Add an inviter key when joining rooms

src/github.com/matrix-org/go-neb/clients/clients.go

@@ -173,7 +173,7 @@ func (c *Clients) newClient(config types.ClientConfig) (*matrix.Client, error) {
 				})
 				logger.Print("Accepting invite from user")
 
-				if _, err := client.JoinRoom(event.RoomID, ""); err != nil {
+				if _, err := client.JoinRoom(event.RoomID, "", event.Sender); err != nil {
 					logger.WithError(err).Print("Failed to join room")
 				} else {
 					logger.Print("Joined room")

src/github.com/matrix-org/go-neb/matrix/matrix.go

@@ -65,8 +65,10 @@ func (cli *Client) buildURLWithQuery(urlPath []string, urlQuery map[string]strin
 	return u.String()
 }
 
-// JoinRoom joins the client to a room ID or alias. Returns a room ID.
-func (cli *Client) JoinRoom(roomIDorAlias, serverName string) (string, error) {
+// JoinRoom joins the client to a room ID or alias. If serverName is specified, this will be added as a query param
+// to instruct the homeserver to join via that server. If invitingUserID is specified, the inviting user ID will be
+// inserted into the content of the join request. Returns a room ID.
+func (cli *Client) JoinRoom(roomIDorAlias, serverName, invitingUserID string) (string, error) {
 	var urlPath string
 	if serverName != "" {
 		urlPath = cli.buildURLWithQuery([]string{"join", roomIDorAlias}, map[string]string{
@@ -76,7 +78,12 @@ func (cli *Client) JoinRoom(roomIDorAlias, serverName string) (string, error) {
 		urlPath = cli.buildURL("join", roomIDorAlias)
 	}
 
-	resBytes, err := cli.sendJSON("POST", urlPath, `{}`)
+	content := struct {
+		Inviter string `json:"inviter,omitempty"`
+	}{}
+	content.Inviter = invitingUserID
+
+	resBytes, err := cli.sendJSON("POST", urlPath, content)
 	if err != nil {
 		return "", err
 	}

src/github.com/matrix-org/go-neb/services/github/github.go

@@ -287,7 +287,7 @@ func (s *githubService) Register(oldService types.Service, client *matrix.Client
 
 func (s *githubService) joinWebhookRooms(client *matrix.Client) error {
 	for roomID := range s.Rooms {
-		if _, err := client.JoinRoom(roomID, ""); err != nil {
+		if _, err := client.JoinRoom(roomID, "", ""); err != nil {
 			// TODO: Leave the rooms we successfully joined?
 			return err
 		}