class ChangesetController < ApplicationController
require 'xml/libxml'
+ require 'diff_reader'
- before_filter :authorize, :only => [:create, :update, :delete]
- before_filter :check_write_availability, :only => [:create, :update, :delete]
- before_filter :check_read_availability, :except => [:create, :update, :delete]
+ before_filter :authorize, :only => [:create, :update, :delete, :upload, :include]
+ before_filter :check_write_availability, :only => [:create, :update, :delete, :upload, :include]
+ before_filter :check_read_availability, :except => [:create, :update, :delete, :upload, :download]
+ after_filter :compress_output
# Create a changeset from XML.
def create
render :nothing => true, :status => :method_not_allowed
end
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])
+
+ unless @user.id == changeset.user_id
+ raise OSM::APIUserChangesetMismatchError
+ end
+
+ changeset.open = false
+ changeset.save!
+ render :nothing => true
+ rescue ActiveRecord::RecordNotFound
+ render :nothing => true, :status => :not_found
+ end
+ end
+
+ ##
+ # insert a (set of) points into a changeset bounding box. this can only
+ # increase the size of the bounding box. this is a hint that clients can
+ # set either before uploading a large number of changes, or changes that
+ # the client (but not the server) knows will affect areas further away.
+ def include
+ # only allow POST requests, because although this method is
+ # idempotent, there is no "document" to PUT really...
+ if request.post?
+ cs = Changeset.find(params[:id])
+
+ # check user credentials - only the user who opened a changeset
+ # may alter it.
+ unless @user.id == cs.user_id
+ raise OSM::APIUserChangesetMismatchError
+ end
+
+ # keep an array of lons and lats
+ lon = Array.new
+ lat = Array.new
+
+ # the request is in pseudo-osm format... this is kind-of an
+ # abuse, maybe should change to some other format?
+ doc = XML::Parser.string(request.raw_post).parse
+ doc.find("//osm/node").each do |n|
+ lon << n['lon'].to_f * SCALE
+ lat << n['lat'].to_f * SCALE
+ end
+
+ # add the existing bounding box to the lon-lat array
+ lon << cs.min_lon unless cs.min_lon.nil?
+ lat << cs.min_lat unless cs.min_lat.nil?
+ lon << cs.max_lon unless cs.max_lon.nil?
+ lat << cs.max_lat unless cs.max_lat.nil?
+
+ # collapse the arrays to minimum and maximum
+ cs.min_lon, cs.min_lat, cs.max_lon, cs.max_lat =
+ lon.min, lat.min, lon.max, lat.max
+
+ # save the larger bounding box and return the changeset, which
+ # will include the bigger bounding box.
+ cs.save!
+ render :text => cs.to_xml.to_s, :content_type => "text/xml"
+
+ else
+ render :nothing => true, :status => :method_not_allowed
+ end
+
+ rescue ActiveRecord::RecordNotFound
+ render :nothing => true, :status => :not_found
+ rescue OSM::APIError => ex
+ render ex.render_opts
+ 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
+ # 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
+
+ changeset = Changeset.find(params[:id])
+
+ # access control - only the user who created a changeset may
+ # upload to it.
+ unless @user.id == changeset.user_id
+ raise OSM::APIUserChangesetMismatchError
+ end
+
+ diff_reader = DiffReader.new(request.raw_post, changeset)
+ Changeset.transaction do
+ 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
+
+ ##
+ # 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
+
+ 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