How to mock an endpoint that masked the card number in Wiremock? - wiremock

Question

We have an endpoint that masks card numbers. I want to mock this endpoint with Wiremock. Since it will work for more than one card number, it is not possible for me to prepare a separate mock file for each card. How can I mock this endpoint using a single file? The request sent and the response returned to this request are as follows:
Request:
{
"cardNumber": "1234561234561234"
}
Response:
{
"maskedCard": "123456******1234"
}
I prepared a Wiremock file that works only for 1 card number:
{
"request": {
"method": "POST",
"url": "/maskedCard",
"bodyPatterns": [
{
"matchesJsonPath": "[?(#.cardNumber == '1234561234561234')]"
}
]
},
"response": {
"status": 200,
"headers": {
"Content-Type": "application/json"
},
"jsonBody": {
"maskedCard": "123456******1234"
}
}
}
How can I make this work for all incoming card numbers?

Answer 1

If the cardNumber attached to the request does not matter, then I would just exclude the bodyPatterns for matching.
{
"request": {
"method": "POST",
"url": "/maskedCard"
}
If you then need to take whatever the cardNumber in the request body is and mask it, I'm not aware of any out of the box solution to do that for you. Instead you'll have to write a Response Transformer to change the unmasked cardNumber to the masked CardNumber. Something like...
public class MaskCardNumbers extends ResponseTransformer {
public String getName() {
return "MaskCardNumbers";
}
#Override
public Response transform(Request request, Response response, FileSource files, Parameters parameters) {
Pattern pattern = Pattern.compile("/maskedCard");
Matcher matcher = pattern.matcher(request.getUrl());
if(matcher.matches()) {
// Logic to extract cardNumber - my library of choice is JsonSimple
JSONObject responseBody = (JSONObject) parser.parse(response.getBodyAsString());
String cardNumber = responseBody.get("cardNumber").toString();
// Logic to replace cardNumber
String maskedCard = "";
for (int i = 0; i < cardNumber.length(); i++) {
if (i < 6 || i > 11) {
maskedCard += cardNumber.charAt(i);
} else {
maskedCard += "*";
}
}
// Create response JSON Object
JSONObject responseObject = new JSONObject();
responseObject.put("cardNumber", maskedCard)
// Return responseObject
return Response.Builder.like(response).but().body(responseBody.toJSONString()).build();
}
}
}
You'd then need to make sure that WireMock launches with the transformer attached. Finally, your mapping would look like:
{
"request": {
"method": "POST",
"url": "/maskedCard"
},
"response": {
"status": 200,
"headers": {
"Content-Type": "application/json"
},
"jsonBody": {
"maskedCard": "123456******1234"
}
}
}
You might need to play around with some specifics, but I think that should get the job done, or at least get you most of the way there.