You can add attributes to a request. This is convenient if you want to pass information through the filter chain and influence the behavior of filters for a given request. For example:spring-doc.cn

WebClient client = WebClient.builder()
		.filter((request, next) -> {
			Optional<Object> usr = request.attribute("myAttribute");
			// ...
		})
		.build();

client.get().uri("https://example.org/")
		.attribute("myAttribute", "...")
		.retrieve()
		.bodyToMono(Void.class);

	}
val client = WebClient.builder()
		.filter { request, _ ->
			val usr = request.attributes()["myAttribute"];
			// ...
		}
		.build()

	client.get().uri("https://example.org/")
			.attribute("myAttribute", "...")
			.retrieve()
			.awaitBody<Unit>()

Note that you can configure a defaultRequest callback globally at the WebClient.Builder level which lets you insert attributes into all requests, which could be used for example in a Spring MVC application to populate request attributes based on ThreadLocal data.spring-doc.cn