如何使用Spring WebClient使用不同的标头设置进行后续调用？

如何解决如何使用Spring WebClient使用不同的标头设置进行后续调用？

我需要调用第三方API，该API需要事先进行身份验证才能获得身份验证令牌。 Authentication API在json中，但随后的调用在XML中。

我分别有：

webclient.post().uri("/auth").header(ACCEPT,JSON).retrieve()
      .bodyToMono(AuthToken.class);
webclient.post().uri("/api").header(ACCEPT,XML).header("AUTH",authToken).retrive().bodyToFlux();

我应该如何实现能够访问第二个API的方法？我尝试使用token = firstCall.block()在方法内分配变量，但出现block() is not supported错误。

解决方法

您只需要像这样转换原始通量即可：

webclient.post().uri("/auth")
    .header(ACCEPT,JSON)
    .retrieve()
    .bodyToMono(AuthToken.class)
    .flatMapMany(authToken -> webclient.post().uri("/api")
    .header(ACCEPT,XML)
    .header("AUTH",authToken).retrive().bodyToFlux();

更好的解决方案是使用将为您https://docs.spring.io/spring-framework/docs/current/spring-framework-reference/web-reactive.html#webflux-client-filter

提取令牌的ExchangeFilterFunction。

类似的东西（未经测试可能有错误）：

WebClient authWebClient = WebClient.builder().build();
WebClient webClient = WebClient.builder()
        .filter(((request,next) -> authWebClient.post()
                .uri("/auth")
                .accept(MediaType.APPLICATION_JSON)
                .retrieve()
                .bodyToMono(AuthToken.class)
                .flatMap(authToken -> next.exchange(ClientRequest.from(request)
                        .headers(headers -> headers.add("AUTH",authToken))
                        .build()))
        ))
        .build();

webClient.post().uri("/api")
        .accept(MediaType.APPLICATION_XML)
        .retrieve()
        .bodyToFlux(MyData.class);

这是基本操作，但您可以添加缓存以避免令牌过期而再次请求或获取... 请注意，存在用于基本oauth2的内置ExchangeFilterFunction ...

使用弹簧配置包装一切：

@Configuration
public class WebClientConfiguration {
    @Bean
    public WebClient authWebClient(final WebClient.Builder webClientBuilder) {
        return webClientBuilder.build();
    }

    @Bean
    public ExchangeFilterFunction authFilter(final WebClient authWebClient) {
        return (request,authToken.toString()))
                        .build()));
    }

    @Bean
    public WebClient webClient(final WebClient.Builder webClientBuilder,final ExchangeFilterFunction authFilter) {
        return webClientBuilder
                .filter(authFilter)
                .build();
    }
}

或者，如果您想避免使用lambda：

@Configuration
public class WebClientConfiguration {
@Bean
    public WebClient authWebClient(final WebClient.Builder webClientBuilder) {
        return webClientBuilder.build();
    }

    @Bean
    public WebClient webClient(final WebClient.Builder webClientBuilder,final AuthFilter authFilter) {
        return webClientBuilder
                .filter(authFilter)
                .build();
    }
    
    @Bean
    public AuthFilter authFilter(WebClient authWebClient) {
        return new AuthFilter(authWebClient);
    }
}

public class AuthFilter implements ExchangeFilterFunction {

    private final WebClient authWebClient;

    public AuthFilter(WebClient authWebClient) {
        this.authWebClient = authWebClient;
    }

    @Override
    public Mono<ClientResponse> filter(final ClientRequest request,final ExchangeFunction next) {
        return authWebClient.post()
                .uri("/auth")
                .accept(MediaType.APPLICATION_JSON)
                .retrieve()
                .bodyToMono(AuthToken.class)
                .flatMap(authToken -> next.exchange(ClientRequest.from(request)
                        .headers(headers -> headers.add("AUTH",authToken.toString()))
                        .build()));
    }

}