Added the "maps" Pylons project.

[dead/census-tools.git] / www / maps / maps / templates / javascript / routing.mako

diff --git a/www/maps/maps/templates/javascript/routing.mako b/www/maps/maps/templates/javascript/routing.mako
new file mode 100644 (file)
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--- /dev/null
+++ b/www/maps/maps/templates/javascript/routing.mako
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+function post_directions_result(url, directions_result) {
+  /* Create a new form, and add it to the DOM. Then, create a hidden
+     input control as a child of the form which contains the data that
+     we'd like to post. Finally, add the form to the document's body,
+     and submit it. */
+  var new_form = document.createElement("form");
+  new_form.method = "post";
+  new_form.action = url;
+  var new_input = document.createElement("input");
+  new_input.setAttribute("id", "directions_result");
+  new_input.setAttribute("name", "directions_result");
+  new_input.setAttribute("type", "hidden");
+  new_input.setAttribute("value", directions_result);
+  new_form.appendChild(new_input);
+  document.body.appendChild(new_form);
+  new_form.submit();
+}
+
+
+var producers = new Array();
+var consumers = new Array();
+
+/* The URL encoding changes all of our double quotes to ", so we
+ * have to convert them back before we do anything with the JSON
+ * data. */
+var locations_json = "${c.json}";
+locations_json = locations_json.replace(/"/g, '"');
+var locations = JSON.parse(locations_json);
+
+for (var location_idx = 0; location_idx < locations.length; location_idx++) {
+  if (locations[location_idx].type == 'producer') {
+    producers.push(locations[location_idx]);
+  }
+  else {
+    consumers.push(locations[location_idx]);
+  }
+}
+
+
+// Start another JSON array, this time containing our route data.
+var json_string = '[';
+var completed_requests = 0;
+var total_requests = (producers.length * consumers.length);
+
+function routing_callback(result, status) {
+  /* This is the callback that gets applied to each
+   * DirectionsResult. It occurs asynchronously, which is why we keep
+   * track of the total/completed requests. Only the last call to
+   * complete should actually do something with the final result. */
+  if (status == google.maps.DirectionsStatus.OK) {
+    json_string += JSON.stringify(result);
+
+    for (var trip_idx = 0; trip_idx < result.trips.length; trip_idx++) {
+      num_routes = result.trips[trip_idx].routes.length;
+      if (num_routes > 1) {
+         alert("Unexpected number of routes (" +
+             result.trips.routes.length.toString() +
+             ") on trip number " + trip_idx.toString() + '.');
+      }
+    }
+  }
+  else {
+    alert("Error, status: " + status);
+  }
+
+  completed_requests += 1;
+
+  if (completed_requests == total_requests) {
+    // Close the array, and do something with the result.
+    json_string += ']';
+    post_directions_result('/directions/json_to_kml', json_string)
+  }
+  else {
+    // Continue the array.
+    json_string += ',';
+  }
+  
+}
+
+
+
+function get_directions(pairs_to_skip) {
+  /* We can only get directions for 10 producer/consumer pairs at a
+   * time. We pass the pairs_to_skip variable back to this function
+   * via setTimeout so that we can skip the ones we've already
+   * submitted. */
+
+  // Create the object that will do the direction-getting.
+  var directions_service = new google.maps.DirectionsService();
+  var requests_submitted = 0;
+  
+  // And ask it to get directions for each producer/consumer pair.
+  for (var i = 0; i < producers.length; i++) {
+    for (var j = 0; j < consumers.length; j++) {
+
+      var pair_number = (i * consumers.length) + (j+1);
+
+      if (pair_number <= pairs_to_skip || requests_submitted > 9) {
+       continue;
+      }
+
+      var producer_latlng = new google.maps.LatLng(producers[i].latitude,
+                                                  producers[i].longitude);
+      
+      var consumer_latlng = new google.maps.LatLng(consumers[i].latitude,
+                                                  consumers[i].longitude);
+
+      var directions_request = {
+       origin: producer_latlng,
+       destination: consumer_latlng,
+       provideTripAlternatives: true,
+
+       travelMode: google.maps.DirectionsTravelMode.DRIVING
+      }
+
+      /* The function routing_callback(...) gets applied to the result
+       * of route(). Ideally, that result will be a DirectionsResult
+       * object containing directions. This executes
+       * asynchronously. */
+      directions_service.route(directions_request, routing_callback);
+
+      requests_submitted += 1;      
+    }
+  }
+
+  if (pairs_to_skip < total_requests) {
+    // Next time around, skip whatever requests we submitted this
+    // time.
+    pairs_to_skip += requests_submitted;
+
+    /* 5 seconds is the smallest timeout that will work here. */
+    window.setTimeout("get_directions(" + pairs_to_skip + ");", 5000);
+  }
+      
+  return;
+}
+
+
+function onload_handler(e) {
+  // Avoid problems with the implicit event argument to onload
+  // handlers.
+  get_directions(0);
+}
+
+
+window.onload = onload_handler;