gistfile1.xml

<sfdc:query config-ref="Salesforce" query="SELECT Id, Name, Body FROM Attachment WHERE Id = '#[message.inboundProperties['id']]'" />
        <choice>
            <when expression="return ((ArrayList)payload).size &gt; 0">
                <processor-chain>
                    <expression-transformer expression="return payload[0]"/>
                    <set-variable variableName="attachName" value="#[payload['name']]" />
                    <set-payload value="#[payload['body']]" />
                    <base64-decoder-transformer />
                    <scripting:transformer doc:name="to InputStream">
                        <scripting:script engine="Groovy">
                            <scripting:text><![CDATA[return new java.io.ByteArrayInputStream(payload)]]></scripting:text>
                        </scripting:script>
                    </scripting:transformer>
                    <boxnet:upload-stream config-ref="Boxnet" filename="#[flowVars['attachName']]" />
                </processor-chain>
            </when>
            <otherwise>
                <processor-chain>
                    <logger message="No ATTACHMENT found" level="ERROR"/>
                </processor-chain>
            </otherwise>
        </choice>