So I’d love to basically say “Consider a stub mapping a match if all parameters in the body match while ignoring

device_id

”

You can use a few strategies, but I think the one I’d request would be to use

equalToJson

with

"ignoreExtraElements": true

https://wiremock.org/docs/request-matching/#less-strict-matching

{
  "request": {
    ...
    "bodyPatterns" : [ {
      "equalToJson" : "{ \"total_results\": 4  }",
      "ignoreArrayOrder" : true,
      "ignoreExtraElements" : true
    } ]
    ...
  },
  ...
}

You can also un-stringify that JSON I _think_:

...
"equalToJson": { "total_results": 4 },
"ignoreExtraElements": true,
...

Oh snap

I missed the placeholder bit

So maybe I could do

{
  "deviceId": "${json-unit.any-string}"
}

That’s super helpful, thanks! I’ll post an update if I get this working for future readers 🙂

But I don’t see a way to further configure that

equalToJson

But getting:

{
  "errors": [
    {
      "code": 10,
      "source": {
        "pointer": "/requestBodyPattern/equalToJson"
      },
      "title": "Error parsing JSON",
      "detail": "Unrecognized field \"equalToJson\" (class com.github.tomakehurst.wiremock.recording.RequestBodyAutomaticPatternFactory), not marked as ignorable"
    }
  ]
}

This is the POST

body

to

http://{{Local IP}}:{{Port}}/__admin/recordings/start

But if I do

{
  "targetBaseUrl": "{{Target URL}}",
  "captureHeaders": {
    "X-Maestro-Test-Id": {}
  },
  "requestBodyPattern": {
    "matcher": "equalToJson"
  },
  "persist": true,
  "repeatsAsScenarios": false
}

it succeeds, but obviously that’s not what I want (it’s not configuring the device id param at all)

Instead, I think we’d want to add something to that

filters

field?

"filters" : {
    "urlPathPattern" : "/api/.*",
    "method" : "GET",
    "allowNonProxied": true
  },

from the docs, so maybe something like…

"filters" : {
    "urlPathPattern" : "/api/.*",
    "method" : "GET",
    "allowNonProxied": true,
    "bodyPatterns": [ {
      "equalToJson": "{ \"device_id\": \"${json-unit.any-string}\" }",
      "ignoreExtraElements": true
    } ]
  },

?

Ah it didn’t work. But I do see that at least

equalToJson

is being registered/configured

Also, this

filters

key… Makes it sound like only the requests matching that filter will be mapped/recorded? 🤔

Which isn’t actually what we want

Yeah OK I just confirmed that’s what’s happening (cleared out mappings prior to recording with that filter config).

I’m probably doing a bad job of explaining the ideal end result 😂 But I think to summarize:

Record all requests/responses for future playbacks, but when playing back, consider this response a match for this request IFF everything about the request EXCEPT the request body

device_id

parameter match (but matching entirely is obviously acceptable as well).

I thought this sounded familiar - 2+ years ago I just recommended manually changing them with global find + replace in your IDE 😅 https://stackoverflow.com/a/66317444/11625850

Unless the

StubMappingTransformer

allows me to do it in an automated fashion (I meant avoiding the manual find and replace haha)!

I’m not fully understanding how I’d do what I want, but it seeeeeems possible

"transformers" : [ "device_id" ],
  "transformerParameters" : {
    "device_id" : "000000000000000"
  }

Or something 😂

A transformer is an implementations of

StubMappingTransformer

and needs to be registered when starting WireMock as described in Extending WireMock.

Ah, this is the bit that I probably can’t do via CLI

Ahh… I can write one and pass it via

--extensions

I think I’ll look into that!

So excitingly I got the above “working” in that I can build a fat JAR that contains both Wiremock and my extensions, spin up the server with

java -jar my-wiremock-extensions-1.0-SNAPSHOT.jar --bind-address 127.0.0.1 --extensions com.expample.DeviceIdTransformer --verbose

and when saving stub mappings it correctly transforms the mapping’s request body matcher to only be

"equalToJson": "{\"password\":\"myPassword\",\"email\":\"<mailto:94669@example.org|94669@example.org>\"}"

. I learned late last night that I was thinking about the matching logic wrong. The real logic is “ignore everything from the request body other than email/password, haha. Much simpler to reason about.

THAT SAID, it’s still not working 😢 I get

[custom matcher]                                           |                                                     <<<<< custom matcher does not match

in the console when this request is hit. The header I’m diffing on as well as the URL seem to match, it’s just the body matcher that is borked

My understanding of the

ignoreExtraElements

is that a request body should be able to contain N number of elements and my

equalToJson

can contain M number of elements (where M < N) and it can match so long as all elements in M are exactly the same in N, but maybe I’m wrong?

OK I actually got it working 🎉 I had to pass

null

to the 2 custom matcher fields. Previously I was just passing along the fields from the original stub mapping. Not exactly sure what changed because out output JSON stayed the same, but it worked 🙃