Fix 404 on thumbnails that are too small

Fixes https://github.com/turt2live/matrix-media-repo/issues/444

Also fixes a memory issue where we'd decode the entire image before deciding that the image is too small for thumbnailing.

api/r0/thumbnail.go

@@ -9,6 +9,7 @@ import (
 	"github.com/turt2live/matrix-media-repo/api/_apimeta"
 	"github.com/turt2live/matrix-media-repo/api/_responses"
 	"github.com/turt2live/matrix-media-repo/api/_routers"
+	"github.com/turt2live/matrix-media-repo/database"
 	"github.com/turt2live/matrix-media-repo/pipelines/pipeline_download"
 	"github.com/turt2live/matrix-media-repo/pipelines/pipeline_thumbnail"
 	"github.com/turt2live/matrix-media-repo/util"
@@ -132,6 +133,27 @@ func ThumbnailMedia(r *http.Request, rctx rcontext.RequestContext, user _apimeta
 			}
 		} else if errors.Is(err, common.ErrMediaNotYetUploaded) {
 			return _responses.NotYetUploaded()
+		} else if errors.Is(err, common.ErrMediaDimensionsTooSmall) {
+			if stream == nil {
+				return _responses.NotFoundError() // something went wrong so just 404 the thumbnail
+			}
+
+			// We have a stream, and an error about image size, so we know there should be a media record
+			mediaDb := database.GetInstance().Media.Prepare(rctx)
+			record, err := mediaDb.GetById(server, mediaId)
+			if err != nil {
+				rctx.Log.Error("Unexpected error locating media record: ", err)
+				sentry.CaptureException(err)
+				return _responses.InternalServerError("Unexpected Error")
+			} else {
+				return &_responses.DownloadResponse{
+					ContentType:       record.ContentType,
+					Filename:          record.UploadName,
+					SizeBytes:         record.SizeBytes,
+					Data:              stream,
+					TargetDisposition: "infer",
+				}
+			}
 		}
 		rctx.Log.Error("Unexpected error locating media: ", err)
 		sentry.CaptureException(err)

common/errors.go

@@ -15,3 +15,4 @@ var ErrWrongUser = errors.New("wrong user")
 var ErrExpired = errors.New("expired")
 var ErrAlreadyUploaded = errors.New("already uploaded")
 var ErrMediaNotYetUploaded = errors.New("media not yet uploaded")
+var ErrMediaDimensionsTooSmall = errors.New("media is too small dimensionally")

pipelines/pipeline_thumbnail/pipeline.go

@@ -110,6 +110,14 @@ func Execute(ctx rcontext.RequestContext, origin string, mediaId string, opts Th
 		// Step 6: Generate the thumbnail and return that
 		record, r, err := thumbnails.Generate(ctx, mediaRecord, opts.Width, opts.Height, opts.Method, opts.Animated)
 		if err != nil {
+			if !opts.RecordOnly && errors.Is(err, common.ErrMediaDimensionsTooSmall) {
+				d, err := download.OpenStream(ctx, mediaRecord.Locatable, opts.StartByte, opts.EndByte)
+				if err != nil {
+					return nil, err
+				} else {
+					return d, common.ErrMediaDimensionsTooSmall
+				}
+			}
 			return nil, err
 		}
 		recordSf.OverwriteCacheKey(sfKey, record)
@@ -121,7 +129,7 @@ func Execute(ctx rcontext.RequestContext, origin string, mediaId string, opts Th
 		// Step 7: Create a limited stream
 		return download.CreateLimitedStream(ctx, r, opts.StartByte, opts.EndByte)
 	})
-	if errors.Is(err, common.ErrMediaQuarantined) {
+	if errors.Is(err, common.ErrMediaQuarantined) || errors.Is(err, common.ErrMediaDimensionsTooSmall) {
 		cancel()
 		return nil, r, err
 	}

thumbnailing/i/apng.go

@@ -10,6 +10,7 @@ import (
 	"github.com/kettek/apng"
 	"github.com/turt2live/matrix-media-repo/common/rcontext"
 	"github.com/turt2live/matrix-media-repo/thumbnailing/m"
+	"github.com/turt2live/matrix-media-repo/thumbnailing/u"
 )
 
 type apngGenerator struct {
@@ -69,7 +70,7 @@ func (d apngGenerator) GenerateThumbnail(b io.Reader, contentType string, width
 		draw.Draw(frameImg, image.Rect(frame.XOffset, frame.YOffset, frameImg.Rect.Max.X, frameImg.Rect.Max.Y), img, image.Point{X: 0, Y: 0}, draw.Src)
 
 		// Do the thumbnailing on the copied frame
-		frameThumb, err := pngGenerator{}.GenerateThumbnailImageOf(frameImg, width, height, method, ctx)
+		frameThumb, err := u.MakeThumbnail(frameImg, method, width, height)
 		if err != nil {
 			return nil, errors.New("apng: error generating thumbnail frame: " + err.Error())
 		}

thumbnailing/i/gif.go

@@ -56,7 +56,7 @@ func (d gifGenerator) GenerateThumbnail(b io.Reader, contentType string, width i
 		draw.Draw(frameImg, frameImg.Bounds(), img, image.Point{X: 0, Y: 0}, draw.Over)
 
 		// Do the thumbnailing on the copied frame
-		frameThumb, err := pngGenerator{}.GenerateThumbnailImageOf(frameImg, width, height, method, ctx)
+		frameThumb, err := u.MakeThumbnail(frameImg, method, width, height)
 		if err != nil {
 			return nil, errors.New("gif: error generating thumbnail frame: " + err.Error())
 		}

thumbnailing/i/jpg.go

@@ -43,12 +43,6 @@ func (d jpgGenerator) GenerateThumbnail(b io.Reader, contentType string, width i
 		return nil, errors.New("jpg: error decoding thumbnail: " + err.Error())
 	}
 
-	var shouldThumbnail bool
-	shouldThumbnail, width, height, _, method = u.AdjustProperties(src, width, height, animated, false, method)
-	if !shouldThumbnail {
-		return nil, nil
-	}
-
 	thumb, err := u.MakeThumbnail(src, method, width, height)
 	if err != nil {
 		return nil, errors.New("jpg: error making thumbnail: " + err.Error())

thumbnailing/i/mp3.go

@@ -105,7 +105,7 @@ func (d mp3Generator) GenerateFromStream(audio beep.StreamSeekCloser, format bee
 	if meta != nil && meta.Picture() != nil {
 		artwork, _, _ := image.Decode(bytes.NewBuffer(meta.Picture().Data))
 		if artwork != nil {
-			artworkImg, _ = pngGenerator{}.GenerateThumbnailImageOf(artwork, sq, sq, "crop", rcontext.Initial())
+			artworkImg, _ = u.MakeThumbnail(artwork, "crop", sq, sq)
 		}
 	}
 
@@ -129,7 +129,7 @@ func (d mp3Generator) GenerateFromStream(audio beep.StreamSeekCloser, format bee
 			defer f.Close()
 			tmp, _, _ := image.Decode(f)
 			if tmp != nil {
-				artworkImg, _ = pngGenerator{}.GenerateThumbnailImageOf(tmp, ax, ay, "crop", rcontext.Initial())
+				artworkImg, _ = u.MakeThumbnail(tmp, "crop", ax, ay)
 			}
 		}
 		if artworkImg == nil {

thumbnailing/i/png.go

@@ -45,7 +45,7 @@ func (d pngGenerator) GenerateThumbnail(b io.Reader, contentType string, width i
 }
 
 func (d pngGenerator) GenerateThumbnailOf(src image.Image, width int, height int, method string, ctx rcontext.RequestContext) (*m.Thumbnail, error) {
-	thumb, err := d.GenerateThumbnailImageOf(src, width, height, method, ctx)
+	thumb, err := u.MakeThumbnail(src, method, width, height)
 	if err != nil || thumb == nil {
 		return nil, err
 	}
@@ -67,16 +67,6 @@ func (d pngGenerator) GenerateThumbnailOf(src image.Image, width int, height int
 	}, nil
 }
 
-func (d pngGenerator) GenerateThumbnailImageOf(src image.Image, width int, height int, method string, ctx rcontext.RequestContext) (image.Image, error) {
-	var shouldThumbnail bool
-	shouldThumbnail, width, height, _, method = u.AdjustProperties(src, width, height, false, false, method)
-	if !shouldThumbnail {
-		return nil, nil
-	}
-
-	return u.MakeThumbnail(src, method, width, height)
-}
-
 func init() {
 	generators = append(generators, pngGenerator{})
 }

thumbnailing/thumbnail.go

@@ -9,6 +9,7 @@ import (
 	"github.com/turt2live/matrix-media-repo/common/rcontext"
 	"github.com/turt2live/matrix-media-repo/thumbnailing/i"
 	"github.com/turt2live/matrix-media-repo/thumbnailing/m"
+	"github.com/turt2live/matrix-media-repo/thumbnailing/u"
 	"github.com/turt2live/matrix-media-repo/util"
 	"github.com/turt2live/matrix-media-repo/util/readers"
 )
@@ -43,6 +44,13 @@ func GenerateThumbnail(imgStream io.ReadCloser, contentType string, width int, h
 		return nil, common.ErrMediaTooLarge
 	}
 
+	// TODO: Why does AdjustProperties even take `canAnimate` if it's always been hardcoded to `false`? (see git blame on this comment)
+	var shouldThumbnail bool
+	shouldThumbnail, width, height, _, method = u.AdjustProperties(w, h, width, height, animated, false, method)
+	if !shouldThumbnail {
+		return nil, common.ErrMediaDimensionsTooSmall
+	}
+
 	return generator.GenerateThumbnail(buffered.GetRewoundReader(), contentType, width, height, method, animated, ctx)
 }
 

thumbnailing/u/dimensions.go

 package u
 
-import (
-	"image"
-)
-
-func AdjustProperties(img image.Image, desiredWidth int, desiredHeight int, wantAnimated bool, canAnimate bool, method string) (bool, int, int, bool, string) {
-	srcWidth := img.Bounds().Max.X
-	srcHeight := img.Bounds().Max.Y
+func AdjustProperties(srcWidth int, srcHeight int, desiredWidth int, desiredHeight int, wantAnimated bool, canAnimate bool, method string) (bool, int, int, bool, string) {
+	//srcWidth := img.Bounds().Max.X
+	//srcHeight := img.Bounds().Max.Y
 
 	aspectRatio := float32(srcHeight) / float32(srcWidth)
 	targetAspectRatio := float32(desiredHeight) / float32(desiredWidth)