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     post_data('/directions/json_to_kml', json_string)
  53   }
  54   else {
  55     // Continue the array.
  56     json_string += ',';
  57   }
  58
  59 }
  60
  61
  62
  63 function get_directions(pairs_to_skip) {
  64   /* We can only get directions for 10 producer/consumer pairs at a
  65    * time. We pass the pairs_to_skip variable back to this function
  66    * via setTimeout so that we can skip the ones we've already
  67    * submitted. */
  68
  69   // Create the object that will do the direction-getting.
  70   var directions_service = new google.maps.DirectionsService();
  71   var requests_submitted = 0;
  72
  73   // And ask it to get directions for each producer/consumer pair.
  74   for (var i = 0; i < producers.length; i++) {
  75     for (var j = 0; j < consumers.length; j++) {
  76
  77       var pair_number = (i * consumers.length) + (j+1);
  78
  79       if (pair_number <= pairs_to_skip || requests_submitted > 9) {
  80         continue;
  81       }
  82
  83       var producer_latlng = new google.maps.LatLng(producers[i].latitude,
  84                                                    producers[i].longitude);
  85
  86       var consumer_latlng = new google.maps.LatLng(consumers[i].latitude,
  87                                                    consumers[i].longitude);
  88
  89       var directions_request = {
  90         origin: producer_latlng,
  91         destination: consumer_latlng,
  92         provideTripAlternatives: true,
  93
  94         travelMode: google.maps.DirectionsTravelMode.DRIVING
  95       }
  96
  97       /* The function routing_callback(...) gets applied to the result
  98        * of route(). Ideally, that result will be a DirectionsResult
  99        * object containing directions. This executes
 100        * asynchronously. */
 101       directions_service.route(directions_request, routing_callback);
 102
 103       requests_submitted += 1;
 104     }
 105   }
 106
 107   if (pairs_to_skip < total_requests) {
 108     // Next time around, skip whatever requests we submitted this
 109     // time.
 110     pairs_to_skip += requests_submitted;
 111
 112     /* 5 seconds is the smallest timeout that will work here. */
 113     window.setTimeout("get_directions(" + pairs_to_skip + ");", 5000);
 114   }
 115
 116   return;
 117 }
 118
 119
 120 function onload_handler(e) {
 121   // Avoid problems with the implicit event argument to onload
 122   // handlers.
 123   get_directions(0);
 124 }
 125
 126
 127 window.onload = onload_handler;