These query languages can be used to extract values from JSON or XML. Each has its own syntax allowing you to select a node to extract a value from. The table below shows some of the syntax allowed by each language. 


XPathJSONPathDescription
/$The base node in the object.
.@The current object in the node path.
/. or []Accessing a child node, or specific child node
..n/aAccessing the parent of the current node.
//..Recursive child decent.
**Wildcard operator to access any node.
@n/aAccessing an attribute.
[][]Accessing an element within a list of nodes.
|[,]Union of two sets of nodes.
n/a[start:end:step]Accessing elements as a slice of a set of elements.
[]?()Accessing nodes with a filter applied.


Here is some example text in JSON and XML.


{ 
  "messages": {
    "staging": [ 
      { 
        "author"  : "tim_bot",
        "category": "information",
        "message" : "Building..."
      },
      { 
        "author"  : "tim_bot",
        "category": "information",
        "message" : "Testing..."
      },
      { 
        "author"  : "tim_bot",
        "category": "information",
        "message" : "Completed!"
      }
    ],
    "production": [
      { 
        "author"  : "jill_bot",
        "category": "information",
        "message" : "Building..."
      },
      { 
        "author"  : "jill_bot",
        "category": "error",
        "message" : "Build Failed!"
      }
    ]
  }
}



<?xml version="1.0" encoding="UTF-8" ?>
<messages>
  <staging>
    <author>tim_bot</author>
    <category>information</category>
    <message>Building...</message>
  </staging>
  <staging>
    <author>tim_bot</author>
    <category>information</category>
    <message>Testing...</message>
  </staging>
  <staging>
    <author>tim_bot</author>
    <category>information</category>
    <message>Completed!</message>
  </staging>
  <production>
    <author>jill_bot</author>
    <category>information</category>
    <message>Building...</message>
  </production>
  <production>
    <author>jill_bot</author>
    <category>error</category>
    <message>Build Failed!</message>
  </production>
</messages>



The following are XPath and JSONPath examples that could be used to extract information from the example text.

XPathJSONPathResult
/messages/staging/author$.messages.staging[*].authorThe authors of all messages sent to staging
//author$..authorAll the authors of all messages
/messages/*$.messages.*All channels messages were sent to. Staging and production.
/messages//category$.messages..categoryThe categories of all messages.
//staging[3]$..staging[2]The third message sent to staging.
//staging[last()]$..staging[(@.length-1)]
$..staging[-1:]		The last message sent to staging.
//staging[position()<3]$..staging[0,1]
$..staging[:2]		The first two messages sent to staging.
//staging[category="error"]$..staging[?(@.category="error")]All the messages sent to staging with an error category. This would return no values.
//*$..*All nodes in the response.
  • No labels