Convert XML to JSON

The API Platform enables developers to convert messages from the extensible markup language (XML) format to JavaScript object notation (JSON) format to the by using the XMLtoJSON policy type. This policy is useful for enabling backend XML services to support RESTful apps that require JSON (for example, due to a lack of an XML parsing capabilities on the client).

In a typical mediation scenario, a JSONtoXML policy on the inbound request flow is often paired with an XMLtoJSON policy on the outbound response flow. By combining policies this way, a JSON API can be exposed for backend services that natively support only XML.

For scenarios where APIs are consumed by diverse clients apps which may require either JSON and XML, the format of the response can be dynamically set by configuring JSONtoXML and XMLtoJSON policies to execute conditionally. See the API Platform Developer Guide topic Customize responses for mobile devices for an implementation of this scenario.

The HTTP Content-type header of the source message must be set to text/xml. If the HTTP Content-type header of the source message is not text/xml, the policy is not enforced.

The payload of the XML message is parsed and converted into JSON, and the HTTP Content-type header of the XML-formatted message is set to application/json.

Sample

This policy type defines a set of reasonable defaults. The minimal policy configuration required to convert XML to JSON is the following:

<XMLToJSON name="ConvertToJSON">
  <Options>
  </Options>
  <OutputVariable>response</OutputVariable>
  <Source>response</Source>
</XMLToJSON>

Assuming that the intent is to convert an XML-formatted response into a JSON-formatted response, the policy would be attached to a response Flow (for example, the ProxyEndpoint response PostFlow). This configuration takes a JSON-formatted response message as the source, and then creates an XML-formatted message that is populated in the response OutputVariable. The API Platform automatically uses the content of this variable as the message for next processing step.

Configuring an XML to JSON policy

For more advanced control over mapping XML to JSON structures, use the following configuration elements. All fields are optional. However, if you specify NamespaceBlockName, you must also specify DefaultNamespaceNodeName and NamespaceSeparator.

<a>
  <b>100</b>
  <c>value</c>
</a>

{
    "a": {
        "b": 100,
        "c": "value"
    }
}

{
    "a": {
        "b": "100",
        "c": "value"
    }
}

<a>
  <b>true</b>
  <c>value</c>
</a>

{
    "a": {
        "b": true,
        "c": "value"
    }
}

{
    "a": {
        "b": "true",
        "c": "value"
    }
}

<a>
  <b></b>
  <c>value</c>
</a>

{
  "a": {
    "b": null,
    "c": "value"
  }
}

{
  "a": {
    "b": {},
    "c": "value"
  }
}

<a xmlns="http://ns.com" xmlns:ns1="http://ns1.com">
  <ns1:b>value</ns1:b>
</a>

{
    "a": {
        "b": "value"
    }
}

{
    "a": {
        "#namespaces": {
            "&": "http://ns.com",
            "ns1": "http://ns1.com"
        },
        "ns1%b": "value"
    }
}

<a>
  <b>value1</b>
  <c>value2<d>value3</d>value4</c>
</a>

{
    "a": {
        "b": {
            "TEXT": "value1"
        },
        "c": {
            "TEXT": [
                "value2",
                "value4"
            ],
            "d": {
                "TEXT": "value3"
            }
        }
    }
}

{
    "a": {
        "b": "value1",
        "c": {
            "TEXT": [
                "value2",
                "value4"
            ],
            {
                "d": "value3",
                
            }
        }
    }

<a att1="value1" att2="value2"/>

{
    "a": {
        "ATT_BLOCK": {
            "@att1": "value1",
            "@att2": "value2"
        }
    }
}

{
    "a": {
        "ATT_BLOCK": {
            "att1": "value1",
            "att2": "value2"
        }
    }
}

{
    "a": {
        "@att1": "value1",
        "@att2": "value2"
    }
}

{
    "a": {
        "att1": "value1",
        "att2": "value2"
    }
}

<a>value</a>

PREFIX_{
    "a": "value"
}_SUFFIX

PREFIX_{
  "a" : "value"
}

{
  "a" : "value"
}_SUFFIX

{
    "a": "value"
}

Policy schema

Each policy must conform to a policy schema. All policy constructs such as elements and attributes mentioned above are defined in a schema. To download the schema, click here.

Example - XML to JSON

<XMLToJSON name="mypolicy">
    <Source>request</Source>
    <OutputVariable>response</OutputVariable>
    <Options>
        <RecognizeNumber>true</RecognizeNumber>
        <RecognizeBoolean>true</RecognizeBoolean>
        <RecognizeNull>true</RecognizeNull>
        <NullValue>NULL</NullValue>
        <NamespaceSeparator>%</NamespaceSeparator>
        <NamespaceBlockName>#namespaces</NamespaceBlockName>
        <DefaultNamespaceNodeName>&</DefaultNamespaceNodeName>
        <TextAlwaysAsProperty>false</TextAlwaysAsProperty>
        <TextNodeName>TEXT</TextNodeName>
        <AttributeBlockName>ATT_BLOCK</AttributeBlockName>
        <AttributePrefix>@</AttributePrefix>
        <OutputPrefix>PREFIX_</OutputPrefix>
        <OutputSuffix>_SUFFIX</OutputSuffix>
    </Options>
</XMLToJSON>

<!--Note that you can use format definition to configure the options. The format definition contains all the <options> elements mentioned in the above example (see the below example).-->

<XMLToJSON name="mypolicy">
    <Source>request</Source>
    <OutputVariable>response</OutputVariable>
    <Format>myFormat</Format>
</XMLToJSON>