#!/usr/bin/python -u # -*- coding: utf-8 -*- import cairo import cgi import mapnik import os import shutil import sys import tempfile import resource # Limit maximum CPU time # The Postscript output format can sometimes take hours resource.setrlimit(resource.RLIMIT_CPU,(180,180)) # Limit memory usage # Some odd requests can cause extreme memory usage resource.setrlimit(resource.RLIMIT_AS,(4000000000, 4000000000)) # Routine to output HTTP headers def output_headers(content_type, filename = "", length = 0): print "Content-Type: %s" % content_type if filename: print "Content-Disposition: attachment; filename=\"%s\"" % filename if length: print "Content-Length: %d" % length print "" # Routine to output the contents of a file def output_file(file): file.seek(0) shutil.copyfileobj(file, sys.stdout) # Routine to get the size of a file def file_size(file): return os.fstat(file.fileno()).st_size # Routine to report an error def output_error(message): output_headers("text/html") print "" print "" print "Error" print "" print "" print "

Error

" print "

" % message print "" print "" # Parse CGI parameters form = cgi.FieldStorage() # Make sure we have a user agent if not os.environ.has_key('HTTP_USER_AGENT'): os.environ['HTTP_USER_AGENT'] = 'NONE' # Get the load average loadavg = float(open("/proc/loadavg").readline().split(" ")[0]) # Process the request if loadavg > 35.0: # Abort if the load average on the machine is too high print "Status: 503 Service Unavailable" output_error("The load average on the server is too high at the moment. Please wait a few minutes before trying again.") <% @blocks["user_agents"].each do |user_agent| -%> elif os.environ['HTTP_USER_AGENT'] == '<%= user_agent %>': # Block scraper print "Status: 503 Service Unavailable" output_error("The load average on the server is too high at the moment. Please wait a few minutes before trying again.") <% end -%> elif not form.has_key("bbox"): # No bounding box specified output_error("No bounding box specified") elif not form.has_key("scale"): # No scale specified output_error("No scale specified") elif not form.has_key("format"): # No format specified output_error("No format specified") else: # Create projection object prj = mapnik.Projection("+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"); # Get the bounds of the area to render bbox = [float(x) for x in form.getvalue("bbox").split(",")] if bbox[0] >= bbox[2] or bbox[1] >= bbox[3]: # Bogus bounding box output_error("Invalid bounding box") else: # Project the bounds to the map projection bbox = mapnik.forward_(mapnik.Box2d(*bbox), prj) # Get the style to use style = form.getvalue("style", "default") # Calculate the size of the final rendered image scale = float(form.getvalue("scale")) width = int(bbox.width() / scale / 0.00028) height = int(bbox.height() / scale / 0.00028) # Limit the size of map we are prepared to produce if width * height > 4000000: # Map is too large (limit is approximately A2 size) output_error("Map too large") else: # Create map map = mapnik.Map(width, height) # Load map configuration mapnik.load_map(map, "/srv/tile.openstreetmap.org/styles/%s/project.xml" % style) # Zoom the map to the bounding box map.zoom_to_box(bbox) # Render the map if form.getvalue("format") == "png": image = mapnik.Image(map.width, map.height) mapnik.render(map, image) png = image.tostring("png") output_headers("image/png", "map.png", len(png)) sys.stdout.write(png) elif form.getvalue("format") == "jpeg": image = mapnik.Image(map.width, map.height) mapnik.render(map, image) jpeg = image.tostring("jpeg") output_headers("image/jpeg", "map.jpg", len(jpeg)) sys.stdout.write(jpeg) elif form.getvalue("format") == "svg": file = tempfile.NamedTemporaryFile(prefix = "export") surface = cairo.SVGSurface(file.name, map.width, map.height) mapnik.render(map, surface) surface.finish() output_headers("image/svg+xml", "map.svg", file_size(file)) output_file(file) elif form.getvalue("format") == "pdf": file = tempfile.NamedTemporaryFile(prefix = "export") surface = cairo.PDFSurface(file.name, map.width, map.height) mapnik.render(map, surface) surface.finish() output_headers("application/pdf", "map.pdf", file_size(file)) output_file(file) elif form.getvalue("format") == "ps": file = tempfile.NamedTemporaryFile(prefix = "export") surface = cairo.PSSurface(file.name, map.width, map.height) mapnik.render(map, surface) surface.finish() output_headers("application/postscript", "map.ps", file_size(file)) output_file(file) else: output_error("Unknown format '%s'" % form.getvalue("format"))