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

   1 function post_directions_result(url, directions_result) {
   2   /* Create a new form, and add it to the DOM. Then, create a hidden
   3      input control as a child of the form which contains the data that
   4      we'd like to post. Finally, add the form to the document's body,
   5      and submit it. */
   6   var new_form = document.createElement("form");
   7   new_form.method = "post";
   8   new_form.action = url;
   9   var new_input = document.createElement("input");
  10   new_input.setAttribute("id", "directions_result");
  11   new_input.setAttribute("name", "directions_result");
  12   new_input.setAttribute("type", "hidden");
  13   new_input.setAttribute("value", directions_result);
  14   new_form.appendChild(new_input);
  15   document.body.appendChild(new_form);
  16   new_form.submit();
  17 }
  18
  19
  20 var producers = new Array();
  21 var consumers = new Array();
  22
  23 /* The URL encoding changes all of our double quotes to &quot;, so we
  24  * have to convert them back before we do anything with the JSON
  25  * data. */
  26 var locations_json = "${c.json}";
  27 locations_json = locations_json.replace(/&quot;/g, '"');
  28 var locations = JSON.parse(locations_json);
  29
  30 for (var location_idx = 0; location_idx < locations.length; location_idx++) {
  31   if (locations[location_idx].type == 'producer') {
  32     producers.push(locations[location_idx]);
  33   }
  34   else {
  35     consumers.push(locations[location_idx]);
  36   }
  37 }
  38
  39
  40 // Start another JSON array, this time containing our route data.
  41 var json_string = '[';
  42 var completed_requests = 0;
  43 var total_requests = (producers.length * consumers.length);
  44
  45 function routing_callback(result, status) {
  46   /* This is the callback that gets applied to each
  47    * DirectionsResult. It occurs asynchronously, which is why we keep
  48    * track of the total/completed requests. Only the last call to
  49    * complete should actually do something with the final result. */
  50   if (status == google.maps.DirectionsStatus.OK) {
  51     json_string += JSON.stringify(result);
  52
  53     for (var trip_idx = 0; trip_idx < result.trips.length; trip_idx++) {
  54       num_routes = result.trips[trip_idx].routes.length;
  55       if (num_routes > 1) {
  56           alert("Unexpected number of routes (" +
  57               result.trips.routes.length.toString() +
  58               ") on trip number " + trip_idx.toString() + '.');
  59       }
  60     }
  61   }
  62   else {
  63     alert("Error, status: " + status);
  64   }
  65
  66   completed_requests += 1;
  67
  68   if (completed_requests == total_requests) {
  69     // Close the array, and do something with the result.
  70     json_string += ']';
  71     post_directions_result('/directions/json_to_kml', json_string)
  72   }
  73   else {
  74     // Continue the array.
  75     json_string += ',';
  76   }
  77
  78 }
  79
  80
  81
  82 function get_directions(pairs_to_skip) {
  83   /* We can only get directions for 10 producer/consumer pairs at a
  84    * time. We pass the pairs_to_skip variable back to this function
  85    * via setTimeout so that we can skip the ones we've already
  86    * submitted. */
  87
  88   // Create the object that will do the direction-getting.
  89   var directions_service = new google.maps.DirectionsService();
  90   var requests_submitted = 0;
  91
  92   // And ask it to get directions for each producer/consumer pair.
  93   for (var i = 0; i < producers.length; i++) {
  94     for (var j = 0; j < consumers.length; j++) {
  95
  96       var pair_number = (i * consumers.length) + (j+1);
  97
  98       if (pair_number <= pairs_to_skip || requests_submitted > 9) {
  99         continue;
 100       }
 101
 102       var producer_latlng = new google.maps.LatLng(producers[i].latitude,
 103                                                    producers[i].longitude);
 104
 105       var consumer_latlng = new google.maps.LatLng(consumers[i].latitude,
 106                                                    consumers[i].longitude);
 107
 108       var directions_request = {
 109         origin: producer_latlng,
 110         destination: consumer_latlng,
 111         provideTripAlternatives: true,
 112
 113         travelMode: google.maps.DirectionsTravelMode.DRIVING
 114       }
 115
 116       /* The function routing_callback(...) gets applied to the result
 117        * of route(). Ideally, that result will be a DirectionsResult
 118        * object containing directions. This executes
 119        * asynchronously. */
 120       directions_service.route(directions_request, routing_callback);
 121
 122       requests_submitted += 1;
 123     }
 124   }
 125
 126   if (pairs_to_skip < total_requests) {
 127     // Next time around, skip whatever requests we submitted this
 128     // time.
 129     pairs_to_skip += requests_submitted;
 130
 131     /* 5 seconds is the smallest timeout that will work here. */
 132     window.setTimeout("get_directions(" + pairs_to_skip + ");", 5000);
 133   }
 134
 135   return;
 136 }
 137
 138
 139 function onload_handler(e) {
 140   // Avoid problems with the implicit event argument to onload
 141   // handlers.
 142   get_directions(0);
 143 }
 144
 145
 146 window.onload = onload_handler;