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XSD to JSON Schema Add-on

The XSD to JSON Schema add-on contributes a tool for converting XML Schema files into JSON Schema files.

Compatibility:
This add-on is compatible with the following products:
  • Oxygen XML Editor
  • Oxygen XML Developer
  • Oxygen JSON Editor

Oxygen includes a tool for converting an XML Schema file (XSD) to a JSON Schema file. The XSD to JSON Schema action for invoking the tool can be found in the Tools > JSON Tools menu. It requires an additional add-on to be installed, so the first time you invoke the action, Oxygen will present a dialog box asking if you want to install it. Once installed, you need to restart Oxygen and the XSD to JSON Schema action will invoke the tool.

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Quick Installation

You can drag the following Install button and drop it into the main editor in Oxygen to quickly initiate the installation process:

Install

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Manual Installation

To manually install it the add-on, follow these instructions:

  1. Go to Help > Install new add-ons to open an add-on selection dialog box.
  2. Enter or paste https://www.oxygenxml.com/InstData/Addons/default/updateSite.xml in the Show add-ons from field or select it from the drop-down menu.
    Note:
    If you have issues connecting to the default update site, you can download the add-on package, unzip it, then use the Browse for local files action in the Install new add-ons dialog box to locate the downloaded addon.xml file.
  3. Select the XSD to JSON Schema add-on and click Next.
  4. Read the end-user license agreement, then select I accept all terms of the end-user license agreement and select Install.
  5. Restart the Oxygen application.

Result: The XSD to JSON Schema dialog box is now available and can be selected from the Tools > JSON Tools menu.

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Converting XSD to JSON Schema

To convert an XML Schema (XSD) to a JSON Schema, follow these steps:

  1. Select the XSD to JSON Schema action from the Tools > JSON Tools menu.

    Step Result: The XSD to JSON Schema dialog box is displayed:

    Figure 1. XSD to JSON Schema Dialog Box
  2. In the XSD URL field, choose or enter the URL of the XML Schema document. The conversion supports XSD versions 1.0 and 1.1.
  3. In the Output file field, choose the path for the resulting output file.
  4. [Optional] You can select the Open in Editor option to open the resulting JSON Schema document in the main editing pane.
  5. For the JSON Schema version option, choose the version of the resulting JSON schema. The possible choices are: Draft 4, Draft 6, Draft 7, 2019-09, and 2020-12.
  6. [Optional] If you select the Restrict additional content option, then additionalProperties (for objects) and additionalItems (for arrays) will be set to false in the resulting schema. By default, these keys are not in the schema, meaning that providing additional content (according to the schema) is allowed.
  7. [Optional] You can select the Preserve case of names from the XSD option if you want the names from the XSD to remain unchanged in the resulting JSON Schema. Otherwise, the default JAXB naming algorithm will be applied (for example, "some.nAMe" is changed to "SomeNAMe", or "Some_oth3r_name" is changed to "SomeOth3RName").
  8. Click the Convert button.

Result: The original XSD document is now converted to a JSON Schema document. The resulting JSON Schema will be the specified draft and will contain:

  • The $id of the schema, generated from XSD targetNamespace.
  • The $definitions section, which declares complex and enum types.
  • The anyOf section, which lists possible top-level elements as an array of objects.

Other Possible Results:

  • If an XSD type extends another type, then its schema is combined with the schema of the base type using the allOf keyword.
  • If an extension in XSD defines an element with the same name as an attribute in the base, a property named rest is generated to avoid name conflicts in JSON.
  • If a property of a complex type is a collection property, the schema of the collection items will be wrapped in the JSON array schema.
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Conversion Mappings

The following table lists the specific conversion mapping details.

XML Schema Type JSON Schema Representation
anySimpleType string, number, integer, boolean, null
anyType string, number, integer, boolean, null, object, array
string string
normalizedString string
token string
language string
Name string
NCName string
ID string
IDREF string
IDREFS array of strings
ENTITY string
ENTITIES array of strings
NMTOKEN string
NMTOKENS array of strings
boolean boolean
base64Binary array of integers
hexBinary array of integers
float number
decimal number
integer integer
nonPositiveInteger integer
negativeInteger integer
long integer
int integer
short integer
byte integer
nonNegativeInteger integer
unsignedLong integer
unsignedInt integer
unsignedShort integer
unsignedByte integer
positiveInteger integer
double number
anyURI string with "format":"uri"
QName object with "namespaceURI", "localPart", "prefix"
duration string
dateTime string with "format":"date-time"
date string with "format":"date"
time string with "format":"time"
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Conversion Limitations

In most cases, the conversion creates an equivalent schema, but there are some limitations:

  • Restrictions/facets are not taken into consideration when converting (fractionDigits, pattern, totalDigits, whiteSpace, minInclusive, maxInclusive, and the restrictions for length, except enumeration). However, extensions and indicators are properly converted (minOccurs, maxOccurs, group, sequence, choice).
  • The <documentation> element is not converted into <description>.
  • The @substitutionGroup attribute for an element that has no declared type becomes a reference to the element that can substitute it.
  • The @block attribute is not taken into consideration during the conversion.