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gotosocial/internal/apimodule/fileserver/servefile.go

244 lines
8.6 KiB
Go

/*
GoToSocial
Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
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 <http://www.gnu.org/licenses/>.
*/
package fileserver
import (
"bytes"
"net/http"
"strings"
"github.com/gin-gonic/gin"
"github.com/sirupsen/logrus"
"github.com/superseriousbusiness/gotosocial/internal/db/gtsmodel"
"github.com/superseriousbusiness/gotosocial/internal/media"
)
// ServeFile is for serving attachments, headers, and avatars to the requester from instance storage.
//
// Note: to mitigate scraping attempts, no information should be given out on a bad request except "404 page not found".
// Don't give away account ids or media ids or anything like that; callers shouldn't be able to infer anything.
func (m *FileServer) ServeFile(c *gin.Context) {
l := m.log.WithFields(logrus.Fields{
"func": "ServeFile",
"request_uri": c.Request.RequestURI,
"user_agent": c.Request.UserAgent(),
"origin_ip": c.ClientIP(),
})
l.Trace("received request")
// We use request params to check what to pull out of the database/storage so check everything. A request URL should be formatted as follows:
// "https://example.org/fileserver/[ACCOUNT_ID]/[MEDIA_TYPE]/[MEDIA_SIZE]/[FILE_NAME]"
// "FILE_NAME" consists of two parts, the attachment's database id, a period, and the file extension.
accountID := c.Param(AccountIDKey)
if accountID == "" {
l.Debug("missing accountID from request")
c.String(http.StatusNotFound, "404 page not found")
return
}
mediaType := c.Param(MediaTypeKey)
if mediaType == "" {
l.Debug("missing mediaType from request")
c.String(http.StatusNotFound, "404 page not found")
return
}
mediaSize := c.Param(MediaSizeKey)
if mediaSize == "" {
l.Debug("missing mediaSize from request")
c.String(http.StatusNotFound, "404 page not found")
return
}
fileName := c.Param(FileNameKey)
if fileName == "" {
l.Debug("missing fileName from request")
c.String(http.StatusNotFound, "404 page not found")
return
}
// Only serve media types that are defined in our internal media module
switch mediaType {
case media.MediaHeader, media.MediaAvatar, media.MediaAttachment:
m.serveAttachment(c, accountID, mediaType, mediaSize, fileName)
return
case media.MediaEmoji:
m.serveEmoji(c, accountID, mediaType, mediaSize, fileName)
return
}
l.Debugf("mediatype %s not recognized", mediaType)
c.String(http.StatusNotFound, "404 page not found")
}
func (m *FileServer) serveAttachment(c *gin.Context, accountID string, mediaType string, mediaSize string, fileName string) {
l := m.log.WithFields(logrus.Fields{
"func": "serveAttachment",
"request_uri": c.Request.RequestURI,
"user_agent": c.Request.UserAgent(),
"origin_ip": c.ClientIP(),
})
// This corresponds to original-sized image as it was uploaded, small (which is the thumbnail), or static
switch mediaSize {
case media.MediaOriginal, media.MediaSmall, media.MediaStatic:
default:
l.Debugf("mediasize %s not recognized", mediaSize)
c.String(http.StatusNotFound, "404 page not found")
return
}
// derive the media id and the file extension from the last part of the request
spl := strings.Split(fileName, ".")
if len(spl) != 2 {
l.Debugf("filename %s not parseable", fileName)
c.String(http.StatusNotFound, "404 page not found")
return
}
wantedMediaID := spl[0]
fileExtension := spl[1]
if wantedMediaID == "" || fileExtension == "" {
l.Debugf("filename %s not parseable", fileName)
c.String(http.StatusNotFound, "404 page not found")
return
}
// now we know the attachment ID that the caller is asking for we can use it to pull the attachment out of the db
attachment := &gtsmodel.MediaAttachment{}
if err := m.db.GetByID(wantedMediaID, attachment); err != nil {
l.Debugf("attachment with id %s not retrievable: %s", wantedMediaID, err)
c.String(http.StatusNotFound, "404 page not found")
return
}
// make sure the given account id owns the requested attachment
if accountID != attachment.AccountID {
l.Debugf("account %s does not own attachment with id %s", accountID, wantedMediaID)
c.String(http.StatusNotFound, "404 page not found")
return
}
// now we can start preparing the response depending on whether we're serving a thumbnail or a larger attachment
var storagePath string
var contentType string
var contentLength int
switch mediaSize {
case media.MediaOriginal:
storagePath = attachment.File.Path
contentType = attachment.File.ContentType
contentLength = attachment.File.FileSize
case media.MediaSmall:
storagePath = attachment.Thumbnail.Path
contentType = attachment.Thumbnail.ContentType
contentLength = attachment.Thumbnail.FileSize
}
// use the path listed on the attachment we pulled out of the database to retrieve the object from storage
attachmentBytes, err := m.storage.RetrieveFileFrom(storagePath)
if err != nil {
l.Debugf("error retrieving from storage: %s", err)
c.String(http.StatusNotFound, "404 page not found")
return
}
l.Errorf("about to serve content length: %d attachment bytes is: %d", int64(contentLength), int64(len(attachmentBytes)))
// finally we can return with all the information we derived above
c.DataFromReader(http.StatusOK, int64(contentLength), contentType, bytes.NewReader(attachmentBytes), map[string]string{})
}
func (m *FileServer) serveEmoji(c *gin.Context, accountID string, mediaType string, mediaSize string, fileName string) {
l := m.log.WithFields(logrus.Fields{
"func": "serveEmoji",
"request_uri": c.Request.RequestURI,
"user_agent": c.Request.UserAgent(),
"origin_ip": c.ClientIP(),
})
// This corresponds to original-sized emoji as it was uploaded, or static
switch mediaSize {
case media.MediaOriginal, media.MediaStatic:
default:
l.Debugf("mediasize %s not recognized", mediaSize)
c.String(http.StatusNotFound, "404 page not found")
return
}
// derive the media id and the file extension from the last part of the request
spl := strings.Split(fileName, ".")
if len(spl) != 2 {
l.Debugf("filename %s not parseable", fileName)
c.String(http.StatusNotFound, "404 page not found")
return
}
wantedEmojiID := spl[0]
fileExtension := spl[1]
if wantedEmojiID == "" || fileExtension == "" {
l.Debugf("filename %s not parseable", fileName)
c.String(http.StatusNotFound, "404 page not found")
return
}
// now we know the attachment ID that the caller is asking for we can use it to pull the attachment out of the db
emoji := &gtsmodel.Emoji{}
if err := m.db.GetByID(wantedEmojiID, emoji); err != nil {
l.Debugf("emoji with id %s not retrievable: %s", wantedEmojiID, err)
c.String(http.StatusNotFound, "404 page not found")
return
}
// make sure the instance account id owns the requested emoji
instanceAccount := &gtsmodel.Account{}
if err := m.db.GetWhere("username", m.config.Host, instanceAccount); err != nil {
l.Debugf("error fetching instance account: %s", err)
c.String(http.StatusNotFound, "404 page not found")
return
}
if accountID != instanceAccount.ID {
l.Debugf("account %s does not own emoji with id %s", accountID, wantedEmojiID)
c.String(http.StatusNotFound, "404 page not found")
return
}
// now we can start preparing the response depending on whether we're serving a thumbnail or a larger attachment
var storagePath string
var contentType string
var contentLength int
switch mediaSize {
case media.MediaOriginal:
storagePath = emoji.ImagePath
contentType = emoji.ImageContentType
contentLength = emoji.ImageFileSize
case media.MediaStatic:
storagePath = emoji.ImageStaticPath
contentType = "image/png"
contentLength = emoji.ImageStaticFileSize
}
// use the path listed on the emoji we pulled out of the database to retrieve the object from storage
emojiBytes, err := m.storage.RetrieveFileFrom(storagePath)
if err != nil {
l.Debugf("error retrieving emoji from storage: %s", err)
c.String(http.StatusNotFound, "404 page not found")
return
}
// finally we can return with all the information we derived above
c.DataFromReader(http.StatusOK, int64(contentLength), contentType, bytes.NewReader(emojiBytes), map[string]string{})
}