Update Firebase cloud functions

functions/index.js

@@ -1,9 +1,76 @@
+// Firebase imports
 const functions = require("firebase-functions");
+const admin = require('firebase-admin');
+const cors = require('cors')({ origin: true });
+admin.initializeApp();
 
-// // Create and deploy your first functions
-// // https://firebase.google.com/docs/functions/get-started
-//
-// exports.helloWorld = functions.https.onRequest((request, response) => {
-//   functions.logger.info("Hello logs!", {structuredData: true});
-//   response.send("Hello from Firebase!");
-// });
+// external imports
+const axios = require('axios');
+const parseString = require('xml2js').parseString;
+
+// function to fetch live train data from the Firestore database
+exports.getLiveTrainData = functions.https.onRequest((request, response) => {
+  response.set('Access-Control-Allow-Origin', '*');
+  response.set('Access-Control-Allow-Credentials', 'true');
+  let jsonData = [];
+
+  cors(request, response, () => {
+    // fetch the "liveTrainData" collection
+    admin.firestore().collection('liveTrainData').get().then((snapshot) => {
+      if (snapshot.empty) {
+        response.send("Error fetching data from the database");
+        return;
+      }
+      // iterate through each of the collection's documents
+      snapshot.forEach(doc => {
+        jsonData.push(doc.data());
+      });
+      // response.send(jsonData);
+      response.json({data: jsonData});
+    })
+  });
+})
+
+// function to populate the Firestore database with live train data from Irish Rail
+exports.postLiveTrainData = functions.https.onRequest((request, response) => {
+  response.set('Access-Control-Allow-Origin', '*');
+  response.set('Access-Control-Allow-Credentials', 'true');
+
+  cors(request, response, () => {
+    axios.get('http://api.irishrail.ie/realtime/realtime.asmx/getCurrentTrainsXML')
+          .then((res) => {
+            // XML to JSON
+            parseString(res.data, function(err, result) {
+              let jsonStr = JSON.stringify(result);
+              let jsonObj = JSON.parse(jsonStr);
+              let jsonData = jsonObj.ArrayOfObjTrainPositions.objTrainPositions;
+
+              // batch delete all of the "liveTrainData" collections's documents
+              var db = admin.firestore();
+              admin.firestore().collection('liveTrainData').get().then((snapshot) => {
+                  var batchDelete = db.batch();
+                  snapshot.forEach(doc => {
+                    batchDelete.delete(doc.ref);
+                  });
+
+                  batchDelete.commit().then(function() {
+                    // batch write all train JSON objects to the "liveTrainData" collection
+                    var batchWrite = db.batch();
+                    jsonData.forEach((doc) => {
+                      // set the train's code as the document ID
+                      var docID = db.collection('liveTrainData').doc(doc["TrainCode"][0]);
+                      batchWrite.set(docID, doc);
+                    });
+
+                    batchWrite.commit().then(function () {
+                      response.send("Successfully fetched and uploaded data from Irish Rail");
+                    });
+                  })
+              })
+            })
+          })
+          .catch((error) => {;
+            response.send("Error fetching data from the IrishRail API");
+          })
+  });
+})