msgconv: clean up reuploading attachments to Matrix

pkg/connector/attachments.go

@@ -1,104 +0,0 @@
-// mautrix-discord - A Matrix-Discord puppeting bridge.
-// Copyright (C) 2026 Tulir Asokan
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-package connector
-
-import (
-	"context"
-	"errors"
-	"fmt"
-	"io"
-	"net/http"
-	"net/url"
-	"path"
-	"strconv"
-
-	"github.com/bwmarrin/discordgo"
-	"maunium.net/go/mautrix/bridgev2"
-
-	"go.mau.fi/mautrix-discord/pkg/attachment"
-)
-
-func downloadDiscordAttachment(cli *http.Client, url string, maxSize int64) ([]byte, error) {
-	req, err := http.NewRequest(http.MethodGet, url, nil)
-	if err != nil {
-		return nil, err
-	}
-	for key, value := range discordgo.DroidDownloadHeaders {
-		req.Header.Set(key, value)
-	}
-
-	resp, err := cli.Do(req)
-	if err != nil {
-		return nil, err
-	}
-	defer resp.Body.Close()
-	if resp.StatusCode > 300 {
-		data, _ := io.ReadAll(resp.Body)
-		return nil, fmt.Errorf("unexpected status %d downloading %s: %s", resp.StatusCode, url, data)
-	}
-	if resp.Header.Get("Content-Length") != "" {
-		length, err := strconv.ParseInt(resp.Header.Get("Content-Length"), 10, 64)
-		if err != nil {
-			return nil, fmt.Errorf("failed to parse content length: %w", err)
-		} else if length > maxSize {
-			return nil, fmt.Errorf("attachment too large (%d > %d)", length, maxSize)
-		}
-		return io.ReadAll(resp.Body)
-	} else {
-		var mbe *http.MaxBytesError
-		data, err := io.ReadAll(http.MaxBytesReader(nil, resp.Body, maxSize))
-		if err != nil && errors.As(err, &mbe) {
-			return nil, fmt.Errorf("attachment too large (over %d)", maxSize)
-		}
-		return data, err
-	}
-}
-
-func (d *DiscordConnector) ReuploadMedia(ctx context.Context, intent bridgev2.MatrixAPI, portal *bridgev2.Portal, upload attachment.AttachmentReupload) (*attachment.ReuploadedAttachment, error) {
-	// TODO(skip): Do we need to check if we've already downloaded this media before?
-	// TODO(skip): Read a maximum size from the config.
-	data, err := downloadDiscordAttachment(http.DefaultClient, upload.DownloadingURL, 1_024*1_024*50)
-	if err != nil {
-		return nil, fmt.Errorf("couldn't download attachment for reupload: %w", err)
-	}
-
-	if upload.FileName == "" {
-		url, err := url.Parse(upload.DownloadingURL)
-		if err != nil {
-			return nil, fmt.Errorf("couldn't parse URL to download for media reupload: %w", err)
-		}
-		fileName := path.Base(url.Path)
-		upload.FileName = fileName
-	}
-
-	if upload.MimeType == "" {
-		mime := http.DetectContentType(data)
-		upload.MimeType = mime
-	}
-
-	mxc, file, err := intent.UploadMedia(ctx, portal.MXID, data, upload.FileName, upload.MimeType)
-	if err != nil {
-		return nil, err
-	}
-
-	return &attachment.ReuploadedAttachment{
-		AttachmentReupload: upload,
-		DownloadedSize:     len(data),
-		MXC:                mxc,
-		EncryptedFile:      file,
-	}, nil
-}

pkg/connector/backfill.go

@@ -100,7 +100,7 @@ func (dc *DiscordClient) FetchMessages(ctx context.Context, fetchParams bridgev2
 
 		converted = append(converted, &bridgev2.BackfillMessage{
 			ID:               networkid.MessageID(msg.ID),
-			ConvertedMessage: dc.connector.MsgConv.ToMatrix(ctx, fetchParams.Portal, intent, dc.UserLogin, msg),
+			ConvertedMessage: dc.connector.MsgConv.ToMatrix(ctx, fetchParams.Portal, intent, dc.UserLogin, dc.Session, msg),
 			Sender:           sender,
 			Timestamp:        ts,
 			StreamOrder:      streamOrder,

pkg/connector/connector.go

@@ -30,14 +30,21 @@ type DiscordConnector struct {
 	MsgConv *msgconv.MessageConverter
 }
 
-var _ bridgev2.NetworkConnector = (*DiscordConnector)(nil)
+var (
+	_ bridgev2.NetworkConnector      = (*DiscordConnector)(nil)
+	_ bridgev2.MaxFileSizeingNetwork = (*DiscordConnector)(nil)
+)
 
 func (d *DiscordConnector) Init(bridge *bridgev2.Bridge) {
 	d.Bridge = bridge
-	d.MsgConv = msgconv.NewMessageConverter(bridge, d.ReuploadMedia)
+	d.MsgConv = msgconv.NewMessageConverter(bridge)
 	d.setUpProvisioningAPIs()
 }
 
+func (d *DiscordConnector) SetMaxFileSize(maxSize int64) {
+	d.MsgConv.MaxFileSize = maxSize
+}
+
 func (d *DiscordConnector) Start(ctx context.Context) error {
 	return nil
 }

pkg/connector/handlediscord.go

@@ -63,7 +63,7 @@ var (
 )
 
 func (m *DiscordMessage) ConvertMessage(ctx context.Context, portal *bridgev2.Portal, intent bridgev2.MatrixAPI) (*bridgev2.ConvertedMessage, error) {
-	return m.Client.connector.MsgConv.ToMatrix(ctx, portal, intent, m.Client.UserLogin, m.Data), nil
+	return m.Client.connector.MsgConv.ToMatrix(ctx, portal, intent, m.Client.UserLogin, m.Client.Session, m.Data), nil
 }
 
 func (m *DiscordMessage) GetID() networkid.MessageID {