Adds an error catch for null responses

cagov · Oct 13, 2021 · 97c30f3 · 97c30f3
2 parents 62bfe42 + f3faf46
commit 97c30f3
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Showing 2 changed files with 81 additions and 8 deletions.
diff --git a/tests/utils/queryApiGateway.test.ts b/tests/utils/queryApiGateway.test.ts
@@ -189,18 +189,34 @@ describe('Querying the API Gateway', () => {
     restore()
   })
 
-  it('handles null unique number response mismatch', async () => {
+  it('handles nullish with unique number response', async () => {
     // Mock process.env
     const restore = mockEnv({
       API_URL: goodUrl,
     })
 
-    const mismatchedResponse = { hasPendingWeeks: false, uniqueNumber: null }
+    const mismatchedResponse = {
+      claimDetails: {
+        programType: '',
+        benefitYearStartDate: null,
+        benefitYearEndDate: null,
+        claimBalance: null,
+        weeklyBenefitAmount: null,
+        lastPaymentIssued: null,
+        lastPaymentAmount: null,
+        monetaryStatus: '',
+      },
+      uniqueNumber: '12345',
+      hasCertificationWeeksAvailable: false,
+      hasPendingWeeks: false,
+      pendingDetermination: [],
+    }
+
     /* eslint-disable  @typescript-eslint/no-unsafe-call */
     fetch.mockResolvedValue(new Response(JSON.stringify(mismatchedResponse)))
     /* eslint-enable  @typescript-eslint/no-unsafe-call */
     await expect(queryApiGateway(goodRequest, goodUniqueNumber)).rejects.toThrow(
-      'Mismatched API response and Header unique number (null and 12345)',
+      'API responded with a null response (queried with 12345, responded with 12345)',
     )
 
     expect(fetch).toHaveBeenCalledTimes(1)
@@ -210,15 +226,18 @@ describe('Querying the API Gateway', () => {
     restore()
   })
 
-  it('handles null unique number request mismatch', async () => {
+  it('handles null unique number response', async () => {
     // Mock process.env
     const restore = mockEnv({
       API_URL: goodUrl,
     })
 
-    const mismatchedUniqueNumber = null
-    await expect(queryApiGateway(goodRequest, mismatchedUniqueNumber)).rejects.toThrow(
-      'Mismatched API response and Header unique number (12345 and null)',
+    const mismatchedResponse = { hasPendingWeeks: false, uniqueNumber: null }
+    /* eslint-disable  @typescript-eslint/no-unsafe-call */
+    fetch.mockResolvedValue(new Response(JSON.stringify(mismatchedResponse)))
+    /* eslint-enable  @typescript-eslint/no-unsafe-call */
+    await expect(queryApiGateway(goodRequest, goodUniqueNumber)).rejects.toThrow(
+      'API responded with a null response (queried with 12345, responded with null)',
     )
 
     expect(fetch).toHaveBeenCalledTimes(1)

diff --git a/utils/queryApiGateway.ts b/utils/queryApiGateway.ts
@@ -14,6 +14,7 @@
 import path from 'path'
 import fs from 'fs'
 import https from 'https'
+import assert from 'assert'
 import { IncomingMessage } from 'http'
 import { Claim } from '../types/common'
 import { Logger } from './logger'
@@ -112,6 +113,46 @@ export function getUniqueNumber(req: IncomingMessage): string {
   return req.headers[idHeaderName.toLowerCase()] as string
 }
 
+/**
+ * Check if the API responded with a null response body
+ *
+ * We do not expect any of these in production, in theory.
+ */
+export function reponseIsNullish(apiBody: Claim): boolean {
+  // This is a trick to make a deep-copy of a JSON object
+  const response: Claim = JSON.parse(JSON.stringify(apiBody)) as Claim
+  const responseUniqueNumber = response.uniqueNumber
+  delete response.uniqueNumber
+
+  // This is an unexpected null response we are seeing in production
+  // where the API responses with a matching UniqueNumber we asked for,
+  // but no claim data
+  const nullishResponse = {
+    claimDetails: {
+      programType: '',
+      benefitYearStartDate: null,
+      benefitYearEndDate: null,
+      claimBalance: null,
+      weeklyBenefitAmount: null,
+      lastPaymentIssued: null,
+      lastPaymentAmount: null,
+      monetaryStatus: '',
+    },
+    hasCertificationWeeksAvailable: false,
+    hasPendingWeeks: false,
+    pendingDetermination: [],
+  }
+
+  try {
+    assert.notStrictEqual(responseUniqueNumber, null, 'Response is null')
+    assert.notDeepStrictEqual(response, nullishResponse, 'Response is null')
+  } catch {
+    return true
+  }
+
+  return false
+}
+
 /**
  * Returns results from API Gateway
  */
@@ -180,7 +221,8 @@ export default async function queryApiGateway(req: IncomingMessage, uniqueNumber
     throw error
   }
 
-  if (apiData?.uniqueNumber !== uniqueNumber) {
+  // Yell real loud if the API returns a different, non-null uniqueNumber
+  if (apiData?.uniqueNumber && apiData?.uniqueNumber !== uniqueNumber) {
     const mismatchError = new Error(
       `Mismatched API response and Header unique number (${apiData.uniqueNumber || 'null'} and ${uniqueNumber})`,
     )
@@ -189,5 +231,17 @@ export default async function queryApiGateway(req: IncomingMessage, uniqueNumber
     throw mismatchError
   }
 
+  // Yell if the API returns a null or null-ish response
+  if (reponseIsNullish(apiData)) {
+    const nullResponseError = new Error(
+      `API responded with a null response (queried with ${uniqueNumber}, responded with ${
+        apiData.uniqueNumber || 'null'
+      })`,
+    )
+    const logger: Logger = Logger.getInstance()
+    logger.log('error', nullResponseError, 'Unexpected API gateway response')
+    throw nullResponseError
+  }
+
   return apiData
 }