cheesy-arena-lite/web/login.go

// Copyright 2018 Team 254. All Rights Reserved.
// Author: pat@patfairbank.com (Patrick Fairbank)
//
// Web routes for authenticating with the server.

package web

import (
	"fmt"
	"github.com/Team254/cheesy-arena/model"
	"github.com/google/uuid"
	"net/http"
	"net/url"
	"time"
)

// Shows the login form.
func (web *Web) loginHandler(w http.ResponseWriter, r *http.Request) {
	web.renderLogin(w, r, "")
}

// Processes the login request.
func (web *Web) loginPostHandler(w http.ResponseWriter, r *http.Request) {
	username := r.PostFormValue("username")
	if err := web.checkAuthPassword(username, r.PostFormValue("password")); err != nil {
		web.renderLogin(w, r, err.Error())
		return
	}

	session := model.UserSession{Token: uuid.New().String(), Username: username, CreatedAt: time.Now()}
	if err := web.arena.Database.CreateUserSession(&session); err != nil {
		handleWebErr(w, err)
		return
	}

	http.SetCookie(w, &http.Cookie{Name: sessionTokenCookie, Value: session.Token})
	redirectUrl := r.URL.Query().Get("redirect")
	if redirectUrl == "" {
		redirectUrl = "/"
	}
	http.Redirect(w, r, redirectUrl, 303)
}

func (web *Web) renderLogin(w http.ResponseWriter, r *http.Request, errorMessage string) {
	template, err := web.parseFiles("templates/login.html", "templates/base.html")
	if err != nil {
		handleWebErr(w, err)
		return
	}
	data := struct {
		*model.EventSettings
		ErrorMessage string
	}{web.arena.EventSettings, errorMessage}
	err = template.ExecuteTemplate(w, "base", data)
	if err != nil {
		handleWebErr(w, err)
		return
	}
}

// Returns true if the given user is authorized for admin operations. Used for HTTP cookie authentication.
func (web *Web) userIsAdmin(w http.ResponseWriter, r *http.Request) bool {
	if web.arena.EventSettings.AdminPassword == "" {
		// Disable auth if there is no password configured.
		return true
	}
	session := web.getUserSessionFromCookie(r)
	if session != nil && session.Username == adminUser {
		return true
	} else {
		redirect := r.URL.Path
		if r.URL.RawQuery != "" {
			redirect += "?" + r.URL.RawQuery
		}
		http.Redirect(w, r, "/login?redirect="+url.QueryEscape(redirect), 307)
		return false
	}
}

func (web *Web) getUserSessionFromCookie(r *http.Request) *model.UserSession {
	token, err := r.Cookie(sessionTokenCookie)
	if err != nil {
		return nil
	}
	session, _ := web.arena.Database.GetUserSessionByToken(token.Value)
	return session
}

func (web *Web) checkAuthPassword(user, password string) error {
	if user == adminUser && password == web.arena.EventSettings.AdminPassword {
		return nil
	} else {
		return fmt.Errorf("Invalid login credentials.")
	}
}