How to declare reusable transformer in XML without 'input-channel'?












2















In my application I would like to re-use the same message transformer inside of multiple <int:chain>.



In such chains I perform http requests to different endpoints and I need to add the same basic authentication header. I would like to declare the code for adding a header only once, i.e:



<int:header-enricher id="authHeaderAdder">
<int:header expression="'Basic ' + new String(T(java.util.Base64).encoder.encode(('${http.user}' + ':' + '${http.password}').bytes))"
name="Authorization"/>
</int:header-enricher>


And then I would like to use it with ref in my chain before making http request:



<int:chain input-channel="someHttpChain">
<int:transformer ref="authHeaderAdder"/>
<http:outbound-gateway.../>
<int:transformer ref="someResponseTransformer"/>
</int:chain>


The problem is that I get an error on application startup:




Configuration problem: The 'input-channel' attribute is required for the top-level endpoint element: 'int:header-enricher' with id='authHeaderAdder'




How can I re-use authHeaderAdder without writing any java code and making a <bean/>?










share|improve this question





























    2















    In my application I would like to re-use the same message transformer inside of multiple <int:chain>.



    In such chains I perform http requests to different endpoints and I need to add the same basic authentication header. I would like to declare the code for adding a header only once, i.e:



    <int:header-enricher id="authHeaderAdder">
    <int:header expression="'Basic ' + new String(T(java.util.Base64).encoder.encode(('${http.user}' + ':' + '${http.password}').bytes))"
    name="Authorization"/>
    </int:header-enricher>


    And then I would like to use it with ref in my chain before making http request:



    <int:chain input-channel="someHttpChain">
    <int:transformer ref="authHeaderAdder"/>
    <http:outbound-gateway.../>
    <int:transformer ref="someResponseTransformer"/>
    </int:chain>


    The problem is that I get an error on application startup:




    Configuration problem: The 'input-channel' attribute is required for the top-level endpoint element: 'int:header-enricher' with id='authHeaderAdder'




    How can I re-use authHeaderAdder without writing any java code and making a <bean/>?










    share|improve this question



























      2












      2








      2








      In my application I would like to re-use the same message transformer inside of multiple <int:chain>.



      In such chains I perform http requests to different endpoints and I need to add the same basic authentication header. I would like to declare the code for adding a header only once, i.e:



      <int:header-enricher id="authHeaderAdder">
      <int:header expression="'Basic ' + new String(T(java.util.Base64).encoder.encode(('${http.user}' + ':' + '${http.password}').bytes))"
      name="Authorization"/>
      </int:header-enricher>


      And then I would like to use it with ref in my chain before making http request:



      <int:chain input-channel="someHttpChain">
      <int:transformer ref="authHeaderAdder"/>
      <http:outbound-gateway.../>
      <int:transformer ref="someResponseTransformer"/>
      </int:chain>


      The problem is that I get an error on application startup:




      Configuration problem: The 'input-channel' attribute is required for the top-level endpoint element: 'int:header-enricher' with id='authHeaderAdder'




      How can I re-use authHeaderAdder without writing any java code and making a <bean/>?










      share|improve this question
















      In my application I would like to re-use the same message transformer inside of multiple <int:chain>.



      In such chains I perform http requests to different endpoints and I need to add the same basic authentication header. I would like to declare the code for adding a header only once, i.e:



      <int:header-enricher id="authHeaderAdder">
      <int:header expression="'Basic ' + new String(T(java.util.Base64).encoder.encode(('${http.user}' + ':' + '${http.password}').bytes))"
      name="Authorization"/>
      </int:header-enricher>


      And then I would like to use it with ref in my chain before making http request:



      <int:chain input-channel="someHttpChain">
      <int:transformer ref="authHeaderAdder"/>
      <http:outbound-gateway.../>
      <int:transformer ref="someResponseTransformer"/>
      </int:chain>


      The problem is that I get an error on application startup:




      Configuration problem: The 'input-channel' attribute is required for the top-level endpoint element: 'int:header-enricher' with id='authHeaderAdder'




      How can I re-use authHeaderAdder without writing any java code and making a <bean/>?







      spring-integration






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 21 '18 at 12:45









      B001ᛦ

      1,14251320




      1,14251320










      asked Nov 21 '18 at 12:43









      DerpDerp

      1,04511324




      1,04511324
























          1 Answer
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          2














          You definitely need to use an input-channel on that <int:header-enricher>, e.g. input-channel="authChannel" but inside the <chain> you get a gain to use something like <int:gateway request-channel="authChannel"/>. That's all: you are reusing the same transformer, but via the Spring Integration trick with the MessageChannel.



          Such an approach is cool the way that you can add more endpoint in that authChannel flow without any changes in the original flow where you use that gateway.






          share|improve this answer
























          • Also, even if you declare the enricher handler as a <bean/> instead, it can't be reused in multiple chains because the enricher only has one outputChannel the framework prevents referencing the same handler in multiple places for exactly this reason.

            – Gary Russell
            Nov 21 '18 at 14:35











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          1 Answer
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          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          2














          You definitely need to use an input-channel on that <int:header-enricher>, e.g. input-channel="authChannel" but inside the <chain> you get a gain to use something like <int:gateway request-channel="authChannel"/>. That's all: you are reusing the same transformer, but via the Spring Integration trick with the MessageChannel.



          Such an approach is cool the way that you can add more endpoint in that authChannel flow without any changes in the original flow where you use that gateway.






          share|improve this answer
























          • Also, even if you declare the enricher handler as a <bean/> instead, it can't be reused in multiple chains because the enricher only has one outputChannel the framework prevents referencing the same handler in multiple places for exactly this reason.

            – Gary Russell
            Nov 21 '18 at 14:35
















          2














          You definitely need to use an input-channel on that <int:header-enricher>, e.g. input-channel="authChannel" but inside the <chain> you get a gain to use something like <int:gateway request-channel="authChannel"/>. That's all: you are reusing the same transformer, but via the Spring Integration trick with the MessageChannel.



          Such an approach is cool the way that you can add more endpoint in that authChannel flow without any changes in the original flow where you use that gateway.






          share|improve this answer
























          • Also, even if you declare the enricher handler as a <bean/> instead, it can't be reused in multiple chains because the enricher only has one outputChannel the framework prevents referencing the same handler in multiple places for exactly this reason.

            – Gary Russell
            Nov 21 '18 at 14:35














          2












          2








          2







          You definitely need to use an input-channel on that <int:header-enricher>, e.g. input-channel="authChannel" but inside the <chain> you get a gain to use something like <int:gateway request-channel="authChannel"/>. That's all: you are reusing the same transformer, but via the Spring Integration trick with the MessageChannel.



          Such an approach is cool the way that you can add more endpoint in that authChannel flow without any changes in the original flow where you use that gateway.






          share|improve this answer













          You definitely need to use an input-channel on that <int:header-enricher>, e.g. input-channel="authChannel" but inside the <chain> you get a gain to use something like <int:gateway request-channel="authChannel"/>. That's all: you are reusing the same transformer, but via the Spring Integration trick with the MessageChannel.



          Such an approach is cool the way that you can add more endpoint in that authChannel flow without any changes in the original flow where you use that gateway.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 21 '18 at 14:02









          Artem BilanArtem Bilan

          65.3k84668




          65.3k84668













          • Also, even if you declare the enricher handler as a <bean/> instead, it can't be reused in multiple chains because the enricher only has one outputChannel the framework prevents referencing the same handler in multiple places for exactly this reason.

            – Gary Russell
            Nov 21 '18 at 14:35



















          • Also, even if you declare the enricher handler as a <bean/> instead, it can't be reused in multiple chains because the enricher only has one outputChannel the framework prevents referencing the same handler in multiple places for exactly this reason.

            – Gary Russell
            Nov 21 '18 at 14:35

















          Also, even if you declare the enricher handler as a <bean/> instead, it can't be reused in multiple chains because the enricher only has one outputChannel the framework prevents referencing the same handler in multiple places for exactly this reason.

          – Gary Russell
          Nov 21 '18 at 14:35





          Also, even if you declare the enricher handler as a <bean/> instead, it can't be reused in multiple chains because the enricher only has one outputChannel the framework prevents referencing the same handler in multiple places for exactly this reason.

          – Gary Russell
          Nov 21 '18 at 14:35




















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