Add Mastodon bridge

bridge/config/config.go

@@ -2,6 +2,8 @@ package config
 
 import (
 	"bytes"
+	"errors"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -56,6 +58,38 @@ func (m Message) ParentValid() bool {
 	return m.ParentID != "" && !m.ParentNotFound()
 }
 
+// GetFileInfos extracts typed FileInfo list from the message.
+//
+// This method is guaranteed not to fail. The inner type casting should never
+// fail, but will simply produce a warning if that's the case.
+func (m Message) GetFileInfos(log *logrus.Entry) *[]*FileInfo {
+	var fileInfos []*FileInfo
+
+	for _, file := range m.Extra["file"] {
+		fileInfo, ok := file.(FileInfo)
+		if !ok {
+			// This should never happen, unless a bridge receiving an external message
+			// produces an invalid Extra field where the File is not valid FileInfo.
+			// TODO: log more information about the message for debugging.
+			log.Warn(FileCastError())
+			continue
+		}
+
+		fileInfos = append(fileInfos, &fileInfo)
+	}
+
+	return &fileInfos
+}
+
+// FileInfo is an attachment contained in a message.
+//
+// When receiving an attachment (eg. an image), a bridge should populate the
+// Data/Size fields.
+//
+// When the media server is enabled, for services that don't support file upload
+// (such as IRC), the gateway router will upload the file to the media server
+// and populate the URL/SHA fields. The Data/Size fields are not removed
+// in this process. See handleFiles in gateway/handlers.go
 type FileInfo struct {
 	Name     string
 	Data     *[]byte
@@ -67,6 +101,12 @@ type FileInfo struct {
 	NativeID string
 }
 
+var errFileCast = errors.New("failed to cast config.FileInfo")
+
+func FileCastError() error {
+	return fmt.Errorf("%w", errFileCast)
+}
+
 type ChannelInfo struct {
 	Name        string
 	Account     string

bridge/helper/helper.go

@@ -2,6 +2,7 @@ package helper
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"image/png"
 	"io"
@@ -20,6 +21,12 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+var errHttpGetNotOk = errors.New("HTTP server responded non-OK code")
+
+func HttpGetNotOkError(url string, code int) error {
+	return fmt.Errorf("%w: %s returned code %d", errHttpGetNotOk, url, code)
+}
+
 // DownloadFile downloads the given non-authenticated URL.
 func DownloadFile(url string) (*[]byte, error) {
 	return DownloadFileAuth(url, "")
@@ -42,8 +49,21 @@ func DownloadFileAuth(url string, auth string) (*[]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	defer resp.Body.Close()
-	io.Copy(&buf, resp.Body)
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, HttpGetNotOkError(url, resp.StatusCode)
+	}
+
+	_, err = io.Copy(&buf, resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	err = resp.Body.Close()
+	if err != nil {
+		return nil, err
+	}
+
 	data := buf.Bytes()
 	return &data, nil
 }

bridge/mastodon/mastodon.go

@@ -0,0 +1,251 @@
+package mastodon
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/42wim/matterbridge/bridge"
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/helper"
+
+	mastodon "github.com/mattn/go-mastodon"
+)
+
+var (
+	htmlReplacementTag = regexp.MustCompile("<[^>]*>")
+	channelTypeHome    = "home"
+	channelTypeLocal   = "local"
+	channelTypeRemote  = "remote"
+	channelTypeDirect  = "direct"
+)
+
+var errInvalidChannel = errors.New("invalid channel name")
+
+func InvalidChannelError(name string) error {
+	return fmt.Errorf("%w: %s", errInvalidChannel, name)
+}
+
+type Bmastodon struct {
+	*bridge.Config
+
+	c       *mastodon.Client
+	account *mastodon.Account
+
+	rooms   []string
+	handles []context.CancelFunc
+}
+
+func New(cfg *bridge.Config) bridge.Bridger {
+	b := &Bmastodon{Config: cfg}
+	return b
+}
+
+func (b *Bmastodon) Connect() error {
+	b.Log.Infof("Connecting %s", b.GetString("Server"))
+
+	cfg := mastodon.Config{
+		Server:       b.GetString("Server"),
+		ClientID:     b.GetString("ClientID"),
+		ClientSecret: b.GetString("ClientSecret"),
+		AccessToken:  b.GetString("AccessToken"),
+	}
+	b.c = mastodon.NewClient(&cfg)
+
+	var err error
+
+	b.account, err =
+		b.c.GetAccountCurrentUser(context.Background())
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (b *Bmastodon) Disconnect() error {
+	for _, ctxCancel := range b.handles {
+		ctxCancel()
+	}
+
+	return nil
+}
+
+func (b *Bmastodon) JoinChannel(channel config.ChannelInfo) error {
+	var (
+		channelType string
+		ch          chan mastodon.Event
+		err         error
+	)
+
+	ctx, ctxCancel := context.WithCancel(context.Background())
+
+	switch channel.Name {
+	case "home":
+		channelType = channelTypeHome
+		ch, err = b.c.StreamingUser(ctx)
+	case "local":
+		channelType = channelTypeLocal
+		ch, err = b.c.StreamingPublic(ctx, true)
+	case "remote":
+		channelType = channelTypeRemote
+		ch, err = b.c.StreamingPublic(ctx, false)
+	default:
+		if !strings.HasPrefix(channel.Name, "@") {
+			ctxCancel()
+			return InvalidChannelError(channel.Name)
+		}
+
+		channelType = channelTypeDirect
+		ch, err = b.c.StreamingDirect(ctx)
+	}
+
+	if err != nil {
+		ctxCancel()
+		return err
+	}
+
+	b.rooms = append(b.rooms, channel.Name)
+	b.handles = append(b.handles, ctxCancel)
+
+	go func() {
+		b.Log.Debugf("run golang channel on streaming api call, channel name: %v", channel.Name)
+
+		for msg := range ch {
+			switch t := msg.(type) {
+			case *mastodon.UpdateEvent:
+				switch channelType {
+				case channelTypeHome, channelTypeLocal, channelTypeRemote:
+					b.handleSendRemoteStatus(t.Status, channel.Name)
+				default:
+					b.Log.Debugf("run UpdateEvent on unsupported channelType: %s", channelType)
+				}
+			case *mastodon.ConversationEvent:
+				switch channelType {
+				case channelTypeHome, channelTypeLocal, channelTypeRemote:
+					// Not a conversation
+					b.Log.Debugf("run ConversationEvent on unsupported channelType: %s", channelType)
+				default:
+					b.handleSendRemoteStatus(t.Conversation.LastStatus, channel.Name)
+				}
+			}
+		}
+	}()
+
+	return nil
+}
+
+func (b *Bmastodon) Send(msg config.Message) (string, error) {
+	ctx := context.Background()
+
+	// Standard Message Send
+	if msg.Event == "" {
+		sentMessage, err := b.handleSendingMessage(ctx, &msg)
+		if err != nil {
+			b.Log.Errorf("Could not send message to room %v from %v: %v", msg.Channel, msg.Username, err)
+
+			return "", nil
+		}
+
+		return string(sentMessage.ID), nil
+	}
+
+	// Message Deletion
+	if msg.Event == config.EventMsgDelete {
+		if msg.UserID != string(b.account.ID) {
+			b.Log.Errorf("Can not delete a status that is owned by a different account")
+			return "", nil
+		}
+
+		err := b.c.DeleteStatus(context.Background(), mastodon.ID(msg.ID))
+
+		return "", err
+	}
+
+	// Message is not a type that is currently supported
+	return "", nil
+}
+
+func (b *Bmastodon) handleSendRemoteStatus(msg *mastodon.Status, channel string) {
+	if msg.Account.ID == b.account.ID {
+		// Ignore messages that are from the bot user
+		return
+	}
+
+	remoteMessage := config.Message{
+		Text:     htmlReplacementTag.ReplaceAllString(msg.Content, ""),
+		Channel:  channel,
+		Username: msg.Account.DisplayName,
+		UserID:   string(msg.Account.ID),
+		Account:  b.Account,
+		Avatar:   msg.Account.Avatar,
+		ID:       string(msg.ID),
+		Extra:    map[string][]any{},
+	}
+	if len(msg.MediaAttachments) > 0 {
+		remoteMessage.Extra["file"] = []any{}
+	}
+
+	for _, media := range msg.MediaAttachments {
+		b, err2 := helper.DownloadFile(media.RemoteURL)
+		if err2 != nil {
+			// TODO: log
+			continue
+		}
+
+		remoteMessage.Extra["file"] = append(remoteMessage.Extra["file"], config.FileInfo{
+			Name:   media.Description,
+			Data:   b,
+			Size:   int64(len(*b)),
+			Avatar: false,
+		})
+	}
+
+	b.Log.Debugf("<= Message is %#v", remoteMessage)
+
+	b.Remote <- remoteMessage
+}
+
+func (b *Bmastodon) handleSendingMessage(ctx context.Context, msg *config.Message) (*mastodon.Status, error) {
+	toot := mastodon.Toot{
+		Status:      msg.Text,
+		InReplyToID: "",
+		MediaIDs:    []mastodon.ID{},
+		Sensitive:   false,
+		SpoilerText: "",
+		Visibility:  "public",
+		Language:    "",
+	}
+	if strings.HasPrefix(msg.Channel, "#") {
+		toot.Status += " " + msg.Channel
+	}
+
+	if strings.HasPrefix(msg.Channel, "@") {
+		toot.Visibility = "private"
+	}
+
+	if msg.ParentID != "" {
+		toot.InReplyToID = mastodon.ID(msg.ParentID)
+		if toot.Visibility == "public" {
+			toot.Visibility = "unlisted"
+		}
+	}
+
+	for _, file := range *msg.GetFileInfos(b.Log) {
+		attachment, err := b.c.UploadMediaFromMedia(ctx, &mastodon.Media{
+			File:        bytes.NewReader(*file.Data),
+			Description: file.Comment,
+		})
+		if err != nil {
+			b.Log.Error(err)
+			continue
+		}
+
+		toot.MediaIDs = append(toot.MediaIDs, attachment.ID)
+	}
+
+	return b.c.PostStatus(ctx, &toot)
+}

docs/protocols/README.md

@@ -21,6 +21,10 @@ Matterbridge supports many protocols, although not all of them support all featu
     - [xmpp docs](xmpp/)
     - [xmpp settings](xmpp/settings.md)
   - Channel format: `channel_name` (for `channel_name@muc.server.org` where `muc.server.org` has been configured as `Muc` for the corresponding xmpp account)
+- [Mastodon](https://joinmastodon.org/)
+  - Matterbridge docs:
+    - [mastodon docs](mastodon/)
+    - [mastodon application](mastodon/application.md)
 - [Matrix](https://matrix.org)
   - Matterbridge docs:
     - [matrix docs](matrix/)