node.new 'tag'
 108       e['k'] = tag.k
 109       e['v'] = tag.v
 110       el1 << e
 111     end
 112     return el1
 113   end
 114
 115   def self.find_for_nodes(ids, options = {})
 116     if ids.empty?
 117       return []
 118     else
 119       self.with_scope(:find => { :joins => "INNER JOIN current_relation_members ON current_relation_members.id = current_relations.id", :conditions => "current_relation_members.member_type = 'node' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
 120         return self.find(:all, options)
 121       end
 122     end
 123   end
 124
 125   def self.find_for_ways(ids, options = {})
 126     if ids.empty?
 127       return []
 128     else
 129       self.with_scope(:find => { :joins => "INNER JOIN current_relation_members ON current_relation_members.id = current_relations.id", :conditions => "current_relation_members.member_type = 'way' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
 130         return self.find(:all, options)
 131       end
 132     end
 133   end
 134
 135   def self.find_for_relations(ids, options = {})
 136     if ids.empty?
 137       return []
 138     else
 139       self.with_scope(:find => { :joins => "INNER JOIN current_relation_members ON current_relation_members.id = current_relations.id", :conditions => "current_relation_members.member_type = 'relation' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
 140         return self.find(:all, options)
 141       end
 142     end
 143   end
 144
 145   # FIXME is this really needed?
 146   def members
 147     unless @members
 148       @members = Array.new
 149       self.relation_members.each do |member|
 150         @members += [[member.member_type,member.member_id,member.member_role]]
 151       end
 152     end
 153     @members
 154   end
 155
 156   def tags
 157     unless @tags
 158       @tags = Hash.new
 159       self.relation_tags.each do |tag|
 160         @tags[tag.k] = tag.v
 161       end
 162     end
 163     @tags
 164   end
 165
 166   def members=(m)
 167     @members = m
 168   end
 169
 170   def tags=(t)
 171     @tags = t
 172   end
 173
 174   def add_member(type,id,role)
 175     @members = Array.new unless @members
 176     @members += [[type,id,role]]
 177   end
 178
 179   def add_tag_keyval(k, v)
 180     @tags = Hash.new unless @tags
 181     @tags[k] = v
 182   end
 183
 184   def save_with_history!
 185     Relation.transaction do
 186       t = Time.now
 187       self.version += 1
 188       self.timestamp = t
 189       self.save!
 190
 191       tags = self.tags
 192       RelationTag.delete_all(['id = ?', self.id])
 193       tags.each do |k,v|
 194         tag = RelationTag.new
 195         tag.k = k
 196         tag.v = v
 197         tag.id = self.id
 198         tag.save!
 199       end
 200
 201       members = self.members
 202       RelationMember.delete_all(['id = ?', self.id])
 203       members.each do |n|
 204         mem = RelationMember.new
 205         mem.id = self.id
 206         mem.member_type = n[0];
 207         mem.member_id = n[1];
 208         mem.member_role = n[2];
 209         mem.save!
 210       end
 211
 212       old_relation = OldRelation.from_relation(self)
 213       old_relation.timestamp = t
 214       old_relation.save_with_dependencies!
 215     end
 216   end
 217
 218   def delete_with_history(user)
 219     if self.visible
 220       if RelationMember.find(:first, :joins => "INNER JOIN current_relations ON current_relations.id=current_relation_members.id", :conditions => [ "visible = 1 AND member_type='relation' and member_id=?", self.id ])
 221         raise OSM::APIPreconditionFailedError.new
 222       else
 223         self.user_id = user.id
 224         self.tags = []
 225         self.members = []
 226         self.visible = false
 227         save_with_history!
 228       end
 229     else
 230       raise OSM::APIAlreadyDeletedError.new
 231     end
 232   end
 233
 234   def update_from(new_relation, user)
 235     if !new_relation.preconditions_ok?
 236       raise OSM::APIPreconditionFailedError.new
 237     elsif new_relation.version != version
 238       raise OSM::APIVersionMismatchError.new(new_relation.version, version)
 239     else
 240       self.user_id = user.id
 241       self.tags = new_relation.tags
 242       self.members = new_relation.members
 243       self.visible = true
 244       save_with_history!
 245     end
 246   end
 247
 248   def preconditions_ok?
 249     # These are hastables that store an id in the index of all
 250     # the nodes/way/relations that have already been added.
 251     # Once we know the id of the node/way/relation exists
 252     # we check to see if it is already existing in the hashtable
 253     # if it does, then we return false. Otherwise
 254     # we add it to the relevant hash table, with the value true..
 255     # Thus if you have nodes with the ids of 50 and 1 already in the
 256     # relation, then the hash table nodes would contain:
 257     # => {50=>true, 1=>true}
 258     nodes = Hash.new
 259     ways = Hash.new
 260     relations = Hash.new
 261     self.members.each do |m|
 262       if (m[0] == "node")
 263         n = Node.find(:first, :conditions => ["id = ?", m[1]])
 264         unless n and n.visible
 265           return false
 266         end
 267         if nodes[m[1]]
 268           return false
 269         else
 270           nodes[m[1]] = true
 271         end
 272       elsif (m[0] == "way")
 273         w = Way.find(:first, :conditions => ["id = ?", m[1]])
 274         unless w and w.visible and w.preconditions_ok?
 275           return false
 276         end
 277         if ways[m[1]]
 278           return false
 279         else
 280           ways[m[1]] = true
 281         end
 282       elsif (m[0] == "relation")
 283         e = Relation.find(:first, :conditions => ["id = ?", m[1]])
 284         unless e and e.visible and e.preconditions_ok?
 285           return false
 286         end
 287         if relations[m[1]]
 288           return false
 289         else
 290           relations[m[1]] = true
 291         end
 292       else
 293         return false
 294       end
 295     end
 296     return true
 297   rescue
 298     return false
 299   end
 300
 301   # Temporary method to match interface to nodes
 302   def tags_as_hash
 303     return self.tags
 304   end
 305 end