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
def fix_way(w, node_ids)
- w.nds.each { |nd|
- new_id = node_ids[nd.node_id]
- nd.node_id = new_id unless new_id.nil?
- }
+ w.nds = w.instance_eval { @nds }.
+ map { |nd| node_ids[nd] || nd }
+ return w
end
def fix_rel(r, ids)
- r.members.each { |memb|
- new_id = ids[memb.member_type][memb.member_id]
- nd.member_id = new_id unless new_id.nil?
- }
+ r.members = r.instance_eval { @members }.
+ map { |memb| [memb[0], ids[memb[0]][memb[1].to_i] || memb[1], memb[2]] }
+ return r
+ end
+
+ def read
+ begin
+ changeset = Changeset.find(params[:id])
+ render :text => changeset.to_xml.to_s, :content_type => "text/xml"
+ rescue ActiveRecord::RecordNotFound
+ render :nothing => true, :status => :not_found
+ end
+ end
+
+ def close
+ begin
+ unless request.put?
+ render :nothing => true, :status => :method_not_allowed
+ return
+ end
+ changeset = Changeset.find(params[:id])
+ changeset.open = false
+ changeset.save!
+ render :nothing => true
+ rescue ActiveRecord::RecordNotFound
+ render :nothing => true, :status => :not_found
+ 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
- if not 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
- # FIXME: this should really be done without loading the whole XML file
- # into memory.
- p = XML::Parser.new
- p.string = request.raw_post
- doc = p.parse
-
- node_ids, way_ids, rel_ids = {}, {}, {}
- ids = {"node"=>node_ids, "way"=>way_ids, "relation"=>rel_ids}
-
+ changeset = Changeset.find(params[:id])
+
+ diff_reader = DiffReader.new(request.raw_post, changeset)
Changeset.transaction do
- doc.find('//osm/create/node').each do |nd|
- create_prim node_ids, Node.from_xml_node(nd, true), nd
- end
- doc.find('//osm/create/way').each do |nd|
- way = Way.from_xml_node(nd, true)
- raise OSM::APIPreconditionFailedError.new if !way.preconditions_ok?
- create_prim way_ids, fix_way(way, node_ids), nd
- end
- doc.find('//osm/create/relation').each do |nd|
- relation = Relation.from_xml_node(nd, true)
- raise OSM::APIPreconditionFailedError.new if !way.preconditions_ok?
- create_prim relation_ids, fix_rel(relation, ids), nd
- end
+ 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
- doc.find('//osm/modify/node').each do |nd|
- unless NodeController.update_internal nil, Node.from_xml_node(nd)
- raise OSM::APIPreconditionFailedError.new
- end
- end
- doc.find('//osm/modify/way').each do |nd|
- unless WayController.update_internal nil, fix_way(Way.from_xml_node(nd), node_ids)
- raise OSM::APIPreconditionFailedError.new
- end
- end
- doc.find('//osm/modify/relation').each do |nd|
- unless RelationController.update_internal nil, fix_rel(Relation.from_xml_node(nd), ids)
- raise OSM::APIPreconditionFailedError.new
- end
+ ##
+ # 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"
- doc.find('//osm/delete/node').each do |nd|
- unless NodeController.delete_internal nil, Node.from_xml_node(n)
- raise OSM::APIPreconditionFailedError.new
- end
- end
- doc.find('//osm/delete/way').each do |nd|
- Way.from_xml_node(nd).delete_with_relations_and_history(@user)
- end
- doc.find('//osm/delete/relation').each do |nd|
- unless RelationController.delete_internal nil, fix_rel(Relation.from_xml_node(nd), ids)
- raise OSM::APIPreconditionFailedError.new
- end
- end
+ # 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
- render :text => "Ok, Fine. Upload worked without errors.\n", :status => 200
+ 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