From 839aeda0ba3e5d99ac54c0c1e8504dc768beacf1 Mon Sep 17 00:00:00 2001
From: itsayushpandey <pandey.ayu@gmail.com>
Date: Wed, 24 Apr 2024 23:01:25 -0600
Subject: [PATCH] Added redis cache for closestCrimeAPI

---
 Dockerfile        |  2 +-
 fetchCrimeData.js | 91 +++++++++++++++++++++++++++--------------------
 2 files changed, 53 insertions(+), 40 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 1367cdc..5434605 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -16,4 +16,4 @@ RUN npm install
 EXPOSE 3000
 
 # Command to run backend server (adjust as per your backend setup)
-CMD ["node", "fetchCrimeData.js"]
+CMD ["node","--env-file=.env", "fetchCrimeData.js"]
diff --git a/fetchCrimeData.js b/fetchCrimeData.js
index 06b14b8..11ace71 100644
--- a/fetchCrimeData.js
+++ b/fetchCrimeData.js
@@ -135,50 +135,67 @@ app.post("/closestCrimeData", async (req, res) => {
 
     const closestCrimeDataList = [];
 
-    const crimeDataCursor = db.collection("boulderCrimeData").find();
+    const cacheKey = objectHash.sha1([req.latitude, req.longitude]);
+    console.log("Cached key" + cacheKey);
+    cachedValue = await readData(cacheKey);
+    console.log("Cached value found: " + cachedValue);
+    if (cachedValue) {
+      // No need to call DB as we have values in cache and can skip it.
+      const responseStatus = new ResponseStatus(200, "OK", "Success");
+      res.json(new Response(closestCrimeDataList, responseStatus));
+    } else {
+      const crimeDataCursor = db.collection("boulderCrimeData").find();
 
-    const allCrimeData = await crimeDataCursor.toArray();
+      const allCrimeData = await crimeDataCursor.toArray();
 
-    const routeProcessingPromises = routeList.map(async (route) => {
-      const closestCrimeData = [];
+      const routeProcessingPromises = routeList.map(async (route) => {
+        const closestCrimeData = [];
 
-      for (const [targetLat, targetLong] of route) {
-        let closestCrime = null;
-        let minDistance = Infinity;
+        for (const [targetLat, targetLong] of route) {
+          let closestCrime = null;
+          let minDistance = Infinity;
 
-        for (const crime of allCrimeData) {
-          const distance = calculateDistance(
-            targetLat,
-            targetLong,
-            crime.latitude,
-            crime.longitude,
-          );
-          if (distance < minDistance) {
-            minDistance = distance;
-            closestCrime = crime;
+          for (const crime of allCrimeData) {
+            const distance = calculateDistance(
+              targetLat,
+              targetLong,
+              crime.latitude,
+              crime.longitude,
+            );
+            if (distance < minDistance) {
+              minDistance = distance;
+              closestCrime = crime;
+            }
           }
-        }
 
-        if (closestCrime) {
-          closestCrimeData.push({
-            latitude: targetLat,
-            longitude: targetLong,
-            crimeData: closestCrime.crimeData,
-          });
-        } else {
-          closestCrimeData.push({
-            message: "No crime data found near this location.",
-          });
+          if (closestCrime) {
+            closestCrimeData.push({
+              latitude: targetLat,
+              longitude: targetLong,
+              crimeData: closestCrime.crimeData,
+            });
+          } else {
+            closestCrimeData.push({
+              message: "No crime data found near this location.",
+            });
+          }
         }
-      }
-      closestCrimeDataList.push(closestCrimeData);
-    });
+        closestCrimeDataList.push(closestCrimeData);
+      });
 
-    await Promise.all(routeProcessingPromises);
-    await client.close();
+      await Promise.all(routeProcessingPromises);
+      await client.close();
 
-    const responseStatus = new ResponseStatus(200, "OK", "Success");
-    res.json(new Response(closestCrimeDataList, responseStatus));
+      console.log(
+        "Saving in cache" +
+          cacheKey +
+          ", value= " +
+          crimeDataResponse.data.crimes,
+      );
+      writeData(cacheKey, crimeDataResponse.data.crimes);
+      const responseStatus = new ResponseStatus(200, "OK", "Success");
+      res.json(new Response(closestCrimeDataList, responseStatus));
+    }
   } catch (err) {
     console.error(err);
     ResponseUtils.setResponseError(res, 500, "Internal Server Error");
@@ -243,10 +260,6 @@ app.post("/closestCrimeData1", async (req, res) => {
   }
 });
 
-// app.listen(port, () => {
-//   console.log(`Server is running on http://localhost:${port}`);
-// });
-
 async function initializeExpressServer() {
   //initialize an Express application
   app.use(express.json());