validate - DataPower API Gateway

Use the validate policy to validate the payload in an assembly flow against a schema.

Gateway support

Note: This page describes the validate policy implementation in the DataPower® API Gateway. If you are using the DataPower Gateway (v5 compatible), see validate - DataPower Gateway (v5 compatible).

For information on the different types of gateway, see API Connect gateway types.

Table 1. Table showing which gateways support this policy, and the corresponding policy version
Gateway	Policy version
DataPower API Gateway	2.0.0 2.1.0 (DataPower API Gateway Version 10.0.0.1 or later) 2.2.0 DataPower API Gateway Version 10.0.1.1 or later) 2.3.0 DataPower API Gateway Version 10.0.1.3 or later)

This topic describes how to configure the policy in your OpenAPI source; for details on how to configure the policy in the assembly user interface, see Validate - DataPower API Gateway.

About

The validate policy has the following format:

- validate:
    version: version
    title: title
    description: description
    validate-against: validation_mechanism
         .
         .
         .
       properties_specific_to_the specified_validation_mechanism
         .
         .
         .

Apply this policy by adding an assembly extension with an execute field to your OpenAPI definition file.

Note: With the DataPower API Gateway, the input to the validate policy must be parsed data. One way to produce parsed data is to use a parse policy before a validate policy in your assembly flow, which provides explicit control of the parse action.

Properties

The following table describes the policy properties:

Table 2. validate policy properties
Property	Required	Description	Data type
version	Yes	The policy version number	string
title	No	A title for the policy.	string
description	No	A policy description.	string
input	No	Identifies a variable in the API context. The content of the `body` field of the variable, which is represented by `variable_name.body`, is the input data to validate. By default, the variable name is `message`.	string
output	No	Specifies the name of a variable in the API context. If the validation passes, the body field of the output variable, which is represented by `variable_name.body`, stores the output of the assembly validate action. If the schema to validate is a JSON schema, the validation also adds any default values that are missing from the payload. If the validation fails, no output is stored. If an output variable is not specified, the results of the assembly validate action are not saved.	string
validate-against	Yes	Specifies the schema to be used for validating the payload. Valid values: `definition`: A previously defined schema will be used to validate the payload that is returned from other invoke actions or tasks in the assembly flow. In addition, supply a `definition` property to specify the required schema. `url`: the schema is identified by a URL location. In addition, supply the following properties: `json-schema` field: the URL of the JSON schema to be used for validating a JSON payload. `xml-validation-mode`, specify one of the following values to define how an XML payload is validated: `xsd`: use an XML schema; in addition, supply an `xml-schema` property that specifies the URL of the XML schema. `wsdl`: use a WSDL schema; in addition, supply an `xml-schema` property that specifies the URL of the WSDL schema to be used for validating a SOAP payload.. `soap-body`: validate the body of a SOAP message against the XML schema only. Note: The following limitations apply to schemas used for JSON validation, which include JSON schemas and OpenAPI documents that are used as schemas for validation. Exceeding these limits can impact compilation performance and is not supported. Maximum of 6,500 lines. Each key and each item in an array count as a line. Maximum recursion depth of 250. Maximum of 3,000 items in `enum` lists. `wsdl`: (use with a SOAP service based API only) use the XML schema in the WSDL file associated with the API operation or the API path. `body-param`: validate the request input against the schema definition that is specified in the `schema` property for the request parameter for this operation. `response-param`: validate the response to be returned to the client application, against the schema definition that is specified in the `schema` property for the response parameter for this operation. `graphql`: (use with a GraphQL proxy API only) validate the payload against the GraphQL schema that has been imported into the GraphQL proxy API. In addition, either the GraphQL query or response, depending on the input, is analyzed against the GraphQL schema to calculate the cost, and the result is placed in the API context. For more information on GraphQL proxy APIs, see Creating a GraphQL proxy API and GraphQL context variables. .	string

You can also apply a validate policy by using the API Designer assembly editor to add a built-in policy to the API. For more information, see Validate - DataPower API Gateway in the built-in policies section.

Example 1

- validate:
    version: 2.0.0
    title: 'validate, response parameter schema'
    validate-against: response-param

Example 2

- validate:
    version: 2.0.0
    title: 'validate, predefined schema'
    validate-against: definition
    definition: '#/definitions/RouteOutput'

Example 3

- validate:
    version: 2.0.0
    title: 'validate, JSON and XML schema URLs'
    validate-against: url
    json-schema: 'https://my.json.schema'
    xml-validation-mode: xsd
    xml-schema: 'https://my.xml.schema'