feat: Better handling of GovPay errors (#3654)

theopensystemslab · Sep 11, 2024 · ec024a8 · ec024a8
1 parent 579c7ba
commit ec024a8
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Showing 3 changed files with 105 additions and 47 deletions.
diff --git a/api.planx.uk/modules/pay/controller.ts b/api.planx.uk/modules/pay/controller.ts
@@ -1,7 +1,7 @@
 import assert from "assert";
 import { Request } from "express";
 import { responseInterceptor } from "http-proxy-middleware";
-import { logPaymentStatus } from "./helpers.js";
+import { handleGovPayErrors, logPaymentStatus } from "./helpers.js";
 import { usePayProxy } from "./proxy.js";
 import { $api } from "../../client/index.js";
 import { ServerError } from "../../errors/index.js";
@@ -46,9 +46,12 @@ export const makePaymentViaProxy: PaymentProxyController = async (
       pathRewrite: (path) => path.replace(/^\/pay.*$/, ""),
       selfHandleResponse: true,
       onProxyRes: responseInterceptor(
-        async (responseBuffer, _proxyRes, _req, _res) => {
+        async (responseBuffer, _proxyRes, _req, { statusCode }) => {
           const responseString = responseBuffer.toString("utf8");
           const govUkResponse = JSON.parse(responseString);
+
+          if (statusCode >= 400) return handleGovPayErrors(govUkResponse);
+
           await logPaymentStatus({
             sessionId,
             flowId,
@@ -79,27 +82,32 @@ export const makeInviteToPayPaymentViaProxy: PaymentRequestProxyController = (
     {
       pathRewrite: (path) => path.replace(/^\/pay.*$/, ""),
       selfHandleResponse: true,
-      onProxyRes: responseInterceptor(async (responseBuffer) => {
-        const responseString = responseBuffer.toString("utf8");
-        const govUkResponse = JSON.parse(responseString);
-        await logPaymentStatus({
-          sessionId,
-          flowId,
-          teamSlug,
-          govUkResponse,
-        });
-
-        try {
-          await addGovPayPaymentIdToPaymentRequest(
-            paymentRequestId,
+      onProxyRes: responseInterceptor(
+        async (responseBuffer, _proxyRes, _req, { statusCode }) => {
+          const responseString = responseBuffer.toString("utf8");
+          const govUkResponse = JSON.parse(responseString);
+
+          if (statusCode >= 400) return handleGovPayErrors(govUkResponse);
+
+          await logPaymentStatus({
+            sessionId,
+            flowId,
+            teamSlug,
             govUkResponse,
-          );
-        } catch (error) {
-          throw Error(error as string);
-        }
+          });
 
-        return responseBuffer;
-      }),
+          try {
+            await addGovPayPaymentIdToPaymentRequest(
+              paymentRequestId,
+              govUkResponse,
+            );
+          } catch (error) {
+            throw Error(error as string);
+          }
+
+          return responseBuffer;
+        },
+      ),
     },
     req,
     res,
@@ -125,32 +133,36 @@ export function fetchPaymentViaProxyWithCallback(
       {
         pathRewrite: () => `/${req.params.paymentId}`,
         selfHandleResponse: true,
-        onProxyRes: responseInterceptor(async (responseBuffer) => {
-          const govUkResponse = JSON.parse(responseBuffer.toString("utf8"));
-
-          await logPaymentStatus({
-            sessionId,
-            flowId,
-            teamSlug,
-            govUkResponse,
-          });
-
-          try {
-            await callback(req, govUkResponse);
-          } catch (e) {
-            throw Error(e as string);
-          }
-
-          // only return payment status, filter out PII
-          return JSON.stringify({
-            payment_id: govUkResponse.payment_id,
-            amount: govUkResponse.amount,
-            state: govUkResponse.state,
-            _links: {
-              next_url: govUkResponse._links?.next_url,
-            },
-          });
-        }),
+        onProxyRes: responseInterceptor(
+          async (responseBuffer, _proxyRes, _req, { statusCode }) => {
+            const govUkResponse = JSON.parse(responseBuffer.toString("utf8"));
+
+            if (statusCode >= 400) return handleGovPayErrors(govUkResponse);
+
+            await logPaymentStatus({
+              sessionId,
+              flowId,
+              teamSlug,
+              govUkResponse,
+            });
+
+            try {
+              await callback(req, govUkResponse);
+            } catch (e) {
+              throw Error(e as string);
+            }
+
+            // only return payment status, filter out PII
+            return JSON.stringify({
+              payment_id: govUkResponse.payment_id,
+              amount: govUkResponse.amount,
+              state: govUkResponse.state,
+              _links: {
+                next_url: govUkResponse._links?.next_url,
+              },
+            });
+          },
+        ),
       },
       req,
       res,

diff --git a/api.planx.uk/modules/pay/helpers.ts b/api.planx.uk/modules/pay/helpers.ts
@@ -2,6 +2,17 @@ import { gql } from "graphql-request";
 import airbrake from "../../airbrake.js";
 import { $api } from "../../client/index.js";
 
+/**
+ * Gracefully handle GovPay errors
+ * Docs: https://docs.payments.service.gov.uk/api_reference/#responses
+ */
+export const handleGovPayErrors = (res: unknown) =>
+  JSON.stringify({
+    message:
+      "GovPay responded with an error when attempting to proxy to their API",
+    govPayResponse: res,
+  });
+
 export async function logPaymentStatus({
   sessionId,
   flowId,

diff --git a/api.planx.uk/modules/pay/index.test.ts b/api.planx.uk/modules/pay/index.test.ts
@@ -168,3 +168,38 @@ describe("fetching status of a GOV.UK payment", () => {
       });
   });
 });
+
+test("handling GovPay error responses", async () => {
+  const govUKErrorResponse = {
+    code: "govUKErrorResponse",
+    description:
+      "Account is not fully configured. Please refer to documentation to setup your account or contact support with your error code - https://www.payments.service.gov.uk/support/ .",
+  };
+
+  nock("https://publicapi.payments.service.gov.uk/v1/payments")
+    .post("")
+    .reply(400, govUKErrorResponse);
+
+  await supertest(app)
+    .post(
+      "/pay/southwark?flowId=7cd1c4b4-4229-424f-8d04-c9fdc958ef4e&sessionId=f2d8ca1d-a43b-43ec-b3d9-a9fec63ff19c",
+    )
+    .send({
+      amount: 100,
+      reference: "12343543",
+      description: "New application",
+      return_url: "https://editor.planx.uk",
+      metadata: {
+        source: "PlanX",
+        flow: "apply-for-a-lawful-development-certificate",
+        inviteToPay: false,
+      },
+    })
+    .expect(400)
+    .then((res) => {
+      expect(res.body.message).toMatch(
+        /GovPay responded with an error when attempting to proxy to their API/,
+      );
+      expect(res.body.govPayResponse).toEqual(govUKErrorResponse);
+    });
+});