fix: use header flags in wsproxy server (#10985)

codersdk/client.go

@@ -530,3 +530,33 @@ func WithQueryParam(key, value string) RequestOption {
 		r.URL.RawQuery = q.Encode()
 	}
 }
+
+// HeaderTransport is a http.RoundTripper that adds some headers to all requests.
+// @typescript-ignore HeaderTransport
+type HeaderTransport struct {
+	Transport http.RoundTripper
+	Header    http.Header
+}
+
+var _ http.RoundTripper = &HeaderTransport{}
+
+func (h *HeaderTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	for k, v := range h.Header {
+		for _, vv := range v {
+			req.Header.Add(k, vv)
+		}
+	}
+	if h.Transport == nil {
+		h.Transport = http.DefaultTransport
+	}
+	return h.Transport.RoundTrip(req)
+}
+
+func (h *HeaderTransport) CloseIdleConnections() {
+	type closeIdler interface {
+		CloseIdleConnections()
+	}
+	if tr, ok := h.Transport.(closeIdler); ok {
+		tr.CloseIdleConnections()
+	}
+}

codersdk/workspaceagents.go

@@ -273,11 +273,8 @@ func (c *Client) DialWorkspaceAgent(dialCtx context.Context, agentID uuid.UUID,
 
 	ip := tailnet.IP()
 	var header http.Header
-	headerTransport, ok := c.HTTPClient.Transport.(interface {
-		Header() http.Header
-	})
-	if ok {
-		header = headerTransport.Header()
+	if headerTransport, ok := c.HTTPClient.Transport.(*HeaderTransport); ok {
+		header = headerTransport.Header
 	}
 	conn, err := tailnet.NewConn(&tailnet.Options{
 		Addresses:           []netip.Prefix{netip.PrefixFrom(ip, 128)},