stufflog3/internal/auth/auth.go

package auth

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"git.aiterp.net/stufflog3/stufflog3-api/internal/slerrors"
	"github.com/gin-gonic/gin"
	"net/http"
	"strings"
)

var contextKey = struct{}{}

func UserID(ctx context.Context) string {
	if c, ok := ctx.(*gin.Context); ok {
		return UserID(c.Request.Context())
	}

	return ctx.Value(&contextKey).(string)
}

func DummyMiddleware(uuid string) gin.HandlerFunc {
	return func(c *gin.Context) {
		c.Request = c.Request.WithContext(
			context.WithValue(c.Request.Context(), &contextKey, uuid),
		)
	}
}

func abortRequest(c *gin.Context) {
	c.AbortWithStatusJSON(http.StatusUnauthorized, slerrors.ErrorResponse{
		Code:    http.StatusUnauthorized,
		Message: "You're not supposed to be here!",
	})
}

// TrustingJwtParserMiddleware is meant to be put behind an AWS API gateway that has already
// verified this token.
func TrustingJwtParserMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		auth := c.GetHeader("Authorization")
		split := strings.Split(auth, ".")

		if len(split) >= 3 {
			data, err := base64.RawStdEncoding.DecodeString(split[1])
			if err != nil {
				abortRequest(c)
				return
			}

			fields := make(map[string]interface{})
			err = json.Unmarshal(data, &fields)
			if err != nil {
				abortRequest(c)
				return
			}

			if sub, ok := fields["sub"].(string); ok {
				c.Request = c.Request.WithContext(
					context.WithValue(c.Request.Context(), &contextKey, sub),
				)
			} else {
				abortRequest(c)
				return
			}
		} else {
			abortRequest(c)
		}
	}
}