Add MxId/Token login option for Matrix (#1438)

* Add possibility for using MxId/Token with Matrix

Makes it possible to configure a Matrix bot to use Matrix ID + Access token instead of username/password. This makes it possible to use the bot in environments where password login is disabled (for example SSO environments).

Matrix user ID's are commonly referred to as "MXID's". I thought about (ab)using "Login" here but it felt like a bad idea given it's used as "username" for the password login. None of the other configuration items felt fitting.

Closes #1429

* MxId -> MxID

* Add err != nil to matrix.NewClient

3 files changed, 34 insertions, 18 deletions

diff --git a/bridge/config/config.go b/bridge/config/config.go
index b5e03fcf..a6e3c546 100644
--- a/bridge/config/config.go
+++ b/bridge/config/config.go
@@ -120,6 +120,7 @@ type Protocol struct {
 	MessageQueue           int        // IRC, size of message queue for flood control
 	MessageSplit           bool       // IRC, split long messages with newlines on MessageLength instead of clipping
 	Muc                    string     // xmpp
+	MxID                   string     // matrix
 	Name                   string     // all protocols
 	Nick                   string     // all protocols
 	NickFormatter          string     // mattermost, slack
@@ -142,7 +143,7 @@ type Protocol struct {
 	ReplaceNicks           [][]string // all protocols
 	RemoteNickFormat       string     // all protocols
 	RunCommands            []string   // IRC
-	Server                 string     // IRC,mattermost,XMPP,discord
+	Server                 string     // IRC,mattermost,XMPP,discord,matrix
 	SessionFile            string     // msteams,whatsapp
 	ShowJoinPart           bool       // all protocols
 	ShowTopicChange        bool       // slack
@@ -157,7 +158,7 @@ type Protocol struct {
 	Team                   string     // mattermost, keybase
 	TeamID                 string     // msteams
 	TenantID               string     // msteams
-	Token                  string     // gitter, slack, discord, api
+	Token                  string     // gitter, slack, discord, api, matrix
 	Topic                  string     // zulip
 	URL                    string     // mattermost, slack // DEPRECATED
 	UseAPI                 bool       // mattermost, slack
diff --git a/bridge/matrix/matrix.go b/bridge/matrix/matrix.go
index 69d0264b..9516a4fa 100644
--- a/bridge/matrix/matrix.go
+++ b/bridge/matrix/matrix.go
@@ -75,22 +75,33 @@ func New(cfg *bridge.Config) bridge.Bridger {
 func (b *Bmatrix) Connect() error {
 	var err error
 	b.Log.Infof("Connecting %s", b.GetString("Server"))
-	b.mc, err = matrix.NewClient(b.GetString("Server"), "", "")
-	if err != nil {
-		return err
-	}
-	resp, err := b.mc.Login(&matrix.ReqLogin{
-		Type:       "m.login.password",
-		User:       b.GetString("Login"),
-		Password:   b.GetString("Password"),
-		Identifier: matrix.NewUserIdentifier(b.GetString("Login")),
-	})
-	if err != nil {
-		return err
+	if b.GetString("MxID") != "" && b.GetString("Token") != "" {
+		b.mc, err = matrix.NewClient(
+			b.GetString("Server"), b.GetString("MxID"), b.GetString("Token"),
+		)
+		if err != nil {
+			return err
+		}
+		b.UserID = b.GetString("MxID")
+		b.Log.Info("Using existing Matrix credentials")
+	} else {
+		b.mc, err = matrix.NewClient(b.GetString("Server"), "", "")
+		if err != nil {
+			return err
+		}
+		resp, err := b.mc.Login(&matrix.ReqLogin{
+			Type:       "m.login.password",
+			User:       b.GetString("Login"),
+			Password:   b.GetString("Password"),
+			Identifier: matrix.NewUserIdentifier(b.GetString("Login")),
+		})
+		if err != nil {
+			return err
+		}
+		b.mc.SetCredentials(resp.UserID, resp.AccessToken)
+		b.UserID = resp.UserID
+		b.Log.Info("Connection succeeded")
 	}
-	b.mc.SetCredentials(resp.UserID, resp.AccessToken)
-	b.UserID = resp.UserID
-	b.Log.Info("Connection succeeded")
 	go b.handlematrix()
 	return nil
 }
diff --git a/matterbridge.toml.sample b/matterbridge.toml.sample
index 5c1698a1..2819b287 100644
--- a/matterbridge.toml.sample
+++ b/matterbridge.toml.sample
@@ -1245,12 +1245,16 @@ ShowTopicChange=false
 #REQUIRED
 Server="https://matrix.org"
 
-#login/pass of your bot.
+#Authentication for your bot.
+#You can use either login/password OR mxid/token. The latter will be preferred if found.
 #Use a dedicated user for this and not your own!
 #Messages sent from this user will not be relayed to avoid loops.
 #REQUIRED
 Login="yourlogin"
 Password="yourpass"
+#OR
+MxID="@yourlogin:domain.tld"
+Token="tokenforthebotuser"
 
 #Whether to send the homeserver suffix. eg ":matrix.org" in @username:matrix.org
 #to other bridges, or only send "username".(true only sends username)