4. How to setup functional validation rule

Input data to setup a rule: Always Rule takes precedence

Defined Rule would be applied for any input data processed by the given rest api and its kind of intelligence/smartness applied(validated) on the input request and rejected with the output error message defined in the validation rule.

**Rest Api URL: ** used to create rule via api https://live.virtualandemo.com/swagger-ui/index.html?url=/yaml/VirtualService/virtualservices.yaml

live.virtualandemo.com ==> localhost:8080 or your deployed server.

---

Pre-Requisite to set up the data:

"type": "Rule" --> type should be set as "Rule"

Validation Rule: Example-1

When the pet identifier is not a valid number(0), Then reject with the error code as "PET_1000" and error message as "Pet identifier is not valid"

  "rule": "input.id == 0"  

==> Rule can be built using spring SPEL_ Refer SPEL Link

"output": { "code": "PET_1000", "message": "Pet identifier is not valid"} ==> if the above rule/condition satisfied then the given error code and error message would returned via requested virtualized service.

To build the rule : input.id==0 and it's part of field in the input request ==> "input": { "category": { "id": 100, "name": "Golden-Club" }, "name": "Nemo", "photoUrls": [ "fish.jpg" ], "status": "available", "tags": [ { "id": 100, "name": "movie" } ]}

**Rule Input Data:**
{
    "httpStatusCode": "400",
    "url": "/pets",

    "type": "Rule",
    "method": "POST",
    "rule": "input.id == 0",
    "input": { "category": { "id": 100, "name": "Golden-Club" }, "name": "Nemo", "photoUrls": [  "fish.jpg" ], 
                       "status": "available", "tags": [ {  "id": 100, "name": "movie" } ]},
    "output": { "code": "PET_1000",  "message": "Pet identifier is not valid"},
    "contentType" : "JSON"
  }

Validation Rule: Example-2

When the age is below 21, Then reject with the error code as "AGE_RESTRICT" and error message as "You are not eligible to purchase"

  "rule": "T(java.time.Period).between(input.dateOfBirth, T(java.time.LocalDate).now()).getYears() < 22" 

==> Rule can be built using spring SPEL Refer SPEL Link

"output": { "code": "AGE_RESTRICT", "message": "You are not eligible to purchase"}" ==> if the above rule fails then this error message would be send back via virtualized service

To build the rule: input.dateOfBirth and it is part of field in the input request ==> "input": { "dateOfBirth": "2009-02-07", "firstName": "John", "lastName": "David", "spokenLanguages": { "additionalProp1": "Tamil", "additionalProp2": "English" }, "username": "djohn"}"

**Rule Input Data:**
{
    "httpStatusCode": "400",
    "url": "/persons",
    "type": "Rule",
    "method": "POST",
    "input":  {  "dateOfBirth": "2009-02-07",  "firstName": "John",  "lastName": "David",  
                       "spokenLanguages": { "additionalProp1": "Tamil",    
                       "additionalProp2": "English"  },  "username": "djohn"},
    "rule": "T(java.time.Period).between(input.dateOfBirth, T(java.time.LocalDate).now()).getYears() < 22",
    "output": {  "code": "AGE_RESTRICT",  "message": "You are not eligible to purchase"},
    "contentType": "JSON"
}

Validation Rule: Example-3

When the user sends as pet identifier is not a valid number(0), Then reject with the error code as "PET_1000" and error message as "Pet identifier is not valid"

  "rule": "parameters['petId'] == 0",

==> Rule can be built using spring SPEL Refer SPEL Link

"output": { "code": "PET_1000", "message": "Pet identifier is not valid"} ==> if the above rule/condition satisfied then the given error code and error message would returned via requested virtualized service.

To build the rule using : parameters['petId']==0 and it was part of of field in the availableParams ==> "availableParams": [ { "key": "petId", "value": "100" } ]

**Rule Input Data:**
{
    "httpStatusCode": "400",
    "url": "/pets/{petId}",
    "type": "Rule",
    "requestType": "REST",
    "method": "GET",
    "rule": "parameters['petId'] == 0",
    "output": { "code": "PET_1000",  "message": "Pet identifier is not valid"},
    "availableParams": [
      {
        "key": "petId",
        "value": "100"
	  }
    ],
    "contentType": "JSON"
}

Benefits:

1. Pre-build all the rule conditions against the contract and shared with API Partners.
2. Provides capability to upfront share the Error code and Message with API Partners/Consumers.
3. API Partners can run these use cases upfront during as early in the development phase 👍 "Shift Left"

Usually these use-cases would be tested only during the real end to end integration testing of SDLC/AGILE development which is late to fix the defect and Some additional cost involved for fixing these integration issues.

Cost saving: Reference