：如何向HTTP出站网关添加自定义HTTP报头？

Question

我试图使用Spring的<int-http:outbound-gateway>和<int:header-enricher>组件传递一些自定义的headers，但是它在我的配置中不起作用。

我试过两种配置。第一个属性为"mapped-request-headers“：

<int:chain input-channel="requestChannel" output-channel="replyChannel">
    <int:header-enricher>
        <int:header name="test" value="test"></int:header>
    </int:header-enricher>
    <int-http:outbound-gateway id="gateway"
        encode-uri="true" url="http://localhost:8080/webapp/service/{request}"
        http-method="GET" mapped-request-headers="test, HTTP_REQUEST_HEADERS">
        <int-http:uri-variable name="request" expression="payload"/>
    </int-http:outbound-gateway>
</int:chain>

第二个属性为"header-mapper“，具有相对的DefaultHttpHeaderMapper配置：

<int:chain input-channel="requestChannel" output-channel="replyChannel">
    <int:header-enricher>
        <int:header name="test" value="test"></int:header>
    </int:header-enricher>
    <int-http:outbound-gateway id="gateway"
        encode-uri="true" url="http://localhost:8080/webapp/service/{request}"
        http-method="GET" header-mapper="headerMapper">
        <int-http:uri-variable name="request" expression="payload"/>
    </int-http:outbound-gateway>
</int:chain>

<bean id="headerMapper" class="org.springframework.integration.http.support.DefaultHttpHeaderMapper">
    <property name="outboundHeaderNames" value="HTTP_REQUEST_HEADERS, test" />
    <property name="userDefinedHeaderPrefix" value="" />
</bean>

但在这两种情况下，远程应用程序加载的消息头如下所示：

GenericMessage[
    payload={},
    headers={
        http_requestMethod=GET,
        replyChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@4c8b7a27,
        errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@4c8b7a27,
        host=localhost: 8080,
        http_requestUrl=http://localhost:8080/webapp/service/hello,
        connection=keep-alive,
        id=3c2a21ba-b7f5-e5e9-c821-45251d406318,
        cache-control=no-cache,
        pragma=no-cache,
        user-agent=Java/1.8.0_65,
        accept=[
            text/html,
            image/gif,
            image/jpeg,
            */*;q=.2,
            */*;q=.2],
        timestamp=1469009855797
    }
]

没有跟踪我试图添加到请求消息中的"test“标头。

向<int-http:outbound-gateway>添加自定义头的正确方法是什么？

这也是很好的任何其他工作解决方案。

更新

从Gary指示，我打开了调试模式。

这是一件非常有趣的事情:日志显示头测试“将映射”。

message sent: GenericMessage [payload=hello, headers={id=79f98422-418b-f00f-1e21-09461b1ff80c, timestamp=1469021452494}]
2016-07-20 15:53:57 DEBUG org.springframework.integration.http.support.DefaultHttpHeaderMapper.fromHeaders:402 (executor-4) - outboundHeaderNames=[test, HTTP_REQUEST_HEADERS]
2016-07-20 15:53:57 DEBUG org.springframework.integration.http.support.DefaultHttpHeaderMapper.shouldMapHeader:537 (executor-4) - headerName=[test] WILL be mapped, matched pattern=test
2016-07-20 15:53:57 DEBUG org.springframework.integration.http.support.DefaultHttpHeaderMapper.fromHeaders:420 (executor-4) - setting headerName=[X-test], value=test
2016-07-20 15:53:57 DEBUG org.springframework.http.client.support.HttpAccessor.createRequest:79 (executor-4) - Created GET request for "http://localhost:8080/webapp/service/hello"

我在服务器端实现了一个简单的过滤器，它拦截每个HTTP请求，并在日志上打印该请求的每个标头。

其结果是：

x-test=test
cache-control=no-cache
pragma=no-cache
user-agent=Java/1.8.0_65
host=localhost:8080
accept=text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
connection=keep-alive

因此，头"x-test"出现在HttpServletRequest实例上。

但之后，我可以在日志中看到另一条消息(我只报告了对此上下文具有重要意义的消息)：

2016-07-20 15:53:57 DEBUG org.springframework.web.servlet.DispatcherServlet.doService:865 (http-nio-8080-exec-1) - DispatcherServlet with name 'dispatcherServer' processing GET request for [/webapp/service/hello]
2016-07-20 15:53:57 DEBUG org.springframework.integration.http.support.DefaultHttpHeaderMapper.toHeaders:436 (http-nio-8080-exec-1) - inboundHeaderNames=[Accept, Accept-Charset, Accept-Encoding, Accept-Language, Accept-Ranges, Authorization, Cache-Control, Connection, Content-Length, Content-Type, Cookie, Date, Expect, From, Host, If-Match, If-Modified-Since, If-None-Match, If-Range, If-Unmodified-Since, Max-Forwards, Pragma, Proxy-Authorization, Range, Referer, TE, Upgrade, User-Agent, Via, Warning]
2016-07-20 15:53:57 DEBUG org.springframework.integration.http.support.DefaultHttpHeaderMapper.shouldMapHeader:561 (http-nio-8080-exec-1) - headerName=[x-test] WILL NOT be mapped
2016-07-20 15:53:57 DEBUG org.springframework.integration.handler.AbstractMessageHandler.handleMessage:115 (executor-4) - ServiceActivator for [org.springframework.integration.handler.MethodInvokingMessageProcessor@6ae60a] (channelServiceActivator) received message: GenericMessage [payload={}, headers={http_requestMethod=GET, replyChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@565fe0d8, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@565fe0d8, host=localhost:8080, http_requestUrl=http://localhost:8080/webapp/service/hello, connection=keep-alive, id=9578f82d-7fc2-fe94-d8bf-3225ec955b22, cache-control=no-cache, pragma=no-cache, user-agent=Java/1.8.0_65, accept=[text/html, image/gif, image/jpeg, */*;q=.2, */*;q=.2], timestamp=1469022837172}]

现在日志上说，头"x-test将不会被映射“。怎么可能？因为它没有出现在inboundHeaderNames中？

实际上，标题似乎在GenericMessage中“消失了”：

GenericMessage [
    payload={}, 
    headers={
        http_requestMethod=GET,
        replyChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@16b10fb6,
        errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@16b10fb6,
        host=localhost:8080,
        http_requestUrl=http://localhost:8080/webapp/service/hello,
        connection=keep-alive,
        id=ba2af515-9e29-4d84-d176-5b9d0d066cb0,
        cache-control=no-cache,
        pragma=no-cache,
        user-agent=Java/1.8.0_65,
        accept=[text/html,
            image/gif,
            image/jpeg,
            */*;q=.2,
            */*;q=.2],
        timestamp=1469021452542
    }
]

我不明白为什么当前的头在HTTP请求中，但它不存在于消息通道的标题中。

Answer 1

我已经找到了这个问题的答案。

<int-http:outbound-gateway>映射必须插入到“退出” HTTP请求中的标头。

<int-http:inbound-gateway>映射包含在“输入” HTTP请求中的标头。

因此，必须定义一个"header-mapper"，即：

• 映射用于"inboundHeaderNames"的<int-http:inbound-gateway>
• 映射用于"outboundHeaderNames"的<int-http:outbound-gateway>

在我的示例中，“出站端”(客户端应用程序)的解决方案是：

<int:chain input-channel="requestChannel" output-channel="replyChannel">
    <int:header-enricher>
        <int:header name="test" value="test"></int:header>
    </int:header-enricher>
    <int-http:outbound-gateway id="gateway"
        encode-uri="true" url="http://localhost:8080/webapp/service/{request}"
        http-method="GET" header-mapper="headerMapper">
        <int-http:uri-variable name="request" expression="payload"/>
    </int-http:outbound-gateway>
</int:chain>

<bean id="headerMapper" class="org.springframework.integration.http.support.DefaultHttpHeaderMapper">
    <property name="outboundHeaderNames" value="HTTP_REQUEST_HEADERS, test" />
    <property name="userDefinedHeaderPrefix" value="" />
</bean>

"outboundHeaderNames"必须使用必须映射到“出站请求”(在本例中为“test”)中映射的头名称来设置。

而“入站端”(接收方应用程序)的解决方案是：

<int-http:inbound-gateway id="gateway" request-channel="requestChannel"
      path="/service/**" supported-methods="GET"
      reply-channel="outputChannel" header-mapper="headerMapper">
</int-http:inbound-gateway>

<bean id="headerMapper" class="org.springframework.integration.http.support.DefaultHttpHeaderMapper">
    <property name="inboundHeaderNames" value="*" />
</bean>

设置为"*"的确保在消息头中映射源请求的所有头部。

使用这种方法，我们可以将自定义头传递给HTTP请求中的任何URL，并且可以在消息通道上下文中的服务器端恢复它们。

Answer 2

打开调试日志；您应该看到有关头映射的消息，如下所示.

08:46:44.987调试主.headerName=id不会被映射 08:46:44.987调试主.headerName=test将被映射，匹配的pattern=test 08:46:44.987调试主.设置headerName=X-test，value=foo

(这是在您的第一个示例中-自定义头当前默认获得X-前缀)。