Improve behaviour of browse pages when no bounding box is available

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

diff --git a/app/controllers/changeset_controller.rb b/app/controllers/changeset_controller.rb
index 8c042ef8d463abf11e7e253eff9709e579bd11c6..36b3b5124ed3b725d3cc518f33096dc2150c0cc5 100644 (file)
--- a/app/controllers/changeset_controller.rb
+++ b/app/controllers/changeset_controller.rb
@@ -1,62 +1,61 @@
 # The ChangesetController is the RESTful interface to Changeset objects
 
 class ChangesetController < ApplicationController
 # The ChangesetController is the RESTful interface to Changeset objects
 
 class ChangesetController < ApplicationController

+  layout 'site'

   require 'xml/libxml'
   require 'xml/libxml'

-  require 'diff_reader'

 
 

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

 
 

-  # Help methods for checking boundary sanity and area size
-  include MapBoundary
+  # Helper methods for checking consistency
+  include ConsistencyValidations

 
   # 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
 
   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
   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
   end

-  
-  def close 
-    begin
-      unless request.put?
-        render :nothing => true, :status => :method_not_allowed
-        return
-      end

 
 

-      changeset = Changeset.find(params[:id])
+  ##
+  # marks a changeset as closed. this may be called multiple times
+  # on the same changeset, so is idempotent.
+  def close
+    assert_method :put

 
 

-      unless @user.id == changeset.user_id 
-        raise OSM::APIUserChangesetMismatchError 
-      end
+    changeset = Changeset.find(params[:id])
+    check_changeset_consistency(changeset, @user)

 
 

-      changeset.open = false
-      changeset.save!
-      render :nothing => true
-    rescue ActiveRecord::RecordNotFound
-      render :nothing => true, :status => :not_found
-    end
+    # to close the changeset, we'll just set its closed_at time to
+    # 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!
+    render :text => ""

   end
 
   ##
   end
 
   ##


@@ -64,53 +63,40 @@ class ChangesetController < ApplicationController
   # increase the size of the bounding box. this is a hint that clients can
   # set either before uploading a large number of changes, or changes that
   # the client (but not the server) knows will affect areas further away.
   # increase the size of the bounding box. this is a hint that clients can
   # set either before uploading a large number of changes, or changes that
   # the client (but not the server) knows will affect areas further away.

-  def include
+  def expand_bbox

     # only allow POST requests, because although this method is
     # idempotent, there is no "document" to PUT really...
     # 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])
+    assert_method :post

 
 

-      # check user credentials - only the user who opened a changeset
-      # may alter it.
-      unless @user.id == cs.user_id 
-        raise OSM::APIUserChangesetMismatchError 
-      end
-
-      # keep an array of lons and lats
-      lon = Array.new
-      lat = Array.new
+    cs = Changeset.find(params[:id])
+    check_changeset_consistency(cs, @user)

 
 

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

 
 

-      # 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?
+    # 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

 
 

-      # 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
+    # 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?

 
 

-      # 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"
+    # 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

 
 

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


@@ -123,208 +109,355 @@ 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 
-  # http://wiki.openstreetmap.org/index.php/OSM_Protocol_Version_0.6
+  # 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
     # 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])
 
     changeset = Changeset.find(params[:id])

+    check_changeset_consistency(changeset, @user)

 
 

-    # access control - only the user who created a changeset may
-    # upload to it.
-    unless @user.id == changeset.user_id 
-      raise OSM::APIUserChangesetMismatchError 
-    end
-    

     diff_reader = DiffReader.new(request.raw_post, changeset)
     Changeset.transaction do
       result = diff_reader.commit
       render :text => result.to_s, :content_type => "text/xml"
     end
     diff_reader = DiffReader.new(request.raw_post, changeset)
     Changeset.transaction do
       result = diff_reader.commit
       render :text => result.to_s, :content_type => "text/xml"
     end

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

   end
 
   ##
   # download the changeset as an osmChange document.
   #
   # to make it easier to revert diffs it would be better if the osmChange
   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 
+  # 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
 
     render :text => result.to_s, :content_type => "text/xml"
           end
         end
     end
 
     render :text => result.to_s, :content_type => "text/xml"

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

   end
 
   ##
   # query changesets by bounding box, time, user or open/closed status.
   def query
   end
 
   ##
   # 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'])
-    cond_merge conditions, conditions_user(params['user'])
-    cond_merge conditions, conditions_time(params['time'])
-    cond_merge conditions, conditions_open(params['open'])
+    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'])

 
     # 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"

+  end

 
 

-  rescue ActiveRecord::RecordNotFound
-    render :nothing => true, :status => :not_found
-  rescue OSM::APIError => ex
-    render ex.render_opts
-  rescue String => s
-    render :text => s, :content_type => "text/plain", :status => :bad_request
+  ##
+  # updates a changeset's tags. none of the changeset's attributes are
+  # user-modifiable, so they will be ignored.
+  #
+  # changesets are not (yet?) versioned, so we don't have to deal with
+  # history tables here. changesets are locked to a single user, however.
+  #
+  # after succesful update, returns the XML of the changeset.
+  def update
+    # request *must* be a PUT.
+    assert_method :put
+
+    changeset = Changeset.find(params[:id])
+    new_changeset = Changeset.from_xml(request.raw_post)
+
+    unless new_changeset.nil?
+      check_changeset_consistency(changeset, @user)
+      changeset.update_from(new_changeset, @user)
+      render :text => changeset.to_xml, :mime_type => "text/xml"
+    else
+
+      render :text => "", :status => :bad_request
+    end

   end
 
   ##
   end
 
   ##

-  # 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
+  # list edits (open changesets) in reverse chronological order
+  def list
+    if request.format == :atom and params[:page]
+      redirect_to params.merge({ :page => nil }), :status => :moved_permanently
+    else
+      changesets = conditions_nonempty(Changeset.all)
+
+      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
+        else
+          render_unknown_user params[:display_name]
+          return
+        end
+      end
+
+      if params[:friends]
+        if @user
+          changesets = changesets.where(:user_id => @user.friend_users.public)
+        elsif request.format == :html
+          require_user
+          return
+        end
+      end
+
+      if params[:nearby]
+        if @user
+          changesets = changesets.where(:user_id => @user.nearby)
+        elsif request.format == :html
+          require_user
+          return
+        end
+      end
+
+      if params[:bbox]
+        bbox = BoundingBox.from_bbox_params(params)
+      elsif params[:minlon] and params[:minlat] and params[:maxlon] and params[:maxlat]
+        bbox = BoundingBox.from_lon_lat_params(params)
+      end
+
+      if bbox
+        changesets = conditions_bbox(changesets, bbox)
+        bbox_link = render_to_string :partial => "bbox", :object => bbox
+      end
+
+      if user
+        user_link = render_to_string :partial => "user", :object => user
+      end
+
+      if params[:friends] and @user
+        @title =  t 'changeset.list.title_friend'
+        @heading =  t 'changeset.list.heading_friend'
+        @description = t 'changeset.list.description_friend'
+      elsif params[:nearby] and @user
+        @title = t 'changeset.list.title_nearby'
+        @heading = t 'changeset.list.heading_nearby'
+        @description = t 'changeset.list.description_nearby'
+      elsif 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
+
+      @edits = changesets.order("changesets.created_at DESC").offset((@page - 1) * @page_size).limit(@page_size).preload(:user, :changeset_tags)
+
+      render :action => :list

     end
   end
 
   ##
     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 "Bounding box should be min_lon,min_lat,max_lon,max_lat" unless bbox.count(',') == 3
-      bbox = sanitise_boundaries(bbox.split(/,/))
-      raise "Minimum longitude should be less than maximum." unless bbox[0] <= bbox[2]
-      raise "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]
+  # list edits as an atom feed
+  def feed
+    list
+  end
+
+private
+  #------------------------------------------------------------
+  # utility functions below.
+  #------------------------------------------------------------
+
+  ##
+  # 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?
-      u = User.find(user.to_i)
-      raise OSM::APINotFoundError unless u.data_public?
-      return ['user_id = ?', u.id]
+  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?
+
+      # 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
+
+        raise OSM::APINotFoundError if @user.nil? or @user.id != u.id
+      end
+      return changesets.where(:user_id => u.id)

     else
     else

-      return nil
+      return changesets

     end
   end
 
   ##
     end
   end
 
   ##

-  # restrict changes to those during a particular time period
-  def conditions_time(time) 
+  # restrict changes to those closed during a particular time period
+  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
       # low, second is high - same as with bounding boxes.
       if time.count(',') == 1

-        from, to = time.split(/,/).collect { |t| Date.parse(t) }
-        return ['created_at > ? and created_at < ?', from, to]
+        # check that we actually have 2 elements in the array
+        times = time.split(/,/)
+        raise OSM::APIBadUserInput.new("bad time range") if times.size != 2
+
+        from, to = times.collect { |t| DateTime.parse(t) }
+        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 ['created_at > ?', Date.parse(time)]
+        return changesets.where("closed_at >= ?", DateTime.parse(time))

       end
     else
       end
     else

-      return nil
+      return changesets

     end
     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.

   rescue ArgumentError => ex
   rescue ArgumentError => ex

-    raise ex.message.to_s
+    raise OSM::APIBadUserInput.new(ex.message.to_s)
+  rescue RuntimeError => ex
+    raise OSM::APIBadUserInput.new(ex.message.to_s)
+  end
+
+  ##
+  # 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 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)
+  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
 
   ##
   end
 
   ##

-  # restrict changes to those which are open
-  def conditions_open(open)
-    return open.nil? ? nil : ['open = ?', true]
+  # eliminate empty changesets (where the bbox has not been set)
+  # this should be applied to all changeset list displays
+  def conditions_nonempty(changesets)
+    return changesets.where("num_changes > 0")

   end
 
 end
   end
 
 end