--- /dev/null
+#!/usr/bin/ruby
+
+require 'rubygems'
+require 'proj4'
+require 'xml/libxml'
+require 'set'
+require 'pg'
+require 'time'
+
+module Expire
+ # projection object to go from latlon -> spherical mercator
+ PROJ = Proj4::Projection.new(["+proj=merc", "+a=6378137", "+b=6378137",
+ "+lat_ts=0.0", "+lon_0=0.0", "+x_0=0.0",
+ "+y_0=0", "+k=1.0", "+units=m",
+ "+nadgrids=@null", "+no_defs +over"])
+
+ # width/height of the spherical mercator projection
+ SIZE=40075016.6855784
+ # the size of the meta tile blocks
+ METATILE = 8
+ # the directory root for meta tiles
+ HASH_ROOT = "/tiles/default/"
+ # lowest zoom that we want to expire
+ # MIN_ZOOM=12
+ MIN_ZOOM=13
+ # highest zoom that we want to expire
+ MAX_ZOOM=18
+ # database parameters
+ DBNAME="gis"
+ DBHOST=""
+ #DBPORT=5432
+ DBPORT=5432
+ DBTABLE="planet_osm_nodes"
+
+ # turns a spherical mercator coord into a tile coord
+ def Expire.tile_from_merc(point, zoom)
+ # renormalise into unit space [0,1]
+ point.x = 0.5 + point.x / SIZE
+ point.y = 0.5 - point.y / SIZE
+ # transform into tile space
+ point.x = point.x * 2 ** zoom
+ point.y = point.y * 2 ** zoom
+ # chop of the fractional parts
+ [point.x.to_int, point.y.to_int, zoom]
+ end
+
+ # turns a latlon -> tile x,y given a zoom level
+ def Expire.tile_from_latlon(latlon, zoom)
+ # first convert to spherical mercator
+ point = PROJ.forward(latlon)
+ tile_from_merc(point, zoom)
+ end
+
+ # this must match the definition of xyz_to_meta in mod_tile
+ def Expire.xyz_to_meta(root, x, y, z)
+ # mask off the final few bits
+ x &= ~(METATILE - 1)
+ y &= ~(METATILE - 1)
+ # generate the path
+ hash_path = (0..4).collect { |i|
+ (((x >> 4*i) & 0xf) << 4) | ((y >> 4*i) & 0xf)
+ }.reverse.join('/')
+ root + '/' + z.to_s + '/' + hash_path + ".meta"
+ end
+
+ # time to reset to, some very stupidly early time, before OSM started
+ EXPIRY_TIME = Time.parse("2000-01-01 00:00:00")
+
+ # expire the meta tile by setting the modified time back
+ def Expire.expire_meta(meta)
+ puts "Expiring #{meta}"
+ File.utime(EXPIRY_TIME, EXPIRY_TIME, meta)
+ end
+
+ def Expire.expire(change_file)
+ do_expire(change_file) do |set|
+ new_set = Set.new
+ meta_set = Set.new
+
+ # turn all the tiles into expires, putting them in the set
+ # so that we don't expire things multiple times
+ set.each do |xy|
+ # this has to match the routine in mod_tile
+ meta = xyz_to_meta(HASH_ROOT, xy[0], xy[1], xy[2])
+
+ meta_set.add(meta) if File.exist? meta
+
+ # add the parent into the set for the next round
+ new_set.add([xy[0] / 2, xy[1] / 2, xy[2] - 1])
+ end
+
+ # expire all meta tiles
+ meta_set.each do |meta|
+ expire_meta(meta)
+ end
+
+ # return the new set, consisting of all the parents
+ new_set
+ end
+ end
+
+ def Expire.do_expire(change_file, &block)
+ # read in the osm change file
+ doc = XML::Document.file(change_file)
+
+ # hash map to contain all the nodes
+ nodes = Hash.new
+
+ # we put all the nodes into the hash, as it doesn't matter whether the node was
+ # added, deleted or modified - the tile will need updating anyway.
+ doc.find('//node').each do |node|
+ lat = node['lat'].to_f
+ if lat < -85
+ lat = -85
+ end
+ if lat > 85
+ lat = 85
+ end
+ point = Proj4::Point.new(Math::PI * node['lon'].to_f / 180,
+ Math::PI * lat / 180)
+ nodes[node['id'].to_i] = tile_from_latlon(point, MAX_ZOOM)
+ end
+
+ # now we look for all the ways that have changed and put all of their nodes into
+ # the hash too. this will add too many nodes, as it is possible a long way will be
+ # changed at only a portion of its length. however, due to the non-local way that
+ # mapnik does text placement, it may stil not be enough.
+ #
+ # also, we miss cases where nodes are deleted from ways where that node is not
+ # itself deleted and the coverage of the point set isn't enough to encompass the
+ # change.
+ conn = PG::Connection.new(:host => DBHOST, :port => DBPORT, :dbname => DBNAME)
+ doc.find('//way/nd').each do |node|
+ node_id = node['ref'].to_i
+ unless nodes.include? node_id
+ # this is a node referenced but not added, modified or deleted, so it should
+ # still be in the postgis DB.
+ res = conn.query("select lon, lat from #{DBTABLE} where id=#{node_id};")
+
+ # loop over results, adding tiles to the change set
+ res.each do |row|
+ point = Proj4::Point.new(row[0].to_f / 100.0, row[1].to_f / 100.0)
+ nodes[node_id] = tile_from_merc(point, MAX_ZOOM)
+ end
+
+ # Discard results
+ res.clear
+ end
+ end
+
+ # create a set of all the tiles at the maximum zoom level which are touched by
+ # any of the nodes we've collected. we'll create the tiles at other zoom levels
+ # by a simple recursion.
+ set = Set.new nodes.values
+
+ # expire tiles and shrink to the set of parents
+ (MAX_ZOOM).downto(MIN_ZOOM) do |z|
+ # allow the block to work on the set, returning the set at the next
+ # zoom level
+ set = yield set
+ end
+ end
+end
projects / chef.git / blobdiff