Go net/http/CookieJar

client.go

package main

import (
	"log/slog"
	"net/http"
	"net/http/cookiejar"
	"os"
)

func main() {
	jar, err := cookiejar.New(nil)
	if err != nil {
		slog.Error("Could not create cookie jar", "Error", err)
		os.Exit(1)
	}

	client := http.Client{
		Transport:     nil,
		CheckRedirect: nil,
		Jar: 		   jar,
		Timeout:       0,
	}

	//
	// First request
	// - client.Jar.Cookies() must be empty
	// - request.Cookies() must be empty
	//
	slog.Info("First Request - no cookies in the cookie jar / no cookies sent to server")
	slog.Info("CookieJar must be empty", "CookieJar", client.Jar)

	get, err := client.Get("http://localhost:8080/")

	slog.Info("Cookies sent with request", "Cookies", get.Request.Cookies())

	if err != nil {
		panic(err)
	}

	//
	// Second request
	// - client.Jar.Cookies() must have one item
	// - request.Cookies() must have one item
	//

	slog.Info("Second Request - one cookie in the cookie jar / one cookie sent to server")
	slog.Info("CookieJar must have one cookie", "CookieJar", client.Jar)

	get, err = client.Get("http://localhost:8080/")

	slog.Info("Cookies sent with request", "Cookies", get.Request.Cookies())
}

console-output.log

2024/10/13 12:05:15 INFO First Request - no cookies in the cookie jar / no cookies sent to server
2024/10/13 12:05:15 INFO CookieJar must be empty CookieJar="&{psList:<nil> mu:{state:0 sema:0} entries:map[] nextSeqNum:0}"
2024/10/13 12:05:15 INFO Cookies sent with request Cookies=[]
2024/10/13 12:05:15 INFO Second Request - one cookie in the cookie jar / one cookie sent to server
2024/10/13 12:05:15 INFO CookieJar must have one cookie CookieJar="&{psList:<nil> mu:{state:0 sema:0} entries:map[localhost:map[localhost;/;JSESSIONID:{Name:JSESSIONID Value:ABSCDEDASDSSDSSE.oai007 Domain:localhost Path:/ SameSite: Secure:false HttpOnly:true Persistent:false HostOnly:true Expires:{wall:0 ext:315537897599 loc:<nil>} Creation:{wall:13959721864439615168 ext:6148372 loc:0x3fe35a0} LastAccess:{wall:13959721864439615168 ext:6148372 loc:0x3fe35a0} seqNum:0}]] nextSeqNum:1}"
2024/10/13 12:05:15 INFO Cookies sent with request Cookies="[JSESSIONID=ABSCDEDASDSSDSSE.oai007]"

Process finished with the exit code 0

wiremock.json

{
  "mappings": [
    {
      "request": {
        "method": "GET",
        "urlPath": "/"
      },
      "response": {
        "status": 200,
        "body": "SUCCESS",
        "headers": {
          "Set-Cookie": [
            "JSESSIONID=ABSCDEDASDSSDSSE.oai007; path=/; HttpOnly"
          ]
        }
      }
    }
  ]
}

wiremock.log

2024-10-13 12:05:15.757 Request received:
[0:0:0:0:0:0:0:1] - GET /

Host: [localhost:8080]
User-Agent: [Go-http-client/1.1]
Accept-Encoding: [gzip]



Matched response definition:
{
  "status" : 200,
  "body" : "SUCCESS",
  "headers" : {
    "Set-Cookie" : "JSESSIONID=ABSCDEDASDSSDSSE.oai007; path=/; HttpOnly"
  }
}

Response:
HTTP/1.1 200
Set-Cookie: [JSESSIONID=ABSCDEDASDSSDSSE.oai007; path=/; HttpOnly]
Matched-Stub-Id: [e4fbb9f6-44b9-46fb-9294-e4852a84e201]

2024-10-13 12:05:15.760 Request received:
[0:0:0:0:0:0:0:1] - GET /

Host: [localhost:8080]
User-Agent: [Go-http-client/1.1]
Cookie: [JSESSIONID=ABSCDEDASDSSDSSE.oai007]
Accept-Encoding: [gzip]



Matched response definition:
{
  "status" : 200,
  "body" : "SUCCESS",
  "headers" : {
    "Set-Cookie" : "JSESSIONID=ABSCDEDASDSSDSSE.oai007; path=/; HttpOnly"
  }
}

Response:
HTTP/1.1 200
Set-Cookie: [JSESSIONID=ABSCDEDASDSSDSSE.oai007; path=/; HttpOnly]
Matched-Stub-Id: [e4fbb9f6-44b9-46fb-9294-e4852a84e201]