如何在DataWeave中正确获取XML的u:Id属性值

问题现象 #

输入的SOAP格式XML中，<o:UsernameToken>节点的u:Id属性带有具体UUID值，但经过DataWeave 2.0脚本转换后，输出的该属性值变为null。

原因分析 #

核心原因是脚本未明确处理自定义命名空间（u:前缀对应的命名空间）下的属性，DataWeave默认转换逻辑不会自动保留非默认命名空间的属性，且原脚本未显式引用该属性值。

解决方案 #

在DataWeave脚本中先声明u命名空间，再在映射<o:UsernameToken>节点时，显式指定保留u:Id属性并直接引用输入payload中的对应值。

示例代码 #

输入Payload（SOAP XML）

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
                  xmlns:o="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"
                  xmlns:u="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
    <soapenv:Header>
        <o:Security soapenv:mustUnderstand="1">
            <o:UsernameToken u:Id="uuid-abc123-def456-789">
                <o:Username>testUser</o:Username>
                <o:Password Type="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText">testPass</o:Password>
            </o:UsernameToken>
        </o:Security>
    </soapenv:Header>
    <soapenv:Body>
        <!-- 业务内容 -->
    </soapenv:Body>
</soapenv:Envelope>

原问题脚本（导致u:Id为null）

%dw 2.0
output application/xml
ns soapenv http://schemas.xmlsoap.org/soap/envelope/
ns o http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd
---
soapenv#Envelope: {
    soapenv#Header: {
        o#Security @(soapenv#mustUnderstand: "1"): {
            o#UsernameToken: {
                o#Username: payload.soapenv#Envelope.soapenv#Header.o#Security.o#UsernameToken.o#Username,
                o#Password @(Type: payload.soapenv#Envelope.soapenv#Header.o#Security.o#UsernameToken.o#Password.@Type): payload.soapenv#Envelope.soapenv#Header.o#Security.o#UsernameToken.o#Password
            }
        }
    },
    soapenv#Body: payload.soapenv#Envelope.soapenv#Body
}

修改后的正确脚本

%dw 2.0
output application/xml
ns soapenv http://schemas.xmlsoap.org/soap/envelope/
ns o http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd
ns u http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd
---
soapenv#Envelope: {
    soapenv#Header: {
        o#Security @(soapenv#mustUnderstand: "1"): {
            o#UsernameToken @(u#Id: payload.soapenv#Envelope.soapenv#Header.o#Security.o#UsernameToken.@u#Id): {
                o#Username: payload.soapenv#Envelope.soapenv#Header.o#Security.o#UsernameToken.o#Username,
                o#Password @(Type: payload.soapenv#Envelope.soapenv#Header.o#Security.o#UsernameToken.o#Password.@Type): payload.soapenv#Envelope.soapenv#Header.o#Security.o#UsernameToken.o#Password
            }
        }
    },
    soapenv#Body: payload.soapenv#Envelope.soapenv#Body
}

正确输出结果

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
                  xmlns:o="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"
                  xmlns:u="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
    <soapenv:Header>
        <o:Security soapenv:mustUnderstand="1">
            <o:UsernameToken u:Id="uuid-abc123-def456-789">
                <o:Username>testUser</o:Username>
                <o:Password Type="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText">testPass</o:Password>
            </o:UsernameToken>
        </o:Security>
    </soapenv:Header>
    <soapenv:Body>
        <!-- 业务内容 -->
    </soapenv:Body>
</soapenv:Envelope>

关键修改点 #

1. 新增u命名空间的声明，确保脚本能识别该前缀对应的命名空间规则。
2. 在o#UsernameToken节点后添加@(u#Id: payload...@u#Id)，显式将输入中的u:Id属性值映射到输出节点。

内容的提问来源于stack exchange，提问作者smcodemeister