feat(utils): add cache-utils for merging cache-control headers

src/html/data-sections.js

@@ -17,6 +17,7 @@ const {
 } = require('ferrum');
 const removePosition = require('unist-util-remove-position');
 const dotprop = require('dot-prop');
+const { merge } = require('../utils/cache-helper');
 
 const pattern = /{{([^{}]+)}}/g;
 /**
@@ -158,9 +159,17 @@ async function fillDataSections(context, { downloader, logger }) {
 
           // remember that we are using this source so that we can compute the
           // surrogate key later
-
           setdefault(context.content, 'sources', []);
           context.content.sources.push(node.url);
+
+          // pass the cache control header through
+          const res = setdefault(context, 'response', {});
+          const headers = setdefault(res, 'headers', {});
+
+          headers['Cache-Control'] = merge(
+            headers['Cache-Control'],
+            downloadeddata.headers.get('cache-control'),
+          );
         } catch (e) {
           logger.warn(`Unable to parse JSON for data embed ${node.url}: ${e.message}`);
           return node;

src/utils/cache-helper.js

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2020 Adobe. All rights reserved.
+ * This file is licensed to you 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 REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+function directives(expression = '') {
+  const retval = expression.split(',')
+    .map((s) => s.trim())
+    .filter((s) => !!s)
+    .map((s) => s.split('='))
+    .map(([
+      directive,
+      value]) => [directive, Number.isNaN(Number.parseInt(value, 10))
+      ? true
+      : Number.parseInt(value, 10)])
+    .reduce((obj, [directive, value]) => {
+      obj[directive] = value;
+      return obj;
+    }, {});
+  return retval;
+}
+
+function format(dirs = {}) {
+  return Object.entries(dirs)
+    .map(([directive, value]) => ((value === true || value === 1) ? directive : `${directive}=${value}`))
+    .join(', ');
+}
+
+function merge(in1 = '', in2 = '') {
+  const dirs1 = typeof in1 === 'string' ? directives(in1) : in1;
+  const dirs2 = typeof in2 === 'string' ? directives(in2) : in2;
+
+  const keys = [...Object.keys(dirs1), ...Object.keys(dirs2)];
+
+  const mergeval = keys.reduce((merged, key) => {
+    merged[key] = Math.min(
+      dirs1[key] || Number.MAX_SAFE_INTEGER,
+      dirs2[key] || Number.MAX_SAFE_INTEGER,
+    );
+    return merged;
+  }, {});
+
+  return typeof in1 === 'string' ? format(mergeval) : mergeval;
+}
+
+module.exports = { directives, format, merge };

test/testCacheHelper.js

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2020 Adobe. All rights reserved.
+ * This file is licensed to you 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 REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+/* eslint-env mocha */
+const assert = require('assert');
+const { directives, format, merge } = require('../src/utils/cache-helper');
+
+describe('Cache Helper Tests (surrogate)', () => {
+  it('directive parses directives', () => {
+    assert.deepStrictEqual(directives('max-age=300'), {
+      'max-age': 300,
+    });
+
+    assert.deepStrictEqual(directives('s-maxage=300,  max-age=300'), {
+      's-maxage': 300,
+      'max-age': 300,
+    });
+
+    assert.deepStrictEqual(directives('s-maxage=300,  max-age=300, public'), {
+      's-maxage': 300,
+      'max-age': 300,
+      public: true,
+    });
+
+    assert.deepStrictEqual(directives(''), {});
+
+    assert.deepStrictEqual(directives(), {});
+  });
+
+  it('format formats directives', () => {
+    assert.equal(format({}), '');
+    assert.equal(format(undefined), '');
+
+    assert.equal(format({
+      'max-age': 300,
+      public: true,
+    }), 'max-age=300, public');
+  });
+
+  it('merge merges two directives', () => {
+    assert.deepEqual(merge({}, {}), {});
+
+    assert.deepEqual(merge({
+      'max-age': 300,
+    }, {
+      's-maxage': 300,
+    }), {
+      's-maxage': 300,
+      'max-age': 300,
+    });
+
+    assert.deepEqual(merge({
+      'max-age': 300,
+      's-maxage': 600,
+    }, {
+      's-maxage': 300,
+      'max-age': 600,
+    }), {
+      's-maxage': 300,
+      'max-age': 300,
+    });
+
+    assert.deepEqual(merge({
+      public: true,
+    }, {
+      private: true,
+    }), {
+      public: true,
+      private: true,
+    });
+
+    assert.equal(merge('max-age=300, public', 'max-age=600'), 'max-age=300, public');
+
+    assert.equal(merge(), '');
+  });
+});

test/testDataEmbeds.js

@@ -104,6 +104,9 @@ describe('Integration Test with Data Embeds', () => {
       .reply(() => [404]);
 
     nock('https://adobeioruntime.net')
+      .defaultReplyHeaders({
+        'Cache-Control': 'max-age=3600',
+      })
       .get(/.*/)
       .reply(() => [status, data]);
 
@@ -125,7 +128,11 @@ describe('Integration Test with Data Embeds', () => {
 
     const result = await pipe(
       (mycontext) => {
-        mycontext.response = { status: 200, body: mycontext.content.document.body.innerHTML };
+        if (!mycontext.response) {
+          mycontext.response = {};
+        }
+        mycontext.response.status = 200;
+        mycontext.response.body = mycontext.content.document.body.innerHTML;
       },
       context,
       action,
@@ -213,6 +220,8 @@ https://docs.google.com/spreadsheets/d/e/someotheruri/pubhtml
 
     assert.equal(res1.response.headers['Surrogate-Key'], 'PbTcuh0tIarmUOZM');
     assert.equal(res2.response.headers['Surrogate-Key'], 'IkqgcxcG5+q8/cOT');
+
+    assert.equal(res1.response.headers['Cache-Control'], 'max-age=3600');
   });
 
   it('html.pipe processes data embeds in main document', async () => testEmbeds(