From e62fbb5b28e1a3ebbbd681e4d2a663b0fff4a069 Mon Sep 17 00:00:00 2001
From: Shaun Sharples <shaun.sharples@gmail.com>
Date: Wed, 18 Oct 2023 16:32:51 +0200
Subject: [PATCH] Add Cache-Control: no-cache to headers

---
 CHANGELOG.md                   | 1 +
 src/Servant/API/EventStream.hs | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e079577..f1bb803 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 - Update version bounds to support GHC 9.6 and servant 0.20
 - Drop support for `jsForAPI` and the dependency on `servant-js`
 - Remove dependency on pipes, breaking change for `eventSource` function
+- Add "Cache-Control: no-cache" to headers
 
 ## 0.2.1.0 -- 2021-04-21
 
diff --git a/src/Servant/API/EventStream.hs b/src/Servant/API/EventStream.hs
index 1119d56..29908c0 100644
--- a/src/Servant/API/EventStream.hs
+++ b/src/Servant/API/EventStream.hs
@@ -73,7 +73,7 @@ type EventSource = SourceIO ServerEvent
 
 -- | This is mostly to guide reverse-proxies like 
 --   <https://www.nginx.com/resources/wiki/start/topics/examples/x-accel/#x-accel-buffering nginx>
-type EventSourceHdr = Headers '[Header "X-Accel-Buffering" Text] EventSource
+type EventSourceHdr = Headers '[Header "X-Accel-Buffering" Text, Header "Cache-Control" Text] EventSource
 
 -- | See details at
 --   https://hackage.haskell.org/package/wai-extra-3.1.6/docs/Network-Wai-EventSource-EventStream.html#v:eventToBuilder
@@ -81,4 +81,4 @@ instance MimeRender EventStream ServerEvent where
   mimeRender _ = maybe "" toLazyByteString . eventToBuilder
 
 eventSource :: EventSource -> EventSourceHdr
-eventSource = addHeader @"X-Accel-Buffering" "no"
\ No newline at end of file
+eventSource = addHeader @"X-Accel-Buffering" "no" . addHeader @"Cache-Control" "no-cache"
\ No newline at end of file