catalog-backend: moved createEntityArrayJsonStream to response utils

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

plugins/catalog-backend/src/service/createRouter.ts

@@ -41,7 +41,6 @@ import { parseEntityFacetParams } from './request/parseEntityFacetParams';
 import { parseEntityOrderParams } from './request/parseEntityOrderParams';
 import { LocationService, RefreshService } from './types';
 import {
-  createEntityArrayJsonStream,
   disallowReadonlyMode,
   encodeCursor,
   expandLegacyCompoundRelationsInEntity,
@@ -61,6 +60,7 @@ import { LocationAnalyzer } from '@backstage/plugin-catalog-node';
 import { AuthorizedValidationService } from './AuthorizedValidationService';
 import { DeferredPromise, createDeferred } from '@backstage/types';
 import {
+  createEntityArrayJsonStream,
   processEntitiesResponseItems,
   writeEntitiesResponse,
   writeSingleEntityResponse,

plugins/catalog-backend/src/service/response/createEntityArrayJsonStream.ts

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2024 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { EntitiesResponseItems } from '../../catalog/types';
+import { Response } from 'express';
+
+export interface EntityArrayJsonStream {
+  send(entities: EntitiesResponseItems): boolean;
+  complete(): void;
+  close(): void;
+}
+
+// Helps stream EntitiesResponseItems[] as a JSON response stream to avoid performance issues
+export function createEntityArrayJsonStream(
+  res: Response,
+): EntityArrayJsonStream {
+  // Imitate the httpRouter behavior of pretty-printing in development
+  const prettyPrint = process.env.NODE_ENV === 'development';
+  let firstSend = true;
+  let completed = false;
+
+  return {
+    send(response) {
+      if (firstSend) {
+        res.setHeader('Content-Type', 'application/json; charset=utf-8');
+        res.status(200);
+        res.flushHeaders();
+      }
+
+      if (response.type === 'raw') {
+        let needsDrain = false;
+        for (const item of response.entities) {
+          const prefix = firstSend ? '[' : ',';
+          firstSend = false;
+          needsDrain ||= !res.write(prefix + item, 'utf8');
+        }
+        return !needsDrain;
+      }
+
+      let data: string;
+      if (prettyPrint) {
+        data = JSON.stringify(response.entities, null, 2);
+        data = firstSend ? data.slice(0, -2) : `,\n${data.slice(2, -2)}`;
+      } else {
+        data = JSON.stringify(response.entities);
+        data = firstSend ? data.slice(0, -1) : `,${data.slice(1, -1)}`;
+      }
+
+      firstSend = false;
+      return res.write(data, 'utf8');
+    },
+    complete() {
+      if (firstSend) {
+        res.json([]);
+      } else {
+        res.end(prettyPrint ? '\n]' : ']', 'utf8');
+      }
+      completed = true;
+    },
+    close() {
+      if (!completed) {
+        res.end();
+      }
+    },
+  };
+}

plugins/catalog-backend/src/service/response/index.ts

@@ -20,3 +20,4 @@ export {
   entitiesResponseToObjects,
 } from './process';
 export { writeSingleEntityResponse, writeEntitiesResponse } from './write';
+export { createEntityArrayJsonStream } from './createEntityArrayJsonStream';

plugins/catalog-backend/src/service/util.ts

@@ -15,12 +15,11 @@
  */
 
 import { InputError, NotAllowedError } from '@backstage/errors';
-import { Request, Response } from 'express';
+import { Request } from 'express';
 import lodash from 'lodash';
 import { z } from 'zod';
 import {
   Cursor,
-  EntitiesResponseItems,
   QueryEntitiesCursorRequest,
   QueryEntitiesInitialRequest,
   QueryEntitiesRequest,
@@ -167,64 +166,3 @@ export function expandLegacyCompoundRelationsInEntity(entity: Entity): Entity {
   }
   return entity;
 }
-
-export interface EntityArrayJsonStream {
-  send(entities: EntitiesResponseItems): boolean;
-  complete(): void;
-  close(): void;
-}
-
-// Helps stream EntitiesResponseItems[] as a JSON response stream to avoid performance issues
-export function createEntityArrayJsonStream(
-  res: Response,
-): EntityArrayJsonStream {
-  // Imitate the httpRouter behavior of pretty-printing in development
-  const prettyPrint = process.env.NODE_ENV === 'development';
-  let firstSend = true;
-  let completed = false;
-
-  return {
-    send(response) {
-      if (firstSend) {
-        res.setHeader('Content-Type', 'application/json; charset=utf-8');
-        res.status(200);
-        res.flushHeaders();
-      }
-
-      if (response.type === 'raw') {
-        let needsDrain = false;
-        for (const item of response.entities) {
-          const prefix = firstSend ? '[' : ',';
-          firstSend = false;
-          needsDrain ||= !res.write(prefix + item, 'utf8');
-        }
-        return !needsDrain;
-      }
-
-      let data: string;
-      if (prettyPrint) {
-        data = JSON.stringify(response.entities, null, 2);
-        data = firstSend ? data.slice(0, -2) : `,\n${data.slice(2, -2)}`;
-      } else {
-        data = JSON.stringify(response.entities);
-        data = firstSend ? data.slice(0, -1) : `,${data.slice(1, -1)}`;
-      }
-
-      firstSend = false;
-      return res.write(data, 'utf8');
-    },
-    complete() {
-      if (firstSend) {
-        res.json([]);
-      } else {
-        res.end(prettyPrint ? '\n]' : ']', 'utf8');
-      }
-      completed = true;
-    },
-    close() {
-      if (!completed) {
-        res.end();
-      }
-    },
-  };
-}