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Kony Fabric console User Guide: Integration > Advanced Configurations > Why Use Rules

Rules

Kony Fabric provides the ability to write custom code as pre and post processors to modify request and response parameters to service calls. Historically custom code can be implemented either in Java or JavaScript. To simplify implementing custom logic in pre and post processors, a new Rules option is introduced from Kony Fabric V8 SP4. You can use the Rules option to define your custom logic as a set of rules. This option makes defining pre and post processor custom logic closer to human language and is built using MVEL.

Note: The Rules functionality is supported only for the pre and post processor of integration services.

Built-in Objects

The following objects help you to write rules in Kony Fabric.

Objects Description
"configurationParameters"

Used to access the Server and Client App parameters that are set by the developer in the App Services console. This is equivalent to using ConfigurableParameters in Java.
"continueExecution"

Used in the Pre-processor to terminate back-end calls.

Set the value to false if you want to terminate the back-end call. By default, the value is set to true.
"customMetrics"

This is used to access custom metrics.

For more details to create custom reports and Metrics, refer Custom Reporting – Metrics, Reports, and Dashboard Guide
“deviceHeadersMap”

Used to set headers that are passed to the client and is equivalent to using setDeviceHeaders in Java.
"headerMap"

Used to access the header map of a request. A client can directly access the header map or the individual key-value pairs of the header map.
“identityHandler"

Used to access the identity attributes when a service is protected by an identity service.

"inputMap"

Used to access the input map of a request. A client can directly access the input map or the individual key-value pairs of the input map.
"logger" Used to add a log statement with the appropriate level.
"response"

Used to modify the response body and is equivalent to using setResponse in Java.
"results"

Used to modify the results. A Result is an abstraction of a back-end response. The Result is a collection of Params, Data-sets, and Records. For more details, refer Result.
"resultCache"

Used to access the cache in pre-processor and post-processor. This is equivalent to using ResultCache in Java.
"servicesManager"

Used to invoke an integration service with the specified service id, operation id and version.
"session"

Used to modify the session that is associated with the request.

For more details, refer Session

A client can access values from the session and the individual attributes of the session.
“statusCode” Used to set the status code of the response and is equivalent to using setStatusCode in Java.
"ua"

Used to access the User Agent Header of the request.

Sample Rules

ClosedModify request input
Use Case

Changing request input before sending it to the back end.

For example, you can map the account type received from the request to an account code.
Rule 
name: "Convert account type to account code in pre-processor"
description: "Rule to convert account type to account code" 
condition: "AccountType == \"Loan Account\""
actions:
   - "inputMap.AccountCode = 1" 
   - "inputMap.Message = \"This is a loan account\""

The given sample rules above checks the account type, if the account type is Loan Account, then the associated account code is set to 1.

The inputMap object is used to access the parameters in the request that comes from the device.
ClosedModify result
Use Case

Modifying the result of an operation.

For example, you can add the account type in the result depending upon the account code.
Rule 
name: "Add parameter in result"
description: "Add a parameter in result for a specific account type"
condition: "AccountCode == 1"
actions:
    - "results.addParam(\"AccountType\", \"Loan Account\")"

The given sample rule checks the account code, if the account code is equal to 1, then the account type parameter is set as Loan Account.

The results object is used to modify the result of an operation.
ClosedModify response, status code and headers sent to a device
Use Case

Changing the response body, status code, and headers that are sent to the device.

For example, you can categorize the customer based on the quarterly average balance and send specific headers to the device to render appropriate UX of client application.
Rule 
name: "Modify response in rules."
description: "Set response message, status code and headers sent to device."
condition: "quarterlyAvgBalance >= 100000"
actions:
	- "response = \"{\\\"category\\\": \\\"Preferred customer\\\"}\""
	- "statusCode = 200"
	- "deviceHeadersMap.put(\"X-Kony-Preferred-Customer\", \"true\")"

The given sample rule checks the quarterlyAvgBalance parameter. If the parameter is greater than or equal to 100000, then the response body, status code and headers sent to the device are changed.

The response object is used to modify the response body.

The statusCode object is used to set the status code.

The deviceHeadersMap object is used to modify headers that are sent to the device.
ClosedAbort call to a back end
Use case

Aborting the call to back end in pre-processor.

For example, you can allow requests only from mobile devices.
Rule 
name: "Abort call to back end"
description: "Check if user agent is not mobile then abort the call to back end"
priority: 1
condition: "ua != \"mobile\""
actions:
   - "continueExecution = false;"
   - "results.addErrMsgParam(\"Platform not supported\");"
   - "results.addHttpStatusCodeParam(404);"
   - "results.addOpstatusParam(-1);"

The given sample rule checks the user agent, if the user agent is not equal to mobile, then the request is canceled by setting the continueExecution action to false.

The continueExecution object is used to control the further execution of the request. By default, it is set to true. If it is set to false, then request is not sent to the back end.
ClosedAccess cache
Use case

Accessing data from the cache.

For example, you can populate a country code in the cache if it is not present.
Rule 
name: "Access cache in rules"
description: "Checks if country code for India is present in cache, if not it will store in the cache"
priority: 1
condition: "resultCache.retrieveFromCache(\"india\") == null"
actions:
    - "resultCache.insertIntoCache(\"india \", \"+91\")"

The given sample rule checks the stored value in the cache. If the cache is empty, then the country code is added to the cache.

The resultCache object is used to access the cache.
ClosedInvoke integration service
Use case

Invoking an Integration service in pre-processor and post-processor.

For example, you can invoke an SMS or email service based on a request parameter.
Rule 
---
name: "Invoke send email integration service"
description: "Execute integration service to send email if sendEmail is true in input map."
priority: 1
condition: "inputMap.get(\"sendEmail\") == \"true\""
actions:
    - servicesManager.invokeIntegration("RulesIntegrationService", "SendEmail")
 
 ---
name: "Invoke send SMS integration service"
description: "Execute integration service to send SMS if sendSms is true in input map"
priority: 1
condition: "inputMap.get(\"sendSms\") == \"true\""
actions: 
    - servicesManager.invokeIntegration("RulesIntegrationService", "SendSms")

In the sample, based on the parameters sent from the device, we are invoking services either to send an SMS or email or both.

The servicesManager object is used to invoke an integration service from rules pre/post processor.
ClosedAccess Identity data
Use case

Accessing the Identity data.

For example, you can access the Identity data such as the app id and the user profile for the request.
Rule 
name: "Access Identity Info"
description: "Accesses  identity info like first name, last name, email id, and app id in rules"
priority: 1
condition: "setIdentityDetails == true"
actions:
    - "results.addParam(\"FirstName\", identityHandler.getUserProfile().getFirstName())"
    - "results.addParam(\"LastName\", identityHandler.getUserProfile().getLastName())"
    - "results.addParam(\"Email\", identityHandler.getUserProfile().getEmailId())"
    - "results.addParam(\"AppId\", identityHandler.getAppId())"

The given sample rule accesses the identity information such as first name, last name, email id, and app id and sends it to the device.

The identityHandler object is used to access identity information.
ClosedAccess session
Use case

Accessing data from the session.

For example, you can fetch the authorization token from the session and set it in the header of the back-end call.
Rule 
name: "Access session data"
description: "Check if authorization token is present in session then set the same in header"
priority: 1
condition: "session.containsKey("\authToken\")"
actions:
    - "headerMap.authToken = authToken"

The given sample rule checks for an authorization token. If the authorization token is present in the session, then it is added to the header.

The session object is used to access the session data.
ClosedAccess custom metrics
Use case

Accessing custom metrics in pre-processor and post-processor.
Rule 
name: "Access custom metrics in rules"
description: "Set custom metrics of product if enabled in request."
priority: 1
condition: "enableCustomMetrics == true"
actions:
   - "com.konylabs.middleware.metrics.KonyCustomMetricsDataSet metricsDataset = new com.konylabs.middleware.metrics.KonyCustomMetricsDataSet();"
   - "metricsDataset.setMetricsString(\"Product Name\", \"Kony Quantum\");"
   - "metricsDataset.setMetricsBoolean(\"Is Released\", true);"
   - "metricsDataset.setMetricsTimestamp(\"Release date\", \"2019-03-12\", \"yyyy-MM-dd\");"
   - "customMetrics.addCustomMetrics(metricsDataset);"

The given sample rule assigns values to the custom metrics.

The customMetrics object is used to access custom metrics.
ClosedMultiple rules in same pre/post processors
Use case

Writing multiple rules in the same pre-processor and post-processor.

You can write multiple rules in the same pre/post processor by using --- (three hyphens) as the separator.

Note: Please do not give separator after last rule.

Rule 
---
name: "Convert account code to type for loan account"
description: "Rule for loan account to convert account type to code and add message in result"
condition: "AccountCode == 1"
actions:
   - "results.addParam(\"AccountType\", \"Loan Account\")"
   - "results.addParam(\"Message\", \"This is a Loan Account\")"
---
name: "Convert account code to type for saving account"
description: "Rule for saving account to convert account type to code and add message in result"
condition: "AccountCode == 2"
actions:
   - "results.addParam(\"AccountType\", \"Saving Account\")"
   - "results.addParam(\"Message\", \"This is a Saving Account\")"
---
name: "Convert account code to type for current account"
description: "Rule for current account to convert account type to code and add message in result"
condition: "AccountCode == 3"
actions:
   - "results.addParam(\"AccountType\", \"Current Account\")"
   - "results.addParam(\"Message\", \"This is a Current Account\")"

The given sample rule invokes multiple rules.
ClosedIterate over a set of values
Use case

Iterating over a set of values.
Rules 
name: "Iterate over records using for loop in rules."
description: "Add 80% of price as discounted price of book."
condition: "\"giveDiscount\" == true"
actions:
     - "for (com.konylabs.middleware.dataobject.Record record : results.getDatasetById(\"books\").getAllRecords()) {
		com.konylabs.middleware.dataobject.Record bookRecord = record.getRecordById(\"book\"); 
		double price = Double.parseDouble(bookRecord.getParamValueByName(\"price\")); 
		bookRecord.addParam(\"discountedPrice\", price * 0.8);
	}"

The given sample rule iterates a books dataset and adds discounted prices for each book in the dataset.

 

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