ITM 300 - Cloud Foundations

Module 09: Product 9 Lab - Vehicle History Update

list

Quick Oil Change and Repair

Product Objective

Technicians have quested to be able to see past repair history for the vehicles. We'll be adding this new feature to the app.

Create new lambda function

Create a new lambda function

Update the index.mjs code

import { getVehicleHistory } from './adminVehicleHistory.mjs';

const commonHeaders = {
  'Content-Type': 'application/json',
  'Access-Control-Allow-Headers': 'Content-Type',
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Methods': 'OPTIONS,POST,GET,PUT'
};

export const handler = async (event) => {
  try {

    const httpMethod = event.httpMethod;
    const path = event.path;
    const resource = event.resource;
    const pathParameters = event.pathParameters;
    const queryParameters = event.queryStringParameters;
    const requestBody = event.body ? JSON.parse(event.body) : null;    
    let jsonArray = [];

    switch (httpMethod) {
      case "GET":  
        if(pathParameters && pathParameters.id){
          jsonArray = await getVehicleHistory(pathParameters.id);
          // jsonArray = {message:"Yep"};
        }
        else {
          jsonArray = {message:"No Plate Provided"};
        }
        break;

    }

    const response = {
      statusCode: 200,
      body: JSON.stringify(jsonArray),
      headers: commonHeaders
    };
    return response;
  } catch (error) {
    console.error('Error:', error);
    const response = {
      statusCode: 500,
      body: JSON.stringify({ message: 'Internal Server Error' }),
      headers: commonHeaders
    };
    return response;
  }
};

Create a new file adminVehicleHistory.mjs and update it with this code

import { SNSClient, PublishCommand } from "@aws-sdk/client-sns"; // ES Modules import
import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
import {
  DynamoDBDocumentClient,
  QueryCommand,
  PutCommand,
  GetCommand,
  DeleteCommand,
  UpdateCommand,
} from "@aws-sdk/lib-dynamodb";

const client = new DynamoDBClient({});

const mydynamodb = DynamoDBDocumentClient.from(client);

const tableName = "VehicleServices";    

export const getVehicleHistory = async (license_plate) => {
    try {
        const params = {
            TableName: tableName,
            KeyConditionExpression: "#license_plate = :license_plate",
            ExpressionAttributeNames: {
                "#license_plate": "license_plate"
            },
            ExpressionAttributeValues: {
                ":license_plate": license_plate
            }
        };      
        const body = await mydynamodb.send(new QueryCommand(params));
        return body.Items; // Return JSON string of items
    } catch (error) {
        console.error("Error fetching DynamoDB service requests:", error);
        throw error; // Re-throw the error to handle it further up the call stack
    }
}

Click Deploy

Update the API Gateway

search Search for API Gateway

We'll create two resources. The first is the main area for vehicle-history

Now we'll create the second that will respond for specific histories based on license plate number.

You should have /vehicle-history/{id} selected. We'll now create the GET method.

Deploy API (this may take a couple of minutes)

Update code

Connect to your Vehicle App EC2 Instance

Download the newest website app:

wget https://github.com/byui-cse/itm300-course/raw/main/source/module-09/rebuildapp.sh

chmod +x ./rebuildapp.sh

Next run the script which will download the newest files. 

sudo bash ./rebuildapp.sh

Password

You can use the credentials you created earlier for janedoe

Username: janedoe

Password: Ilove2SeeTheTemple!!

If you changed your username or password then use those instead.

Now when you log in to your app you should have an area that will allow you to search for vehicle histories based on license plate number. Also, the license plate numbers in the current service requests will also be linked to quickly go to the vehicle histories.

Submit a screenshot of the history page for one of the vehicles.

Summary

In this lab, students added a new feature to an existing AWS-based application, enabling technicians to view the repair history of vehicles. This involved creating a new AWS Lambda function, setting up appropriate resources in the API Gateway, and updating the application code. The lab walked through creating and configuring the Lambda function, updating the API Gateway to handle new endpoints, and deploying the changes to the application.

Code Review

Take a minute and review the lambda function code that you added. Identify what is happening with the code. If you don't understand a line of code, use an AI resource like chatGPT to dig into what the code is doing by asking questions until you understand the code.

Review the code found in the /var/www/html folder. Specifically look at the following code:

How does this code interact with the lambda functions that were created in the lab? Identify any code that you do not understand and research it using generative AI.

Reflection Questions