390 lines
13 KiB
Ruby
390 lines
13 KiB
Ruby
# The ChangesetController is the RESTful interface to Changeset objects
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class ChangesetController < ApplicationController
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require 'xml/libxml'
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require 'diff_reader'
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before_filter :authorize, :only => [:create, :update, :delete, :upload, :include, :close]
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before_filter :check_write_availability, :only => [:create, :update, :delete, :upload, :include]
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before_filter :check_read_availability, :except => [:create, :update, :delete, :upload, :download, :query]
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after_filter :compress_output
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# Help methods for checking boundary sanity and area size
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include MapBoundary
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# Create a changeset from XML.
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def create
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if request.put?
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cs = Changeset.from_xml(request.raw_post, true)
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if cs
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cs.user_id = @user.id
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cs.save_with_tags!
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render :text => cs.id.to_s, :content_type => "text/plain"
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else
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render :nothing => true, :status => :bad_request
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end
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else
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render :nothing => true, :status => :method_not_allowed
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end
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end
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def read
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begin
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changeset = Changeset.find(params[:id])
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render :text => changeset.to_xml.to_s, :content_type => "text/xml"
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rescue ActiveRecord::RecordNotFound
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render :nothing => true, :status => :not_found
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end
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end
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##
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# marks a changeset as closed. this may be called multiple times
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# on the same changeset, so is idempotent.
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def close
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unless request.put?
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render :nothing => true, :status => :method_not_allowed
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return
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end
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changeset = Changeset.find(params[:id])
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unless @user.id == changeset.user_id
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raise OSM::APIUserChangesetMismatchError
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end
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# to close the changeset, we'll just set its closed_at time to
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# now. this might not be enough if there are concurrency issues,
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# but we'll have to wait and see.
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changeset.closed_at = DateTime.now
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changeset.save!
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render :nothing => true
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rescue ActiveRecord::RecordNotFound
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render :nothing => true, :status => :not_found
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rescue OSM::APIError => ex
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render ex.render_opts
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end
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##
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# insert a (set of) points into a changeset bounding box. this can only
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# increase the size of the bounding box. this is a hint that clients can
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# set either before uploading a large number of changes, or changes that
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# the client (but not the server) knows will affect areas further away.
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def include
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# only allow POST requests, because although this method is
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# idempotent, there is no "document" to PUT really...
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if request.post?
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cs = Changeset.find(params[:id])
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# check user credentials - only the user who opened a changeset
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# may alter it.
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unless @user.id == cs.user_id
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raise OSM::APIUserChangesetMismatchError
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end
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# keep an array of lons and lats
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lon = Array.new
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lat = Array.new
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# the request is in pseudo-osm format... this is kind-of an
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# abuse, maybe should change to some other format?
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doc = XML::Parser.string(request.raw_post).parse
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doc.find("//osm/node").each do |n|
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lon << n['lon'].to_f * GeoRecord::SCALE
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lat << n['lat'].to_f * GeoRecord::SCALE
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end
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# add the existing bounding box to the lon-lat array
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lon << cs.min_lon unless cs.min_lon.nil?
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lat << cs.min_lat unless cs.min_lat.nil?
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lon << cs.max_lon unless cs.max_lon.nil?
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lat << cs.max_lat unless cs.max_lat.nil?
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# collapse the arrays to minimum and maximum
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cs.min_lon, cs.min_lat, cs.max_lon, cs.max_lat =
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lon.min, lat.min, lon.max, lat.max
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# save the larger bounding box and return the changeset, which
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# will include the bigger bounding box.
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cs.save!
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render :text => cs.to_xml.to_s, :content_type => "text/xml"
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else
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render :nothing => true, :status => :method_not_allowed
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end
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rescue ActiveRecord::RecordNotFound
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render :nothing => true, :status => :not_found
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rescue OSM::APIError => ex
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render ex.render_opts
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end
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##
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# Upload a diff in a single transaction.
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#
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# This means that each change within the diff must succeed, i.e: that
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# each version number mentioned is still current. Otherwise the entire
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# transaction *must* be rolled back.
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#
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# Furthermore, each element in the diff can only reference the current
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# changeset.
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#
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# Returns: a diffResult document, as described in
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# http://wiki.openstreetmap.org/index.php/OSM_Protocol_Version_0.6
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def upload
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# only allow POST requests, as the upload method is most definitely
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# not idempotent, as several uploads with placeholder IDs will have
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# different side-effects.
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# see http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9.1.2
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unless request.post?
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render :nothing => true, :status => :method_not_allowed
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return
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end
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changeset = Changeset.find(params[:id])
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# access control - only the user who created a changeset may
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# upload to it.
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unless @user.id == changeset.user_id
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raise OSM::APIUserChangesetMismatchError
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end
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diff_reader = DiffReader.new(request.raw_post, changeset)
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Changeset.transaction do
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result = diff_reader.commit
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render :text => result.to_s, :content_type => "text/xml"
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end
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rescue ActiveRecord::RecordNotFound
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render :nothing => true, :status => :not_found
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rescue OSM::APIError => ex
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render ex.render_opts
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end
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##
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# download the changeset as an osmChange document.
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#
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# to make it easier to revert diffs it would be better if the osmChange
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# format were reversible, i.e: contained both old and new versions of
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# modified elements. but it doesn't at the moment...
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#
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# this method cannot order the database changes fully (i.e: timestamp and
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# version number may be too coarse) so the resulting diff may not apply
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# to a different database. however since changesets are not atomic this
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# behaviour cannot be guaranteed anyway and is the result of a design
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# choice.
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def download
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changeset = Changeset.find(params[:id])
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# get all the elements in the changeset and stick them in a big array.
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elements = [changeset.old_nodes,
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changeset.old_ways,
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changeset.old_relations].flatten
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# sort the elements by timestamp and version number, as this is the
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# almost sensible ordering available. this would be much nicer if
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# global (SVN-style) versioning were used - then that would be
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# unambiguous.
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elements.sort! do |a, b|
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if (a.timestamp == b.timestamp)
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a.version <=> b.version
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else
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a.timestamp <=> b.timestamp
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end
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end
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# create an osmChange document for the output
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result = OSM::API.new.get_xml_doc
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result.root.name = "osmChange"
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# generate an output element for each operation. note: we avoid looking
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# at the history because it is simpler - but it would be more correct to
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# check these assertions.
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elements.each do |elt|
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result.root <<
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if (elt.version == 1)
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# first version, so it must be newly-created.
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created = XML::Node.new "create"
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created << elt.to_xml_node
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else
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# get the previous version from the element history
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prev_elt = elt.class.find(:first, :conditions =>
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['id = ? and version = ?',
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elt.id, elt.version])
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unless elt.visible
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# if the element isn't visible then it must have been deleted, so
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# output the *previous* XML
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deleted = XML::Node.new "delete"
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deleted << prev_elt.to_xml_node
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else
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# must be a modify, for which we don't need the previous version
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# yet...
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modified = XML::Node.new "modify"
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modified << elt.to_xml_node
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end
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end
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end
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render :text => result.to_s, :content_type => "text/xml"
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rescue ActiveRecord::RecordNotFound
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render :nothing => true, :status => :not_found
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rescue OSM::APIError => ex
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render ex.render_opts
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end
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##
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# query changesets by bounding box, time, user or open/closed status.
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def query
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# create the conditions that the user asked for. some or all of
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# these may be nil.
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conditions = conditions_bbox(params['bbox'])
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conditions = cond_merge conditions, conditions_user(params['user'])
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conditions = cond_merge conditions, conditions_time(params['time'])
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conditions = cond_merge conditions, conditions_open(params['open'])
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# create the results document
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results = OSM::API.new.get_xml_doc
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# add all matching changesets to the XML results document
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Changeset.find(:all,
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:conditions => conditions,
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:limit => 100,
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:order => 'created_at desc').each do |cs|
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results.root << cs.to_xml_node
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end
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render :text => results.to_s, :content_type => "text/xml"
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rescue ActiveRecord::RecordNotFound
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render :nothing => true, :status => :not_found
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rescue OSM::APIError => ex
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render ex.render_opts
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end
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##
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# updates a changeset's tags. none of the changeset's attributes are
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# user-modifiable, so they will be ignored.
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#
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# changesets are not (yet?) versioned, so we don't have to deal with
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# history tables here. changesets are locked to a single user, however.
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#
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# after succesful update, returns the XML of the changeset.
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def update
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# request *must* be a PUT.
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unless request.put?
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render :nothing => true, :status => :method_not_allowed
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return
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end
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changeset = Changeset.find(params[:id])
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new_changeset = Changeset.from_xml(request.raw_post)
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unless new_changeset.nil?
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changeset.update_from(new_changeset, @user)
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render :text => changeset.to_xml, :mime_type => "text/xml"
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else
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render :nothing => true, :status => :bad_request
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end
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rescue ActiveRecord::RecordNotFound
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render :nothing => true, :status => :not_found
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rescue OSM::APIError => ex
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render ex.render_opts
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end
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#------------------------------------------------------------
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# utility functions below.
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#------------------------------------------------------------
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##
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# merge two conditions
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def cond_merge(a, b)
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if a and b
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a_str = a.shift
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b_str = b.shift
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return [ a_str + " and " + b_str ] + a + b
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elsif a
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return a
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else b
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return b
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end
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end
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##
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# if a bounding box was specified then parse it and do some sanity
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# checks. this is mostly the same as the map call, but without the
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# area restriction.
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def conditions_bbox(bbox)
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unless bbox.nil?
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raise OSM::APIBadUserInput.new("Bounding box should be min_lon,min_lat,max_lon,max_lat") unless bbox.count(',') == 3
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bbox = sanitise_boundaries(bbox.split(/,/))
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raise OSM::APIBadUserInput.new("Minimum longitude should be less than maximum.") unless bbox[0] <= bbox[2]
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raise OSM::APIBadUserInput.new("Minimum latitude should be less than maximum.") unless bbox[1] <= bbox[3]
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return ['min_lon < ? and max_lon > ? and min_lat < ? and max_lat > ?',
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bbox[2] * GeoRecord::SCALE, bbox[0] * GeoRecord::SCALE, bbox[3]* GeoRecord::SCALE, bbox[1] * GeoRecord::SCALE]
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else
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return nil
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end
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end
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##
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# restrict changesets to those by a particular user
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def conditions_user(user)
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unless user.nil?
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# user input checking, we don't have any UIDs < 1
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raise OSM::APIBadUserInput.new("invalid user ID") if user.to_i < 1
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u = User.find(user.to_i)
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# should be able to get changesets of public users only, or
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# our own changesets regardless of public-ness.
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unless u.data_public?
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# get optional user auth stuff so that users can see their own
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# changesets if they're non-public
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setup_user_auth
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raise OSM::APINotFoundError if @user.nil? or @user.id != u.id
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end
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return ['user_id = ?', u.id]
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else
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return nil
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end
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end
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##
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# restrict changes to those during a particular time period
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def conditions_time(time)
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unless time.nil?
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# if there is a range, i.e: comma separated, then the first is
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# low, second is high - same as with bounding boxes.
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if time.count(',') == 1
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# check that we actually have 2 elements in the array
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times = time.split(/,/)
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raise OSM::APIBadUserInput.new("bad time range") if times.size != 2
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from, to = times.collect { |t| DateTime.parse(t) }
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return ['closed_at >= ? and created_at <= ?', from, to]
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else
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# if there is no comma, assume its a lower limit on time
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return ['closed_at >= ?', DateTime.parse(time)]
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end
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else
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return nil
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end
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# stupid DateTime seems to throw both of these for bad parsing, so
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# we have to catch both and ensure the correct code path is taken.
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rescue ArgumentError => ex
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raise OSM::APIBadUserInput.new(ex.message.to_s)
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rescue RuntimeError => ex
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raise OSM::APIBadUserInput.new(ex.message.to_s)
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end
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##
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# restrict changes to those which are open
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def conditions_open(open)
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return open.nil? ? nil : ['closed_at >= ?', DateTime.now]
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end
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end
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