From c92bc858f7665b6ea1a2e2d80455e47faf1aefec Mon Sep 17 00:00:00 2001
From: Jerome Fitzgerald <jeromes@gmail.com>
Date: Wed, 14 Feb 2018 12:02:48 -0500
Subject: [PATCH] [refactor] poweredByHeader (#3716) (#3807)
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This reverts `fb7c862` per @timneutkens

- Removes the errors/*.md associated
- Puts back `poweredByHeader` for `next.config.js`
- Reincorporates test:

X-Powered-By header
    ✓ should set it by default (3ms)
    ✓ should not set it when poweredByHeader==false (5ms)

Also tested with `yarn link` and verified.
---
 errors/powered-by-header-option-removed.md    | 15 --------------
 server/config.js                              |  4 +---
 server/index.js                               |  4 +++-
 .../integration/production/test/index.test.js | 20 +++++++++++++++++++
 4 files changed, 24 insertions(+), 19 deletions(-)
 delete mode 100644 errors/powered-by-header-option-removed.md

diff --git a/errors/powered-by-header-option-removed.md b/errors/powered-by-header-option-removed.md
deleted file mode 100644
index 216fbda8..00000000
--- a/errors/powered-by-header-option-removed.md
+++ /dev/null
@@ -1,15 +0,0 @@
-# The poweredByHeader has been removed
-
-#### Why This Error Occurred
-
-Starting at Next.js version 5.0.0 the `poweredByHeader` option has been removed.
-
-#### Possible Ways to Fix It
-
-If you still want to remove `x-powered-by` you can use one of the custom-server examples.
-
-And then manually remove the header using `res.removeHeader('x-powered-by')`
-
-### Useful Links
-
-- [Custom Server documentation + examples](https://github.com/zeit/next.js#custom-server-and-routing)
diff --git a/server/config.js b/server/config.js
index 4ea6bc23..7ed863c0 100644
--- a/server/config.js
+++ b/server/config.js
@@ -5,6 +5,7 @@ const cache = new Map()
 const defaultConfig = {
   webpack: null,
   webpackDevMiddleware: null,
+  poweredByHeader: true,
   distDir: '.next',
   assetPrefix: '',
   configOrigin: 'default',
@@ -33,9 +34,6 @@ function loadConfig (dir, customConfig) {
   if (path && path.length) {
     const userConfigModule = require(path)
     userConfig = userConfigModule.default || userConfigModule
-    if (userConfig.poweredByHeader === true || userConfig.poweredByHeader === false) {
-      console.warn('> the `poweredByHeader` option has been removed https://err.sh/zeit/next.js/powered-by-header-option-removed')
-    }
     userConfig.configOrigin = 'next.config.js'
   }
 
diff --git a/server/index.js b/server/index.js
index 9fe619b9..1b1e546b 100644
--- a/server/index.js
+++ b/server/index.js
@@ -323,7 +323,9 @@ export default class Server {
       return
     }
 
-    res.setHeader('X-Powered-By', `Next.js ${pkg.version}`)
+    if (this.config.poweredByHeader) {
+      res.setHeader('X-Powered-By', `Next.js ${pkg.version}`)
+    }
     return sendHTML(req, res, html, req.method, this.renderOpts)
   }
 
diff --git a/test/integration/production/test/index.test.js b/test/integration/production/test/index.test.js
index ac58096d..47da09c8 100644
--- a/test/integration/production/test/index.test.js
+++ b/test/integration/production/test/index.test.js
@@ -134,6 +134,26 @@ describe('Production Usage', () => {
       await app.render(req, res, req.url)
       expect(headers['X-Powered-By']).toEqual(`Next.js ${pkg.version}`)
     })
+
+    it('should not set it when poweredByHeader==false', async () => {
+      const req = { url: '/stateless', headers: {} }
+      const originalConfigValue = app.config.poweredByHeader
+      app.config.poweredByHeader = false
+      const res = {
+        getHeader () {
+          return false
+        },
+        setHeader (key, value) {
+          if (key === 'XPoweredBy') {
+            throw new Error('Should not set the XPoweredBy header')
+          }
+        },
+        end () {}
+      }
+
+      await app.render(req, res, req.url)
+      app.config.poweredByHeader = originalConfigValue
+    })
   })
 
   dynamicImportTests(context, (p, q) => renderViaHTTP(context.appPort, p, q))