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echo/middleware/jwt.go
2020-01-25 09:48:53 -08:00

268 lines
7.2 KiB
Go

package middleware
import (
"fmt"
"net/http"
"reflect"
"strings"
"github.com/dgrijalva/jwt-go"
"github.com/labstack/echo/v4"
)
type (
// JWTConfig defines the config for JWT middleware.
JWTConfig struct {
// Skipper defines a function to skip middleware.
Skipper Skipper
// BeforeFunc defines a function which is executed just before the middleware.
BeforeFunc BeforeFunc
// SuccessHandler defines a function which is executed for a valid token.
SuccessHandler JWTSuccessHandler
// ErrorHandler defines a function which is executed for an invalid token.
// It may be used to define a custom JWT error.
ErrorHandler JWTErrorHandler
// ErrorHandlerWithContext is almost identical to ErrorHandler, but it's passed the current context.
ErrorHandlerWithContext JWTErrorHandlerWithContext
// Signing key to validate token. Used as fallback if SigningKeys has length 0.
// Required. This or SigningKeys.
SigningKey interface{}
// Map of signing keys to validate token with kid field usage.
// Required. This or SigningKey.
SigningKeys map[string]interface{}
// Signing method, used to check token signing method.
// Optional. Default value HS256.
SigningMethod string
// Context key to store user information from the token into context.
// Optional. Default value "user".
ContextKey string
// Claims are extendable claims data defining token content.
// Optional. Default value jwt.MapClaims
Claims jwt.Claims
// TokenLookup is a string in the form of "<source>:<name>" that is used
// to extract token from the request.
// Optional. Default value "header:Authorization".
// Possible values:
// - "header:<name>"
// - "query:<name>"
// - "param:<name>"
// - "cookie:<name>"
TokenLookup string
// AuthScheme to be used in the Authorization header.
// Optional. Default value "Bearer".
AuthScheme string
keyFunc jwt.Keyfunc
}
// JWTSuccessHandler defines a function which is executed for a valid token.
JWTSuccessHandler func(echo.Context)
// JWTErrorHandler defines a function which is executed for an invalid token.
JWTErrorHandler func(error) error
// JWTErrorHandlerWithContext is almost identical to JWTErrorHandler, but it's passed the current context.
JWTErrorHandlerWithContext func(error, echo.Context) error
jwtExtractor func(echo.Context) (string, error)
)
// Algorithms
const (
AlgorithmHS256 = "HS256"
)
// Errors
var (
ErrJWTMissing = echo.NewHTTPError(http.StatusBadRequest, "missing or malformed jwt")
)
var (
// DefaultJWTConfig is the default JWT auth middleware config.
DefaultJWTConfig = JWTConfig{
Skipper: DefaultSkipper,
SigningMethod: AlgorithmHS256,
ContextKey: "user",
TokenLookup: "header:" + echo.HeaderAuthorization,
AuthScheme: "Bearer",
Claims: jwt.MapClaims{},
}
)
// JWT returns a JSON Web Token (JWT) auth middleware.
//
// For valid token, it sets the user in context and calls next handler.
// For invalid token, it returns "401 - Unauthorized" error.
// For missing token, it returns "400 - Bad Request" error.
//
// See: https://jwt.io/introduction
// See `JWTConfig.TokenLookup`
func JWT(key interface{}) echo.MiddlewareFunc {
c := DefaultJWTConfig
c.SigningKey = key
return JWTWithConfig(c)
}
// JWTWithConfig returns a JWT auth middleware with config.
// See: `JWT()`.
func JWTWithConfig(config JWTConfig) echo.MiddlewareFunc {
// Defaults
if config.Skipper == nil {
config.Skipper = DefaultJWTConfig.Skipper
}
if config.SigningKey == nil && len(config.SigningKeys) == 0 {
panic("echo: jwt middleware requires signing key")
}
if config.SigningMethod == "" {
config.SigningMethod = DefaultJWTConfig.SigningMethod
}
if config.ContextKey == "" {
config.ContextKey = DefaultJWTConfig.ContextKey
}
if config.Claims == nil {
config.Claims = DefaultJWTConfig.Claims
}
if config.TokenLookup == "" {
config.TokenLookup = DefaultJWTConfig.TokenLookup
}
if config.AuthScheme == "" {
config.AuthScheme = DefaultJWTConfig.AuthScheme
}
config.keyFunc = func(t *jwt.Token) (interface{}, error) {
// Check the signing method
if t.Method.Alg() != config.SigningMethod {
return nil, fmt.Errorf("unexpected jwt signing method=%v", t.Header["alg"])
}
if len(config.SigningKeys) > 0 {
if kid, ok := t.Header["kid"].(string); ok {
if key, ok := config.SigningKeys[kid]; ok {
return key, nil
}
}
return nil, fmt.Errorf("unexpected jwt key id=%v", t.Header["kid"])
}
return config.SigningKey, nil
}
// Initialize
parts := strings.Split(config.TokenLookup, ":")
extractor := jwtFromHeader(parts[1], config.AuthScheme)
switch parts[0] {
case "query":
extractor = jwtFromQuery(parts[1])
case "param":
extractor = jwtFromParam(parts[1])
case "cookie":
extractor = jwtFromCookie(parts[1])
}
return func(next echo.HandlerFunc) echo.HandlerFunc {
return func(c echo.Context) error {
if config.Skipper(c) {
return next(c)
}
if config.BeforeFunc != nil {
config.BeforeFunc(c)
}
auth, err := extractor(c)
if err != nil {
if config.ErrorHandler != nil {
return config.ErrorHandler(err)
}
if config.ErrorHandlerWithContext != nil {
return config.ErrorHandlerWithContext(err, c)
}
return err
}
token := new(jwt.Token)
// Issue #647, #656
if _, ok := config.Claims.(jwt.MapClaims); ok {
token, err = jwt.Parse(auth, config.keyFunc)
} else {
t := reflect.ValueOf(config.Claims).Type().Elem()
claims := reflect.New(t).Interface().(jwt.Claims)
token, err = jwt.ParseWithClaims(auth, claims, config.keyFunc)
}
if err == nil && token.Valid {
// Store user information from token into context.
c.Set(config.ContextKey, token)
if config.SuccessHandler != nil {
config.SuccessHandler(c)
}
return next(c)
}
if config.ErrorHandler != nil {
return config.ErrorHandler(err)
}
if config.ErrorHandlerWithContext != nil {
return config.ErrorHandlerWithContext(err, c)
}
return &echo.HTTPError{
Code: http.StatusUnauthorized,
Message: "invalid or expired jwt",
Internal: err,
}
}
}
}
// jwtFromHeader returns a `jwtExtractor` that extracts token from the request header.
func jwtFromHeader(header string, authScheme string) jwtExtractor {
return func(c echo.Context) (string, error) {
auth := c.Request().Header.Get(header)
l := len(authScheme)
if len(auth) > l+1 && auth[:l] == authScheme {
return auth[l+1:], nil
}
return "", ErrJWTMissing
}
}
// jwtFromQuery returns a `jwtExtractor` that extracts token from the query string.
func jwtFromQuery(param string) jwtExtractor {
return func(c echo.Context) (string, error) {
token := c.QueryParam(param)
if token == "" {
return "", ErrJWTMissing
}
return token, nil
}
}
// jwtFromParam returns a `jwtExtractor` that extracts token from the url param string.
func jwtFromParam(param string) jwtExtractor {
return func(c echo.Context) (string, error) {
token := c.Param(param)
if token == "" {
return "", ErrJWTMissing
}
return token, nil
}
}
// jwtFromCookie returns a `jwtExtractor` that extracts token from the named cookie.
func jwtFromCookie(name string) jwtExtractor {
return func(c echo.Context) (string, error) {
cookie, err := c.Cookie(name)
if err != nil {
return "", ErrJWTMissing
}
return cookie.Value, nil
}
}