Add the fetchPrescriptionDataLambda using the LambdaFunction class

packages/cdk/resources/LambdaFunction/fetchPrescriptionData.ts

@@ -0,0 +1,98 @@
+import {APIGatewayProxyHandler} from "aws-lambda"
+import axios from "axios"
+import {DynamoDB} from "aws-sdk"
+
+const APIGEE_BASE_URL = process.env.APIGEE_BASE_URL || "https://internal-dev.api.service.nhs.uk"
+const TABLE_NAME = process.env.TABLE_NAME || "DefaultTableName"
+const TOKEN_KEY = "apigeeAccessToken"
+
+const dynamoDb = new DynamoDB.DocumentClient()
+
+/**
+ * Helper function to fetch or refresh the token from DynamoDB.
+ * @returns {Promise<string>} The access token.
+ */
+async function getToken(): Promise<string> {
+  // Fetch token from DynamoDB
+  const result = await dynamoDb.get({
+    TableName: TABLE_NAME,
+    Key: {id: TOKEN_KEY}
+  }).promise()
+
+  const tokenData = result.Item
+
+  // Check if a valid token exists
+  if (tokenData && tokenData.expiry > Date.now()) {
+    return tokenData.token
+  }
+
+  // Otherwise, generate a new token
+  const newToken = await generateNewToken()
+  const expiryTime = Date.now() + 60 * 60 * 1000 // 1 hour expiry
+
+  // Store the new token in DynamoDB
+  await dynamoDb.put({
+    TableName: TABLE_NAME,
+    Item: {
+      id: TOKEN_KEY,
+      token: newToken,
+      expiry: expiryTime
+    }
+  }).promise()
+
+  return newToken
+}
+
+/**
+ * Generate a new access token.
+ * This could be a call to a secondary Lambda or an external provider.
+ * @returns {Promise<string>} The generated token.
+ */
+async function generateNewToken(): Promise<string> {
+  // Placeholder for actual token generation logic
+  return "new-generated-token"
+}
+
+/**
+ * Lambda function handler to fetch prescription data.
+ * @param event The API Gateway request event.
+ * @returns {Promise<any>} The response from Apigee.
+ */
+export const handler: APIGatewayProxyHandler = async (event) => {
+  const prescriptionId = event.pathParameters?.id
+
+  if (!prescriptionId) {
+    return {
+      statusCode: 400,
+      body: JSON.stringify({error: "Prescription ID is required"})
+    }
+  }
+
+  try {
+    const token = await getToken()
+
+    const url = `${APIGEE_BASE_URL}/clinical-prescription-tracker/${prescriptionId}`
+    const response = await axios.get(url, {
+      headers: {
+        Authorization: `Bearer ${token}`,
+        "Content-Type": "application/json"
+      }
+    })
+
+    return {
+      statusCode: 200,
+      body: JSON.stringify(response.data)
+    }
+  } catch (error) {
+    console.error("Error fetching prescription data:", error)
+
+    const errorMessage = error.response
+      ? `Apigee responded with ${error.response.status}: ${error.response.statusText}`
+      : "Unexpected error occurred while fetching data"
+
+    return {
+      statusCode: 500,
+      body: JSON.stringify({error: errorMessage})
+    }
+  }
+}

packages/cdk/stacks/StatelessResourcesStack.ts

@@ -15,11 +15,14 @@ import {
   ViewerProtocolPolicy
 } from "aws-cdk-lib/aws-cloudfront"
 import {RestApiOrigin, S3BucketOrigin} from "aws-cdk-lib/aws-cloudfront-origins"
+import {LambdaIntegration} from "aws-cdk-lib/aws-apigateway"
 import {Bucket} from "aws-cdk-lib/aws-s3"
 
 import {RestApiGateway} from "../resources/RestApiGateway"
 import {CloudfrontFunction} from "../resources/Cloudfront/CloudfrontFunction"
 import {CloudfrontDistribution} from "../resources/CloudfrontDistribution"
+import {LambdaFunction} from "../resources/LambdaFunction"
+import {getDefaultLambdaOptions} from "../resources/LambdaFunction/helpers"
 import {nagSuppressions} from "../nagSuppressions"
 
 export interface StatelessResourcesStackProps extends StackProps {
@@ -29,12 +32,12 @@ export interface StatelessResourcesStackProps extends StackProps {
 }
 
 /**
- * Clinical Prescription Tracker UI Stateful Resources
+ * Clinical Prescription Tracker UI Stateless Resources
 
  */
 
 export class StatelessResourcesStack extends Stack {
-  public constructor(scope: App, id: string, props: StatelessResourcesStackProps){
+  public constructor(scope: App, id: string, props: StatelessResourcesStackProps) {
     super(scope, id, props)
 
     // Context
@@ -51,7 +54,30 @@ export class StatelessResourcesStack extends Stack {
       stackName: props.stackName
     })
 
-    // --- Methods & Resources
+    // --- Lambda for fetchPrescriptionData
+    const lambdaOptions = getDefaultLambdaOptions({
+      functionName: `${props.serviceName}-fetchPrescriptionData`,
+      packageBasePath: "packages/cdk/resources/LambdaFunction",
+      entryPoint: "fetchPrescriptionData.ts"
+    })
+
+    const fetchPrescriptionDataLambda = new LambdaFunction(this, "FetchPrescriptionDataLambda", {
+      ...lambdaOptions,
+      serviceName: props.serviceName,
+      stackName: props.stackName,
+      lambdaEnvironmentVariables: {
+        APIGEE_BASE_URL: process.env.APIGEE_BASE_URL || "https://internal-dev.api.service.nhs.uk",
+        TABLE_NAME: process.env.TABLE_NAME || "DefaultTableName"
+      }
+    })
+
+    // --- API Gateway Route for /api/prescription-search/{id}
+    const api = apiGateway.restApiGateway
+    const prescriptionSearchResource = api.root
+      .addResource("api")
+      .addResource("prescription-search")
+      .addResource("{id}")
+    prescriptionSearchResource.addMethod("GET", new LambdaIntegration(fetchPrescriptionDataLambda.lambda))
 
     // - Cloudfront
     // --- Origins
@@ -137,7 +163,7 @@ export class StatelessResourcesStack extends Stack {
         origin: staticContentBucketOrigin,
         allowedMethods: AllowedMethods.ALLOW_GET_HEAD_OPTIONS,
         viewerProtocolPolicy: ViewerProtocolPolicy.REDIRECT_TO_HTTPS,
-        functionAssociations:[
+        functionAssociations: [
           {
             function: s3404UriRewriteFunction.function,
             eventType: FunctionEventType.VIEWER_REQUEST