gengitkan/internal/route/oauth2.go

package route

import (
	"net/http"

	"forge.cadoles.com/wpetit/gengitkan/internal/middleware"
	"github.com/pkg/errors"
	"gitlab.com/wpetit/goweb/middleware/container"
	"gitlab.com/wpetit/goweb/service/session"
	"golang.org/x/oauth2"
)

func handleOAuth2Callback(w http.ResponseWriter, r *http.Request) {

	ctn := container.Must(r.Context())
	sess, err := session.Must(ctn).Get(w, r)
	if err != nil {
		panic(errors.Wrap(err, "could not retrieve session"))
	}

	expectedState := sess.Get(middleware.SessionOAuth2State)
	state := r.FormValue("state")

	if state != expectedState {
		http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
		return
	}

	giteaOAuth2Config := middleware.GiteaOAuth2Config(ctn)

	code := r.FormValue("code")
	token, err := giteaOAuth2Config.Exchange(oauth2.NoContext, code)
	if err != nil {
		panic(errors.Wrap(err, "could not exchange oauth2 token"))
	}

	sess.Set(middleware.SessionOAuth2AccessToken, token.AccessToken)
	sess.Set(middleware.SessionOAuth2State, "")

	if err := sess.Save(w, r); err != nil {
		panic(errors.Wrap(err, "could not save session"))
	}

	http.Redirect(w, r, "/", http.StatusSeeOther)

}