Parsing curl response in xml format with xmllint-CodePudding

I am trying to parse the curl response in xml format to retrieve value of 'version'. I am using below command:

curl -v -k -X GET -u username:password -H "Content-Type: application/xml" -H "Accept: application/xml" http://dev_server_host:8080/rest/process/list/template?process=notification_process | xmllint  --xpath "//proc:version" -

PFB, sample response of this curl command when I don't use xmllint.

<proc:basicProcessTemplate  xmlns:proc="http://www.example.com/bx/2009/management/processManagerType">
    <proc:processQName>
        <proc:moduleName>some_awesome_notification_module</proc:moduleName>
        <proc:processName>notification_process</proc:processName>
        <proc:version>1.0.0.20220215185833172</proc:version>
    </proc:processQName>
    <proc:description>sample process to send notifications</proc:description>
</proc:basicProcessTemplate>

However, when I use xmllint as mentioned above, below error is shown in terminal:

XPath error : Undefined namespace prefix
xmlXPathEval: evaluation failed
XPath evaluation failure

Can you please help to identify correct xpath which I can send in xmllint command to retrieve value of 'version'.

Please Note: As I am using query parameter 'process', only one 'proc:processQName' element will be returned in response. Array is not expected in response for 'proc:processQName' element.

CodePudding user response：

The namespace is used but not defined in the node you are looking for.

Therefore you have to modify your query to check the node's name and namespace separately:

xmllint --xpath '//*[
  namespace-uri() = "http://www.example.com/bx/2009/management/processManagerType"
  and local-name() = "version"
]/text()'

1.0.0.20220215185833172

If the namespace is defined in a parent node (as it is the case in your root node), you can simplify the query by checking by reference:

xmllint --xpath '//*[
  namespace-uri() = namespace-uri(/*) and local-name() = "version"
]/text()'

1.0.0.20220215185833172

If your query doesn't rely on the specific namespace, you can also omit that part entirely and select nodes with any namespace (matching the name, though):

xmllint --xpath '//*[local-name() = "version"]/text()'

1.0.0.20220215185833172

You might also be interested in using another, less pedantic tool instead:

With XMLStarlet you can essentially use your original query string:

xmlstarlet sel -t -v "//proc:version"

1.0.0.20220215185833172

With xq, querying is a little bit different because under the hood it is actually running a jq query:

xq -r '.. | ."proc:version"? // empty'

1.0.0.20220215185833172