Supply hints for OSRM

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

diff --git a/app/controllers/changeset_controller.rb b/app/controllers/changeset_controller.rb
index 8d029aae50d10078483c9ba9961ff7cb1566f5d5..735fa73a88c31a1820515aa9e4677011946be8b3 100644 (file)
--- a/app/controllers/changeset_controller.rb
+++ b/app/controllers/changeset_controller.rb
@@ -4,19 +4,18 @@ class ChangesetController < ApplicationController
   layout 'site'
   require 'xml/libxml'
 
   layout 'site'
   require 'xml/libxml'
 

-  before_filter :authorize_web, :only => [:list, :list_user, :list_bbox]
-  before_filter :set_locale, :only => [:list, :list_user, :list_bbox]
+  skip_before_filter :verify_authenticity_token, :except => [:list]
+  before_filter :authorize_web, :only => [:list, :feed]
+  before_filter :set_locale, :only => [:list, :feed]

   before_filter :authorize, :only => [:create, :update, :delete, :upload, :include, :close]
   before_filter :authorize, :only => [:create, :update, :delete, :upload, :include, :close]

+  before_filter :require_allow_write_api, :only => [:create, :update, :delete, :upload, :include, :close]

   before_filter :require_public_data, :only => [:create, :update, :delete, :upload, :include, :close]
   before_filter :check_api_writable, :only => [:create, :update, :delete, :upload, :include]
   before_filter :require_public_data, :only => [:create, :update, :delete, :upload, :include, :close]
   before_filter :check_api_writable, :only => [:create, :update, :delete, :upload, :include]

-  before_filter :check_api_readable, :except => [:create, :update, :delete, :upload, :download, :query]
+  before_filter :check_api_readable, :except => [:create, :update, :delete, :upload, :download, :query, :list, :feed]
+  before_filter(:only => [:list, :feed]) { |c| c.check_database_readable(true) }

   after_filter :compress_output
   after_filter :compress_output

-  around_filter :api_call_handle_error
-
-  filter_parameter_logging "<osmChange version"
-
-  # Help methods for checking boundary sanity and area size
-  include MapBoundary
+  around_filter :api_call_handle_error, :except => [:list, :feed]
+  around_filter :web_timeout, :only => [:list, :feed]

 
   # Helper methods for checking consistency
   include ConsistencyValidations
 
   # Helper methods for checking consistency
   include ConsistencyValidations


@@ -27,39 +26,36 @@ class ChangesetController < ApplicationController
 
     cs = Changeset.from_xml(request.raw_post, true)
 
 
     cs = Changeset.from_xml(request.raw_post, true)
 

-    if cs
-      cs.user_id = @user.id
-      cs.save_with_tags!
-      render :text => cs.id.to_s, :content_type => "text/plain"
-    else
-      raise OSM::APIBadXMLError.new(Changeset, request.raw_post);
-    end
+    # Assume that Changeset.from_xml has thrown an exception if there is an error parsing the xml
+    cs.user_id = @user.id
+    cs.save_with_tags!
+    render :text => cs.id.to_s, :content_type => "text/plain"

   end
 
   ##
   end
 
   ##

-  # Return XML giving the basic info about the changeset. Does not 
+  # Return XML giving the basic info about the changeset. Does not

   # return anything about the nodes, ways and relations in the changeset.
   def read
     changeset = Changeset.find(params[:id])
     render :text => changeset.to_xml.to_s, :content_type => "text/xml"
   end
   # return anything about the nodes, ways and relations in the changeset.
   def read
     changeset = Changeset.find(params[:id])
     render :text => changeset.to_xml.to_s, :content_type => "text/xml"
   end

-  
+

   ##
   # marks a changeset as closed. this may be called multiple times
   # on the same changeset, so is idempotent.
   ##
   # marks a changeset as closed. this may be called multiple times
   # on the same changeset, so is idempotent.

-  def close 
+  def close

     assert_method :put
     assert_method :put

-    
-    changeset = Changeset.find(params[:id])    
+
+    changeset = Changeset.find(params[:id])

     check_changeset_consistency(changeset, @user)
 
     # to close the changeset, we'll just set its closed_at time to
     check_changeset_consistency(changeset, @user)
 
     # to close the changeset, we'll just set its closed_at time to

-    # now. this might not be enough if there are concurrency issues, 
+    # now. this might not be enough if there are concurrency issues,

     # but we'll have to wait and see.
     changeset.set_closed_time_now
 
     changeset.save!
     # but we'll have to wait and see.
     changeset.set_closed_time_now
 
     changeset.save!

-    render :nothing => true
+    render :text => ""

   end
 
   ##
   end
 
   ##


@@ -74,11 +70,11 @@ class ChangesetController < ApplicationController
 
     cs = Changeset.find(params[:id])
     check_changeset_consistency(cs, @user)
 
     cs = Changeset.find(params[:id])
     check_changeset_consistency(cs, @user)

-    
+

     # keep an array of lons and lats
     lon = Array.new
     lat = Array.new
     # 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
     # 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


@@ -86,17 +82,17 @@ class ChangesetController < ApplicationController
       lon << n['lon'].to_f * GeoRecord::SCALE
       lat << n['lat'].to_f * GeoRecord::SCALE
     end
       lon << n['lon'].to_f * GeoRecord::SCALE
       lat << n['lat'].to_f * GeoRecord::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?
     # 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
     # collapse the arrays to minimum and maximum

-    cs.min_lon, cs.min_lat, cs.max_lon, cs.max_lat = 
+    cs.min_lon, cs.min_lat, cs.max_lon, cs.max_lat =

       lon.min, lat.min, lon.max, lat.max
       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!
     # save the larger bounding box and return the changeset, which
     # will include the bigger bounding box.
     cs.save!


@@ -113,7 +109,7 @@ class ChangesetController < ApplicationController
   # Furthermore, each element in the diff can only reference the current
   # changeset.
   #
   # Furthermore, each element in the diff can only reference the current
   # changeset.
   #

-  # Returns: a diffResult document, as described in 
+  # Returns: a diffResult document, as described in

   # http://wiki.openstreetmap.org/wiki/OSM_Protocol_Version_0.6
   def upload
     # only allow POST requests, as the upload method is most definitely
   # http://wiki.openstreetmap.org/wiki/OSM_Protocol_Version_0.6
   def upload
     # only allow POST requests, as the upload method is most definitely


@@ -124,7 +120,7 @@ class ChangesetController < ApplicationController
 
     changeset = Changeset.find(params[:id])
     check_changeset_consistency(changeset, @user)
 
     changeset = Changeset.find(params[:id])
     check_changeset_consistency(changeset, @user)

-    
+

     diff_reader = DiffReader.new(request.raw_post, changeset)
     Changeset.transaction do
       result = diff_reader.commit
     diff_reader = DiffReader.new(request.raw_post, changeset)
     Changeset.transaction do
       result = diff_reader.commit


@@ -136,62 +132,61 @@ class ChangesetController < ApplicationController
   # download the changeset as an osmChange document.
   #
   # to make it easier to revert diffs it would be better if the osmChange
   # 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 
+  # 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
   # 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 
+  # 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])
   # 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 
+
+    # get all the elements in the changeset which haven't been redacted
+    # and stick them in a big array.
+    elements = [changeset.old_nodes.unredacted,
+                changeset.old_ways.unredacted,
+                changeset.old_relations.unredacted].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.
     # unambiguous.

-    elements.sort! do |a, b| 
+    elements.sort! do |a, b|

       if (a.timestamp == b.timestamp)
         a.version <=> b.version
       else
       if (a.timestamp == b.timestamp)
         a.version <=> b.version
       else

-        a.timestamp <=> b.timestamp 
+        a.timestamp <=> b.timestamp

       end
     end
       end
     end

-    
+
+    # create changeset and user caches
+    changeset_cache = {}
+    user_display_name_cache = {}
+

     # 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
     # 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 
+    # at the history because it is simpler - but it would be more correct to

     # check these assertions.
     elements.each do |elt|
       result.root <<
     # check these assertions.
     elements.each do |elt|
       result.root <<

-        if (elt.version == 1) 
+        if (elt.version == 1)

           # first version, so it must be newly-created.
           created = XML::Node.new "create"
           # first version, so it must be newly-created.
           created = XML::Node.new "create"

-          created << elt.to_xml_node
+          created << elt.to_xml_node(changeset_cache, user_display_name_cache)

         else
         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
           unless elt.visible

-            # if the element isn't visible then it must have been deleted, so
-            # output the *previous* XML
+            # if the element isn't visible then it must have been deleted

             deleted = XML::Node.new "delete"
             deleted = XML::Node.new "delete"

-            deleted << prev_elt.to_xml_node
+            deleted << elt.to_xml_node(changeset_cache, user_display_name_cache)

           else
           else

-            # must be a modify, for which we don't need the previous version
-            # yet...
+            # must be a modify

             modified = XML::Node.new "modify"
             modified = XML::Node.new "modify"

-            modified << elt.to_xml_node
+            modified << elt.to_xml_node(changeset_cache, user_display_name_cache)

           end
         end
     end
           end
         end
     end


@@ -202,28 +197,32 @@ class ChangesetController < ApplicationController
   ##
   # query changesets by bounding box, time, user or open/closed status.
   def query
   ##
   # query changesets by bounding box, time, user or open/closed status.
   def query

+    # find any bounding box
+    if params['bbox']
+      bbox = BoundingBox.from_bbox_params(params)
+    end
+

     # create the conditions that the user asked for. some or all of
     # these may be nil.
     # create the conditions that the user asked for. some or all of
     # these may be nil.

-    conditions = conditions_bbox(params['bbox'])
-    conditions = cond_merge conditions, conditions_user(params['user'])
-    conditions = cond_merge conditions, conditions_time(params['time'])
-    conditions = cond_merge conditions, conditions_open(params['open'])
-    conditions = cond_merge conditions, conditions_closed(params['closed'])
+    changesets = Changeset.all
+    changesets = conditions_bbox(changesets, bbox)
+    changesets = conditions_user(changesets, params['user'], params['display_name'])
+    changesets = conditions_time(changesets, params['time'])
+    changesets = conditions_open(changesets, params['open'])
+    changesets = conditions_closed(changesets, params['closed'])
+    changesets = conditions_ids(changesets, params['changesets'])

 
     # create the results document
     results = OSM::API.new.get_xml_doc
 
     # add all matching changesets to the XML results document
 
     # create the results document
     results = OSM::API.new.get_xml_doc
 
     # add all matching changesets to the XML results document

-    Changeset.find(:all, 
-                   :conditions => conditions, 
-                   :limit => 100,
-                   :order => 'created_at desc').each do |cs|
+    changesets.order("created_at DESC").limit(100).each do |cs|

       results.root << cs.to_xml_node
     end
 
     render :text => results.to_s, :content_type => "text/xml"
   end
       results.root << cs.to_xml_node
     end
 
     render :text => results.to_s, :content_type => "text/xml"
   end

-  
+

   ##
   # updates a changeset's tags. none of the changeset's attributes are
   # user-modifiable, so they will be ignored.
   ##
   # updates a changeset's tags. none of the changeset's attributes are
   # user-modifiable, so they will be ignored.


@@ -244,167 +243,142 @@ class ChangesetController < ApplicationController
       changeset.update_from(new_changeset, @user)
       render :text => changeset.to_xml, :mime_type => "text/xml"
     else
       changeset.update_from(new_changeset, @user)
       render :text => changeset.to_xml, :mime_type => "text/xml"
     else

-      
-      render :nothing => true, :status => :bad_request
+
+      render :text => "", :status => :bad_request

     end
   end
 
     end
   end
 

-  
-  

   ##
   # list edits (open changesets) in reverse chronological order
   def list
   ##
   # list edits (open changesets) in reverse chronological order
   def list

-    conditions = conditions_nonempty
+    if request.format == :atom and params[:max_id]
+      redirect_to params.merge({ :max_id => nil }), :status => :moved_permanently
+      return
+    end

 
 

-    # @changesets = Changeset.find(:all, :order => "closed_at DESC", :conditions => ['closed_at < ?', DateTime.now], :limit=> 20)
+    if params[:display_name]
+      user = User.find_by_display_name(params[:display_name])
+      if !user || !user.active?
+        render_unknown_user params[:display_name]
+        return
+      end
+    end

 
 

-    #@edit_pages, @edits = paginate(:changesets,
-    #                                :include => [:user, :changeset_tags],
-    #                                :conditions => conditions,
-    #                                :order => "changesets.created_at DESC",
-    #                                :per_page => 20)
-    #
+    if (params[:friends] || params[:nearby]) && !@user && request.format == :html
+      require_user
+      return
+    end

 
 

-    @edits =  Changeset.find(:all,
-                             :order => "changesets.created_at DESC",
-                             :conditions => conditions,
-                             :limit => 20)
-  end
-  
-  ##
-  # list edits (changesets) belonging to a user
-  def list_user
-    user = User.find_by_display_name(params[:display_name], :conditions => {:visible => true})
-    
-    if user
-      @display_name = user.display_name
-      if not user.data_public? and @user != user
-        @edits = nil
-        render
-      else
-        conditions = cond_merge conditions, ['user_id = ?', user.id]
-        conditions = cond_merge conditions, conditions_nonempty
-        @edit_pages, @edits = paginate(:changesets,
-                                        :include => [:user, :changeset_tags],
-                                        :conditions => conditions,
-                                        :order => "changesets.created_at DESC",
-                                        :per_page => 20)
-      end
+    if request.format == :html and !params[:list]
+      require_oauth
+      render :action => :history, :layout => map_layout

     else
     else

-      @not_found_user = params[:display_name]
-      render :template => 'user/no_such_user', :status => :not_found
+      changesets = conditions_nonempty(Changeset.all)
+
+      if params[:display_name]
+        if user.data_public? or user == @user
+          changesets = changesets.where(:user_id => user.id)
+        else
+          changesets = changesets.where("false")
+        end
+      elsif params[:bbox]
+        changesets = conditions_bbox(changesets, BoundingBox.from_bbox_params(params))
+      elsif params[:friends] && @user
+        changesets = changesets.where(:user_id => @user.friend_users.public)
+      elsif params[:nearby] && @user
+        changesets = changesets.where(:user_id => @user.nearby)
+      end
+
+      if params[:max_id]
+        changesets = changesets.where("changesets.id <= ?", params[:max_id])
+      end
+
+      @edits = changesets.order("changesets.id DESC").limit(20).preload(:user, :changeset_tags)
+
+      render :action => :list, :layout => false

     end
   end
     end
   end

-  
+

   ##
   ##

-  # list changesets in a bbox
-  def list_bbox
-    # support 'bbox' param or alternatively 'minlon', 'minlat' etc       
-    if params['bbox']
-       bbox = params['bbox']
-    elsif params['minlon'] and params['minlat'] and params['maxlon'] and params['maxlat']
-       bbox = h(params['minlon']) + ',' + h(params['minlat']) + ',' + h(params['maxlon']) + ',' + h(params['maxlat'])
-    elsif params['format'] == "rxml"
-      raise OSM::APIBadUserInput.new("Bounding box must be supplied for the RSS feed")
-    else
-      #TODO: fix bugs in location determination for history tab (and other tabs) then uncomment this redirect
-      #redirect_to :action => 'list'
-      
-      # For now just render immediately, and skip the db
-      render
-      return
-    end
-       
-    conditions = conditions_bbox(bbox);
-    conditions = cond_merge conditions, conditions_nonempty
-    
-    @edit_pages, @edits = paginate(:changesets,
-                                   :include => [:user, :changeset_tags],
-                                   :conditions => conditions,
-                                   :order => "changesets.created_at DESC",
-                                   :per_page => 20)
-                                   
-    @bbox = sanitise_boundaries(bbox.split(/,/)) unless bbox==nil
+  # list edits as an atom feed
+  def feed
+    list

   end
   end

-  
+

 private
   #------------------------------------------------------------
   # utility functions below.
 private
   #------------------------------------------------------------
   # utility functions below.

-  #------------------------------------------------------------  
-
-  ##
-  # merge two conditions
-  def cond_merge(a, b)
-    if a and b
-      a_str = a.shift
-      b_str = b.shift
-      return [ a_str + " AND " + b_str ] + a + b
-    elsif a 
-      return a
-    else b
-      return b
-    end
-  end
+  #------------------------------------------------------------

 
   ##
 
   ##

-  # if a bounding box was specified then parse it and do some sanity 
-  # checks. this is mostly the same as the map call, but without the 
-  # area restriction.
-  def conditions_bbox(bbox)
-    unless bbox.nil?
-      raise OSM::APIBadUserInput.new("Bounding box should be min_lon,min_lat,max_lon,max_lat") unless bbox.count(',') == 3
-      bbox = sanitise_boundaries(bbox.split(/,/))
-      raise OSM::APIBadUserInput.new("Minimum longitude should be less than maximum.") unless bbox[0] <= bbox[2]
-      raise OSM::APIBadUserInput.new("Minimum latitude should be less than maximum.") unless bbox[1] <= bbox[3]
-      return ['min_lon < ? and max_lon > ? and min_lat < ? and max_lat > ?',
-              bbox[2] * GeoRecord::SCALE, bbox[0] * GeoRecord::SCALE, bbox[3]* GeoRecord::SCALE, bbox[1] * GeoRecord::SCALE]
+  # if a bounding box was specified do some sanity checks.
+  # restrict changesets to those enclosed by a bounding box
+  # we need to return both the changesets and the bounding box
+  def conditions_bbox(changesets, bbox)
+    if  bbox
+      bbox.check_boundaries
+      bbox = bbox.to_scaled
+      return changesets.where("min_lon < ? and max_lon > ? and min_lat < ? and max_lat > ?",
+                              bbox.max_lon.to_i, bbox.min_lon.to_i,
+                              bbox.max_lat.to_i, bbox.min_lat.to_i)

     else
     else

-      return nil
+      return changesets

     end
   end
 
   ##
   # restrict changesets to those by a particular user
     end
   end
 
   ##
   # restrict changesets to those by a particular user

-  def conditions_user(user)
-    unless user.nil?
-      # user input checking, we don't have any UIDs < 1
-      raise OSM::APIBadUserInput.new("invalid user ID") if user.to_i < 1
+  def conditions_user(changesets, user, name)
+    unless user.nil? and name.nil?
+      # shouldn't provide both name and UID
+      raise OSM::APIBadUserInput.new("provide either the user ID or display name, but not both") if user and name
+
+      # use either the name or the UID to find the user which we're selecting on.
+      u = if name.nil?
+            # user input checking, we don't have any UIDs < 1
+            raise OSM::APIBadUserInput.new("invalid user ID") if user.to_i < 1
+            u = User.find(user.to_i)
+          else
+            u = User.find_by_display_name(name)
+          end
+
+      # make sure we found a user
+      raise OSM::APINotFoundError.new if u.nil?

 
 

-      u = User.find(user.to_i)
-      # should be able to get changesets of public users only, or 
+      # should be able to get changesets of public users only, or

       # our own changesets regardless of public-ness.
       unless u.data_public?
         # get optional user auth stuff so that users can see their own
         # changesets if they're non-public
         setup_user_auth
       # our own changesets regardless of public-ness.
       unless u.data_public?
         # get optional user auth stuff so that users can see their own
         # changesets if they're non-public
         setup_user_auth

-        
+

         raise OSM::APINotFoundError if @user.nil? or @user.id != u.id
       end
         raise OSM::APINotFoundError if @user.nil? or @user.id != u.id
       end

-      return ['user_id = ?', u.id]
+      return changesets.where(:user_id => u.id)

     else
     else

-      return nil
+      return changesets

     end
   end
 
   ##
   # restrict changes to those closed during a particular time period
     end
   end
 
   ##
   # restrict changes to those closed during a particular time period

-  def conditions_time(time) 
+  def conditions_time(changesets, time)

     unless time.nil?
     unless time.nil?

-      # if there is a range, i.e: comma separated, then the first is 
+      # if there is a range, i.e: comma separated, then the first is

       # low, second is high - same as with bounding boxes.
       if time.count(',') == 1
         # check that we actually have 2 elements in the array
         times = time.split(/,/)
       # low, second is high - same as with bounding boxes.
       if time.count(',') == 1
         # check that we actually have 2 elements in the array
         times = time.split(/,/)

-        raise OSM::APIBadUserInput.new("bad time range") if times.size != 2 
+        raise OSM::APIBadUserInput.new("bad time range") if times.size != 2

 
         from, to = times.collect { |t| DateTime.parse(t) }
 
         from, to = times.collect { |t| DateTime.parse(t) }

-        return ['closed_at >= ? and created_at <= ?', from, to]
+        return changesets.where("closed_at >= ? and created_at <= ?", from, to)

       else
         # if there is no comma, assume its a lower limit on time
       else
         # if there is no comma, assume its a lower limit on time

-        return ['closed_at >= ?', DateTime.parse(time)]
+        return changesets.where("closed_at >= ?", DateTime.parse(time))

       end
     else
       end
     else

-      return nil
+      return changesets

     end
     # stupid DateTime seems to throw both of these for bad parsing, so
     # we have to catch both and ensure the correct code path is taken.
     end
     # stupid DateTime seems to throw both of these for bad parsing, so
     # we have to catch both and ensure the correct code path is taken.


@@ -418,25 +392,47 @@ private
   # return changesets which are open (haven't been closed yet)
   # we do this by seeing if the 'closed at' time is in the future. Also if we've
   # hit the maximum number of changes then it counts as no longer open.
   # return changesets which are open (haven't been closed yet)
   # we do this by seeing if the 'closed at' time is in the future. Also if we've
   # hit the maximum number of changes then it counts as no longer open.

-  # if parameter 'open' is nill then open and closed changsets are returned
-  def conditions_open(open)
-    return open.nil? ? nil : ['closed_at >= ? and num_changes <= ?', 
-                              Time.now.getutc, Changeset::MAX_ELEMENTS]
+  # if parameter 'open' is nill then open and closed changesets are returned
+  def conditions_open(changesets, open)
+    if open.nil?
+      return changesets
+    else
+      return changesets.where("closed_at >= ? and num_changes <= ?",
+                              Time.now.getutc, Changeset::MAX_ELEMENTS)
+    end

   end
   end

-  
+

   ##
   # query changesets which are closed
   # ('closed at' time has passed or changes limit is hit)
   ##
   # query changesets which are closed
   # ('closed at' time has passed or changes limit is hit)

-  def conditions_closed(closed)
-    return closed.nil? ? nil : ['closed_at < ? and num_changes > ?', 
-                                Time.now.getutc, Changeset::MAX_ELEMENTS]
+  def conditions_closed(changesets, closed)
+    if closed.nil?
+      return changesets
+    else
+      return changesets.where("closed_at < ? or num_changes > ?",
+                              Time.now.getutc, Changeset::MAX_ELEMENTS)
+    end
+  end
+
+  ##
+  # query changesets by a list of ids
+  # (either specified as array or comma-separated string)
+  def conditions_ids(changesets, ids)
+    if ids.nil?
+      return changesets
+    elsif ids.empty?
+      raise OSM::APIBadUserInput.new("No changesets were given to search for")
+    else
+      ids = ids.split(',').collect { |n| n.to_i }
+      return changesets.where(:id => ids)
+    end

   end
 
   ##
   # eliminate empty changesets (where the bbox has not been set)
   # this should be applied to all changeset list displays
   end
 
   ##
   # eliminate empty changesets (where the bbox has not been set)
   # this should be applied to all changeset list displays

-  def conditions_nonempty()
-    return ['min_lat IS NOT NULL']
+  def conditions_nonempty(changesets)
+    return changesets.where("num_changes > 0")

   end
   end

-  
+

 end
 end