Read headers in lower case

Author: francisco-videira-nhs

lambdas/api-handler/src/handlers/get-letters.ts

@@ -1,7 +1,7 @@
 import { APIGatewayProxyEventQueryStringParameters, APIGatewayProxyHandler } from "aws-lambda";
 import { getLettersForSupplier } from "../services/letter-operations";
 import { createLetterRepository } from "../infrastructure/letter-repo-factory";
-import { assertNotEmpty } from "../utils/validation";
+import { assertNotEmpty, lowerCaseKeys } from "../utils/validation";
 import { ApiErrorDetail } from '../contracts/errors';
 import { lambdaConfig } from "../config/lambda-config";
 import pino from 'pino';
@@ -27,8 +27,9 @@ export const getLetters: APIGatewayProxyHandler = async (event) => {
 
   try {
     assertNotEmpty(event.headers, new Error("The request headers are empty"));
-    correlationId = assertNotEmpty(event.headers[lambdaConfig.APIM_CORRELATION_HEADER], new Error("The request headers don't contain the APIM correlation id"));
-    const supplierId = assertNotEmpty(event.headers[lambdaConfig.SUPPLIER_ID_HEADER], new ValidationError(ApiErrorDetail.InvalidRequestMissingSupplierId));
+    const lowerCasedHeaders = lowerCaseKeys(event.headers);
+    correlationId = assertNotEmpty(lowerCasedHeaders[lambdaConfig.APIM_CORRELATION_HEADER], new Error("The request headers don't contain the APIM correlation id"));
+    const supplierId = assertNotEmpty(lowerCasedHeaders[lambdaConfig.SUPPLIER_ID_HEADER], new ValidationError(ApiErrorDetail.InvalidRequestMissingSupplierId));
     const limitNumber = getLimitOrDefault(event.queryStringParameters, maxLimit);
 
     const letters = await getLettersForSupplier(

lambdas/api-handler/src/handlers/patch-letter.ts

@@ -6,7 +6,7 @@ import { ApiErrorDetail } from '../contracts/errors';
 import { ValidationError } from '../errors';
 import { mapErrorToResponse } from '../mappers/error-mapper';
 import { lambdaConfig } from "../config/lambda-config";
-import { assertNotEmpty } from '../utils/validation';
+import { assertNotEmpty, lowerCaseKeys } from '../utils/validation';
 import { mapToLetterDto } from '../mappers/letter-mapper';
 
 const letterRepo = createLetterRepository();
@@ -16,8 +16,9 @@ export const patchLetter: APIGatewayProxyHandler = async (event) => {
 
   try {
     assertNotEmpty(event.headers, new Error('The request headers are empty'));
-    correlationId = assertNotEmpty(event.headers[lambdaConfig.APIM_CORRELATION_HEADER], new Error("The request headers don't contain the APIM correlation id"));
-    const supplierId = assertNotEmpty(event.headers[lambdaConfig.SUPPLIER_ID_HEADER], new ValidationError(ApiErrorDetail.InvalidRequestMissingSupplierId));
+    const lowerCasedHeaders = lowerCaseKeys(event.headers);
+    correlationId = assertNotEmpty(lowerCasedHeaders[lambdaConfig.APIM_CORRELATION_HEADER], new Error("The request headers don't contain the APIM correlation id"));
+    const supplierId = assertNotEmpty(lowerCasedHeaders[lambdaConfig.SUPPLIER_ID_HEADER], new ValidationError(ApiErrorDetail.InvalidRequestMissingSupplierId));
     const letterId = assertNotEmpty( event.pathParameters?.id, new ValidationError(ApiErrorDetail.InvalidRequestMissingLetterIdPathParameter));
     const body = assertNotEmpty(event.body, new ValidationError(ApiErrorDetail.InvalidRequestMissingBody));
 

lambdas/api-handler/src/utils/__tests__/validation.test.ts

@@ -1,4 +1,4 @@
-import { assertNotEmpty } from "../validation";
+import { assertNotEmpty, lowerCaseKeys } from "../validation";
 
 describe("assertNotEmpty", () => {
   const error = new Error();
@@ -52,3 +52,16 @@ describe("assertNotEmpty", () => {
     expect(result).toBe(arr);
   });
 });
+
+describe("lowerCaseKeys", () => {
+  it("lowers case on header keys", () => {
+    const headers: Record<string, number> = {'Aa_Bb-Cc':1, 'b':2};
+    const result = lowerCaseKeys(headers);
+    expect(result).toEqual({'aa_bb-cc':1, 'b':2});
+  });
+
+  it("handles empty input", () => {
+    const result = lowerCaseKeys({});
+    expect(result).toEqual({});
+  });
+});

lambdas/api-handler/src/utils/validation.ts

@@ -16,3 +16,7 @@ export function assertNotEmpty<T>(
 
   return value;
 }
+
+export function lowerCaseKeys(obj: Record<string, any>): Record<string, any> {
+  return Object.fromEntries(Object.entries(obj).map(([k, v]) => [k.toLowerCase(), v]));
+}