ginoidc/keycloakclaims/claims.go

package keycloakclaims

import (
	"errors"
	"log"

	"code.icod.de/dalu/ginoidc/ginerror"
	"github.com/gin-gonic/gin"
)

// Claims represent the condensed and stripped version of Keycloak's JWT claims payload
type Claims struct {
	Sub         string `json:"sub,omitempty"`
	RealmAccess struct {
		Roles []string `json:"roles,omitempty"`
	} `json:"realm_access,omitempty"`
	PreferredUsername string `json:"preferred_username,omitempty"`
}

// FromRequest returns a Claims instance or nil if and error occurs.
// In case of an error it sets or appends to the "oidcerrors" context value of *gin.Context
func FromRequest(cx *gin.Context) *Claims {
	claimsValue, found := cx.Get("claims")
	if !found {
		const errText = "claims not present"
		errorType := ginerror.Error{
			Description: errText,
			Error:       errors.New(errText),
		}
		if e := addOrExtendErrors(cx, "oidcerrors", errorType); e != nil {
			log.Println(e.Error())
		}
		return nil
	}

	claims, ok := claimsValue.(map[string]interface{})
	if !ok {
		const errText = "claims are not of type map[string]interface{}"
		errorType := ginerror.Error{
			Description: errText,
			Error:       errors.New(errText),
		}
		if e := addOrExtendErrors(cx, "oidcerrors", errorType); e != nil {
			log.Println(e.Error())
		}
		return nil
	}

	c := new(Claims)
	c.Sub, _ = claims["sub"].(string)
	c.PreferredUsername, _ = claims["preferred_username"].(string)
	c.RealmAccess, _ = claims["realm_access"].(struct {
		Roles []string `json:"roles,omitempty"`
	})
	return c
}

// addOrExtendErrors adds or appends to the options.ErrorContextKeyName values
func addOrExtendErrors(cx *gin.Context, key string, newerror ginerror.Error) error {
	errorsValue, errorsFound := cx.Get("oidcerrors")
	if !errorsFound {
		var errs []ginerror.Error
		errs = append(errs, newerror)
		// TODO: find a way to get the error context key from options
		cx.Set("oidcerrors", errs)
		return nil
	} else {
		errs, ok := errorsValue.([]ginerror.Error)
		if !ok {
			return errors.New("claims: errorsValue is not of type []ginerror.Error")
		} else {
			errs = append(errs, newerror)
			// TODO: find a way to get the error context key from options
			cx.Set("oidcerrors", errs)
			return nil
		}
	}
}