feat: add panic recovery middleware (#3687)

coderd/httpapi/request.go

@@ -0,0 +1,30 @@
+package httpapi
+
+import "net/http"
+
+const (
+	// XForwardedHostHeader is a header used by proxies to indicate the
+	// original host of the request.
+	XForwardedHostHeader = "X-Forwarded-Host"
+)
+
+// RequestHost returns the name of the host from the request.  It prioritizes
+// 'X-Forwarded-Host' over r.Host since most requests are being proxied.
+func RequestHost(r *http.Request) string {
+	host := r.Header.Get(XForwardedHostHeader)
+	if host != "" {
+		return host
+	}
+
+	return r.Host
+}
+
+func IsWebsocketUpgrade(r *http.Request) bool {
+	vs := r.Header.Values("Upgrade")
+	for _, v := range vs {
+		if v == "websocket" {
+			return true
+		}
+	}
+	return false
+}