From 09a1dfabc4a78b332aef54fb237322fd7738a545 Mon Sep 17 00:00:00 2001
From: Joonas Loppi <joonas+code@joonas.fi>
Date: Mon, 6 Mar 2023 14:40:41 +0200
Subject: [PATCH] ezhttp: don't override 'Accept' header with RespondsJSON...()

---
 net/http/ezhttp/conffns.go     |  4 +++-
 net/http/ezhttp/ezhttp_test.go | 17 +++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/net/http/ezhttp/conffns.go b/net/http/ezhttp/conffns.go
index 0dcb51a..467b3ed 100644
--- a/net/http/ezhttp/conffns.go
+++ b/net/http/ezhttp/conffns.go
@@ -68,7 +68,9 @@ func RespondsJSONDisallowUnknownFields(obj interface{}) ConfigPiece {
 
 func respondsJSON(ref interface{}, allowUnknownFields bool) ConfigPiece {
 	return After(func(conf *Config) {
-		conf.Request.Header.Set("Accept", jsonContentType)
+		if conf.Request.Header.Get("Accept") == "" { // don't override if we have explicit `Accept` header
+			conf.Request.Header.Set("Accept", jsonContentType)
+		}
 
 		conf.OutputsJson = true
 		conf.OutputsJsonRef = ref
diff --git a/net/http/ezhttp/ezhttp_test.go b/net/http/ezhttp/ezhttp_test.go
index 0a66116..61eda4a 100644
--- a/net/http/ezhttp/ezhttp_test.go
+++ b/net/http/ezhttp/ezhttp_test.go
@@ -150,6 +150,23 @@ func TestAuthBearer(t *testing.T) {
 	assert.EqualString(t, string(respBody), "Echoing Authorization: Bearer LOLOLOLOL")
 }
 
+func TestRespondsJSONDoesntOverrideExplicitAccept(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, `{"AcceptEchoed": "%s"}`, r.Header.Get("Accept"))
+	}))
+	defer ts.Close()
+
+	respJSON := struct {
+		AcceptEchoed string
+	}{}
+
+	// before the fix, RespondsJSONDisallowUnknownFields() used to override explicit header
+	_, err := Get(context.TODO(), ts.URL, Header("Accept", "text/foobar"), RespondsJSONDisallowUnknownFields(&respJSON))
+	assert.Ok(t, err)
+
+	assert.EqualString(t, respJSON.AcceptEchoed, "text/foobar")
+}
+
 func TestAuthBasic(t *testing.T) {
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		fmt.Fprintf(w, "Echoing Authorization: %s", r.Header.Get("Authorization"))