Discord Oauth2 support (#4476)

* add discord auth

* add vendor for discord

* fix syntax error

* make fmt

* update version of goth in use

* update markbates/goth

vendor/github.com/markbates/goth/providers/discord/discord.go

@@ -0,0 +1,210 @@
+// Package discord implements the OAuth2 protocol for authenticating users through Discord.
+// This package can be used as a reference implementation of an OAuth2 provider for Discord.
+package discord
+
+import (
+	"bytes"
+	"encoding/json"
+	"io"
+	"io/ioutil"
+
+	"github.com/markbates/goth"
+	"golang.org/x/oauth2"
+
+	"fmt"
+	"net/http"
+)
+
+const (
+	authURL      string = "https://discordapp.com/api/oauth2/authorize"
+	tokenURL     string = "https://discordapp.com/api/oauth2/token"
+	userEndpoint string = "https://discordapp.com/api/users/@me"
+)
+
+const (
+	// allows /users/@me without email
+	ScopeIdentify string = "identify"
+	// enables /users/@me to return an email
+	ScopeEmail string = "email"
+	// allows /users/@me/connections to return linked Twitch and YouTube accounts
+	ScopeConnections string = "connections"
+	// allows /users/@me/guilds to return basic information about all of a user's guilds
+	ScopeGuilds string = "guilds"
+	// allows /invites/{invite.id} to be used for joining a user's guild
+	ScopeJoinGuild string = "guilds.join"
+	// allows your app to join users to a group dm
+	ScopeGroupDMjoin string = "gdm.join"
+	// for oauth2 bots, this puts the bot in the user's selected guild by default
+	ScopeBot string = "bot"
+	// 	this generates a webhook that is returned in the oauth token response for authorization code grants
+	ScopeWebhook string = "webhook.incoming"
+)
+
+// New creates a new Discord provider, and sets up important connection details.
+// You should always call `discord.New` to get a new Provider. Never try to create
+// one manually.
+func New(clientKey string, secret string, callbackURL string, scopes ...string) *Provider {
+	p := &Provider{
+		ClientKey:    clientKey,
+		Secret:       secret,
+		CallbackURL:  callbackURL,
+		providerName: "discord",
+	}
+	p.config = newConfig(p, scopes)
+	return p
+}
+
+// Provider is the implementation of `goth.Provider` for accessing Discord
+type Provider struct {
+	ClientKey    string
+	Secret       string
+	CallbackURL  string
+	HTTPClient   *http.Client
+	config       *oauth2.Config
+	providerName string
+}
+
+// Name gets the name used to retrieve this provider.
+func (p *Provider) Name() string {
+	return p.providerName
+}
+
+// SetName is to update the name of the provider (needed in case of multiple providers of 1 type)
+func (p *Provider) SetName(name string) {
+	p.providerName = name
+}
+
+func (p *Provider) Client() *http.Client {
+	return goth.HTTPClientWithFallBack(p.HTTPClient)
+}
+
+// Debug is no-op for the Discord package.
+func (p *Provider) Debug(debug bool) {}
+
+// BeginAuth asks Discord for an authentication end-point.
+func (p *Provider) BeginAuth(state string) (goth.Session, error) {
+
+	url := p.config.AuthCodeURL(state, oauth2.AccessTypeOnline)
+
+	s := &Session{
+		AuthURL: url,
+	}
+	return s, nil
+}
+
+// FetchUser will go to Discord and access basic info about the user.
+func (p *Provider) FetchUser(session goth.Session) (goth.User, error) {
+
+	s := session.(*Session)
+
+	user := goth.User{
+		AccessToken:  s.AccessToken,
+		Provider:     p.Name(),
+		RefreshToken: s.RefreshToken,
+		ExpiresAt:    s.ExpiresAt,
+	}
+
+	if user.AccessToken == "" {
+		// data is not yet retrieved since accessToken is still empty
+		return user, fmt.Errorf("%s cannot get user information without accessToken", p.providerName)
+	}
+
+	req, err := http.NewRequest("GET", userEndpoint, nil)
+	if err != nil {
+		return user, err
+	}
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("Authorization", "Bearer "+s.AccessToken)
+	resp, err := p.Client().Do(req)
+	if err != nil {
+		if resp != nil {
+			resp.Body.Close()
+		}
+		return user, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return user, fmt.Errorf("%s responded with a %d trying to fetch user information", p.providerName, resp.StatusCode)
+	}
+
+	bits, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return user, err
+	}
+
+	err = json.NewDecoder(bytes.NewReader(bits)).Decode(&user.RawData)
+	if err != nil {
+		return user, err
+	}
+
+	err = userFromReader(bytes.NewReader(bits), &user)
+	if err != nil {
+		return user, err
+	}
+
+	return user, err
+}
+
+func userFromReader(r io.Reader, user *goth.User) error {
+	u := struct {
+		Name          string `json:"username"`
+		Email         string `json:"email"`
+		AvatarID      string `json:"avatar"`
+		MFAEnabled    bool   `json:"mfa_enabled"`
+		Discriminator string `json:"discriminator"`
+		Verified      bool   `json:"verified"`
+		ID            string `json:"id"`
+	}{}
+
+	err := json.NewDecoder(r).Decode(&u)
+	if err != nil {
+		return err
+	}
+
+	user.Name = u.Name
+	user.Email = u.Email
+	user.AvatarURL = "https://media.discordapp.net/avatars/" + u.ID + "/" + u.AvatarID + ".jpg"
+	user.UserID = u.ID
+
+	return nil
+}
+
+func newConfig(p *Provider, scopes []string) *oauth2.Config {
+	c := &oauth2.Config{
+		ClientID:     p.ClientKey,
+		ClientSecret: p.Secret,
+		RedirectURL:  p.CallbackURL,
+		Endpoint: oauth2.Endpoint{
+			AuthURL:  authURL,
+			TokenURL: tokenURL,
+		},
+		Scopes: []string{},
+	}
+
+	if len(scopes) > 0 {
+		for _, scope := range scopes {
+			c.Scopes = append(c.Scopes, scope)
+		}
+	} else {
+		c.Scopes = []string{ScopeIdentify}
+	}
+
+	return c
+}
+
+//RefreshTokenAvailable refresh token is provided by auth provider or not
+func (p *Provider) RefreshTokenAvailable() bool {
+	return true
+}
+
+//RefreshToken get new access token based on the refresh token
+func (p *Provider) RefreshToken(refreshToken string) (*oauth2.Token, error) {
+	token := &oauth2.Token{RefreshToken: refreshToken}
+	ts := p.config.TokenSource(oauth2.NoContext, token)
+	newToken, err := ts.Token()
+	if err != nil {
+		return nil, err
+	}
+	return newToken, err
+}

vendor/github.com/markbates/goth/providers/discord/session.go

@@ -0,0 +1,65 @@
+package discord
+
+import (
+	"encoding/json"
+	"errors"
+	"github.com/markbates/goth"
+	"golang.org/x/oauth2"
+	"strings"
+	"time"
+)
+
+// Session stores data during the auth process with Discord
+type Session struct {
+	AuthURL      string
+	AccessToken  string
+	RefreshToken string
+	ExpiresAt    time.Time
+}
+
+// GetAuthURL will return the URL set by calling the `BeginAuth` function on
+// the Discord provider.
+func (s Session) GetAuthURL() (string, error) {
+	if s.AuthURL == "" {
+		return "", errors.New(goth.NoAuthUrlErrorMessage)
+	}
+	return s.AuthURL, nil
+}
+
+// Authorize completes the authorization with Discord and returns the access
+// token to be stored for future use.
+func (s *Session) Authorize(provider goth.Provider, params goth.Params) (string, error) {
+	p := provider.(*Provider)
+	token, err := p.config.Exchange(oauth2.NoContext, params.Get("code"))
+	if err != nil {
+		return "", err
+	}
+
+	if !token.Valid() {
+		return "", errors.New("Invalid token received from provider")
+	}
+
+	s.AccessToken = token.AccessToken
+	s.RefreshToken = token.RefreshToken
+	s.ExpiresAt = token.Expiry
+	return token.AccessToken, err
+}
+
+// Marshal marshals a session into a JSON string.
+func (s Session) Marshal() string {
+	j, _ := json.Marshal(s)
+	return string(j)
+}
+
+// String is equivalent to Marshal. It returns a JSON representation of the
+// of the session.
+func (s Session) String() string {
+	return s.Marshal()
+}
+
+// UnmarshalSession will unmarshal a JSON string into a session.
+func (p *Provider) UnmarshalSession(data string) (goth.Session, error) {
+	s := &Session{}
+	err := json.NewDecoder(strings.NewReader(data)).Decode(s)
+	return s, err
+}

vendor/github.com/markbates/goth/providers/facebook/facebook.go

@@ -37,6 +37,7 @@ func New(clientKey, secret, callbackURL string, scopes ...string) *Provider {
 		providerName: "facebook",
 	}
 	p.config = newConfig(p, scopes)
+	p.Fields = "email,first_name,last_name,link,about,id,name,picture,location"
 	return p
 }
 
@@ -46,6 +47,7 @@ type Provider struct {
 	Secret       string
 	CallbackURL  string
 	HTTPClient   *http.Client
+	Fields       string
 	config       *oauth2.Config
 	providerName string
 }
@@ -60,6 +62,16 @@ func (p *Provider) SetName(name string) {
 	p.providerName = name
 }
 
+// SetCustomFields sets the fields used to return information
+// for a user.
+//
+// A list of available field values can be found at
+// https://developers.facebook.com/docs/graph-api/reference/user
+func (p *Provider) SetCustomFields(fields []string) *Provider {
+	p.Fields = strings.Join(fields, ",")
+	return p
+}
+
 func (p *Provider) Client() *http.Client {
 	return goth.HTTPClientWithFallBack(p.HTTPClient)
 }
@@ -99,7 +111,7 @@ func (p *Provider) FetchUser(session goth.Session) (goth.User, error) {
 
 	reqUrl := fmt.Sprint(
 		endpointProfile,
-		strings.Join(p.config.Scopes, ","),
+		p.Fields,
 		"&access_token=",
 		url.QueryEscape(sess.AccessToken),
 		"&appsecret_proof=",
@@ -177,31 +189,17 @@ func newConfig(provider *Provider, scopes []string) *oauth2.Config {
 		},
 		Scopes: []string{
 			"email",
-			"first_name",
-			"last_name",
-			"link",
-			"about",
-			"id",
-			"name",
-			"picture",
-			"location",
 		},
 	}
 
-	// creates possibility to invoke field method like 'picture.type(large)'
-	var found bool
-	for _, sc := range scopes {
-		sc := sc
-		for i, defScope := range c.Scopes {
-			if defScope == strings.Split(sc, ".")[0] {
-				c.Scopes[i] = sc
-				found = true
-			}
+	defaultScopes := map[string]struct{}{
+		"email": {},
+	}
+
+	for _, scope := range scopes {
+		if _, exists := defaultScopes[scope]; !exists {
+			c.Scopes = append(c.Scopes, scope)
 		}
-		if !found {
-			c.Scopes = append(c.Scopes, sc)
-		}
-		found = false
 	}
 
 	return c