Golang JWT middleware example: adding validation results to context

I am looking at the example for JWT middleware in Go.

In my API backend as-is, I use the Echo framework (specifically, based off this example). This is no big issue itself, as Echo has a very useful echo.WrapMiddleware() function for turning regular bare HTTP handler middlewares into Echo ones. I literally just add the following in jwt.go:

func EchoEnsureValidToken() (echo.MiddlewareFunc, error) {
	mw := echo.WrapMiddleware(EnsureValidToken())
	return mw, nil
}

and then use it in my app as per normal. However, I’m running into an issue with my handler functions.

main.go:

package main

import (
	"log"
	"os"

	database "tlmgateway/db"
	_ "tlmgateway/docs"
	"tlmgateway/handlers"
	"tlmgateway/logger"
	"tlmgateway/middlewares"

	"tlmgateway/services"
	"tlmgateway/stores"

	"go.uber.org/zap"
)

var GO_ENV = os.Getenv("GO_ENV")

// @title Go clean echo API v1
// @version 1.0
// @description This is a sample server.
// @termsOfService http://swagger.io/terms/

// @host localhost:3000
// @BasePath /
// @schemes http
func main() {
	err := logger.New()
	if err != nil {
		log.Fatal(err)
	}

	db, err := database.New(GO_ENV == "development")
	if err != nil {
		logger.Fatal("failed to connect to the database", zap.Error(err))
	}

	e := handlers.Echo()

	s := stores.New(db)
	ss := services.New(s)
	h := handlers.New(ss)

	jwtCheck, err := middlewares.EchoEnsureValidToken()
	if err != nil {
		logger.Fatal("failed to set JWT middleware", zap.Error(err))
	}

	handlers.SetDefault(e)
	handlers.SetApi(e, h, jwtCheck)

	PORT := os.Getenv("PORT")
	if PORT == "" {
		PORT = "3001"
	}

	logger.Fatal("failed to start server", zap.Error(e.Start(":"+PORT)))
}

But in Echo, the routing and handlers are done a bit differently:

package handlers

import (
	"net/http"
	"strings"

	"repo/services"
	"repo/utils"

	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
	echoSwagger "github.com/swaggo/echo-swagger"
)

type Handlers struct {
	RecordHandler
}

func New(s *services.Services) *Handlers {
	return &Handlers{
		RecordHandler:      &recordHandler{s.Record},
	}
}

func SetDefault(e *echo.Echo) {
	utils.SetHTMLTemplateRenderer(e)

	e.GET("/", func(c echo.Context) error {
		return c.String(http.StatusOK, "OK")
	})
	e.GET("/healthcheck", HealthCheckHandler)
	e.GET("/swagger/*", echoSwagger.WrapHandler)
}

func SetApi(e *echo.Echo, h *Handlers, m echo.MiddlewareFunc) {
	g := e.Group("/api/v1")
	g.Use(m)

	// Organizations
	g.GET("/record", h.RecordHandler.GetRecords)
}

func Echo() *echo.Echo {
	e := echo.New()

	e.Use(middleware.Logger())
	e.Use(middleware.Recover())
	e.Pre(middleware.RemoveTrailingSlash())
	e.Use(middleware.CORSWithConfig(middleware.CORSConfig{
		AllowOrigins: []string{"*"},
	}))
	e.Use(middleware.GzipWithConfig(middleware.GzipConfig{
		Skipper: func(c echo.Context) bool {
			return strings.Contains(c.Request().URL.Path, "swagger")
		},
	}))

	return e
}

My issue is, these handlers simply take the Context and go from there. They’re defined like this:

GetRecords(c echo.Context) error

The question then is, how do I add something like ValidatedClaims and CustomClaims from the middleware function in the example to the context so that it can be used where I need to use it? The above code is more for illustration purposes, since the only implementation issue I’m having is “add validation results to context”.

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