133 lines
3.6 KiB
Go
133 lines
3.6 KiB
Go
package main
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import (
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"crypto/rand"
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"encoding/base64"
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"fmt"
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"html/template"
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"net/http"
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"github.com/bwmarrin/discordgo"
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"github.com/gorilla/mux"
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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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defaultLayout = "templates/layout.html"
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templateDir = "templates/"
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)
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var (
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discordOauthConfig = &oauth2.Config{
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RedirectURL: "",
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ClientID: "",
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ClientSecret: "",
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Scopes: []string{"identify", "guilds"},
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Endpoint: *endp,
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}
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// Some random string, random for each request
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oauthStateString string
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endp = &oauth2.Endpoint{
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AuthURL: "https://discordapp.com/api/oauth2/authorize",
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TokenURL: "https://discordapp.com/api/oauth2/token",
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}
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tmpls = map[string]*template.Template{}
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// TODO change secret
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store *sessions.CookieStore
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)
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// startWebServer
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func startWebServer(port string, ci string, cs string, redirectURL string) {
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tmpls["home.html"] = template.Must(template.ParseFiles(templateDir+"home.html", defaultLayout))
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store = sessions.NewCookieStore([]byte(cs))
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discordOauthConfig.ClientID = ci
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discordOauthConfig.ClientSecret = cs
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discordOauthConfig.RedirectURL = redirectURL + "/discordCallback"
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r := mux.NewRouter()
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r.HandleFunc("/", handleMain)
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r.HandleFunc("/logout", handleLogout)
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r.HandleFunc("/discordLogin", handlediscordLogin)
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r.HandleFunc("/discordCallback", handlediscordCallback)
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http.Handle("/static/", http.StripPrefix("/static/", http.FileServer(http.Dir("static"))))
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http.Handle("/", r)
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http.ListenAndServe(":"+port, nil)
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}
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func handleMain(w http.ResponseWriter, r *http.Request) {
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session, _ := store.Get(r, "session-name")
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if session.Values["discordUsername"] != nil {
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fmt.Fprintf(w, "<html><body>you are logged in as %s. <a href=\"/logout\">logout</a></body></html>", session.Values["discordUsername"])
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return
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}
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tmpls["home.html"].ExecuteTemplate(w, "base", map[string]interface{}{})
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}
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func handleLogout(w http.ResponseWriter, r *http.Request) {
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cookie := &http.Cookie{
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Name: "session-name",
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Value: "",
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Path: "/",
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MaxAge: -1,
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}
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http.SetCookie(w, cookie)
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http.Redirect(w, r, "/", http.StatusFound)
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}
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func handlediscordLogin(w http.ResponseWriter, r *http.Request) {
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b := make([]byte, 16)
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rand.Read(b)
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oauthStateString = base64.URLEncoding.EncodeToString(b)
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session, _ := store.Get(r, "session-name")
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session.Values["state"] = oauthStateString
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session.Save(r, w)
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url := discordOauthConfig.AuthCodeURL(oauthStateString)
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http.Redirect(w, r, url, http.StatusTemporaryRedirect)
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}
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func handlediscordCallback(w http.ResponseWriter, r *http.Request) {
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session, err := store.Get(r, "session-name")
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if err != nil {
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fmt.Fprintln(w, "aborted")
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return
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}
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if r.URL.Query().Get("state") != session.Values["state"] {
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fmt.Fprintln(w, "no state match; possible csrf OR cookies not enabled")
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return
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}
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state := r.FormValue("state")
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if state != oauthStateString {
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fmt.Printf("invalid oauth state, expected '%s', got '%s'\n", oauthStateString, state)
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http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
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return
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}
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token, err := discordOauthConfig.Exchange(oauth2.NoContext, r.FormValue("code"))
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if err != nil {
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fmt.Fprintln(w, "Code exchange (could not get token) failed with ", err)
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return
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}
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if !token.Valid() {
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fmt.Fprintln(w, "retrieved invalid token")
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return
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}
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dg, err := discordgo.New("Bearer " + token.AccessToken)
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if err != nil {
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fmt.Println("Error while creating discord session: ", err)
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return
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}
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user, _ := dg.User("@me")
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session.Values["discordUserID"] = user.ID
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session.Values["discordUsername"] = user.Username
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session.Values["accessToken"] = token.AccessToken
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session.Save(r, w)
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http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
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}
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