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

   1 var producers = new Array();
   2 var consumers = new Array();
   3
   4 var postback_url = "${c.postback_url}";
   5
   6 /* The URL encoding changes all of our double quotes to &quot;, so we
   7  * have to convert them back before we do anything with the JSON
   8  * data. */
   9 var locations_json = "${c.json}";
  10 locations_json = locations_json.replace(/&quot;/g, '"');
  11 var locations = JSON.parse(locations_json);
  12
  13 for (var location_idx = 0; location_idx < locations.length; location_idx++) {
  14   if (locations[location_idx].type == 'producer') {
  15     producers.push(locations[location_idx]);
  16   }
  17   else {
  18     consumers.push(locations[location_idx]);
  19   }
  20 }
  21
  22
  23 // Start another JSON array, this time containing our route data.
  24 var json_string = '[';
  25 var completed_requests = 0;
  26 var total_requests = (producers.length * consumers.length);
  27
  28 function routing_callback(result, status) {
  29   /* This is the callback that gets applied to each
  30    * DirectionsResult. It occurs asynchronously, which is why we keep
  31    * track of the total/completed requests. Only the last call to
  32    * complete should actually do something with the final result. */
  33   if (status == google.maps.DirectionsStatus.OK) {
  34     json_string += JSON.stringify(result);
  35
  36     for (var trip_idx = 0; trip_idx < result.trips.length; trip_idx++) {
  37       num_routes = result.trips[trip_idx].routes.length;
  38       if (num_routes > 1) {
  39           alert("Unexpected number of routes (" +
  40               result.trips.routes.length.toString() +
  41               ") on trip number " + trip_idx.toString() + '.');
  42       }
  43     }
  44   }
  45   else {
  46     alert("Error, status: " + status);
  47   }
  48
  49   completed_requests += 1;
  50
  51   if (completed_requests == total_requests) {
  52     // Close the array, and do something with the result.
  53     json_string += ']';
  54     var F = new Form();
  55     F.post_data(postback_url, json_string);
  56   }
  57   else {
  58     // Continue the array.
  59     json_string += ',';
  60   }
  61
  62 }
  63
  64
  65
  66 function get_directions(pairs_to_skip) {
  67   /* We can only get directions for 10 producer/consumer pairs at a
  68    * time. We pass the pairs_to_skip variable back to this function
  69    * via setTimeout so that we can skip the ones we've already
  70    * submitted. */
  71
  72   // Create the object that will do the direction-getting.
  73   var directions_service = new google.maps.DirectionsService();
  74   var requests_submitted = 0;
  75
  76   // And ask it to get directions for each producer/consumer pair.
  77   for (var i = 0; i < producers.length; i++) {
  78     for (var j = 0; j < consumers.length; j++) {
  79
  80       var pair_number = (i * consumers.length) + (j+1);
  81
  82       if (pair_number <= pairs_to_skip || requests_submitted > 9) {
  83         continue;
  84       }
  85
  86       /* We'll pass these to the DirectionsRequest object. They aren't
  87        * necessarily LatLngs, since if either the latitude or
  88        * longitude is missing, we'll fall back to using the name. */
  89       var producer_latlng;
  90       var consumer_latlng;
  91
  92       if (producers[i].latitude && producers[i].longitude) {
  93         producer_latlng = new google.maps.LatLng(producers[i].latitude,
  94                                                  producers[i].longitude);
  95       }
  96       else {
  97         producer_latlng = producers[i].name;
  98       }
  99
 100       if (consumers[i].latitude && consumers[i].longitude) {
 101         consumer_latlng = new google.maps.LatLng(consumers[i].latitude,
 102                                                  consumers[i].longitude);
 103       }
 104       else {
 105         consumer_latlng = consumers[i].name;
 106       }
 107
 108       var directions_request = {
 109         origin: producer_latlng,
 110         destination: consumer_latlng,
 111         provideTripAlternatives: true,
 112         travelMode: google.maps.DirectionsTravelMode.DRIVING
 113       }
 114
 115       /* The function routing_callback(...) gets applied to the result
 116        * of route(). Ideally, that result will be a DirectionsResult
 117        * object containing directions. This executes
 118        * asynchronously. */
 119       directions_service.route(directions_request, routing_callback);
 120
 121       requests_submitted += 1;
 122     }
 123   }
 124
 125   if (pairs_to_skip < total_requests) {
 126     // Next time around, skip whatever requests we submitted this
 127     // time.
 128     pairs_to_skip += requests_submitted;
 129
 130     /* 5 seconds is the smallest timeout that will work here. */
 131     window.setTimeout("get_directions(" + pairs_to_skip + ");", 5000);
 132   }
 133
 134   return;
 135 }
 136
 137
 138 function onload_handler(e) {
 139   // Avoid problems with the implicit event argument to onload
 140   // handlers.
 141   get_directions(0);
 142 }
 143
 144
 145 window.onload = onload_handler;