Add fuzzy search

api/common/post-fuzzy-search.js

@@ -0,0 +1,62 @@
+import Fuse from "fuse.js";
+import * as dynamoDbLib from "../libs/dynamodb-lib";
+
+async function getPostDetails(postId) {
+  const params = {
+    TableName: "NaadanChords",
+    ProjectionExpression:
+      "postId, category, createdAt, updatedAt, postType, title, userId",
+    Key: {
+      postId,
+    },
+  };
+  let result = await dynamoDbLib.call("get", params);
+  return result.Item;
+}
+
+export async function fuzzySearch(query) {
+  let allPostIds = [];
+  let params = {
+    TableName: "NaadanChords",
+    IndexName: "postType-updatedAt-index",
+    KeyConditionExpression: "postType = :postType",
+    ExpressionAttributeValues: {
+      ":postType": "POST",
+    },
+    ScanIndexForward: false,
+    ProjectionExpression: "postId",
+  };
+
+  let lek = "init";
+  while (lek) {
+    const data = await dynamoDbLib.call("query", params);
+    allPostIds.push(...data.Items);
+    lek = data.LastEvaluatedKey;
+    if (lek) params.ExclusiveStartKey = lek;
+  }
+
+  const options = {
+    includeScore: true,
+    threshold: 0.5,
+    isCaseSensitive: false,
+    keys: ["postId"],
+  };
+
+  const scanResult = new Fuse(allPostIds, options);
+  let result = scanResult.search(query, { limit: 15 });
+
+  if (result.length > 0) {
+    allPostIds = result.map((item) => item.item.postId);
+  } else {
+    return { Items: [] };
+  }
+
+  // Get post details
+  result = { Items: [] };
+  for (let i = 0; i < allPostIds.length; i++) {
+    const res = await getPostDetails(allPostIds[i]);
+    result.Items.push(res);
+  }
+
+  return result;
+}

api/posts-service/list.js

@@ -3,6 +3,7 @@ import * as userNameLib from "../libs/username-lib";
 import * as searchFilterLib from "../libs/searchfilter-lib";
 import { appendRatings } from "../common/post-ratings";
 import { appendCommentsCount } from "../common/post-comments";
+import { fuzzySearch } from "../common/post-fuzzy-search";
 
 export async function main(event, context, callback) {
   var lastEvaluatedKey;
@@ -120,18 +121,23 @@ export async function main(event, context, callback) {
       result = await dynamoDbLib.call("scan", params);
 
       if (result?.Items?.length === 0) {
-        // No search results
-        const emptySearchWriteParams = {
-          TableName: "NaadanChordsEmptySearch",
-          Item: {
-            timestamp: Date.now(),
-            searchQuery: event.search,
-            ipAddress: event.sourceIP,
-            type: "SEARCH",
-          },
-        };
-
-        await dynamoDbLib.call("put", emptySearchWriteParams);
+        // Try fuzzy search over post ids
+        result = await fuzzySearch(event.search);
+
+        if (result?.Items?.length === 0) {
+          // No search results
+          const emptySearchWriteParams = {
+            TableName: "NaadanChordsEmptySearch",
+            Item: {
+              timestamp: Date.now(),
+              searchQuery: event.search,
+              ipAddress: event.sourceIP,
+              type: "SEARCH",
+            },
+          };
+
+          await dynamoDbLib.call("put", emptySearchWriteParams);
+        }
       }
     } else {
       result = await dynamoDbLib.call("query", params);

api/posts-service/package.json

@@ -13,6 +13,7 @@
   },
   "dependencies": {
     "aws-sdk": "^2.1359.0",
+    "fuse.js": "^7.0.0",
     "serverless-domain-manager": "^5.1.0",
     "serverless-webpack": "^5.5.4",
     "webpack-node-externals": "^2.5.2"