Issue 4359 pretty print response

packages/integration-testsuite/src/httpServerTests.ts

@@ -18,6 +18,7 @@ import {
   GraphQLSchema,
   GraphQLString,
   type ValidationContext,
+  type FormattedExecutionResult,
 } from 'graphql';
 import gql from 'graphql-tag';
 import {
@@ -2060,6 +2061,31 @@ export function defineIntegrationTestSuiteHttpServerTests(
           expect(res.body.errors[0].message).toEqual(expected);
         });
       });
+
+      it('uses stringifyResult parameter', async () => {
+        const app = await createApp({
+          schema,
+          stringifyResult: (value: FormattedExecutionResult) => {
+            let result = JSON.stringify(value, null, 1); // stringify, with line-breaks and indents
+            result = result.replace('it works', 'stringifyResults works!'); // replace text with something custom
+            return result;
+          },
+        });
+        const expected = {
+          testString: 'stringifyResults works!',
+        };
+        const query = {
+          query: 'query test{ testString }',
+        };
+        const req = request(app)
+          .get('/')
+          .set('apollo-require-preflight', 't')
+          .query(query);
+        return req.then((res) => {
+          expect(res.status).toEqual(200);
+          expect(res.body.data).toEqual(expected);
+        });
+      });
     });
 
     if (options.serverIsStartedInBackground) {

packages/server/src/ApolloServer.ts

@@ -15,6 +15,7 @@ import {
   type TypedQueryDocumentNode,
   type ValidationContext,
   type ValidationRule,
+  type FormattedExecutionResult,
 } from 'graphql';
 import {
   type KeyValueCache,
@@ -179,6 +180,7 @@ export interface ApolloServerInternals<TContext extends BaseContext> {
   // flip default behavior.
   status400ForVariableCoercionErrors?: boolean;
   __testing_incrementalExecutionResults?: GraphQLExperimentalIncrementalExecutionResults;
+  stringifyResult?: (value: FormattedExecutionResult) => string;
 }
 
 function defaultLogger(): Logger {
@@ -332,6 +334,7 @@ export class ApolloServer<in out TContext extends BaseContext = BaseContext> {
         config.status400ForVariableCoercionErrors ?? false,
       __testing_incrementalExecutionResults:
         config.__testing_incrementalExecutionResults,
+      stringifyResult: config.stringifyResult,
     };
   }
 

packages/server/src/externalTypes/constructor.ts

@@ -8,6 +8,7 @@ import type { Logger } from '@apollo/utils.logger';
 import type { IExecutableSchemaDefinition } from '@graphql-tools/schema';
 import type {
   DocumentNode,
+  FormattedExecutionResult,
   GraphQLFieldResolver,
   GraphQLFormattedError,
   GraphQLSchema,
@@ -88,7 +89,7 @@ interface ApolloServerOptionsBase<TContext extends BaseContext> {
   includeStacktraceInErrorResponses?: boolean;
   logger?: Logger;
   allowBatchedHttpRequests?: boolean;
-
+  stringifyResult?: (value: FormattedExecutionResult) => string;
   introspection?: boolean;
   plugins?: ApolloServerPlugin<TContext>[];
   persistedQueries?: PersistedQueryOptions | false;

packages/server/src/runHttpQuery.ts

@@ -260,9 +260,11 @@ export async function runHttpQuery<TContext extends BaseContext>({
       ...graphQLResponse.http,
       body: {
         kind: 'complete',
-        string: prettyJSONStringify(
-          orderExecutionResultFields(graphQLResponse.body.singleResult),
-        ),
+        string: internals.stringifyResult
+          ? internals.stringifyResult(graphQLResponse.body.singleResult)
+          : prettyJSONStringify(
+              orderExecutionResultFields(graphQLResponse.body.singleResult),
+            ),
       },
     };
   }