1 class Changeset < ActiveRecord::Base
6 has_many :changeset_tags, :foreign_key => 'id'
13 has_many :old_relations
15 validates_presence_of :user_id, :created_at, :closed_at
17 # over-expansion factor to use when updating the bounding box
20 # maximum number of elements allowed in a changeset
23 # maximum time a changeset is allowed to be open for (note that this
24 # is in days - so one hour is Rational(1,24)).
27 # idle timeout increment, one hour as a rational number of days.
28 IDLE_TIMEOUT = 1.hour #Rational(1,24)
30 # Use a method like this, so that we can easily change how we
31 # determine whether a changeset is open, without breaking code in at
34 # a changeset is open (that is, it will accept further changes) when
35 # it has not yet run out of time and its capacity is small enough.
36 # note that this may not be a hard limit - due to timing changes and
37 # concurrency it is possible that some changesets may be slightly
38 # longer than strictly allowed or have slightly more changes in them.
39 return ((closed_at > DateTime.now) and (num_changes <= MAX_ELEMENTS))
42 def set_closed_time_now
43 closed_at = DateTime.now
46 def self.from_xml(xml, create=false)
54 doc.find('//osm/changeset').each do |pt|
56 cs.created_at = Time.now
57 # initial close time is 1h ahead, but will be increased on each
59 cs.closed_at = Time.now + IDLE_TIMEOUT
60 # initially we have no changes in a changeset
64 pt.find('tag').each do |tag|
65 cs.add_tag_keyval(tag['k'], tag['v'])
68 rescue Exception => ex
76 # returns the bounding box of the changeset. it is possible that some
77 # or all of the values will be nil, indicating that they are undefined.
79 @bbox ||= [ min_lon, min_lat, max_lon, max_lat ]
83 # expand the bounding box to include the given bounding box. also,
84 # expand a little bit more in the direction of the expansion, so that
85 # further expansions may be unnecessary. this is an optimisation
86 # suggested on the wiki page by kleptog.
87 def update_bbox!(array)
88 # ensure that bbox is cached and has no nils in it. if there are any
89 # nils, just use the bounding box update to write over them.
90 @bbox = bbox.zip(array).collect { |a, b| a.nil? ? b : a }
92 # FIXME - this looks nasty and violates DRY... is there any prettier
94 @bbox[0] = array[0] + EXPAND * (@bbox[0] - @bbox[2]) if array[0] < @bbox[0]
95 @bbox[1] = array[1] + EXPAND * (@bbox[1] - @bbox[3]) if array[1] < @bbox[1]
96 @bbox[2] = array[2] + EXPAND * (@bbox[2] - @bbox[0]) if array[2] > @bbox[2]
97 @bbox[3] = array[3] + EXPAND * (@bbox[3] - @bbox[1]) if array[3] > @bbox[3]
99 # update active record. rails 2.1's dirty handling should take care of
100 # whether this object needs saving or not.
101 self.min_lon, self.min_lat, self.max_lon, self.max_lat = @bbox
105 # the number of elements is also passed in so that we can ensure that
106 # a single changeset doesn't contain too many elements. this, of course,
107 # destroys the optimisation described in the bbox method above.
108 def add_changes!(elements)
109 self.num_changes += elements
119 self.changeset_tags.each do |tag|
130 def add_tag_keyval(k, v)
131 @tags = Hash.new unless @tags
138 # do the changeset update and the changeset tags update in the
139 # same transaction to ensure consistency.
140 Changeset.transaction do
141 # set the auto-close time to be one hour in the future unless
142 # that would make it more than 24h long, in which case clip to
143 # 24h, as this has been decided is a reasonable time limit.
144 if (closed_at - created_at) > (MAX_TIME_OPEN - IDLE_TIMEOUT)
145 self.closed_at = created_at + MAX_TIME_OPEN
147 self.closed_at = DateTime.now + IDLE_TIMEOUT
152 ChangesetTag.delete_all(['id = ?', self.id])
155 tag = ChangesetTag.new
165 doc = OSM::API.new.get_xml_doc
166 doc.root << to_xml_node()
170 def to_xml_node(user_display_name_cache = nil)
171 el1 = XML::Node.new 'changeset'
172 el1['id'] = self.id.to_s
174 user_display_name_cache = {} if user_display_name_cache.nil?
176 if user_display_name_cache and user_display_name_cache.key?(self.user_id)
177 # use the cache if available
178 elsif self.user.data_public?
179 user_display_name_cache[self.user_id] = self.user.display_name
181 user_display_name_cache[self.user_id] = nil
184 el1['user'] = user_display_name_cache[self.user_id] unless user_display_name_cache[self.user_id].nil?
185 el1['uid'] = self.user_id.to_s if self.user.data_public?
187 self.tags.each do |k,v|
188 el2 = XML::Node.new('tag')
194 el1['created_at'] = self.created_at.xmlschema
195 el1['closed_at'] = self.closed_at.xmlschema unless is_open?
196 el1['open'] = is_open?.to_s
198 el1['min_lon'] = (bbox[0].to_f / GeoRecord::SCALE).to_s unless bbox[0].nil?
199 el1['min_lat'] = (bbox[1].to_f / GeoRecord::SCALE).to_s unless bbox[1].nil?
200 el1['max_lon'] = (bbox[2].to_f / GeoRecord::SCALE).to_s unless bbox[2].nil?
201 el1['max_lat'] = (bbox[3].to_f / GeoRecord::SCALE).to_s unless bbox[3].nil?
203 # NOTE: changesets don't include the XML of the changes within them,
204 # they are just structures for tagging. to get the osmChange of a
205 # changeset, see the download method of the controller.
211 # update this instance from another instance given and the user who is
212 # doing the updating. note that this method is not for updating the
213 # bounding box, only the tags of the changeset.
214 def update_from(other, user)
215 # ensure that only the user who opened the changeset may modify it.
216 unless user.id == self.user_id
217 raise OSM::APIUserChangesetMismatchError
220 # can't change a closed changeset
222 raise OSM::APIChangesetAlreadyClosedError
225 # copy the other's tags
226 self.tags = other.tags