www/maps/maps/templates/javascript/routing.mako

   1 var producers = new Array();
   2 var consumers = new Array();
   3
   4 /* The URL encoding changes all of our double quotes to &quot;, so we
   5  * have to convert them back before we do anything with the JSON
   6  * data. */
   7 var locations_json = "${c.json}";
   8 locations_json = locations_json.replace(/&quot;/g, '"');
   9 var locations = JSON.parse(locations_json);
  10
  11 for (var location_idx = 0; location_idx < locations.length; location_idx++) {
  12   if (locations[location_idx].type == 'producer') {
  13     producers.push(locations[location_idx]);
  14   }
  15   else {
  16     consumers.push(locations[location_idx]);
  17   }
  18 }
  19
  20
  21 // Start another JSON array, this time containing our route data.
  22 var json_string = '[';
  23 var completed_requests = 0;
  24 var total_requests = (producers.length * consumers.length);
  25
  26 function routing_callback(result, status) {
  27   /* This is the callback that gets applied to each
  28    * DirectionsResult. It occurs asynchronously, which is why we keep
  29    * track of the total/completed requests. Only the last call to
  30    * complete should actually do something with the final result. */
  31   if (status == google.maps.DirectionsStatus.OK) {
  32     json_string += JSON.stringify(result);
  33
  34     for (var trip_idx = 0; trip_idx < result.trips.length; trip_idx++) {
  35       num_routes = result.trips[trip_idx].routes.length;
  36       if (num_routes > 1) {
  37           alert("Unexpected number of routes (" +
  38               result.trips.routes.length.toString() +
  39               ") on trip number " + trip_idx.toString() + '.');
  40       }
  41     }
  42   }
  43   else {
  44     alert("Error, status: " + status);
  45   }
  46
  47   completed_requests += 1;
  48
  49   if (completed_requests == total_requests) {
  50     // Close the array, and do something with the result.
  51     json_string += ']';
  52     mu = new MapUtils();
  53     mu.post_data('/directions/json_to_kml', json_string);
  54   }
  55   else {
  56     // Continue the array.
  57     json_string += ',';
  58   }
  59
  60 }
  61
  62
  63
  64 function get_directions(pairs_to_skip) {
  65   /* We can only get directions for 10 producer/consumer pairs at a
  66    * time. We pass the pairs_to_skip variable back to this function
  67    * via setTimeout so that we can skip the ones we've already
  68    * submitted. */
  69
  70   // Create the object that will do the direction-getting.
  71   var directions_service = new google.maps.DirectionsService();
  72   var requests_submitted = 0;
  73
  74   // And ask it to get directions for each producer/consumer pair.
  75   for (var i = 0; i < producers.length; i++) {
  76     for (var j = 0; j < consumers.length; j++) {
  77
  78       var pair_number = (i * consumers.length) + (j+1);
  79
  80       if (pair_number <= pairs_to_skip || requests_submitted > 9) {
  81         continue;
  82       }
  83
  84       var producer_latlng = new google.maps.LatLng(producers[i].latitude,
  85                                                    producers[i].longitude);
  86
  87       var consumer_latlng = new google.maps.LatLng(consumers[i].latitude,
  88                                                    consumers[i].longitude);
  89
  90       var directions_request = {
  91         origin: producer_latlng,
  92         destination: consumer_latlng,
  93         provideTripAlternatives: true,
  94
  95         travelMode: google.maps.DirectionsTravelMode.DRIVING
  96       }
  97
  98       /* The function routing_callback(...) gets applied to the result
  99        * of route(). Ideally, that result will be a DirectionsResult
 100        * object containing directions. This executes
 101        * asynchronously. */
 102       directions_service.route(directions_request, routing_callback);
 103
 104       requests_submitted += 1;
 105     }
 106   }
 107
 108   if (pairs_to_skip < total_requests) {
 109     // Next time around, skip whatever requests we submitted this
 110     // time.
 111     pairs_to_skip += requests_submitted;
 112
 113     /* 5 seconds is the smallest timeout that will work here. */
 114     window.setTimeout("get_directions(" + pairs_to_skip + ");", 5000);
 115   }
 116
 117   return;
 118 }
 119
 120
 121 function onload_handler(e) {
 122   // Avoid problems with the implicit event argument to onload
 123   // handlers.
 124   get_directions(0);
 125 }
 126
 127
 128 window.onload = onload_handler;