Drop Visit:Exit events, and only create SNS obj if we need to

index.js

@@ -1,50 +1,59 @@
 /**
  * Queues custom geolocation events sent from devices such as iPhones.
+ * Designed to be invoked by the AWS API Gateway as a Lambda Proxy function.
  *
  * @author Tim Malone <tim@timmalone.id.au>
  * @see ::runGeoEvent
  * @see http://proximityevents.com/faq/index.html
  */
 
-const AWS = require( 'aws-sdk' );
-AWS.config.region = 'ap-southeast-2';
-
-const sns = new AWS.SNS();
-
 exports.handler = ( event, context, callback ) => {
 
+  // Prepare the API response.
+  const response = {
+    isBase64Encoded: false,
+    statusCode:      200,
+    headers:         {}
+  };
+
   // Put together the event data we want.
   const geoEventData = JSON.parse( event.body );
   geoEventData.person = event.queryStringParameters.person;
-
+
+  // Drop Visit:Exit events, as they'll often supply an old address way too late.
+  if ( 'Visit:Exit' === geoEventData.event_type ) {
+    response.body = JSON.stringify({ message: 'Dropped.' });
+    callback( null, response );
+    return;
+  }
+
   // Remove some data we don't need.
   delete geoEventData.event_id;
   delete geoEventData.trigger_id;
 
+ // Store an SNS message to process everything else we need, so we can return quickly.
+
   const snsMessage = {
     Message:  JSON.stringify( geoEventData ),
     TopicArn: process.env.SNS_QUEUE
   };
 
+  const AWS = require( 'aws-sdk' );
+  AWS.config.region = 'ap-southeast-2';
+
+  const sns = new AWS.SNS();
+
   sns.publish( snsMessage, ( error, data ) => {
-
-    const response = {
-      isBase64Encoded: false,
-      headers: {}
-    };
-
+
     if ( error ) {
       console.log( error );
       response.statusCode = 500;
       response.body = JSON.stringify({ error: error });
     } else {
-      console.log( data );
-      response.statusCode = 200;
       response.body = JSON.stringify({ message: 'Queued.' });
     }
-    
+
     callback( null, response );
-
-  });
 
+  }); // Sns.publish.
 }; // Exports.handler.