Merge pull request #15 from bbc/swr-refresh

Task: do not cache 5xx for SWR
bbc · May 14, 2018 · a9fb8d1 · a9fb8d1
2 parents 5eb8624 + 84e5e27
commit a9fb8d1
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diff --git a/lib/maxAge.js b/lib/maxAge.js
@@ -31,6 +31,10 @@ function revalidate(cached, url, cache, opts) {
 
       bluebird.resolve(refresh(url))
         .then((res) => {
+          if (res.statusCode >= 500) {
+            throw new Error(`Failed to refresh ${url}, got status ${res.statusCode}`);
+          }
+
           storeInCache(cache, SEGMENT, url, res.toJSON(), getMaxAge(res));
         })
         .catch(() => { })

diff --git a/test/maxAge.js b/test/maxAge.js
@@ -304,6 +304,38 @@ describe('Max-Age', () => {
       assert.equal(cached.item.body, 'We ALL love jonty');
     });
 
+    it('does not update cache for failed requests', async () => {
+      const cache = createCache();
+      const refreshClient = httpTransport.createClient();
+
+      const maxage = 1;
+      const swr = maxage * 2;
+      const responseHeaders = { 'cache-control': `max-age=${maxage},stale-while-revalidate=${swr}` };
+
+      api
+        .get('/')
+        .reply(200, 'First Response', responseHeaders);
+
+      api
+        .get('/')
+        .reply(500, 'Second Response', responseHeaders);
+
+      const opts = {
+        'staleWhileRevalidate': true,
+        refresh: () => {
+          return refreshClient.get('http://www.example.com/').asResponse();
+        }
+      };
+
+      await requestWithCache(cache, opts);
+      await bluebird.delay((maxage * 1000));
+      await requestWithCache(cache, opts);
+      await bluebird.delay(100);
+
+      const cached = await cache.get(bodySegment);
+      assert.equal(cached.item.body, 'First Response');
+    });
+
     it('does not revalidate for PUT requests', async () => {
       assertGetOnly('put');
     });