// StateHandler checks for a state cookie. If found, the state value is read
// and added to the ctx. Otherwise, a non-guessable value is added to the ctx
// and to a (short-lived) state cookie issued to the requester.
//
// Implements OAuth 2 RFC 6749 10.12 CSRF Protection. If you wish to issue
// state params differently, write a ContextHandler which sets the ctx state,
// using oauth2 WithState(ctx, state) since it is required by LoginHandler
// and CallbackHandler.
func StateHandler(config gologin.CookieConfig, success ctxh.ContextHandler) ctxh.ContextHandler {
fn := func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
cookie, err := req.Cookie(config.Name)
if err == nil {
// add the cookie state to the ctx
ctx = WithState(ctx, cookie.Value)
} else {
// add Cookie with a random state
val := randomState()
http.SetCookie(w, internal.NewCookie(config, val))
ctx = WithState(ctx, val)
}
success.ServeHTTP(ctx, w, req)
}
return ctxh.ContextHandlerFunc(fn)
}
// CookieTempHandler persists or retrieves the request token secret (temporary
// credentials). If the request token can be read from the ctx (login phase),
// the secret is set in a short-lived cookie to be read later. Otherwise
// (callback phase) the cookie is read to retrieve the request token secret
// and add it to the ctx.
// If the ctx contains no request token and the request has no temp cookie,
// the failure handler is called.
//
// Some OAuth1 providers (Twitter, Digits) do NOT require temp secrets to be
// kept between the login phase and callback phase. To implement those
// providers, use the EmptyTempHandler instead.
func CookieTempHandler(config gologin.CookieConfig, success, failure ctxh.ContextHandler) ctxh.ContextHandler {
if failure == nil {
failure = gologin.DefaultFailureHandler
}
fn := func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
_, requestSecret, err := RequestTokenFromContext(ctx)
if err == nil {
// add request secret to a short-lived cookie
http.SetCookie(w, internal.NewCookie(config, requestSecret))
success.ServeHTTP(ctx, w, req)
return
}
// read request secret from the short-lived cookie to add to ctx
cookie, err := req.Cookie(config.Name)
if err != nil {
ctx = gologin.WithError(ctx, err)
failure.ServeHTTP(ctx, w, req)
return
}
ctx = WithRequestToken(ctx, "", cookie.Value)
success.ServeHTTP(ctx, w, req)
}
return ctxh.ContextHandlerFunc(fn)
}