Cap feed entries with configurable limit

Author: clementbiron

config/default.json

@@ -47,6 +47,11 @@
     },
     "dataset": {
       "publishingSchedule": "30 8 * * MON"
+    },
+    "collection-api": {
+      "feed": {
+        "limit": 100
+      }
     }
   }
 }

config/test.json

@@ -47,7 +47,10 @@
     },
     "collection-api": {
       "port": 3000,
-      "basePath": "/collection-api"
+      "basePath": "/collection-api",
+      "feed": {
+        "limit": 3
+      }
     }
   }
 }

src/collection-api/routes/feed.js

@@ -1,3 +1,4 @@
+import config from 'config';
 import express from 'express';
 import { js2xml } from 'xml-js';
 
@@ -12,6 +13,14 @@ const TAG_AUTHORITY = 'opentermsarchive.org,2026';
 const FEED_AUTHOR_NAME = 'OTA-Bot';
 const DEFAULT_LIMIT = 100;
 
+function getFeedLimit() {
+  if (config.has('@opentermsarchive/engine.collection-api.feed.limit')) {
+    return config.get('@opentermsarchive/engine.collection-api.feed.limit');
+  }
+
+  return DEFAULT_LIMIT;
+}
+
 const RECORD_TYPES = {
   firstRecord: 'First record',
   technicalUpgrade: 'Technical upgrade',
@@ -129,7 +138,7 @@ export default function feedRouter(services) {
    *       - application/atom+xml
    *     responses:
    *       200:
-   *         description: An Atom 1.0 feed listing the latest version records, newest first.
+   *         description: An Atom 1.0 feed listing the latest version records, newest first. The maximum number of entries is server-configured.
    *         content:
    *           application/atom+xml:
    *             schema:
@@ -141,7 +150,7 @@ export default function feedRouter(services) {
     const selfHref = `${baseUrl}/feed`;
     const feedId = `tag:${TAG_AUTHORITY}:feed:${collection.metadata?.id}`;
 
-    const versions = await versionsRepository.findRecent(DEFAULT_LIMIT);
+    const versions = await versionsRepository.findRecent(getFeedLimit());
     const document = buildFeedDocument({ collection, selfHref, feedId, versions, baseUrl });
 
     sendAtom(res, render(document));
@@ -184,7 +193,7 @@ export default function feedRouter(services) {
     const selfHref = `${baseUrl}/feed/${encodeURIComponent(service.id)}`;
     const feedId = `tag:${TAG_AUTHORITY}:feed:${collection.metadata?.id}:${service.id}`;
 
-    const versions = await versionsRepository.findRecent(DEFAULT_LIMIT, { serviceId: service.id });
+    const versions = await versionsRepository.findRecent(getFeedLimit(), { serviceId: service.id });
     const document = buildFeedDocument({ collection, selfHref, feedId, versions, baseUrl });
 
     return sendAtom(res, render(document));
@@ -239,7 +248,7 @@ export default function feedRouter(services) {
     const selfHref = `${baseUrl}/feed/${encodeURIComponent(service.id)}/${encodeURIComponent(termsType)}`;
     const feedId = `tag:${TAG_AUTHORITY}:feed:${collection.metadata?.id}:${service.id}:${termsType}`;
 
-    const versions = await versionsRepository.findRecent(DEFAULT_LIMIT, { serviceId: service.id, termsType });
+    const versions = await versionsRepository.findRecent(getFeedLimit(), { serviceId: service.id, termsType });
     const document = buildFeedDocument({ collection, selfHref, feedId, versions, baseUrl });
 
     return sendAtom(res, render(document));

src/collection-api/routes/feed.test.js

@@ -132,6 +132,13 @@ describe('Feed API', () => {
 
     after(() => repository.removeAll());
 
+    it('lists one entry per saved version up to the configured limit', () => {
+      const limit = config.get('@opentermsarchive/engine.collection-api.feed.limit');
+      const entries = response.text.match(/<entry>/g) || [];
+
+      expect(entries).to.have.length(Math.min(4, limit));
+    });
+
     it('orders entries newest-first', () => {
       const updates = [...response.text.matchAll(/<entry>[\s\S]*?<updated>([^<]+)<\/updated>[\s\S]*?<\/entry>/g)].map(match => match[1]);
 
@@ -227,6 +234,15 @@ describe('Feed API', () => {
         expect(entry).to.match(/term="Technical upgrade"/);
       });
     });
+
+    describe('configurable limit', () => {
+      it('returns at most the configured number of entries', () => {
+        const limit = config.get('@opentermsarchive/engine.collection-api.feed.limit');
+        const entries = response.text.match(/<entry>/g) || [];
+
+        expect(entries.length).to.be.at.most(limit);
+      });
+    });
   });
 
   describe('GET /feed/:serviceId', () => {