feat: add in Vary support

closes: #1253
middyjs · Oct 26, 2024 · 01e049b · 01e049b
1 parent ba24146
commit 01e049b
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Showing 2 changed files with 26 additions and 8 deletions.
diff --git a/packages/http-content-encoding/__tests__/index.js b/packages/http-content-encoding/__tests__/index.js
@@ -25,7 +25,7 @@ test('It should encode string using br', async (t) => {
   deepEqual(response, {
     statusCode: 200,
     body: brotliCompressSync(body).toString('base64'),
-    headers: { 'Content-Encoding': 'br' },
+    headers: { 'Content-Encoding': 'br', Vary: 'Accept-Encoding' },
     isBase64Encoded: true
   })
 })
@@ -45,7 +45,7 @@ test('It should encode stream using br', async (t) => {
   deepEqual(response, {
     statusCode: 200,
     body: brotliCompressSync(body).toString('base64'),
-    headers: { 'Content-Encoding': 'br' }
+    headers: { 'Content-Encoding': 'br', Vary: 'Accept-Encoding' }
   })
 })
 
@@ -65,7 +65,7 @@ test('It should encode string using gzip', async (t) => {
   deepEqual(response, {
     statusCode: 200,
     body: gzipSync(body).toString('base64'),
-    headers: { 'Content-Encoding': 'gzip' },
+    headers: { 'Content-Encoding': 'gzip', Vary: 'Accept-Encoding' },
     isBase64Encoded: true
   })
 })
@@ -88,7 +88,7 @@ test('It should encode stream using gzip', async (t) => {
   deepEqual(response, {
     statusCode: 200,
     body: gzipSync(body).toString('base64'),
-    headers: { 'Content-Encoding': 'gzip' }
+    headers: { 'Content-Encoding': 'gzip', Vary: 'Accept-Encoding' }
   })
 })
 
@@ -107,7 +107,7 @@ test('It should encode string using deflate', async (t) => {
   deepEqual(response, {
     statusCode: 200,
     body: deflateSync(body).toString('base64'),
-    headers: { 'Content-Encoding': 'deflate' },
+    headers: { 'Content-Encoding': 'deflate', Vary: 'Accept-Encoding' },
     isBase64Encoded: true
   })
 })
@@ -130,13 +130,19 @@ test('It should encode stream using deflate', async (t) => {
   deepEqual(response, {
     statusCode: 200,
     body: deflateSync(body).toString('base64'),
-    headers: { 'Content-Encoding': 'deflate' }
+    headers: { 'Content-Encoding': 'deflate', Vary: 'Accept-Encoding' }
   })
 })
 
 test('It should encode using br when context.preferredEncoding is gzip, but has overridePreferredEncoding set', async (t) => {
   const body = compressibleBody
-  const handler = middy((event, context) => ({ statusCode: 200, body }))
+  const handler = middy((event, context) => ({
+    statusCode: 200,
+    body,
+    headers: {
+      Vary: 'Something'
+    }
+  }))
   handler.use(
     httpContentEncoding({
       overridePreferredEncoding: ['br', 'gzip', 'deflate']
@@ -154,7 +160,7 @@ test('It should encode using br when context.preferredEncoding is gzip, but has
   deepEqual(response, {
     statusCode: 200,
     body: brotliCompressSync(body).toString('base64'),
-    headers: { 'Content-Encoding': 'br' },
+    headers: { 'Content-Encoding': 'br', Vary: 'Something, Accept-Encoding' },
     isBase64Encoded: true
   })
 })

diff --git a/packages/http-content-encoding/index.js b/packages/http-content-encoding/index.js
@@ -70,6 +70,7 @@ const httpContentEncodingMiddleware = (opts) => {
     if (response.body?._readableState) {
       request.response.headers['Content-Encoding'] = contentEncoding
       request.response.body = request.response.body.pipe(contentEncodingStream)
+      addVary(response)
       return
     }
 
@@ -87,6 +88,7 @@ const httpContentEncodingMiddleware = (opts) => {
       response.headers['Content-Encoding'] = contentEncoding
       response.body = body
       response.isBase64Encoded = true
+      addVary(response)
     }
 
     request.response = response
@@ -103,4 +105,14 @@ const httpContentEncodingMiddleware = (opts) => {
   }
 }
 
+const addVary = (response) => {
+  // See #1253
+  if (response.headers.Vary) {
+    response.headers.Vary += ', Accept-Encoding'
+  } else if (response.headers.vary) {
+    response.headers.vary += ', Accept-Encoding'
+  } else {
+    response.headers.Vary = 'Accept-Encoding'
+  }
+}
 export default httpContentEncodingMiddleware