Deployable hello function behind api gateway

dynamoClient.js

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+const AWS = require('aws-sdk');
+
+// Set the region
+AWS.config.update({region: 'us-east-2'});
+
+// also set local endpoint while in development
+if (process.env.NODE_ENV === 'development') {
+  AWS.config.update({endpoint: "http://localhost:8000"});
+}
+
+const client = new AWS.DynamoDB.DocumentClient({});
+
+module.exports = client;

handlers/hello/get.js

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+'use strict';
+
+module.exports.hello = async (event, context) => {
+  return {
+    statusCode: 200,
+    body: JSON.stringify({
+      message: 'Go Serverless v1.0! Your function executed successfully!',
+      input: event,
+    }),
+  };
+
+  // Use this code if you don't use the http event with the LAMBDA-PROXY integration
+  // return { message: 'Go Serverless v1.0! Your function executed successfully!', event };
+};

helpers.js

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+const customThrow = (statusCode, message) => {
+  const err = new Error();
+  err.statusCode = statusCode;
+  err.message = message;
+  throw err;
+};
+
+const createResponse = (statusCode, body) => ({
+  statusCode,
+  headers: {
+    "Access-Control-Allow-Origin" : "*", // Required for CORS support to work
+    "Access-Control-Allow-Credentials" : true // Required for cookies, authorization headers with HTTPS
+  },
+  body: JSON.stringify(body),
+});
+
+module.exports = {
+  customThrow,
+  createResponse
+};

services/db.js

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+const dynamoClient = require('../dynamoClient');
+
+const create = async (tableName, item) => {
+  const fullItem = {...item, created_at: Date.now()};
+
+  await dynamoClient.put({
+    TableName: tableName,
+    Item: fullItem
+  }).promise();
+
+  // put does not return saved item, just return our object
+  return fullItem;
+};
+
+const get = async (tableName, keyMap) => {
+  const res = await dynamoClient.get({
+    TableName: tableName,
+    Key: keyMap
+  }).promise();
+
+  return res && res.Item;
+};
+
+const queryByID = async (tableName, idKeyName, id) => {
+  // querying by id can be used when we are querying a table
+  // that has a sortKey, but we don't need to use the sortKey
+  const res = await dynamoClient.query({
+    TableName: "gt_answers",
+    KeyConditionExpression: "#id = :idValue",
+    ExpressionAttributeNames: {
+      "#id": idKeyName,
+    },
+    ExpressionAttributeValues: {
+      ":idValue": id,
+    }
+  }).promise();
+
+  return res && res.Items;
+};
+
+const update = async (tableName, keyMap, ue, eav) => {
+  const res = await dynamoClient.update({
+    TableName: tableName,
+    Key: keyMap,
+    UpdateExpression: ue,
+    ExpressionAttributeValues: eav,
+    ReturnValues: 'UPDATED_NEW'
+  }).promise();
+
+  console.log('update res', res);
+
+  return res;
+};
+
+module.exports = {
+  client: dynamoClient,
+  create,
+  get,
+  queryByID,
+  update
+};

validators/index.js

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+const Ajv = require('ajv');
+const {customThrow} = require('../helpers');
+
+const parseAndValidateBody = async (schema, body) => {
+  let parsedBody;
+
+  try {
+    parsedBody = JSON.parse(body);
+  } catch (err) {
+    customThrow(400, 'Error. Malformed event.parsedBody.');
+  }
+
+  const validation = validateBody(schema, parsedBody);
+
+  if (!validation.isValid) {
+    customThrow(400, validation.error);
+  }
+
+  return parsedBody;
+};
+
+const validateBody = (schema, body) => {
+  const ajv = new Ajv();
+  const validate = ajv.compile(schema);
+  const isValid = validate(body);
+
+  return {
+    isValid: isValid,
+    error: JSON.stringify(validate.errors)
+  }
+};
+
+module.exports = {
+  parseAndValidateBody,
+};

validators/schemas.js

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+const answerSchema = {
+  "type": "object",
+  "properties": {
+    "user_id": {"type": "string"},
+    "question_id": {"type": "string"},
+    "is_correct": {"type": "boolean"}
+  },
+  "required": ["user_id", "question_id", "is_correct"]
+};
+
+const userSchema = {
+  "type": "object",
+  "properties": {
+    "id": {"type": "string"},
+    "score": {"type": "number"}
+  },
+  "required": ["user_id", "question_id", "is_correct"]
+};
+
+const loginFollowUpSchema = {
+  "type": "object",
+  "properties": {
+    "accessToken": {"type": "string"}
+  },
+  "required": ["accessToken"]
+};
+
+module.exports = {
+  answerSchema,
+  userSchema,
+  loginFollowUpSchema
+};
+