Encoded / Encrypted body before verifying a Pact

Question

A server I need to integrate with returns its answers encoded as a JWT. Worse, the response body actually is a json, of the form:

{d: token} with token = JWT.encode({id: 123, field: "John", etc.})

I'd like to use a pact verification on the content of the decoded token. I know I can easily have a pact verifying that I get back a {d: string}, I can't do an exact match on the string (as the JWT contains some varying IDs). What I want is the following, which presumes the addition of a new Pact.JWT functionality.

my_provider. upon_receiving('my request') .with(method: :post, path: '/order', headers: {'Content-Type' => 'application/json'} ).will_respond_with( status: 200, headers: {'Content-Type' => 'application/json; charset=utf-8'}, body: { d: Pact::JWT( { id: Pact.like(123), field: Pact.term(generate: "John", matcher: /J.*/ },signing_key,algo ) })

Short of adding this Pact::JWT, is there a way to achive this kind of result?

I am already using the pact proxy to run my verification. I know you can modify the request before sending it for verification (How do I verify pacts against an API that requires an auth token?). Can you modify the request once you receive it from the proxy server?

If that's the case, I can plan for the following work around:

a switch in my actual code to sometimes expect the answers decoded instead of in the JWT
run my tests once with the swich off (normal code behaviour, mocks returns JWT data encoded.
run my tests a second time with the swich off (code expect data already decoded, mocks return decoded data.)
use the contract json from this second run
hook into the proxy:verify task to decode the JWT on the fly, and use the existing pact mechanisms for verification. (Step that I do not know how to do).

My code is in ruby. I do not have access to the provider.

Any suggestions appreciated! Thanks

score 1 · Answer 1 · answered May 22 '17 at 05:15

1

You can modify the request or response by using (another) proxy app.

class ProxyApp

  def initialize real_provider_app
    @real_provider_app = real_provider_app
  end

  def call env
    response = @real_provider_app.call(env)
    # modify response here
    response
  end
end

Pact.service_provider "My Service Provider" do
  app { ProxyApp.new(RealApp) }
end

answered May 22 '17 at 05:15

Beth Skurrie

1,333
7
8

1

The Pact.service_provider goes into the provider code (if any), and needs a require 'pact/provider' For Rails, the app is defined in config/application, where you have module MyAppName class Application, you'll want MyAppName::Application This answers it, though I'm not using it, rather, I've forked pact-support to add support for a Pact.Jwt object. – André May 23 '17 at 07:26

score 0 · Answer 2 · answered Mar 31 '19 at 20:45

Pact as a tool, I don't expect it to give this behavior out of the box.

In my opinion, the best is,

Do not change source code only for tests
Make sure your tests verifies encoded json only (generate encoded expected json in test & verify that with actual)

Encoded / Encrypted body before verifying a Pact

2 Answers2