From cbb3068a4a9e31a61aa426dc1217fd0ead978e25 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Pr=C3=A9vost?= <prevostclement@gmail.com>
Date: Fri, 24 Mar 2023 17:33:13 +0100
Subject: [PATCH 1/4] GH-14: Don't override cache-control if it has already
 been set

---
 index.js             |  4 +++-
 test/headers.test.js | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/index.js b/index.js
index 236ddf3..9857cc8 100644
--- a/index.js
+++ b/index.js
@@ -75,7 +75,9 @@ function fastifyCaching (instance, options, next) {
     }
 
     instance.addHook('onRequest', (req, res, next) => {
-      res.header('Cache-control', value)
+      if (!res.getHeader('Cache-control')) {
+        res.header('Cache-control', value)
+      }
       next()
     })
   }
diff --git a/test/headers.test.js b/test/headers.test.js
index d941239..3b44a41 100644
--- a/test/headers.test.js
+++ b/test/headers.test.js
@@ -2,6 +2,7 @@
 
 const { test } = require('tap')
 const Fastify = require('fastify')
+const fp = require('fastify-plugin')
 const plugin = require('..')
 
 test('decorators get added', async (t) => {
@@ -139,6 +140,37 @@ test('sets public with max-age and s-maxage header', async (t) => {
   t.equal(response.headers['cache-control'], 'public, max-age=300, s-maxage=12345')
 })
 
+test('do not set headers if another upstream plugin already sets it', async (t) => {
+  t.plan(2)
+
+  const opts = {
+    privacy: plugin.privacy.PUBLIC,
+    expiresIn: 300,
+    serverExpiresIn: 12345
+  }
+
+  const fastify = Fastify()
+  await fastify.register(fp(async (fastify, opts) => {
+    fastify.addHook('onRequest', async (req, reply) => {
+      reply.header('cache-control', 'do not override')
+    })
+  }))
+  await fastify.register(plugin, opts)
+
+  fastify.get('/', (req, reply) => {
+    reply.send({ hello: 'world' })
+  })
+
+  await fastify.ready()
+
+  const response = await fastify.inject({
+    method: 'GET',
+    path: '/'
+  })
+  t.ok(response.headers['cache-control'])
+  t.equal(response.headers['cache-control'], 'do not override')
+})
+
 test('only sets max-age and ignores s-maxage with private header', async (t) => {
   t.plan(2)
 

From af9f77116c8ad60afa28879b040d76313e837475 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment?= <998369+prevostc@users.noreply.github.com>
Date: Fri, 24 Mar 2023 19:13:05 +0100
Subject: [PATCH 2/4] Apply suggestions from code review

Co-authored-by: Manuel Spigolon <behemoth89@gmail.com>
---
 test/headers.test.js | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/test/headers.test.js b/test/headers.test.js
index 3b44a41..9afd1ea 100644
--- a/test/headers.test.js
+++ b/test/headers.test.js
@@ -2,7 +2,6 @@
 
 const { test } = require('tap')
 const Fastify = require('fastify')
-const fp = require('fastify-plugin')
 const plugin = require('..')
 
 test('decorators get added', async (t) => {
@@ -150,11 +149,9 @@ test('do not set headers if another upstream plugin already sets it', async (t)
   }
 
   const fastify = Fastify()
-  await fastify.register(fp(async (fastify, opts) => {
-    fastify.addHook('onRequest', async (req, reply) => {
-      reply.header('cache-control', 'do not override')
-    })
-  }))
+  fastify.addHook('onRequest', async (req, reply) => {
+    reply.header('cache-control', 'do not override')
+  })
   await fastify.register(plugin, opts)
 
   fastify.get('/', (req, reply) => {

From 95baa63c4faf3b661154e7e36faecffd3507627d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Pr=C3=A9vost?= <prevostclement@gmail.com>
Date: Sat, 25 Mar 2023 13:56:20 +0100
Subject: [PATCH 3/4] use hasHeader instead of getHeader

---
 index.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/index.js b/index.js
index 9857cc8..5d7fa6a 100644
--- a/index.js
+++ b/index.js
@@ -75,7 +75,7 @@ function fastifyCaching (instance, options, next) {
     }
 
     instance.addHook('onRequest', (req, res, next) => {
-      if (!res.getHeader('Cache-control')) {
+      if (!res.hasHeader('Cache-control')) {
         res.header('Cache-control', value)
       }
       next()

From 6159450daa117aa753cb896816b3b9f2a1f13fd5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment?= <998369+prevostc@users.noreply.github.com>
Date: Sat, 25 Mar 2023 14:06:32 +0100
Subject: [PATCH 4/4] Cleaner comparison

Co-authored-by: James Sumners <james@sumners.email>
---
 index.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/index.js b/index.js
index 5d7fa6a..dfc2184 100644
--- a/index.js
+++ b/index.js
@@ -75,7 +75,7 @@ function fastifyCaching (instance, options, next) {
     }
 
     instance.addHook('onRequest', (req, res, next) => {
-      if (!res.hasHeader('Cache-control')) {
+      if (res.hasHeader('Cache-control') === false) {
         res.header('Cache-control', value)
       }
       next()