WSO2 Multipart Binary Passthrough and MultipartFormData

We are currently using WSO EI 6.4 as ESB.

We made the configuration to get the behaviour "Binary Passthrough" in axis2.xml for one carbon application

<messageBuilder     contentType="multipart/form-data"   class="org.wso2.carbon.relay.BinaryRelayBuilder"/>
<messageFormatter   contentType="multipart/form-data"   class="org.wso2.carbon.relay.ExpandingMessageFormatter"/>

But now, we need to develop a new carbon application who need to create a multipart message. and so we need to change the configuration to, as decribed in this article

<messageBuilder     contentType="multipart/form-data"   class="org.apache.axis2.builder.MultipartFormDataBuilder" />
<messageFormatter   contentType="multipart/form-data"   class="org.apache.axis2.transport.http.MultipartFormDataFormatter"/>

But if we do that, we will lose the "Binary Passthrough" adn broke the first carbon app.

Is there a possiblitiy to override the messageBuilder and messageFormatter just for one carbon application?

Thank you

---

Solution

With the help of @tmoasz i was able to solve this issue. Here the full solution

<inSequence>

      <!--Extract value from Json-->
      <property name="Data1" expression="json-eval($.Data1)"/>
      <property name="Data2" expression="json-eval($.Data2)"/>
      <property name="File1" expression="json-eval($.File1)"/>

      <!-- remove body and set MessageBuilder
        if body not removed, MultipartFormDataFormatter is not call
      -->
      <script language="js">
        mc.getEnvelope().getBody().getFirstElement().detach();
      </script>
      <builder>
        <messageBuilder contentType="multipart/form-data"
          class="org.apache.axis2.builder.MultipartFormDataBuilder"
          formatterClass="org.apache.axis2.transport.http.MultipartFormDataFormatter"/>
      </builder>

      <payloadFactory media-type="xml">
        <format>
          <root xmlns="">
            <metadata xmlns="http://org.apache.axis2/xsd/form-data"
              filename="key1"
              name="key1">$1</metadata>
            <!-- content is decode from base64-->
            <file xmlns="http://org.apache.axis2/xsd/form-data"
              filename="file1.1"
              name="file1.1"
              content-type="application/xml">$3</file>
            <!-- content is not changed-->
            <metadata xmlns="http://org.apache.axis2/xsd/form-data"
              name="file1.2"
              filename="file1.2"
              content-type="application/xml">$3</metadata>
          </root>
        </format>
        <args>
          <arg expression="get-property('Data1')"/>
          <arg expression="get-property('Data2')"/>
          <arg expression="get-property('File1')"/>
        </args>
      </payloadFactory>

            <!--set messageType to trigger multiPart Formater -->
            <property name="messageType"  scope="axis2" type="STRING" value="multipart/form-data"/>
            <!--remove ContentType to force generate header content-type with boundary information -->
            <property name="ContentType" scope="axis2" action="remove"/>

      <send>
        <endpoint>
          <http method="post" uri-template="http://127.0.0.1:3000/mulitPart/wso2">
            <suspendOnFailure>
              <initialDuration>-1</initialDuration>
              <progressionFactor>-1</progressionFactor>
              <maximumDuration>0</maximumDuration>
            </suspendOnFailure>
            <markForSuspension>
              <retriesBeforeSuspension>0</retriesBeforeSuspension>
            </markForSuspension>
          </http>
        </endpoint>
      </send>


    </inSequence>

Curl for test

curl --location --request POST 'http://127.0.0.1:8280/outgoing-mail' \
--header 'Content-Type: application/json' \
--data-raw '{
    "Data1": "Value1",
    "Data2": "Value2",
    "File1" :  "PHhtbD4gICAKICAgIDxoZWxsbz5TdGFjazwvaGVsbG8+CjwveG1sPg=="
}'

Multipart Generated

--MIMEBoundary_dfa6d9a4ea9eee573969c1fae03dd6667159a66375689ec7
Content-Disposition: form-data; name="key1"; filename="key1"
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: binary

Value1
--MIMEBoundary_dfa6d9a4ea9eee573969c1fae03dd6667159a66375689ec7
Content-Disposition: form-data; name="file1.1"; filename="file1.1"
Content-Type: application/pdf; charset=ISO-8859-1
Content-Transfer-Encoding: binary

<xml>   
    <hello>Stack</hello>
</xml>
--MIMEBoundary_dfa6d9a4ea9eee573969c1fae03dd6667159a66375689ec7
Content-Disposition: form-data; name="file1.2"; filename="file1.2"
Content-Type: application/pdf; charset=ISO-8859-1
Content-Transfer-Encoding: binary

PHhtbD4gICAKICAgIDxoZWxsbz5TdGFjazwvaGVsbG8+CjwveG1sPg==
--MIMEBoundary_dfa6d9a4ea9eee573969c1fae03dd6667159a66375689ec7--

Maybe the BuilderMediator can do that, what you would to achieve. Checkout this: Builder+Mediator documentation.