Refactor AMF respone streaming

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

diff --git a/app/controllers/changeset_controller.rb b/app/controllers/changeset_controller.rb
index ebad59aa038a6e6145e034cd850c79817285ca45..ca501fd43183cc3d45d09d53b01eb4434064fb70 100644 (file)
--- a/app/controllers/changeset_controller.rb
+++ b/app/controllers/changeset_controller.rb
@@ -4,12 +4,17 @@ class ChangesetController < ApplicationController
   layout 'site'
   require 'xml/libxml'
 
   layout 'site'
   require 'xml/libxml'
 

-  session :off, :except => [:list]

   before_filter :authorize_web, :only => [:list]
   before_filter :authorize_web, :only => [:list]

+  before_filter :set_locale, :only => [:list]

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

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

   after_filter :compress_output
   after_filter :compress_output

+  around_filter :api_call_handle_error, :except => [:list]
+  around_filter :web_timeout, :only => [:list]

 
   # Help methods for checking boundary sanity and area size
   include MapBoundary
 
   # Help methods for checking boundary sanity and area size
   include MapBoundary


@@ -19,41 +24,29 @@ class ChangesetController < ApplicationController
 
   # Create a changeset from XML.
   def create
 
   # Create a changeset from XML.
   def create

-    if request.put?
-      cs = Changeset.from_xml(request.raw_post, true)
+    assert_method :put

 
 

-      if cs
-        cs.user_id = @user.id
-        cs.save_with_tags!
-        render :text => cs.id.to_s, :content_type => "text/plain"
-      else
-        render :nothing => true, :status => :bad_request
-      end
-    else
-      render :nothing => true, :status => :method_not_allowed
-    end
+    cs = Changeset.from_xml(request.raw_post, true)
+
+    # 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
 
   ##
   # Return XML giving the basic info about the changeset. Does not 
   # return anything about the nodes, ways and relations in the changeset.
   def read
   end
 
   ##
   # Return XML giving the basic info about the changeset. Does not 
   # return anything about the nodes, ways and relations in the changeset.
   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
+    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.
   def close 
   end
   
   ##
   # marks a changeset as closed. this may be called multiple times
   # on the same changeset, so is idempotent.
   def close 

-    unless request.put?
-      render :nothing => true, :status => :method_not_allowed
-      return
-    end
+    assert_method :put

     
     changeset = Changeset.find(params[:id])    
     check_changeset_consistency(changeset, @user)
     
     changeset = Changeset.find(params[:id])    
     check_changeset_consistency(changeset, @user)


@@ -65,10 +58,6 @@ class ChangesetController < ApplicationController
 
     changeset.save!
     render :nothing => true
 
     changeset.save!
     render :nothing => true

-  rescue ActiveRecord::RecordNotFound
-    render :nothing => true, :status => :not_found
-  rescue OSM::APIError => ex
-    render ex.render_opts

   end
 
   ##
   end
 
   ##


@@ -79,45 +68,37 @@ class ChangesetController < ApplicationController
   def expand_bbox
     # only allow POST requests, because although this method is
     # idempotent, there is no "document" to PUT really...
   def expand_bbox
     # 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_changeset_consistency(cs, @user)
-
-      # 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 * GeoRecord::SCALE
-        lat << n['lat'].to_f * GeoRecord::SCALE
-      end
+    assert_method :post

 
 

-      # 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
+    cs = Changeset.find(params[:id])
+    check_changeset_consistency(cs, @user)
+    
+    # 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 * GeoRecord::SCALE
+      lat << n['lat'].to_f * GeoRecord::SCALE

     end
     end

-
-  rescue ActiveRecord::RecordNotFound
-    render :nothing => true, :status => :not_found
-  rescue OSM::APIError => ex
-    render ex.render_opts
+    
+    # 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"

   end
 
   ##
   end
 
   ##


@@ -131,16 +112,13 @@ class ChangesetController < ApplicationController
   # changeset.
   #
   # Returns: a diffResult document, as described in 
   # changeset.
   #
   # Returns: a diffResult document, as described in 

-  # http://wiki.openstreetmap.org/index.php/OSM_Protocol_Version_0.6
+  # http://wiki.openstreetmap.org/wiki/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
   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
+    assert_method :post

 
     changeset = Changeset.find(params[:id])
     check_changeset_consistency(changeset, @user)
 
     changeset = Changeset.find(params[:id])
     check_changeset_consistency(changeset, @user)


@@ -150,11 +128,6 @@ class ChangesetController < ApplicationController
       result = diff_reader.commit
       render :text => result.to_s, :content_type => "text/xml"
     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
 
   ##
   end
 
   ##


@@ -204,9 +177,7 @@ class ChangesetController < ApplicationController
           created << elt.to_xml_node
         else
           # get the previous version from the element history
           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])
+          prev_elt = elt.class.find([elt.id, elt.version])

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


@@ -222,11 +193,6 @@ class ChangesetController < ApplicationController
     end
 
     render :text => result.to_s, :content_type => "text/xml"
     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
 
   ##


@@ -234,29 +200,22 @@ class ChangesetController < ApplicationController
   def query
     # create the conditions that the user asked for. some or all of
     # these may be nil.
   def query
     # 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.scoped
+    changesets = conditions_bbox(changesets, params['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'])

 
     # 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"
       results.root << cs.to_xml_node
     end
 
     render :text => results.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
   
   ##


@@ -269,11 +228,8 @@ class ChangesetController < ApplicationController
   # after succesful update, returns the XML of the changeset.
   def update
     # request *must* be a PUT.
   # after succesful update, returns the XML of the changeset.
   def update
     # request *must* be a PUT.

-    unless request.put?
-      render :nothing => true, :status => :method_not_allowed
-      return
-    end
-    
+    assert_method :put
+

     changeset = Changeset.find(params[:id])
     new_changeset = Changeset.from_xml(request.raw_post)
 
     changeset = Changeset.find(params[:id])
     new_changeset = Changeset.from_xml(request.raw_post)
 


@@ -285,11 +241,6 @@ class ChangesetController < ApplicationController
       
       render :nothing => true, :status => :bad_request
     end
       
       render :nothing => true, :status => :bad_request
     end

-      
-  rescue ActiveRecord::RecordNotFound
-    render :nothing => true, :status => :not_found
-  rescue OSM::APIError => ex
-    render ex.render_opts

   end
 
   
   end
 
   


@@ -297,110 +248,114 @@ class ChangesetController < ApplicationController
   ##
   # list edits (open changesets) in reverse chronological order
   def list
   ##
   # list edits (open changesets) in reverse chronological order
   def list

-    conditions = conditions_nonempty
-    
-    
-   # @changesets = Changeset.find(:all, :order => "closed_at DESC", :conditions => ['closed_at < ?', DateTime.now], :limit=> 20)
-   
-   
-   #@edit_pages, @edits = paginate(:changesets,
-   #                                :include => [:user, :changeset_tags],
-   #                                :conditions => conditions,
-   #                                :order => "changesets.created_at DESC",
-   #                                :per_page => 20)
-   #
-    
-   @edits =  Changeset.find(:all,
-                                   :order => "changesets.created_at DESC",
-                                   :conditions => conditions,
-                                   :limit => 20)
-    
-  end
-  
-  ##
-  # list edits (changesets) belonging to a user
-  def list_user
-    #find user by display name   
-    user = User.find(:first, :conditions => [ "visible = ? and display_name = ?", true, params[:display_name]])
-    
-    conditions = conditions_user(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)
-    
-    @display_name = user.display_name
-    # FIXME needs rescues in here
-  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 = params['minlon'] + ',' + params['minlat'] + ',' + params['maxlon'] + ',' + params['maxlat']
+    if request.format == :atom and params[:page]
+      redirect_to params.merge({ :page => nil }), :status => :moved_permanently
+    else
+      changesets = conditions_nonempty(Changeset.scoped)
+
+      if params[:display_name]
+        user = User.find_by_display_name(params[:display_name])
+        
+        if user and user.active?
+          if user.data_public? or user == @user
+            changesets = changesets.where(:user_id => user.id)
+          else
+            changesets = changesets.where("false")
+          end
+        elsif request.format == :html
+          @title = t 'user.no_such_user.title'
+          @not_found_user = params[:display_name]
+          render :template => 'user/no_such_user', :status => :not_found
+        end
+      end
+      
+      if params[:bbox]
+        bbox = params[:bbox]
+      elsif params[:minlon] and params[:minlat] and params[:maxlon] and params[:maxlat]
+        bbox = params[:minlon] + ',' + params[:minlat] + ',' + params[:maxlon] + ',' + params[:maxlat]
+      end
+      
+      if bbox
+        changesets = conditions_bbox(changesets, bbox)
+        bbox = BoundingBox.from_s(bbox)
+        bbox_link = render_to_string :partial => "bbox", :object => bbox
+      end
+      
+      if user
+        user_link = render_to_string :partial => "user", :object => user
+      end
+      
+      if user and bbox
+        @title =  t 'changeset.list.title_user_bbox', :user => user.display_name, :bbox => bbox.to_s
+        @heading =  t 'changeset.list.heading_user_bbox', :user => user.display_name, :bbox => bbox.to_s
+        @description = t 'changeset.list.description_user_bbox', :user => user_link, :bbox => bbox_link
+      elsif user
+        @title =  t 'changeset.list.title_user', :user => user.display_name
+        @heading =  t 'changeset.list.heading_user', :user => user.display_name
+        @description = t 'changeset.list.description_user', :user => user_link
+      elsif bbox
+        @title =  t 'changeset.list.title_bbox', :bbox => bbox.to_s
+        @heading =  t 'changeset.list.heading_bbox', :bbox => bbox.to_s
+        @description = t 'changeset.list.description_bbox', :bbox => bbox_link
+      else
+        @title =  t 'changeset.list.title'
+        @heading =  t 'changeset.list.heading'
+        @description = t 'changeset.list.description'
+      end
+
+      @page = (params[:page] || 1).to_i
+      @page_size = 20
+
+      @bbox = bbox
+      
+      @edits = changesets.order("changesets.created_at DESC").offset((@page - 1) * @page_size).limit(@page_size).preload(:user, :changeset_tags)

     end
     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

   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.
   ##
   # 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)
+  def conditions_bbox(changesets, 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]
     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]
+      return changesets.where("min_lon < ? and max_lon > ? and min_lat < ? and max_lat > ?",
+                              (bbox[2] * GeoRecord::SCALE).to_i,
+                              (bbox[0] * GeoRecord::SCALE).to_i,
+                              (bbox[3] * GeoRecord::SCALE).to_i,
+                              (bbox[1] * GeoRecord::SCALE).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 
       # our own changesets regardless of public-ness.
       unless u.data_public?
       # should be able to get changesets of public users only, or 
       # our own changesets regardless of public-ness.
       unless u.data_public?


@@ -410,15 +365,15 @@ private
         
         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?
       # if there is a range, i.e: comma separated, then the first is 
       # low, second is high - same as with bounding boxes.
     unless time.nil?
       # if there is a range, i.e: comma separated, then the first is 
       # low, second is high - same as with bounding boxes.


@@ -428,13 +383,13 @@ private
         raise OSM::APIBadUserInput.new("bad time range") if times.size != 2 
 
         from, to = times.collect { |t| DateTime.parse(t) }
         raise OSM::APIBadUserInput.new("bad time range") if times.size != 2 
 
         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.


@@ -448,25 +403,33 @@ 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 <= ?', 
-                              DateTime.now, 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
   
   ##
   # query changesets which are closed
   # ('closed at' time has passed or changes limit is hit)
   end
   
   ##
   # 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 > ?', 
-                              DateTime.now, 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
 
   ##
   # 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