如何使用 apigee 中的 ExtractVariables 策略读取响应返回的 xml 项目列表的第二个元素? [英] How to read 2nd element of list of xml items returned in response using ExtractVariables policy in apigee?

问题描述

我收到一个 XML 负载响应目标系统，它遵循以下结构...

I am receiving an XML payload response target system that follows the following structure...

    <feed xmlns="http://www.w3.org/2005/Atom">
   <title/>
   <id>7c818dcd-d66a-4273-b043-ff468b956d1b</id>
   <link rel="self" href="http://fhirtest.uhn.ca/baseDstu1/Patient?address=usa"/>
   <link rel="next" href="http://fhirtest.uhn.ca/baseDstu1?_getpages=943fd84d-1f93-4c97-8bba-534e944e74cf&amp;_getpagesoffset=10&amp;_count=10&amp;_format=xml&amp;_pretty=true"/>
   <link rel="fhir-base" href="http://fhirtest.uhn.ca/baseDstu1"/>
  </feed>

并且我正在尝试使用提取变量策略来获取 <link> 标签的 href 属性值，其中属性 rel="next".

and am trying to use an Extract Variables policy to obtain the value of the href attribute of <link> tag where attribute rel="next".

以下是我编写的提取变量策略，用于提取第一个 标签的属性 href 值.

Following is the Extract variable policy i have written that extracts value of attribute href of first <link> tag.

<ExtractVariables name="ReadLinkURLs">
       <Source>response</Source>
       <XMLPayload>
        <Namespaces>
            <Namespace prefix="patient">http://www.w3.org/2005/Atom</Namespace>
        </Namespaces>
        <Variable name="href" type="string">
            <XPath>/patient:feed/patient:link/@href</XPath>
        </Variable>
    </XMLPayload>
       <VariablePrefix>pagingpatient</VariablePrefix>
    </ExtractVariables>

变量 'href' 设置为字符串 "http://fhirtest.uhn.ca/baseDstu1/Patient?address=usa"，即第一个值.您能否建议我为读取 <link> 元素的 href 属性值而必须做出的更改，其中 rel="next".提前致谢.

The variable 'href' is set to the string "http://fhirtest.uhn.ca/baseDstu1/Patient?address=usa", i.e the first value. Can you please suggest the changes i have to make to read the href attribute value of that <link> element in which rel="next". Thanks in advance.

推荐答案

我不知道 apigee，但 XPath 谓词表达式将 元素限制为仅那些具有 rel 属性值等于 "next" 是 [@rel='next'].因此，您的整个 XPath 表达式应如下所示:

I don't know about apigee, but the XPath predicate expression to restrict <link> elements to only those having rel attribute value equals "next" is [@rel='next']. So, your entire XPath expression should look about like this :

<XPath>/patient:feed/patient:link[@rel='next']/@href</XPath>

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