From 9103f5655b05d5f74d036cec9760dc87b566163d Mon Sep 17 00:00:00 2001
From: Nico Flaig <nflaig@protonmail.com>
Date: Mon, 15 Jul 2024 16:19:52 +0100
Subject: [PATCH] fix: default to json if client accepts all media types
 (#6950)

---
 packages/api/src/utils/headers.ts            |  7 ++++++-
 packages/api/src/utils/server/handler.ts     |  2 +-
 packages/api/test/unit/utils/headers.test.ts | 10 +++++++++-
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/packages/api/src/utils/headers.ts b/packages/api/src/utils/headers.ts
index 0646bb109fbb..5ef5346612fa 100644
--- a/packages/api/src/utils/headers.ts
+++ b/packages/api/src/utils/headers.ts
@@ -44,7 +44,12 @@ export function parseAcceptHeader(accept?: string, supported = SUPPORTED_MEDIA_T
         // Normalize here, using 1 as the default qvalue
         const quality = current.includes(";") ? current.split(";") : [current, "q=1"];
 
-        const mediaType = quality[0].trim();
+        let mediaType = quality[0].trim();
+
+        if (mediaType === "*/*") {
+          // Default to json if all media types are accepted
+          mediaType = MediaType.json;
+        }
 
         // If the mime type isn't acceptable, move on to the next entry
         if (!isSupportedMediaType(mediaType, supported)) {
diff --git a/packages/api/src/utils/server/handler.ts b/packages/api/src/utils/server/handler.ts
index 479212493885..a3cd9a43a56a 100644
--- a/packages/api/src/utils/server/handler.ts
+++ b/packages/api/src/utils/server/handler.ts
@@ -44,7 +44,7 @@ export function createFastifyHandler<E extends Endpoint>(
     if (definition.resp.isEmpty) {
       // Ignore Accept header, the response will be sent without body
       responseMediaType = null;
-    } else if (acceptHeader === undefined || acceptHeader === "*/*") {
+    } else if (acceptHeader === undefined) {
       // Default to json to not force user to set header, e.g. when using curl
       responseMediaType = MediaType.json;
     } else {
diff --git a/packages/api/test/unit/utils/headers.test.ts b/packages/api/test/unit/utils/headers.test.ts
index c3bcf6bc79c2..3416335b0dcd 100644
--- a/packages/api/test/unit/utils/headers.test.ts
+++ b/packages/api/test/unit/utils/headers.test.ts
@@ -5,13 +5,15 @@ describe("utils / headers", () => {
   describe("parseAcceptHeader", () => {
     const testCases: {header: string | undefined; expected: MediaType | null}[] = [
       {header: undefined, expected: null},
-      {header: "*/*", expected: null},
+      {header: "*/*", expected: MediaType.json},
       {header: "application/json", expected: MediaType.json},
       {header: "application/octet-stream", expected: MediaType.ssz},
       {header: "application/invalid", expected: null},
       {header: "application/invalid;q=1,application/octet-stream;q=0.1", expected: MediaType.ssz},
       {header: "application/octet-stream;q=0.5,application/json;q=1", expected: MediaType.json},
       {header: "application/octet-stream;q=1,application/json;q=0.1", expected: MediaType.ssz},
+      {header: "application/octet-stream;q=1,application/json;q=0.9", expected: MediaType.ssz},
+      {header: "application/octet-stream;q=1,*/*;q=0.9", expected: MediaType.ssz},
       {header: "application/octet-stream,application/json;q=0.1", expected: MediaType.ssz},
       {header: "application/octet-stream;,application/json;q=0.1", expected: MediaType.json},
       {header: "application/octet-stream;q=2,application/json;q=0.1", expected: MediaType.json},
@@ -20,6 +22,12 @@ describe("utils / headers", () => {
       {header: "application/octet-stream  ; q=0.5 , application/json ; q=1", expected: MediaType.json},
       {header: "application/octet-stream  ; q=1 , application/json ; q=0.1", expected: MediaType.ssz},
       {header: "application/octet-stream;q=1,application/json;q=0.1", expected: MediaType.ssz},
+      {
+        // Default Accept header set by chrome browser
+        header:
+          "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7",
+        expected: MediaType.json,
+      },
 
       // The implementation is order dependent, however, RFC-9110 doesn't specify a preference.
       // The following tests serve to document the behavior at the time of implementation- not a