Empty request body during provider verification

[mikemadisonweb]

More like a question, maybe I misunderstood the concept. I'm trying to verify the provider with a local pact file I generated from the client test. All the tests are running in Docker. I have a POST request with a body, but upon verification the API handler receives an empty request, so validation fails and tests fail. I need some help here.

Software versions

• OS: e.g. Mac OSX 10.15.4
• Consumer Pact library: e.g. Pact go v1.4.0
• Golang Version: go 1.14

Tests executing in the docker containers.

Expected behaviour

Empty request body received by API.

Actual behaviour

Request body from pact file received by API.

Steps to reproduce

This is a simplified version of the tests and the pact file:

package api

import (
    "fmt"
    "log"
    "net/http"
    "os"
    "path/filepath"
    "testing"

    "github.com/pact-foundation/pact-go/dsl"
    "github.com/pact-foundation/pact-go/types"
    "github.com/pact-foundation/pact-go/utils"
)

func TestPactProvider(t *testing.T) {
    var port, _ = utils.GetFreePort()
    var address = fmt.Sprintf("0.0.0.0:%d", port)
    go startApi(address)

    pact := dsl.Pact{
        Provider: "api",
        Consumer: "client",
        LogDir:   os.Getenv("LOG_DIR"),
        LogLevel: "DEBUG",
    }
    _, err := pact.VerifyProvider(t, types.VerifyRequest{
        ProviderBaseURL:    fmt.Sprintf("http://%s", address),
        FailIfNoPactsFound: true,
        PactURLs:           []string{filepath.FromSlash(fmt.Sprintf("%s/client-api.json", os.Getenv("PACT_DIR")))},
        ProviderVersion:    "1.0.0",
    })

    if err != nil {
        t.Fatalf("Error on Verify: %v", err)
    }
}

func startApi(address string) {
    mux := http.NewServeMux()

    mux.HandleFunc("/v1/data", func(w http.ResponseWriter, req *http.Request) {
        w.Header().Add("Content-Type", "application/json")
        var reqRaw []byte
        req.Body.Read(reqRaw)
        fmt.Println(string(reqRaw))
        fmt.Fprintf(w, fmt.Sprintf(`%#v`, string(reqRaw)))
    })

    log.Fatal(http.ListenAndServe(address, mux))
}

{
  "consumer": {
    "name": "client"
  },
  "provider": {
    "name": "api"
  },
  "interactions": [
    {
      "description": "Client data",
      "providerState": "API response",
      "request": {
        "method": "POST",
        "path": "/v1/data",
        "body": {
          "param1": "20.23",
          "param2": "123.24"
        },
        "matchingRules": {
          "$.body.param1": {
            "match": "regex",
            "regex": "^[-+]?\\d*\\.?\\d*$"
          },
          "$.body.param2": {
            "match": "regex",
            "regex": "^[-+]?\\d*\\.?\\d*$"
          }
        }
      },
      "response": {
        "status": 200,
        "headers": {
          "Content-Type": "application/json; charset=utf-8"
        },
        "body": {
          "result": 1.1
        },
        "matchingRules": {
          "$.headers.Content-Type": {
            "match": "regex",
            "regex": "application\\/json"
          },
          "$.body.loc": {
            "match": "type"
          }
        }
      }
    }
  ],
  "metadata": {
    "pactSpecification": {
      "version": "2.0.0"
    }
  }
}

[mefellows]

I'll take a look a little later, but at first glance it looks ok. You might need to specify the content type for the request though also

[mikemadisonweb]

Thanks for the answer! Very strange indeed, I have created a minimal app with this pact and it worked fine: https://bitbucket.org/mikemadweb/pact-go-minimal/src/master/

I will dig deeper for an issue in the original app.

[mefellows]

Awesome, thanks @mikemadisonweb. It is documented in the readme, but only in the example consumer test with a comment. I'll make this for documentation enhancement because it's not immediately obvious.

Thanks for the report and taking the time to create a repro.

[mikemadisonweb]

Ok, so I guess I got the whole picture now. So as I mentioned previously setting Content-Type explicitly solved the case. Still why I received an empty request in the code was a mystery. I'm using Echo framework by the way and it has Bind() method, which populates the request struct depending on the request content type. If the Content-Type header was missing there would be a meaningful message that media type is not supported, seems like Pact uses application/x-www-form-urlencoded as a default. In the case of application/x-www-form-urlencoded Echo does not throw an error if the request body is JSON, but just ignores the body. That is why the request was empty.

I have updated the minimal repo with these details, just in case.

[mefellows]

Thanks! Yes, that all makes sense to me. Pact will do what you tell it, basically, and omitting content-type it will default to something sensible - in this case application/x-www-form-urlencoded (I believe this is standard in many frameworks as there is a body).

As mentioned, I'll make a note that if using JSON the correct header should be sent.

[mefellows]

Docs updated.