doorman/packages/serverless/functions/common/ddb.private.js

const { DynamoDBClient, GetItemCommand, DeleteItemCommand, PutItemCommand } = require("@aws-sdk/client-dynamodb");

exports.createDDBClient = (context) => {
  return new DynamoDBClient({ 
    region: "us-east-1" ,
    credentials: {
      accessKeyId: context.AWS_ACCESS_KEY,
      secretAccessKey: context.AWS_SECRET_ACCESS_KEY,
    },
  });
};

exports.getLockStatusCommand = (door) => {
  return new GetItemCommand({
    TableName: "doorman",
    Key: {
      "PK": {
        S: door,
      },
      "SK": {
        S: "lock",
      }
    },
  });
};

exports.getDoorAliasCommand = (buzzerNumber) => {
  return new GetItemCommand({
    TableName: "doorman",
    Key: {
      "PK": {
        S: buzzerNumber,
      },
      "SK": {
        S: "alias",
      }
    },
  });
};

exports.getDoorConfigCommand = (door) => {
  return new GetItemCommand({
    TableName: "doorman",
    Key: {
      "PK": {
        S: `door-${door}`,
      },
      "SK": {
        S: "config",
      },
    },
  });
};

exports.isLockOpen = (lock) => {
  // ttl is a UTC ms time for how long it is unlocked
  const ttl = lock.Item?.TTL?.N || 0;
  return ttl > Date.now();
};

exports.clearLockStatusCommand = (lock) => {
  return new DeleteItemCommand({
    TableName: "doorman",
    Key: {
      "PK": {
        S: lock.Item.PK.S,
      },
      "SK": {
        S: "lock",
      }
    }
  });
};

exports.setLockStatusCommand = (door, timeoutSeconds, fingerprintObj) => {
  return new PutItemCommand({
    TableName: "doorman",
    Item: {
      "PK": {
        S: door,
      },
      "SK": {
        S: "lock",
      },
      "TTL": {
        N: `${Date.now() + timeoutSeconds * 1000}`,
      },
      "fingerprint": {
        S: JSON.stringify(fingerprintObj),
      }
    }
  });
};