Files
mautrix-discord/pkg/connector/attachments.go
2025-12-11 18:22:36 -08:00

104 lines
3.2 KiB
Go

// mautrix-discord - A Matrix-Discord puppeting bridge.
// Copyright (C) 2024 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"
"go.mau.fi/mautrix-discord/pkg/attachment"
"maunium.net/go/mautrix/bridgev2"
)
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
}