/
whoots_app.rb
67 lines (53 loc) · 1.83 KB
/
whoots_app.rb
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#require 'rubygems'
#require 'erb'
class WhootsApp
def self.call(env)
req = Rack::Request.new(env)
case req.path
when /^\/hi\b/
Rack::Response.new("Hello World!")
when /^\/tms\/\d+\/\d+\/\d+\/\w+\/*/
#'/tms/:z/:x/:y/:layers/*'
params = req.path.split("/")
z,x,y,layer = params[2],params[3],params[4],params[5]
splat = params[6..params.length].join("/")
query_params = req.query_string.split("&")
query_params = Rack::Utils.parse_query(req.query_string)
x = x.to_i
y = y.to_i
z = z.to_i
#for Google/OSM tile scheme we need to alter the y:
y = ((2**z)-y-1)
#calculate the bbox
bbox = get_tile_bbox(x,y,z)
#build up the other params
format = "image/png"
service = "WMS"
version = "1.1.1"
request = "GetMap"
srs = "EPSG:3857"
width = "256"
height = "256"
layers = layer || ""
map = query_params["map"] || ""
base_url = splat
url = base_url + "?"+ "bbox="+bbox+"&format="+format+"&service="+service+"&version="+version+"&request="+request+"&srs="+srs+"&width="+width+"&height="+height+"&layers="+layers+"&map="+map+"&styles="
response = Rack::Response.new
response.redirect(url, 302)
response.finish
else
Rack::Response.new("<html>Not found. <a href='/'>Whoots</a></html>", 404)
end
end
def self.get_tile_bbox(x,y,z)
min_x, min_y = get_merc_coords(x * 256, y * 256, z)
max_x, max_y = get_merc_coords( (x + 1) * 256, (y + 1) * 256, z )
return "#{min_x},#{min_y},#{max_x},#{max_y}"
end
def self.get_merc_coords(x,y,z)
resolution = (2 * Math::PI * 6378137 / 256) / (2 ** z)
merc_x = (x * resolution -2 * Math::PI * 6378137 / 2.0)
merc_y = (y * resolution - 2 * Math::PI * 6378137 / 2.0)
return merc_x, merc_y
end
end