Software AG Products 10.5 | Using API Gateway | Policies | System-defined Stages and Policies | Error Handling | Conditional Error Processing
 
Conditional Error Processing
Error Handling is the process of passing an exception message issued as a result of a run-time error to take any necessary actions. This policy returns a custom error message (and the native provider's service fault content) to the application when the native provider returns a service fault. You can configure conditional error processing and use variables to create custom error messages.
The table lists the properties that you can specify for this policy:
Parameter
Description
Error conditions. Specifies the error conditions and how these error conditions should be processed.
Status Code Error Criteria
Specify the error status code.
Provide a value for the Code.
Header Error Criteria
Provide the details of the custom HTTP header(s) included in the client requests.
Provide the following information:
*Header Name. Specifies the name of the HTTP header.
*Header Value. Specifies the value of the HTTP header.
Payload Criteria
Provide the details of the payload criteria in the API request.
In the Payload identifier section, click Add payload identifier, provide the following information, and click Add.
*Expression type. Specifies the type of expression, which is used for identification. You can select one the following expression type:
*XPath. Provide the following information:
*Payload Expression. Specifies the payload expression that the specified XPath expression type in the request or the response has to be converted to. For example: /name/id.
The response maybe a native service error or API Gateway generated error.
*Namespace Prefix. The namespace prefix of the payload expression to be validated.
*Namespace URI. The namespace URI of the payload expression to be validated.
Note:
You can add multiple namespace prefix and URI by clicking .
*JSONPath. Provide the Payload Expression that specifies the payload expression that the specified JSONPath expression type in the request or the response has to be converted to. For example: $.name.id.
The response maybe a native service error or API Gateway generated error.
*Text. Provide the Payload Expression that specifies the payload expression that the specified Text expression type in the request or response has to be converted to. For example: any valid regular expression.
The response maybe a native service error or API Gateway generated error.
You can add multiple payload identifiers as required.
Note:
Only one payload identifier of each type is allowed. For example, you can add a maximum of three payload identifiers, each being of a different type.
Value: Specifies a value that has to match with the value contained in the error Response.
Pre-Processing. Specifies how the native error response is to be processed before API Gateway processes it. .
Invoke webMethods Integration Server Service
Specify the webMethods IS service to pre-process the error message.
Provide the following information
*webMethods IS Service. Specify the webMethods IS service to be invoked to pre-process the error messages.
You can add multiple entries for webMethods IS service by clicking .
*Run as User. Specifies the authentication mode to invoke the IS service. If this field is left blank the incoming credentials of the user, identified by API Gateway, are used to authenticate and invoke the IS service. You can also specify a particular user, you want API Gateway to use to run the IS service.
*Comply to IS Spec. Mark this as true if you want the input and the output parameters to comply to the IS Spec present in pub.apigateway.invokeISService.specifications folder in wmAPIGateway package.
*webMethods IS Service alias. Start typing the webMethods alias name and select the alias from the type-ahead search results displayed to add one or more aliases.
XSLT Transformation
Provide the XSLT file and feature you want to use to transform the service error response.
Click Browse to select the XSLT file and upload it.
Provide the following information for the XSLT feature:
*Feature Name. Specifies the name of the XSLT feature.
*Feature Value. Specifies the value for the feature.
You can add multiple entries for feature name and value by clicking .
Note:
API Gateway supports XSLT 1.0 and XSLT 2.0.
Custom Error Variables. Specifies the error variables to be used in the custom error message.
Payload Type
Specify the payload type.
Available values are:
*Request. Specifies the request payload type.
*Response. Specifies the response payload type.
Name
Provide a name for the payload type.
Payload Identifier
Provide the details of the payload criteria in the API request.
In the Payload identifier section, click Add payload identifier, provide the following information, and click Add.
*Expression type. Specifies the type of expression contained in the payload request.
*Payload Expression. Specifies the payload expression that the specified expression type in the request has to be converted to.
*Namespace Prefix. The namespace prefix of the payload expression to be validated.
*Namespace URI. The namespace URI of the payload expression to be validated.
Note:
You can add multiple namespace prefix and URI using the Add button.
You can add multiple payload identifiers as required.
Failure Message. Specifies the custom failure message format that API Gateway should send to the application. Specify whether the message should be in the text, json, or xml format.
Send Native Provider Fault Message
Enable this parameter so that API Gateway sends the native SOAP or REST failure message to the application.
When you disable this parameter, the failure message is ignored when a fault is returned by the native API provider.
Post-Processing. Specifies how the error response sent by the native service is to be processed before sending the same to the application.
Invoke webMethods Integration Server Service
Specify the webMethods IS Service for post-processing the error message.
Provide the following information
*webMethods IS Service. Specify the webMethods IS service to be invoked to post-process the error messages.
You can add multiple entries for webMethods IS service by clicking .
*Run as User. Specifies the authentication mode to invoke the IS service. If this field is left blank the incoming credentials of the user, identified by API Gateway, are used to authenticate and invoke the IS service. You can also specify a particular user, you want API Gateway to use to run the IS service.
*Comply to IS Spec. Mark this as true if you want the input and the output parameters to comply to the IS Spec present in pub.apigateway.invokeISService.specifications folder in wmAPIGateway package.
*webMethods IS Service alias. Start typing the webMethods alias name and select the alias from the type-ahead search results displayed to add one or more aliases.
XSLT Transformation
Provide the XSLT file that you want to use to transform the service error response.
Provide the following information for the XSLT feature:
*Feature Name. Specifies the name of the XSLT feature.
*Feature Value. Specifies the value for the feature.
You can add multiple entries for feature names and values by clicking .
Note:
API Gateway supports XSLT 1.0 and XSLT 2.0.