From 6bf9c9fe908bdfbded1d750190cba051f8b9e580 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kornel=20Lesin=CC=81ski?= <kornel@geekhood.net>
Date: Thu, 8 Dec 2016 11:43:20 +0000
Subject: [PATCH] Remove pre-check from forwarded response headers too

---
 index.js             | 12 ++++++++++++
 package.json         |  2 +-
 test/responsetest.js | 19 +++++++++++++++++--
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/index.js b/index.js
index 2e0eff8..4d9ccae 100644
--- a/index.js
+++ b/index.js
@@ -22,6 +22,15 @@ function parseCacheControl(header) {
     return cc;
 }
 
+function formatCacheControl(cc) {
+    let parts = [];
+    for(const k in cc) {
+        const v = cc[k];
+        parts.push(v === true ? k : k + '=' + v);
+    }
+    return parts.join(', ');
+}
+
 module.exports = class CachePolicy {
     constructor(req, res, {shared, cacheHeuristic, ignoreCargoCult, _fromObject} = {}) {
         if (_fromObject) {
@@ -53,9 +62,12 @@ module.exports = class CachePolicy {
         // Assume that if someone uses legacy, non-standard uncecessary options they don't understand caching,
         // so there's no point stricly adhering to the blindly copy&pasted directives.
         if (ignoreCargoCult && "pre-check" in this._rescc && "post-check" in this._rescc) {
+            delete this._rescc['pre-check'];
+            delete this._rescc['post-check'];
             delete this._rescc['no-cache'];
             delete this._rescc['no-store'];
             delete this._rescc['must-revalidate'];
+            this._resHeaders = Object.assign({}, this._resHeaders, {'cache-control': formatCacheControl(this._rescc)});
         }
 
         // When the Cache-Control header field is not present in a request, caches MUST consider the no-cache request pragma-directive
diff --git a/package.json b/package.json
index b8f8d6d..f1837b7 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "http-cache-semantics",
-  "version": "3.3.0",
+  "version": "3.3.1",
   "description": "Parses Cache-Control headers and friends",
   "main": "index.js",
   "repository": "https://github.com/pornel/http-cache-semantics.git",
diff --git a/test/responsetest.js b/test/responsetest.js
index 2e9e227..ef0a4f7 100644
--- a/test/responsetest.js
+++ b/test/responsetest.js
@@ -35,17 +35,32 @@ describe('Response headers', function() {
     });
 
     it('pre-check tolerated', function() {
-        const cache = new CachePolicy(req, {headers:{'cache-control': 'pre-check=0, post-check=0, no-store, no-cache, max-age=100'}});
+        const cc = 'pre-check=0, post-check=0, no-store, no-cache, max-age=100';
+        const cache = new CachePolicy(req, {headers:{'cache-control': cc}});
         assert(cache.stale());
         assert(!cache.storable());
         assert.equal(cache.maxAge(), 0);
+        assert.equal(cache.responseHeaders()['cache-control'], cc);
     });
 
     it('pre-check poison', function() {
-        const cache = new CachePolicy(req, {headers:{'cache-control': 'pre-check=0, post-check=0, no-cache, no-store, max-age=100'}}, {ignoreCargoCult:true});
+        const origCC = 'pre-check=0, post-check=0, no-cache, no-store, max-age=100, custom, foo=bar';
+        const res = {headers:{'cache-control': origCC}};
+        const cache = new CachePolicy(req, res, {ignoreCargoCult:true});
         assert(!cache.stale());
         assert(cache.storable());
         assert.equal(cache.maxAge(), 100);
+
+        const cc = cache.responseHeaders()['cache-control'];
+        assert(!/pre-check/.test(cc), cc);
+        assert(!/post-check/.test(cc), cc);
+        assert(!/no-store/.test(cc), cc);
+
+        assert(/max-age=100/.test(cc));
+        assert(/custom(,|$)/.test(cc));
+        assert(/foo=bar/.test(cc));
+
+        assert.equal(res.headers['cache-control'], origCC);
     });
 
     it('cache with expires', function() {