149 lines
4.0 KiB
Go
149 lines
4.0 KiB
Go
package bouquins
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import (
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"fmt"
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"log"
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"math/rand"
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"net/http"
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"github.com/gorilla/sessions"
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"golang.org/x/oauth2"
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)
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const (
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alphanums = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
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sessionName = "bouquins"
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sessionOAuthState = "oauthState"
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sessionOAuthProvider = "provider"
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sessionUser = "username"
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pProvider = "provider"
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)
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var (
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// Providers contains OAuth2 providers implementations
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Providers []OAuth2Provider
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)
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// LoginModel is login page model
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type LoginModel struct {
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Model
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Providers []OAuth2Provider
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}
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// NewLoginModel constructor for LoginModel
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func (app *Bouquins) NewLoginModel(req *http.Request) *LoginModel {
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// TODO filter configured providers
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return &LoginModel{*app.NewModel("Authentification", "provider", req), Providers}
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}
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// OAuth2Provider allows to get a user from an OAuth2 token
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type OAuth2Provider interface {
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GetUser(app *Bouquins, token *oauth2.Token) (string, error)
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Config(conf *Conf) *oauth2.Config
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Name() string
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Label() string
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Icon() string
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}
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func findProvider(name string) OAuth2Provider {
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for _, p := range Providers {
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if p.Name() == name {
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return p
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}
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}
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return nil
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}
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// generates a 16 characters long random string
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func securedRandString() string {
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b := make([]byte, 16)
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for i := range b {
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b[i] = alphanums[rand.Intn(len(alphanums))]
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}
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return string(b)
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}
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// Session returns current session
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func (app *Bouquins) Session(req *http.Request) *sessions.Session {
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session, _ := app.Cookies.Get(req, sessionName)
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return session
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}
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// Username returns logged in username
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func (app *Bouquins) Username(req *http.Request) string {
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username := app.Session(req).Values[sessionUser]
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if username != nil {
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return username.(string)
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}
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return ""
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}
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// SessionSet sets a value in session
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func (app *Bouquins) SessionSet(name string, value string, res http.ResponseWriter, req *http.Request) {
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session := app.Session(req)
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session.Values[name] = value
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session.Save(req, res)
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}
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// LoginPage redirects to OAuth login page (github)
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func (app *Bouquins) LoginPage(res http.ResponseWriter, req *http.Request) error {
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provider := req.URL.Query().Get(pProvider)
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oauth := app.OAuthConf[provider]
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if oauth != nil {
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app.SessionSet(sessionOAuthProvider, provider, res, req)
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state := securedRandString()
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app.SessionSet(sessionOAuthState, state, res, req)
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url := oauth.AuthCodeURL(state)
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log.Println("OAuth redirect", url)
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http.Redirect(res, req, url, http.StatusTemporaryRedirect)
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return nil
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}
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// choose provider
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return app.render(res, tplProvider, app.NewLoginModel(req))
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}
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// LogoutPage logout connected user
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func (app *Bouquins) LogoutPage(res http.ResponseWriter, req *http.Request) error {
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app.SessionSet(sessionUser, "", res, req)
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return RedirectHome(res, req)
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}
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// CallbackPage handle OAuth 2 callback
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func (app *Bouquins) CallbackPage(res http.ResponseWriter, req *http.Request) error {
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savedState := app.Session(req).Values[sessionOAuthState]
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providerParam := app.Session(req).Values[sessionOAuthProvider]
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if savedState == "" || providerParam == "" {
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return fmt.Errorf("missing oauth data")
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}
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providerName := providerParam.(string)
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oauth := app.OAuthConf[providerName]
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provider := findProvider(providerName)
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if oauth == nil || provider == nil {
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return fmt.Errorf("missing oauth configuration")
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}
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app.SessionSet(sessionOAuthState, "", res, req)
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app.SessionSet(sessionOAuthProvider, "", res, req)
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state := req.FormValue("state")
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if state != savedState {
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return fmt.Errorf("invalid oauth state, expected '%s', got '%s'", "state", state)
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}
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code := req.FormValue("code")
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token, err := oauth.Exchange(oauth2.NoContext, code)
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if err != nil {
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return fmt.Errorf("Code exchange failed with '%s'", err)
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}
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userEmail, err := provider.GetUser(app, token)
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if err != nil {
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return err
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}
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user, err := Account(userEmail)
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if err != nil {
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log.Println("Error loading user", err)
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return fmt.Errorf("Unknown user")
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}
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app.SessionSet(sessionUser, user.DisplayName, res, req)
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log.Println("User logged in", user.DisplayName)
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return RedirectHome(res, req)
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}
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