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Randomly generated media IDs (#1336)

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* Filenames based on hashes but media IDs randomly generated and per-upload metadata

* Lint

* Comment generateMediaID
This commit is contained in:
Neil Alexander 2020-08-25 15:08:37 +01:00 committed by GitHub
parent a4db43e096
commit 287700baee
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GPG key ID: 4AEE18F83AFDEB23
6 changed files with 159 additions and 34 deletions
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100
mediaapi/routing/upload.go
View file

@ -16,7 +16,8 @@ package routing
import (
"context"
"encoding/base64"
"crypto/rand"
"encoding/hex"
"fmt"
"io"
"net/http"
@ -93,6 +94,33 @@ func parseAndValidateRequest(req *http.Request, cfg *config.MediaAPI) (*uploadRe
return r, nil
}
func (r *uploadRequest) generateMediaID(ctx context.Context, db storage.Database) (types.MediaID, error) {
for {
// First try generating a meda ID. We'll do this by
// generating some random bytes and then hex-encoding.
mediaIDBytes := make([]byte, 32)
_, err := rand.Read(mediaIDBytes)
if err != nil {
return "", fmt.Errorf("rand.Read: %w", err)
}
mediaID := types.MediaID(hex.EncodeToString(mediaIDBytes))
// Then we will check if this media ID already exists in
// our database. If it does then we had best generate a
// new one.
existingMetadata, err := db.GetMediaMetadata(ctx, mediaID, r.MediaMetadata.Origin)
if err != nil {
return "", fmt.Errorf("db.GetMediaMetadata: %w", err)
}
if existingMetadata != nil {
// The media ID was already used - repeat the process
// and generate a new one instead.
continue
}
// The media ID was not already used - let's return that.
return mediaID, nil
}
}
func (r *uploadRequest) doUpload(
ctx context.Context,
reqReader io.Reader,
@ -122,14 +150,53 @@ func (r *uploadRequest) doUpload(
}
}
// Look up the media by the file hash. If we already have the file but under a
// different media ID then we won't upload the file again - instead we'll just
// add a new metadata entry that refers to the same file.
existingMetadata, err := db.GetMediaMetadataByHash(
ctx, hash, r.MediaMetadata.Origin,
)
if err != nil {
r.Logger.WithError(err).Error("Error querying the database by hash.")
resErr := jsonerror.InternalServerError()
return &resErr
}
if existingMetadata != nil {
// The file already exists. Make a new media ID up for it.
mediaID, merr := r.generateMediaID(ctx, db)
if merr != nil {
r.Logger.WithError(merr).Error("Failed to generate media ID for existing file")
resErr := jsonerror.InternalServerError()
return &resErr
}
// Then amend the upload metadata.
r.MediaMetadata = &types.MediaMetadata{
MediaID: mediaID,
Origin: r.MediaMetadata.Origin,
ContentType: r.MediaMetadata.ContentType,
FileSizeBytes: r.MediaMetadata.FileSizeBytes,
CreationTimestamp: r.MediaMetadata.CreationTimestamp,
UploadName: r.MediaMetadata.UploadName,
Base64Hash: hash,
UserID: r.MediaMetadata.UserID,
}
// Clean up the uploaded temporary file.
fileutils.RemoveDir(tmpDir, r.Logger)
} else {
// The file doesn't exist. Update the request metadata.
r.MediaMetadata.FileSizeBytes = bytesWritten
r.MediaMetadata.Base64Hash = hash
r.MediaMetadata.MediaID = types.MediaID(base64.RawURLEncoding.EncodeToString(
[]byte(string(r.MediaMetadata.UploadName) + string(r.MediaMetadata.Base64Hash)),
))
r.Logger = r.Logger.WithField("MediaID", r.MediaMetadata.MediaID)
r.MediaMetadata.MediaID, err = r.generateMediaID(ctx, db)
if err != nil {
r.Logger.WithError(err).Error("Failed to generate media ID for new upload")
resErr := jsonerror.InternalServerError()
return &resErr
}
}
r.Logger = r.Logger.WithField("media_id", r.MediaMetadata.MediaID)
r.Logger.WithFields(log.Fields{
"Base64Hash": r.MediaMetadata.Base64Hash,
"UploadName": r.MediaMetadata.UploadName,
@ -137,27 +204,6 @@ func (r *uploadRequest) doUpload(
"ContentType": r.MediaMetadata.ContentType,
}).Info("File uploaded")
// check if we already have a record of the media in our database and if so, we can remove the temporary directory
mediaMetadata, err := db.GetMediaMetadata(
ctx, r.MediaMetadata.MediaID, r.MediaMetadata.Origin,
)
if err != nil {
r.Logger.WithError(err).Error("Error querying the database.")
resErr := jsonerror.InternalServerError()
return &resErr
}
if mediaMetadata != nil {
r.MediaMetadata = mediaMetadata
fileutils.RemoveDir(tmpDir, r.Logger)
return &util.JSONResponse{
Code: http.StatusOK,
JSON: uploadResponse{
ContentURI: fmt.Sprintf("mxc://%s/%s", cfg.Matrix.ServerName, r.MediaMetadata.MediaID),
},
}
}
return r.storeFileAndMetadata(
ctx, tmpDir, cfg.AbsBasePath, db, cfg.ThumbnailSizes,
activeThumbnailGeneration, cfg.MaxThumbnailGenerators,

1
mediaapi/storage/interface.go
View file

@ -24,6 +24,7 @@ import (
type Database interface {
StoreMediaMetadata(ctx context.Context, mediaMetadata *types.MediaMetadata) error
GetMediaMetadata(ctx context.Context, mediaID types.MediaID, mediaOrigin gomatrixserverlib.ServerName) (*types.MediaMetadata, error)
GetMediaMetadataByHash(ctx context.Context, mediaHash types.Base64Hash, mediaOrigin gomatrixserverlib.ServerName) (*types.MediaMetadata, error)
StoreThumbnail(ctx context.Context, thumbnailMetadata *types.ThumbnailMetadata) error
GetThumbnail(ctx context.Context, mediaID types.MediaID, mediaOrigin gomatrixserverlib.ServerName, width, height int, resizeMethod string) (*types.ThumbnailMetadata, error)
GetThumbnails(ctx context.Context, mediaID types.MediaID, mediaOrigin gomatrixserverlib.ServerName) ([]*types.ThumbnailMetadata, error)

26
mediaapi/storage/postgres/media_repository_table.go
View file

@ -59,9 +59,14 @@ const selectMediaSQL = `
SELECT content_type, file_size_bytes, creation_ts, upload_name, base64hash, user_id FROM mediaapi_media_repository WHERE media_id = $1 AND media_origin = $2
`
const selectMediaByHashSQL = `
SELECT content_type, file_size_bytes, creation_ts, upload_name, media_id, user_id FROM mediaapi_media_repository WHERE base64hash = $1 AND media_origin = $2
`
type mediaStatements struct {
insertMediaStmt *sql.Stmt
selectMediaStmt *sql.Stmt
selectMediaByHashStmt *sql.Stmt
}
func (s *mediaStatements) prepare(db *sql.DB) (err error) {
@ -73,6 +78,7 @@ func (s *mediaStatements) prepare(db *sql.DB) (err error) {
return statementList{
{&s.insertMediaStmt, insertMediaSQL},
{&s.selectMediaStmt, selectMediaSQL},
{&s.selectMediaByHashStmt, selectMediaByHashSQL},
}.prepare(db)
}
@ -113,3 +119,23 @@ func (s *mediaStatements) selectMedia(
)
return &mediaMetadata, err
}
func (s *mediaStatements) selectMediaByHash(
ctx context.Context, mediaHash types.Base64Hash, mediaOrigin gomatrixserverlib.ServerName,
) (*types.MediaMetadata, error) {
mediaMetadata := types.MediaMetadata{
Base64Hash: mediaHash,
Origin: mediaOrigin,
}
err := s.selectMediaStmt.QueryRowContext(
ctx, mediaMetadata.Base64Hash, mediaMetadata.Origin,
).Scan(
&mediaMetadata.ContentType,
&mediaMetadata.FileSizeBytes,
&mediaMetadata.CreationTimestamp,
&mediaMetadata.UploadName,
&mediaMetadata.MediaID,
&mediaMetadata.UserID,
)
return &mediaMetadata, err
}

13
mediaapi/storage/postgres/storage.go
View file

@ -67,6 +67,19 @@ func (d *Database) GetMediaMetadata(
return mediaMetadata, err
}
// GetMediaMetadataByHash returns metadata about media stored on this server.
// The media could have been uploaded to this server or fetched from another server and cached here.
// Returns nil metadata if there is no metadata associated with this media.
func (d *Database) GetMediaMetadataByHash(
ctx context.Context, mediaHash types.Base64Hash, mediaOrigin gomatrixserverlib.ServerName,
) (*types.MediaMetadata, error) {
mediaMetadata, err := d.statements.media.selectMediaByHash(ctx, mediaHash, mediaOrigin)
if err != nil && err == sql.ErrNoRows {
return nil, nil
}
return mediaMetadata, err
}
// StoreThumbnail inserts the metadata about the thumbnail into the database.
// Returns an error if the combination of MediaID and Origin are not unique in the table.
func (d *Database) StoreThumbnail(

26
mediaapi/storage/sqlite3/media_repository_table.go
View file

@ -60,11 +60,16 @@ const selectMediaSQL = `
SELECT content_type, file_size_bytes, creation_ts, upload_name, base64hash, user_id FROM mediaapi_media_repository WHERE media_id = $1 AND media_origin = $2
`
const selectMediaByHashSQL = `
SELECT content_type, file_size_bytes, creation_ts, upload_name, media_id, user_id FROM mediaapi_media_repository WHERE base64hash = $1 AND media_origin = $2
`
type mediaStatements struct {
db *sql.DB
writer sqlutil.Writer
insertMediaStmt *sql.Stmt
selectMediaStmt *sql.Stmt
selectMediaByHashStmt *sql.Stmt
}
func (s *mediaStatements) prepare(db *sql.DB, writer sqlutil.Writer) (err error) {
@ -79,6 +84,7 @@ func (s *mediaStatements) prepare(db *sql.DB, writer sqlutil.Writer) (err error)
return statementList{
{&s.insertMediaStmt, insertMediaSQL},
{&s.selectMediaStmt, selectMediaSQL},
{&s.selectMediaByHashStmt, selectMediaByHashSQL},
}.prepare(db)
}
@ -122,3 +128,23 @@ func (s *mediaStatements) selectMedia(
)
return &mediaMetadata, err
}
func (s *mediaStatements) selectMediaByHash(
ctx context.Context, mediaHash types.Base64Hash, mediaOrigin gomatrixserverlib.ServerName,
) (*types.MediaMetadata, error) {
mediaMetadata := types.MediaMetadata{
Base64Hash: mediaHash,
Origin: mediaOrigin,
}
err := s.selectMediaStmt.QueryRowContext(
ctx, mediaMetadata.Base64Hash, mediaMetadata.Origin,
).Scan(
&mediaMetadata.ContentType,
&mediaMetadata.FileSizeBytes,
&mediaMetadata.CreationTimestamp,
&mediaMetadata.UploadName,
&mediaMetadata.MediaID,
&mediaMetadata.UserID,
)
return &mediaMetadata, err
}

13
mediaapi/storage/sqlite3/storage.go
View file

@ -70,6 +70,19 @@ func (d *Database) GetMediaMetadata(
return mediaMetadata, err
}
// GetMediaMetadataByHash returns metadata about media stored on this server.
// The media could have been uploaded to this server or fetched from another server and cached here.
// Returns nil metadata if there is no metadata associated with this media.
func (d *Database) GetMediaMetadataByHash(
ctx context.Context, mediaHash types.Base64Hash, mediaOrigin gomatrixserverlib.ServerName,
) (*types.MediaMetadata, error) {
mediaMetadata, err := d.statements.media.selectMediaByHash(ctx, mediaHash, mediaOrigin)
if err != nil && err == sql.ErrNoRows {
return nil, nil
}
return mediaMetadata, err
}
// StoreThumbnail inserts the metadata about the thumbnail into the database.
// Returns an error if the combination of MediaID and Origin are not unique in the table.
func (d *Database) StoreThumbnail(