flashheart - npm Package Compare versions

Comparing version 2.7.1 to 2.8.0

lib/cachingClient.js

@@ -8,2 +8,3 @@ var _ = require('lodash');
   this.cache = opts.cache;
+  this.staleIfError = opts.staleIfError;
   this.doNotVary = opts.doNotVary || [];
@@ -16,3 +17,6 @@ }
   if (cacheControl) {
-    return !cacheControl['no-cache'] && !cacheControl.private && cacheControl['max-age'] > 0;
+    const hasMaxAge = cacheControl['max-age'] > 0;
+    const hasStaleIfError = cacheControl['stale-if-error'] > 0;
+
+    return !cacheControl['no-cache'] && !cacheControl.private && (hasMaxAge || hasStaleIfError);
   }
@@ -23,13 +27,20 @@
 
-function getMaxAge(res) {
-  var maxAge = -1;
+function getCacheTime(res, directive) {
   var cacheControl = getCacheControl(res);
 
   if (cacheControl) {
-    maxAge = (cacheControl['max-age'] || 0) * 1000;
+    return (cacheControl[directive] || 0) * 1000;
   }
 
-  return maxAge;
+  return -1;
 }
 
+function getMaxAge(res) {
+  return getCacheTime(res, 'max-age');
+}
+
+function getStaleIfError(res) {
+  return getCacheTime(res, 'stale-if-error');
+}
+
 function getCacheControl(res) {
@@ -66,2 +77,6 @@ var cacheControl = res.headers['cache-control'];
 
+function createStaleKeyObject(url, opts, doNotVary) {
+  return _.extend({}, createKeyObject(url, opts, doNotVary), { stale: true });
+}
+
 CachingClient.prototype.get = function (url, opts, cb) {
@@ -80,5 +95,7 @@ if (typeof opts === 'function') {
     var maxAge;
+    var staleIfError;
 
     if (!servedFromCache && res && isCacheable(res)) {
       maxAge = getMaxAge(res);
+      staleIfError = getStaleIfError(res);
       cachedObject = {};
@@ -101,3 +118,9 @@
 
-      cache.set(createKeyObject(url, opts, doNotVary), cachedObject, maxAge, client._handleCacheError.bind(client));
+      if (maxAge) {
+        cache.set(createKeyObject(url, opts, doNotVary), cachedObject, maxAge, client._handleCacheError.bind(client));
+      }
+
+      if (client.staleIfError && staleIfError) {
+        cache.set(createStaleKeyObject(url, opts, doNotVary), cachedObject, staleIfError, client._handleCacheError.bind(client));
+      }
     }
@@ -109,2 +132,12 @@
 
+function createErrorFromCache(cachedError) {
+  var err = new Error(cachedError.message);
+
+  err.statusCode = cachedError.statusCode;
+  err.body = cachedError.body;
+  err.headers = cachedError.headers;
+
+  return err;
+}
+
 CachingClient.prototype._getCachedOrFetch = function (url, opts, cb) {
@@ -120,3 +153,2 @@ var client = this;
     var cacheHit = cached && cached.item && (cached.item.body || cached.item.error);
-    var cachedError;
 
@@ -127,7 +159,3 @@ if (cacheHit) {
       if (cached.item.error) {
-        cachedError = cached.item.error;
-        err = new Error(cachedError.message);
-        err.statusCode = cachedError.statusCode;
-        err.body = cachedError.body;
-        err.headers = cachedError.headers;
+        err = createErrorFromCache(cached.item.error);
       }
@@ -140,3 +168,17 @@
 
-    delegate.getWithResponse(url, opts, cb);
+    delegate.getWithResponse(url, opts, function (err, body, res) {
+      if (err && client.staleIfError) {
+        var originalErr = err;
+
+        return cache.get(createStaleKeyObject(url, opts, doNotVary), function (err, cached) {
+          if (err) client._handleCacheError(err);
+          if (!cached) return cb(originalErr, body, res);
+          if (delegate.stats) delegate.stats.increment(delegate.name + '.cache.stale');
+
+          cb(err, cached.item.body, cached.item.response, true);
+        });
+      }
+
+      cb(err, body, res);
+    });
   });
@@ -143,0 +185,0 @@ };

package.json

 {
   "name": "flashheart",
-  "version": "2.7.1",
+  "version": "2.8.0",
   "description": "A fully-featured REST client built for ease-of-use and resilience",
@@ -5,0 +5,0 @@ "main": "index.js",

README.md

@@ -90,2 +90,17 @@ # flashheart
 
+Optionally, you can enable `staleIfError` which will start listening to the `stale-if-error` directive as well. This stores the response for the duration of the `stale-if-error` directive as well as the `max-age` and will try to retrieve them in this order:
+
+* `max-age` stored version
+* fresh version
+* `stale-if-error` version
+
+This is enabled simply by passing in the `staleIfError` parameter to `createClient`:
+
+```js
+const client = require('flashheart').createClient({
+  cache: storage,
+  staleIfError: true
+});
+```
+
 The cache varies on _all_ request options (and therefore, headers) by default. If you don't want to vary on a particular header, use the `doNotVary` option:
@@ -92,0 +107,0 @@

test/caching.js

@@ -19,3 +19,3 @@ var async = require('async');
   headers: {
-    'cache-control': 'max-age=60',
+    'cache-control': 'max-age=60,stale-if-error=7200',
     'content-type': 'application/json'
@@ -30,6 +30,7 @@ },
   var client;
+  var staleClient;
   var catbox;
 
   var headers = {
-    'cache-control': 'max-age=60'
+    'cache-control': 'max-age=60,stale-if-error=7200'
   };
@@ -42,2 +43,8 @@
 
+  var expectedStaleKey = {
+    segment: 'flashheart:' + require('../package').version,
+    id: url,
+    stale: true
+  };
+
   beforeEach(function () {
@@ -66,2 +73,9 @@ nock.cleanAll();
     });
+    staleClient = Client.createClient({
+      cache: catbox,
+      stats: stats,
+      logger: logger,
+      retries: 0,
+      staleIfError: true
+    });
   });
@@ -80,2 +94,13 @@
 
+  it('caches the stale value if stale-if-error is set', function (done) {
+    staleClient.get(url, function (err) {
+      assert.ifError(err);
+      sinon.assert.calledWith(catbox.set, expectedStaleKey, {
+        body: responseBody,
+        response: expectedCachedResponse
+      }, 7200000);
+      done();
+    });
+  });
+
   it('returns the response from the cache if it exists', function (done) {
@@ -136,2 +161,70 @@ var cachedResponseBody = {
 
+  it('attempts to serve stale if error received and staleIfError is enabled', function (done) {
+    var cachedResponseBody = {
+      foo: 'baz'
+    };
+    var errorResponseCode = 503;
+    var errorResponseBody = {
+      error: 'An error'
+    };
+    var errorHeaders = {
+      'cache-control': 'max-age=5',
+      'content-type': 'application/json',
+      'www-authenticate': 'Bearer realm="/"'
+    };
+
+    catbox.get.withArgs(expectedStaleKey).yields(null, {
+      item: {
+        body: cachedResponseBody,
+        response: expectedCachedResponse
+      }
+    });
+
+    nock.cleanAll();
+    api.get('/').reply(errorResponseCode, errorResponseBody, errorHeaders);
+
+    staleClient.get(url, function (err, body, res) {
+      assert.ifError(err);
+      assert.deepEqual(body, cachedResponseBody);
+      assert.deepEqual(res, expectedCachedResponse);
+      sinon.assert.notCalled(catbox.set);
+      sinon.assert.calledTwice(catbox.get);
+      done();
+    });
+  });
+
+  it('does not store stale cache if staleIfError is not enabled', function (done) {
+    client.get(url, function (err) {
+      assert.ifError(err);
+      sinon.assert.calledOnce(catbox.set);
+      sinon.assert.calledWith(catbox.set, expectedKey, {
+        body: responseBody,
+        response: expectedCachedResponse
+      }, 60000);
+      done();
+    });
+  });
+
+  it('does not read stale cache if staleIfError is not enabled', function (done) {
+    var errorResponseCode = 503;
+    var errorResponseBody = {
+      error: 'An error'
+    };
+    var errorHeaders = {
+      'cache-control': 'max-age=5',
+      'content-type': 'application/json',
+      'www-authenticate': 'Bearer realm="/"'
+    };
+
+    nock.cleanAll();
+    api.get('/').reply(errorResponseCode, errorResponseBody, errorHeaders);
+    client.get(url, function (err) {
+      assert.ok(err);
+      assert.equal(err.statusCode, 503);
+      sinon.assert.calledOnce(catbox.get);
+      sinon.assert.calledWith(catbox.get, expectedKey);
+      done();
+    });
+  });
+
   it('returns an error from the cache if it exists', function (done) {
@@ -292,2 +385,28 @@ var errorResponseBody = {
 
+  it('stores content for stale duration if staleIfError enabled and max-age value is zero', function (done) {
+    var headers = {
+      'cache-control': 'max-age=0,stale-if-error=7200'
+    };
+    var expectedCachedResponse = {
+      statusCode: 200,
+      headers: {
+        'cache-control': 'max-age=0,stale-if-error=7200',
+        'content-type': 'application/json'
+      },
+      elapsedTime: nockElapsedTime
+    };
+
+    nock.cleanAll();
+    api.get('/').reply(200, responseBody, headers);
+    staleClient.get(url, function (err) {
+      assert.ifError(err);
+      sinon.assert.calledOnce(catbox.set);
+      sinon.assert.calledWith(catbox.set, expectedStaleKey, {
+        body: responseBody,
+        response: expectedCachedResponse
+      }, 7200000);
+      done();
+    });
+  });
+
   it('does not cache the response if the max-age value is invalid', function (done) {
@@ -307,2 +426,28 @@ var headers = {
 
+  it('does not store a stale value if stale-if-error missing', function (done) {
+    var headers = {
+      'cache-control': 'max-age=60'
+    };
+    var expectedCachedResponse = {
+      statusCode: 200,
+      headers: {
+        'cache-control': 'max-age=60',
+        'content-type': 'application/json'
+      },
+      elapsedTime: nockElapsedTime
+    };
+
+    nock.cleanAll();
+    api.get('/').reply(200, responseBody, headers);
+    staleClient.get(url, function (err) {
+      assert.ifError(err);
+      sinon.assert.calledOnce(catbox.set);
+      sinon.assert.calledWith(catbox.set, expectedKey, {
+        body: responseBody,
+        response: expectedCachedResponse
+      }, 60000);
+      done();
+    });
+  });
+
   it('respects the doNotVary option when creating a cache key', function (done) {
@@ -427,2 +572,35 @@ var reqheaders = {
 
+  it('increments a counter when a stale response is sent', function (done) {
+    var cachedResponseBody = {
+      foo: 'baz'
+    };
+    var errorResponseCode = 503;
+    var errorResponseBody = {
+      error: 'An error'
+    };
+    var errorHeaders = {
+      'cache-control': 'max-age=5',
+      'content-type': 'application/json',
+      'www-authenticate': 'Bearer realm="/"'
+    };
+
+    catbox.get.withArgs(expectedStaleKey).yields(null, {
+      item: {
+        body: cachedResponseBody,
+        response: expectedCachedResponse
+      }
+    });
+
+    nock.cleanAll();
+    api.get('/').reply(errorResponseCode, errorResponseBody, errorHeaders);
+
+    staleClient.get(url, function (err, body, res) {
+      assert.ifError(err);
+      assert.deepEqual(body, cachedResponseBody);
+      assert.deepEqual(res, expectedCachedResponse);
+      sinon.assert.calledWith(stats.increment, 'http.cache.stale');
+      done();
+    });
+  });
+
   it('increments a counter for each cache miss', function (done) {
@@ -429,0 +607,0 @@ client.get(url, function (err) {

No alert changes

Improved metrics

Total package byte prevSize

281551

increased by2.49%

Lines of code

1806

increased by11.9%

Number of lines in readme file

346

increased by4.53%

No dependency changes