class ChangesetController < ApplicationController
require 'xml/libxml'
+ require 'diff_reader'
before_filter :authorize, :only => [:create, :update, :delete, :upload]
before_filter :check_write_availability, :only => [:create, :update, :delete, :upload]
end
end
+ ##
+ # Upload a diff in a single transaction.
+ #
+ # This means that each change within the diff must succeed, i.e: that
+ # each version number mentioned is still current. Otherwise the entire
+ # transaction *must* be rolled back.
+ #
+ # Furthermore, each element in the diff can only reference the current
+ # changeset.
+ #
+ # Returns: a diffResult document, as described in
+ # http://wiki.openstreetmap.org/index.php/OSM_Protocol_Version_0.6
def upload
- unless request.put?
+ # only allow POST requests, as the upload method is most definitely
+ # not idempotent, as several uploads with placeholder IDs will have
+ # different side-effects.
+ # see http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9.1.2
+ unless request.post?
render :nothing => true, :status => :method_not_allowed
return
end
- p = XML::Reader.new request.raw_post
-
- node_ids, way_ids, rel_ids = {}, {}, {}
- ids = {"node"=>node_ids, "way"=>way_ids, "relation"=>rel_ids}
-
- models = {"node"=>Node, "way"=>Way, "relation"=>Relation}
-
- # FIXME shouldn't this be done through the
- # res = OSM::API.new.get_xml_doc
- # as everything else is?
- res = XML::Document.new
- res.encoding = 'UTF-8'
- root = XML::Node.new 'osm'
- root['version'] = API_VERSION
- root['creator'] = 'OpenStreetMap.org'
- res.root = root
-
- root << XML::Node.new_comment(" Warning: this is a 0.6 result document, " +
- "not a normal OSM file. ")
-
+ changeset = Changeset.find(params[:id])
+
+ diff_reader = DiffReader.new(request.raw_post, changeset)
Changeset.transaction do
- while p.read == 1
- break if p.node_type == 15 # end element
- next unless p.node_type == 1 # element
-
- case p.name
- when 'create':
- while p.read == 1
- break if p.node_type == 15 # end element
- next unless p.node_type == 1 # element
-
- model = models[p.name]
- next if model.nil?
-
- elem = XML::Node.new p.name
- nd = p.expand; p.next
- osm = model.from_xml_node(nd, true)
- elem['old_id'] = nd['id']
-
- case nd.name
- when 'way':
- fix_way(osm, node_ids)
- raise OSM::APIPreconditionFailedError.new if !osm.preconditions_ok?
- when 'relation':
- fix_rel(osm, ids)
- raise OSM::APIPreconditionFailedError.new if !osm.preconditions_ok?
- end
-
- create_prim ids[nd.name], osm, nd
- elem['new_id'] = osm.id.to_s
- elem['new_version'] = osm.version.to_s
- root << elem
- end
- when 'modify':
- while p.read == 1
- break if p.node_type == 15 # end element
- next unless p.node_type == 1 # element
-
- model = models[p.name]
- next if model.nil?
-
- elem = XML::Node.new p.name
- new_osm = model.from_xml_node(p.expand); p.next
- osm = model.find(new_osm.id)
- osm.update_from new_osm, @user
- elem['old_id'] = elem['new_id'] = osm.id.to_s
- elem['new_version'] = osm.version.to_s
- root << elem
- end
- when 'delete':
- while p.read == 1
- break if p.node_type == 15 # end element
- next unless p.node_type == 1 # element
-
- model = models[p.name]
- next if model.nil?
+ result = diff_reader.commit
+ render :text => result.to_s, :content_type => "text/xml"
+ end
+
+ rescue ActiveRecord::RecordNotFound
+ render :nothing => true, :status => :not_found
+ rescue OSM::APIError => ex
+ render ex.render_opts
+ end
- elem = XML::Node.new p.name
- osm = model.find(p.expand['id']); p.next
- osm.delete_with_history(@user)
- elem['old_id'] = elem['new_id'] = osm.id.to_s
- elem['new_version'] = osm.version.to_s
- root << elem
+ ##
+ # download the changeset as an osmChange document.
+ #
+ # to make it easier to revert diffs it would be better if the osmChange
+ # format were reversible, i.e: contained both old and new versions of
+ # modified elements. but it doesn't at the moment...
+ #
+ # this method cannot order the database changes fully (i.e: timestamp and
+ # version number may be too coarse) so the resulting diff may not apply
+ # to a different database. however since changesets are not atomic this
+ # behaviour cannot be guaranteed anyway and is the result of a design
+ # choice.
+ def download
+ changeset = Changeset.find(params[:id])
+
+ # get all the elements in the changeset and stick them in a big array.
+ elements = [changeset.old_nodes,
+ changeset.old_ways,
+ changeset.old_relations].flatten
+
+ # sort the elements by timestamp and version number, as this is the
+ # almost sensible ordering available. this would be much nicer if
+ # global (SVN-style) versioning were used - then that would be
+ # unambiguous.
+ elements.sort! do |a, b|
+ if (a.timestamp == b.timestamp)
+ a.version <=> b.version
+ else
+ a.timestamp <=> b.timestamp
+ end
+ end
+
+ # create an osmChange document for the output
+ result = OSM::API.new.get_xml_doc
+ result.root.name = "osmChange"
+
+ # generate an output element for each operation. note: we avoid looking
+ # at the history because it is simpler - but it would be more correct to
+ # check these assertions.
+ elements.each do |elt|
+ result.root <<
+ if (elt.version == 1)
+ # first version, so it must be newly-created.
+ created = XML::Node.new "create"
+ created << elt.to_xml_node
+ else
+ # get the previous version from the element history
+ prev_elt = elt.class.find(:first, :conditions =>
+ ['id = ? and version = ?',
+ elt.id, elt.version])
+ unless elt.visible
+ # if the element isn't visible then it must have been deleted, so
+ # output the *previous* XML
+ deleted = XML::Node.new "delete"
+ deleted << prev_elt.to_xml_node
+ else
+ # must be a modify, for which we don't need the previous version
+ # yet...
+ modified = XML::Node.new "modify"
+ modified << elt.to_xml_node
end
end
- end
end
- render :text => res.to_s, :content_type => "text/xml"
-
+ render :text => result.to_s, :content_type => "text/xml"
+
+ rescue ActiveRecord::RecordNotFound
+ render :nothing => true, :status => :not_found
rescue OSM::APIError => ex
render ex.render_opts
end
+
end
projects / rails.git / blobdiff