Prepare for Rails 2.1+, as we will no longer be able to use a symbol in the set_fixtu...

[rails.git] / app / controllers / changeset_controller.rb

diff --git a/app/controllers/changeset_controller.rb b/app/controllers/changeset_controller.rb
index 34579d166a4bb8fcf0958a74a565e8a605f01592..7ac4eb91a81dc378331a443d7adb3ae2258b2425 100644 (file)
--- a/app/controllers/changeset_controller.rb
+++ b/app/controllers/changeset_controller.rb
@@ -2,6 +2,7 @@
 
 class ChangesetController < ApplicationController
   require 'xml/libxml'
 
 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]
 
   before_filter :authorize, :only => [:create, :update, :delete, :upload]
   before_filter :check_write_availability, :only => [:create, :update, :delete, :upload]


@@ -45,70 +46,137 @@ class ChangesetController < ApplicationController
       map { |memb| [memb[0], ids[memb[0]][memb[1].to_i] || memb[1], memb[2]] }
     return r
   end
       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
   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
 
       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
     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)
-       fix_way(way, node_ids)
-       raise OSM::APIPreconditionFailedError.new if !way.preconditions_ok?
-       create_prim way_ids, way, nd
-      end
-      doc.find('//osm/create/relation').each do |nd|
-       relation = Relation.from_xml_node(nd, true)
-       fix_rel(relation, ids)
-       raise OSM::APIPreconditionFailedError.new if !relation.preconditions_ok?
-       create_prim rel_ids, relation, 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.new.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

+    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
 
     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

+

 end
 end