lambda-jwt-middleware

A middleware function used for verifying the jwt token from cookies which is compitable with aws-lambda-go

The basic structure of the function is based on this article.

Since it uses Generics feature, Go version 1.18 or greater is required.

Usage

It uses env variable to read the cookie secret if you've encrypted your cookie.

.env

ACCESS_TOKEN_SECRET=yoursecret

Define your own payloadHandler, as the example below, I extract the userId and search the entity in MongoDB, then store the entity into the context.

func payloadHandler(ctx context.Context, payload interface{}) (context.Context, error) {
    userId, ok := payload.(string)
    userObjId, _ := primitive.ObjectIDFromHex(userId)
    if !ok {
        log.Printf("wrong payload format: %v", payload)
        return nil, fmt.Errorf("wrong payload format")
    }

    userRepo := UserRepository.New()
    defer userRepo.Disconnect()()
    var user UserRepository.User

    err := userRepo.FindOne(context.TODO(), bson.M{"_id": userObjId}).Decode(&user)
    if err != nil {
        log.Println(err)
        return nil, err
    }

    ctx = context.WithValue(ctx, helper.ContextKeyUser, user)

    return ctx, nil
}

Then you use the middleware in the lambda.Start() function with the handler and payloadHandler as the arguments.

func main() {
    lambda.Start(jwtmiddleware.Handle(Handler, payloadHandler))
}

Or you can combine the middleware with the payloadHandler to form another function which makes it shorter.

import (
    "github.com/noobj/jwtmiddleware"
    "github.com/noobj/jwtmiddleware/types"
)

func Auth[T types.ApiRequest, R types.ApiResponse](f types.HandlerFunc[T, R]) types.HandlerFunc[T, R] {
    return jwtmiddleware.Handle(f, payloadHandler)
}

func main() {
    lambda.Start(Auth(Handler))
}