fix: respect x-source-last-modified for json

src/json-pipe.js

@@ -13,7 +13,7 @@ import fetchMetadata from './steps/fetch-metadata.js';
 import setCustomResponseHeaders from './steps/set-custom-response-headers.js';
 import { PipelineResponse } from './PipelineResponse.js';
 import jsonFilter from './utils/json-filter.js';
-import { updateLastModified } from './utils/last-modified.js';
+import { extractLastModified, updateLastModified } from './utils/last-modified.js';
 
 /**
  * Runs the default pipeline and returns the response.
@@ -73,7 +73,7 @@ export async function jsonPipe(state, req) {
   });
 
   // set last-modified
-  updateLastModified(state, response, dataResponse.headers.get('last-modified'));
+  updateLastModified(state, response, extractLastModified(dataResponse.headers));
 
   // set surrogate key
   response.headers.set('x-surrogate-key', `${contentBusId}${path}`.replace(/\//g, '_'));

src/steps/fetch-metadata.js

@@ -39,8 +39,8 @@ export default async function fetchMetadata(state, req, res) {
     }
     state.metadata = data;
 
-    if (state.type === 'html') {
-      // also update last-modified (only for html pipeline)
+    if (state.type === 'html' && state.info.selector !== 'plain') {
+      // also update last-modified (only for extensionless html pipeline)
       updateLastModified(state, res, extractLastModified(ret.headers));
     }
     return;

src/utils/last-modified.js

@@ -41,7 +41,8 @@ export function updateLastModified(state, res, httpDate) {
 /**
  * Returns the last modified date from response headers, giving 'x-amz-meta-x-source-last-modified'
  * preference.
- * @param {object} headers
+ * @param {Map<string, string>} headers
+ * @return {string} the last modified date
  */
 export function extractLastModified(headers) {
   return headers.get('x-amz-meta-x-source-last-modified') ?? headers.get('last-modified');

test/json-pipe.test.js

@@ -162,6 +162,38 @@ describe('JSON Pipe Test', () => {
     });
   });
 
+  it('prefers x-source-last-modified', async () => {
+    const state = createDefaultState();
+    state.s3Loader.reply(
+      'helix-content-bus',
+      'foobar/preview/en/index.json',
+      new PipelineResponse(TEST_SINGLE_SHEET, {
+        headers: {
+          'content-type': 'application/json',
+          'x-amz-meta-x-source-location': 'foo-bar',
+          'last-modified': 'Wed, 12 Oct 2009 17:50:00 GMT',
+          'x-amz-meta-x-source-last-modified': 'Wed, 12 Oct 2009 15:50:00 GMT',
+        },
+      }),
+    );
+
+    const resp = await jsonPipe(state, new PipelineRequest('https://json-filter.com/?limit=10&offset=5'));
+    assert.strictEqual(resp.status, 200);
+    assert.deepStrictEqual(await resp.json(), {
+      ':type': 'sheet',
+      offset: 5,
+      limit: 10,
+      total: TEST_DATA.length,
+      data: TEST_DATA.slice(5, 15),
+    });
+    const headers = Object.fromEntries(resp.headers.entries());
+    assert.deepStrictEqual(headers, {
+      'last-modified': 'Wed, 12 Oct 2009 15:50:00 GMT',
+      'x-surrogate-key': 'foobar_en_index.json',
+      'content-type': 'application/json',
+    });
+  });
+
   it('falls back to code bus if content is not found', async () => {
     const state = new PipelineState({
       path: '/en/index.json',

test/rendering.test.js

@@ -395,6 +395,21 @@ describe('Rendering', () => {
       });
     });
 
+    it('ignores last modified from metadata.json for plain', async () => {
+      loader
+        .headers('helix-config.json', 'x-amz-meta-x-source-last-modified', 'Wed, 12 Oct 2009 11:50:00 GMT')
+        .headers('one-section.md', 'x-amz-meta-x-source-last-modified', 'Wed, 12 Oct 2022 12:50:00 GMT')
+        .headers('metadata.json', 'x-amz-meta-x-source-last-modified', 'Wed, 12 Oct 2022 15:33:01 GMT');
+      const { status, body, headers } = await render(new URL('https://helix-pipeline.com/blog/one-section'), '.plain');
+      assert.strictEqual(status, 200);
+      assert.match(body, /<div class="test"><h1 id="hello">Hello<\/h1><p>This is the first section.<\/p><\/div>/);
+      assert.deepStrictEqual(Object.fromEntries(headers.entries()), {
+        'content-type': 'text/html; charset=utf-8',
+        'x-surrogate-key': '0j8f6rmY3lU5kgOE',
+        'last-modified': 'Wed, 12 Oct 2022 12:50:00 GMT',
+      });
+    });
+
     it('uses response headers from metadata.json', async () => {
       loader.rewrite('metadata.json', 'metadata-headers.json');
       const { headers } = await testRender('meta-response-headers', 'head');