Show new participants as they join

.gitignore

@@ -4,6 +4,8 @@
 !frontend/**/*.js
 !backend/*.js
 !backend/**/*.js
+!eventFilters/*.js
+!eventFilters/**/*.js
 !itest/*.js
 !itest/**/*.js
 !content/*.js

backend/connect.js

@@ -0,0 +1,99 @@
+const DynamoDB = require("aws-sdk/clients/dynamodb");
+const schema = require("./schema");
+const db = new DynamoDB.DocumentClient();
+const crypto = require("crypto");
+const logger = require("./logger");
+
+exports.handler = async function (event, context, callback) {
+  logger.log("connect handler called");
+  logger.log("event:");
+  logger.log(JSON.stringify(event));
+  logger.log("context:");
+  logger.log(JSON.stringify(context));
+
+  // validate the connection request
+  if (
+    !event ||
+    !event.queryStringParameters ||
+    !event.queryStringParameters.roomcode ||
+    !event.queryStringParameters.gamename
+  ) {
+    logger.log("missing queryStringParameters");
+    return { statusCode: 400, body: "Bad request" };
+  }
+
+  const roomCode = event.queryStringParameters.roomcode;
+  const gameName = decodeURIComponent(event.queryStringParameters.gamename);
+  const hash = crypto.createHash("sha256");
+  hash.update(gameName);
+  const GAME_NAME_HASH_LENGTH = 64;
+  const gameNameHash = hash
+    .digest("hex")
+    .substring(0, GAME_NAME_HASH_LENGTH)
+    .toLowerCase();
+  if (!event.multiValueHeaders || !event.multiValueHeaders.Cookie) {
+    logger.log("no cookies");
+    return { statusCode: 400, body: "Bad request" };
+  }
+  logger.log("gameNameHash:");
+  logger.log(gameNameHash);
+  const gameCookie = event.headers.Cookie.split(";")
+    .map((cookie) => cookie.trim())
+    .find((cookie) => new RegExp(`^${gameNameHash}=.`).test(cookie));
+  const RIGHT_HAND_SIDE = 1;
+  const cookieSessionKey = gameCookie.split("=")[RIGHT_HAND_SIDE];
+  if (!gameCookie || !cookieSessionKey) {
+    logger.log("no cookie with the right name, looking for " + gameNameHash);
+    return { statusCode: 400, body: "Bad request" };
+  }
+  const getParticipantParams = {
+    TableName: process.env.TABLE_NAME,
+    Key: {
+      [schema.PARTITION_KEY]: roomCode,
+      [schema.SORT_KEY]:
+        `${schema.PARTICIPANT_PREFIX}` +
+        `${schema.SEPARATOR}` +
+        `${gameNameHash}`,
+    },
+  };
+  try {
+    const participantData = await db.get(getParticipantParams).promise();
+    if (participantData.Item[schema.SESSION_KEY] != cookieSessionKey) {
+      logger.log("session key mismatch");
+      return { statusCode: 400, body: "Bad request" };
+    }
+  } catch (e) {
+    logger.log("error getting participant data", e);
+    return { statusCode: 500, body: "Server error" };
+  }
+
+  const now = new Date();
+  var putParams = {
+    TableName: process.env.TABLE_NAME,
+    Item: {
+      [schema.PARTITION_KEY]: `${roomCode}`,
+      [schema.SORT_KEY]:
+        `${schema.CONNECT}` +
+        `${schema.SEPARATOR}` +
+        `${event.requestContext.connectionId}`,
+      [schema.CONNECTION_ID]: event.requestContext.connectionId,
+      [schema.DATE]: now.toISOString(),
+      [schema.MS]: now.getTime(),
+    },
+  };
+
+  try {
+    await db.put(putParams).promise();
+    return {
+      statusCode: 200,
+      body: "Connected",
+    };
+  } catch (e) {
+    logger.log("error on put");
+    logger.log(e);
+    return {
+      statusCode: 500,
+      body: "Server error",
+    };
+  }
+};