From f5c17764cc6ead6a835513fe580e1f419ff4417b Mon Sep 17 00:00:00 2001
From: Ashary Vermaysha <vermaysha@gmail.com>
Date: Tue, 4 Jun 2024 13:26:43 +0700
Subject: [PATCH 1/2] fix: dont add vary value when it is a wildcard

---
 src/main.ts | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/main.ts b/src/main.ts
index 05bcfc9..b1cd81f 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -154,7 +154,13 @@ export const compression = (
       const headerValueArray = Array.isArray(rawHeaderValue)
         ? rawHeaderValue
         : [rawHeaderValue]
-      if (!headerValueArray.some((h) => h.includes('accept-encoding'))) {
+
+      // Add accept-encoding header if it doesn't exist
+      // and if vary not set to *
+      if (
+        !headerValueArray.some((h) => h.includes('accept-encoding')) &&
+        !headerValueArray.includes('*')
+      ) {
         headers.Vary = headerValueArray.concat('accept-encoding').join(', ')
       }
     } else {

From aee4421d8418d24595bb2dc7803b1cb6f26e4090 Mon Sep 17 00:00:00 2001
From: Ashary Vermaysha <vermaysha@gmail.com>
Date: Tue, 4 Jun 2024 13:29:49 +0700
Subject: [PATCH 2/2] test: create unit tests to ensure the issue does not
 occur again

---
 tests/index.test.ts | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tests/index.test.ts b/tests/index.test.ts
index 222c26c..13e5ad6 100644
--- a/tests/index.test.ts
+++ b/tests/index.test.ts
@@ -31,6 +31,7 @@ describe('Compression With Elysia', () => {
     const res = await app.handle(req())
 
     expect(res.headers.get('Content-Encoding')).toBeNull()
+    expect(res.headers.get('vary')).toBeNull()
   })
 
   it('handle brotli compression', async () => {
@@ -45,6 +46,7 @@ describe('Compression With Elysia', () => {
     const res = await app.handle(req())
 
     expect(res.headers.get('Content-Encoding')).toBe('br')
+    expect(res.headers.get('vary')).toBe('accept-encoding')
   })
 
   it('handle deflate compression', async () => {
@@ -54,6 +56,7 @@ describe('Compression With Elysia', () => {
     const res = await app.handle(req())
 
     expect(res.headers.get('Content-Encoding')).toBe('deflate')
+    expect(res.headers.get('vary')).toBe('accept-encoding')
   })
 
   it('handle gzip compression', async () => {
@@ -63,6 +66,7 @@ describe('Compression With Elysia', () => {
     const res = await app.handle(req())
 
     expect(res.headers.get('Content-Encoding')).toBe('gzip')
+    expect(res.headers.get('vary')).toBe('accept-encoding')
   })
 
   it('accept additional headers', async () => {
@@ -77,6 +81,7 @@ describe('Compression With Elysia', () => {
 
     expect(res.headers.get('Content-Encoding')).toBe('deflate')
     expect(res.headers.get('x-powered-by')).toBe('Elysia')
+    expect(res.headers.get('vary')).toBe('accept-encoding')
   })
 
   it('return correct plain/text', async () => {
@@ -87,6 +92,7 @@ describe('Compression With Elysia', () => {
     const res = await app.handle(req())
 
     expect(res.headers.get('Content-Type')).toBe('text/plain')
+    expect(res.headers.get('vary')).toBe('accept-encoding')
   })
 
   it('return correct application/json', async () => {
@@ -99,6 +105,7 @@ describe('Compression With Elysia', () => {
     expect(res.headers.get('Content-Type')).toBe(
       'application/json;charset=utf-8',
     )
+    expect(res.headers.get('vary')).toBe('accept-encoding')
   })
 
   it('return correct image type', async () => {
@@ -109,6 +116,7 @@ describe('Compression With Elysia', () => {
     const res = await app.handle(req())
 
     expect(res.headers.get('Content-Type')).toBe('image/png')
+    expect(res.headers.get('vary')).toBeNull()
   })
 
   it('must be redirected to /not-found', async () => {
@@ -154,6 +162,7 @@ describe('Compression With Elysia', () => {
     const res = await app.handle(req())
 
     expect(res.headers.get('Content-Encoding')).toBe('gzip')
+    expect(res.headers.get('vary')).toBe('accept-encoding')
   })
 
   it('cors should be enable when threshold 1024', async () => {
@@ -202,5 +211,6 @@ describe('Compression With Elysia', () => {
     const res = await app.handle(req())
 
     expect(res.headers.get('access-control-allow-origin')).toBe('*')
+    expect(res.headers.get('vary')).toBe('*')
   })
 })