如何为MarshallingWebServiceOutboundGateway添加自定义HTTP请求头？

核心原因 #

MarshallingWebServiceOutboundGateway是SOAP服务网关，它默认的头映射逻辑（DefaultSoapHeaderMapper）仅处理SOAP信封内的头信息，而非HTTP传输层的请求头。你之前的两种尝试（enrichHeaders、重写populateUserDefinedHeader）都是在操作SOAP头，不会影响HTTP请求头。

可行解决方案 #

方案1：通过WebServiceMessageCallback直接设置HTTP头

在调用网关时，传入请求回调，直接操作SOAP消息的MIME头（对应HTTP请求头），适合需要动态从Integration消息头取值的场景：

@Bean
public IntegrationFlow processRequest() {
    return flow -> flow.channel(INPUT_CHANNEL)
            .transform(requestMapper, "mapFrom")
            .handle(webserviceOutboundGateway, e -> e.requestCallback(message -> {
                if (message instanceof SaajSoapMessage saajMessage) {
                    MimeHeaders mimeHeaders = saajMessage.getSaajMessage().getMimeHeaders();
                    // 从当前Integration消息头中获取动态值
                    MessageHeaders headers = MessageContextHolder.get().getHeaders();
                    mimeHeaders.setHeader(X_TRANSACTION_ID, headers.get(X_TRANSACTION_ID).toString());
                    mimeHeaders.setHeader(CLIENT_ID, headers.get(CLIENT_ID).toString());
                    mimeHeaders.setHeader(CLIENT_SECRET, headers.get(CLIENT_SECRET).toString());
                }
            }))
            .channel(OUTPUT_CHANNEL);
}

方案2：自定义ClientInterceptor全局设置HTTP头

创建拦截器，在SOAP请求发送前注入HTTP头，适合全局复用的场景：

public class HttpHeaderInjectingInterceptor implements ClientInterceptor {

    @Override
    public boolean handleRequest(MessageContext messageContext) throws WebServiceClientException {
        if (messageContext.getRequest() instanceof SaajSoapMessage saajMessage) {
            MimeHeaders mimeHeaders = saajMessage.getSaajMessage().getMimeHeaders();
            // 这里可以固定设置值，或者从上下文获取动态值
            mimeHeaders.setHeader(X_TRANSACTION_ID, "somevalue");
            mimeHeaders.setHeader(CLIENT_ID, "somevalue");
            mimeHeaders.setHeader(CLIENT_SECRET, "somevalue");
        }
        return true;
    }

    @Override
    public boolean handleResponse(MessageContext messageContext) {
        return true;
    }

    @Override
    public boolean handleFault(MessageContext messageContext) {
        return true;
    }

    @Override
    public void afterCompletion(MessageContext messageContext, Exception ex) {}
}

然后在网关配置中添加拦截器：

@Bean
public MarshallingWebServiceOutboundGateway muleMLGatewayWebserviceOutboundGateway(...) {
    MarshallingWebServiceOutboundGateway gateway = ...;
    gateway.setAdviceChain(Collections.singletonList(muleGatewayFailingAdvice()));
    // 注入自定义拦截器
    gateway.getWebServiceTemplate().setInterceptors(Collections.singletonList(new HttpHeaderInjectingInterceptor()));
    return gateway;
}

方案3：通过HttpComponentsMessageSender全局配置HTTP头

如果使用Apache HttpClient作为传输层，可以自定义消息发送器，全局注入HTTP头：

@Bean
public HttpComponentsMessageSender customHttpMessageSender() {
    HttpComponentsMessageSender sender = new HttpComponentsMessageSender();
    sender.setHttpClient(HttpClients.custom()
            .addInterceptorFirst((HttpRequestInterceptor) (request, context) -> {
                request.addHeader(X_TRANSACTION_ID, "somevalue");
                request.addHeader(CLIENT_ID, "somevalue");
                request.addHeader(CLIENT_SECRET, "somevalue");
            })
            .build());
    return sender;
}

@Bean
public MarshallingWebServiceOutboundGateway muleMLGatewayWebserviceOutboundGateway(...) {
    MarshallingWebServiceOutboundGateway gateway = ...;
    gateway.setAdviceChain(Collections.singletonList(muleGatewayFailingAdvice()));
    gateway.getWebServiceTemplate().setMessageSender(customHttpMessageSender());
    return gateway;
}

为什么之前的尝试无效？ #

你重写的DefaultSoapHeaderMapper.populateUserDefinedHeader方法，作用是将Integration消息头映射到SOAP信封的<Header>节点中，这些头是SOAP协议层面的，不会被转换为HTTP请求头。要操作HTTP传输层的头，必须直接干预SOAP消息的MIME头或者传输客户端的配置。

内容的提问来源于stack exchange，提问作者Viktor