fix: relax chunk limits, support proxies, optimize reads

Signed-off-by: skidoodle <contact@albert.lol>

internal/app/config.go

@@ -22,6 +22,7 @@ const (
 	ShutdownTimeout = 10 * time.Second
 
 	UploadChunkSize    = 8 << 20
+	MinChunkSize       = 1 << 20
 	MaxRequestOverhead = 10 << 20
 	PermUserRWX        = 0o700
 	MegaByte           = 1 << 20

internal/app/server.go

@@ -72,10 +72,13 @@ func (app *App) RespondWithLink(writer http.ResponseWriter, request *http.Reques
 		return
 	}
 
-	scheme := "https"
+	scheme := request.Header.Get("X-Forwarded-Proto")
+	if scheme == "" {
+		scheme = "https"
 		if request.TLS == nil {
 			scheme = "http"
 		}
+	}
 
 	if _, err := fmt.Fprintf(writer, "%s://%s\n", scheme, link); err != nil {
 		app.Logger.Error("Failed to write response", "err", err)

internal/app/upload.go

@@ -112,7 +112,7 @@ func (app *App) HandleChunk(writer http.ResponseWriter, request *http.Request) {
 		return
 	}
 
-	maxChunks := int((app.Conf.MaxMB*MegaByte)/UploadChunkSize) + ChunkSafetyMargin
+	maxChunks := int((app.Conf.MaxMB*MegaByte)/MinChunkSize) + ChunkSafetyMargin
 
 	if !reUploadID.MatchString(uid) || idx > maxChunks || idx < 0 {
 		app.SendError(writer, request, http.StatusBadRequest)
@@ -148,7 +148,7 @@ func (app *App) HandleFinish(writer http.ResponseWriter, request *http.Request)
 		return
 	}
 
-	maxChunks := int((app.Conf.MaxMB*MegaByte)/UploadChunkSize) + ChunkSafetyMargin
+	maxChunks := int((app.Conf.MaxMB*MegaByte)/MinChunkSize) + ChunkSafetyMargin
 
 	if !reUploadID.MatchString(uid) || total > maxChunks || total <= 0 {
 		app.SendError(writer, request, http.StatusBadRequest)

internal/crypto/reader.go

@@ -16,6 +16,7 @@ type Decryptor struct {
 	aead       cipher.AEAD
 	size       int64
 	offset     int64
+	phyOffset  int64
 }
 
 func NewDecryptor(readSeeker io.ReadSeeker, aead cipher.AEAD, encryptedSize int64) *Decryptor {
@@ -35,6 +36,7 @@ func NewDecryptor(readSeeker io.ReadSeeker, aead cipher.AEAD, encryptedSize int6
 		aead:       aead,
 		size:       plainSize,
 		offset:     0,
+		phyOffset:  -1,
 	}
 }
 
@@ -49,14 +51,22 @@ func (d *Decryptor) Read(buf []byte) (int, error) {
 	overhead := int64(d.aead.Overhead())
 	actualChunkSize := int64(GCMChunkSize) + overhead
 
-	_, err := d.readSeeker.Seek(chunkIdx*actualChunkSize, io.SeekStart)
+	targetOffset := chunkIdx * actualChunkSize
-	if err != nil {
+
+	if d.phyOffset != targetOffset {
+		if _, err := d.readSeeker.Seek(targetOffset, io.SeekStart); err != nil {
 			return 0, fmt.Errorf("failed to seek: %w", err)
 		}
+		d.phyOffset = targetOffset
+	}
 
 	encrypted := make([]byte, actualChunkSize)
 
 	bytesRead, err := io.ReadFull(d.readSeeker, encrypted)
+	if bytesRead > 0 {
+		d.phyOffset += int64(bytesRead)
+	}
+
 	if err != nil && !errors.Is(err, io.ErrUnexpectedEOF) {
 		return 0, fmt.Errorf("failed to read encrypted data: %w", err)
 	}