Is it possible to use sessionauth of martini with Datastore on google app engine?

Question

I tried to use the example of sessionauth of martini on google app engine and want to save login list in Datastore, but did not know how to deal with appengine.Context. Does anyone has the experience?

Thank you.

Update:

// Auth example is an example application which requires a login
// to view a private link. The username is "testuser" and the password
// is "password". This will require GORP and an SQLite3 database.
package ahl

import (
    //"fmt"
    "github.com/go-martini/martini"
    "github.com/hnakamur/gaesessions"
    "github.com/martini-contrib/binding"
    "github.com/martini-contrib/render"
    "github.com/martini-contrib/sessionauth"
    "github.com/martini-contrib/sessions"
    "net/http"
)

//var namespace string = "ahl"

func init() {
    //store := sessions.NewCookieStore([]byte("secret123"))
    store := gaesessions.NewDatastoreStore("", gaesessions.DefaultNonPersistentSessionDuration)

    m := martini.Classic()
    m.Use(render.Renderer())

    // Default our store to use Session cookies, so we don't leave logged in
    // users roaming around
    //store.Options(sessions.Options{
    //  MaxAge: 0,
    //})
    m.Use(sessions.Sessions("my_session", store))
    m.Use(sessionauth.SessionUser(GenerateAnonymousUser))
    sessionauth.RedirectUrl = "/new-login"
    sessionauth.RedirectParam = "new-next"

    m.Get("/", func(r render.Render) {
        r.HTML(200, "index", nil)
    })

    m.Get("/new-login", func(r render.Render) {
        r.HTML(200, "login", nil)
    })

    m.Post("/new-login", binding.Bind(MyUserModel{}), func(session sessions.Session, postedUser MyUserModel, r render.Render, req *http.Request) {
        // You should verify credentials against a database or some other mechanism at this point.
        // Then you can authenticate this session.
        //user := MyUserModel{}
        user := MyUserModel{1, "testuser", "password", false}
        //err := dbmap.SelectOne(&user, "SELECT * FROM users WHERE username = $1 and password = $2", postedUser.Username, postedUser.Password)
        //if err != nil {
        //  r.Redirect(sessionauth.RedirectUrl)
        //  return
        //} else {
        err := sessionauth.AuthenticateSession(session, &user)
        if err != nil {
            r.JSON(500, err)
        }

        params := req.URL.Query()
        redirect := params.Get(sessionauth.RedirectParam)
        r.Redirect(redirect)
        return
        //}
    })

    m.Get("/private", sessionauth.LoginRequired, func(r render.Render, user sessionauth.User) {
        r.HTML(200, "private", user.(*MyUserModel))
    })

    m.Get("/logout", sessionauth.LoginRequired, func(session sessions.Session, user sessionauth.User, r render.Render) {
        sessionauth.Logout(session, user)
        r.Redirect("/")
    })

    http.Handle("/", m)
}

Answer 1

Yes, it should be possible. The sessionauth package requires you to pass it a *sessions.Store, and there is a gaesessions package that can replace the default cookie/file stores: https://github.com/hnakamur/gaesessions

The sessionauth package has a full example (https://github.com/martini-contrib/sessionauth/blob/master/example/auth_example.go) - just replace sessions.NewCookieStore with gaesessions.NewDatastoreStore.