Method doOAuthStart

oauthproxy.go:825–881

(rw http.ResponseWriter, req *http.Request, overrides url.Values)

}

func (p *OAuthProxy) doOAuthStart(rw http.ResponseWriter, req *http.Request, overrides url.Values) {
	extraParams := p.provider.Data().LoginURLParams(overrides)
	prepareNoCache(rw)

	var (
		err                                              error
		codeChallenge, codeVerifier, codeChallengeMethod string
	)
	if p.provider.Data().CodeChallengeMethod != "" {
		codeChallengeMethod = p.provider.Data().CodeChallengeMethod
		codeVerifier, err = encryption.GenerateCodeVerifierString(96)
		if err != nil {
			logger.Errorf("Unable to build random ASCII string for code verifier: %v", err)
			p.ErrorPage(rw, req, http.StatusInternalServerError, err.Error())
			return
		}

		codeChallenge, err = encryption.GenerateCodeChallenge(p.provider.Data().CodeChallengeMethod, codeVerifier)
		if err != nil {
			logger.Errorf("Error creating code challenge: %v", err)
			p.ErrorPage(rw, req, http.StatusInternalServerError, err.Error())
			return
		}

		extraParams.Add("code_challenge", codeChallenge)
		extraParams.Add("code_challenge_method", codeChallengeMethod)
	}

	csrf, err := cookies.NewCSRF(p.CookieOptions, codeVerifier)
	if err != nil {
		logger.Errorf("Error creating CSRF nonce: %v", err)
		p.ErrorPage(rw, req, http.StatusInternalServerError, err.Error())
		return
	}

	appRedirect, err := p.appDirector.GetRedirect(req)
	if err != nil {
		logger.Errorf("Error obtaining application redirect: %v", err)
		p.ErrorPage(rw, req, http.StatusBadRequest, err.Error())
		return
	}

	callbackRedirect := p.getOAuthRedirectURI(req)
	loginURL := p.provider.GetLoginURL(
		callbackRedirect,
		encodeState(csrf.HashOAuthState(), appRedirect, p.encodeState),
		csrf.HashOIDCNonce(),
		extraParams,
	)
	cookies.ClearExtraCsrfCookies(p.CookieOptions, rw, req)
	if _, err := csrf.SetCookie(rw, req); err != nil {
		logger.Errorf("Error setting CSRF cookie: %v", err)
		p.ErrorPage(rw, req, http.StatusInternalServerError, err.Error())
		return
	}
	http.Redirect(rw, req, loginURL, http.StatusFound)
}