Merge pull request #182 from acj/acj/add-upload-defer-length-support

Implement Upload-Defer-Length Extension

composer.go

@@ -16,6 +16,8 @@ type StoreComposer struct {
 	GetReader          GetReaderDataStore
 	UsesConcater       bool
 	Concater           ConcaterDataStore
+	UsesLengthDeferrer bool
+	LengthDeferrer     LengthDeferrerDataStore
 }
 
 // NewStoreComposer creates a new and empty store composer.
@@ -45,6 +47,9 @@ func newStoreComposerFromDataStore(store DataStore) *StoreComposer {
 	if mod, ok := store.(ConcaterDataStore); ok {
 		composer.UseConcater(mod)
 	}
+	if mod, ok := store.(LengthDeferrerDataStore); ok {
+		composer.UseLengthDeferrer(mod)
+	}
 
 	return composer
 }
@@ -90,6 +95,12 @@ func (store *StoreComposer) Capabilities() string {
 	} else {
 		str += "✗"
 	}
+	str += ` LengthDeferrer: `
+	if store.UsesLengthDeferrer {
+		str += "✓"
+	} else {
+		str += "✗"
+	}
 
 	return str
 }
@@ -120,3 +131,8 @@ func (store *StoreComposer) UseConcater(ext ConcaterDataStore) {
 	store.UsesConcater = ext != nil
 	store.Concater = ext
 }
+
+func (store *StoreComposer) UseLengthDeferrer(ext LengthDeferrerDataStore) {
+	store.UsesLengthDeferrer = ext != nil
+	store.LengthDeferrer = ext
+}

composer.mgo

@@ -31,6 +31,7 @@ type StoreComposer struct {
   USE_FIELD(Locker)
   USE_FIELD(GetReader)
   USE_FIELD(Concater)
+  USE_FIELD(LengthDeferrer)
 }
 
 // NewStoreComposer creates a new and empty store composer.
@@ -50,6 +51,7 @@ func newStoreComposerFromDataStore(store DataStore) *StoreComposer {
   USE_FROM(Locker)
   USE_FROM(GetReader)
   USE_FROM(Concater)
+  USE_FROM(LengthDeferrer)
 
   return composer
 }
@@ -70,6 +72,7 @@ func (store *StoreComposer) Capabilities() string {
   USE_CAP(Locker)
   USE_CAP(GetReader)
   USE_CAP(Concater)
+  USE_CAP(LengthDeferrer)
 
   return str
 }
@@ -85,3 +88,4 @@ USE_FUNC(Finisher)
 USE_FUNC(Locker)
 USE_FUNC(GetReader)
 USE_FUNC(Concater)
+USE_FUNC(LengthDeferrer)

datastore.go

@@ -10,6 +10,8 @@ type FileInfo struct {
 	ID string
 	// Total file size in bytes specified in the NewUpload call
 	Size int64
+	// Indicates whether the total file size is deferred until later
+	SizeIsDeferred bool
 	// Offset in bytes (zero-based)
 	Offset   int64
 	MetaData MetaData
@@ -112,3 +114,11 @@ type ConcaterDataStore interface {
 	// must be respected during concatenation.
 	ConcatUploads(destination string, partialUploads []string) error
 }
+
+// LengthDeferrerDataStore is the interface that must be implemented if the
+// creation-defer-length extension should be enabled. The extension enables a
+// client to upload files when their total size is not yet known. Instead, the
+// client must send the total size as soon as it becomes known.
+type LengthDeferrerDataStore interface {
+	DeclareLength(id string, length int64) error
+}

filestore/filestore.go

@@ -55,6 +55,7 @@ func (store FileStore) UseIn(composer *tusd.StoreComposer) {
 	composer.UseTerminater(store)
 	composer.UseLocker(store)
 	composer.UseConcater(store)
+	composer.UseLengthDeferrer(store)
 }
 
 func (store FileStore) NewUpload(info tusd.FileInfo) (id string, err error) {
@@ -142,6 +143,16 @@ func (store FileStore) ConcatUploads(dest string, uploads []string) (err error)
 	return
 }
 
+func (store FileStore) DeclareLength(id string, length int64) error {
+	info, err := store.GetInfo(id)
+	if err != nil {
+		return err
+	}
+	info.Size = length
+	info.SizeIsDeferred = false
+	return store.writeInfo(id, info)
+}
+
 func (store FileStore) LockUpload(id string) error {
 	lock, err := store.newLock(id)
 	if err != nil {

filestore/filestore_test.go

@@ -18,6 +18,7 @@ var _ tusd.GetReaderDataStore = FileStore{}
 var _ tusd.TerminaterDataStore = FileStore{}
 var _ tusd.LockerDataStore = FileStore{}
 var _ tusd.ConcaterDataStore = FileStore{}
+var _ tusd.LengthDeferrerDataStore = FileStore{}
 
 func TestFilestore(t *testing.T) {
 	a := assert.New(t)
@@ -146,3 +147,28 @@ func TestConcatUploads(t *testing.T) {
 	a.Equal("abcdefghi", string(content))
 	reader.(io.Closer).Close()
 }
+
+func TestDeclareLength(t *testing.T) {
+	a := assert.New(t)
+
+	tmp, err := ioutil.TempDir("", "tusd-filestore-declare-length-")
+	a.NoError(err)
+
+	store := FileStore{tmp}
+
+	originalInfo := tusd.FileInfo{Size: 0, SizeIsDeferred: true}
+	id, err := store.NewUpload(originalInfo)
+	a.NoError(err)
+
+	info, err := store.GetInfo(id)
+	a.Equal(info.Size, originalInfo.Size)
+	a.Equal(info.SizeIsDeferred, originalInfo.SizeIsDeferred)
+
+	size := int64(100)
+	err = store.DeclareLength(id, size)
+	a.NoError(err)
+
+	updatedInfo, err := store.GetInfo(id)
+	a.Equal(updatedInfo.Size, size)
+	a.False(updatedInfo.SizeIsDeferred)
+}

handler_mock_test.go

@@ -4,10 +4,9 @@
 package tusd_test
 
 import (
-	io "io"
-
 	gomock "github.com/golang/mock/gomock"
 	tusd "github.com/tus/tusd"
+	io "io"
 )
 
 // Mock of FullDataStore interface
@@ -105,6 +104,16 @@ func (_mr *_MockFullDataStoreRecorder) FinishUpload(arg0 interface{}) *gomock.Ca
 	return _mr.mock.ctrl.RecordCall(_mr.mock, "FinishUpload", arg0)
 }
 
+func (_m *MockFullDataStore) DeclareLength(id string, length int64) error {
+	ret := _m.ctrl.Call(_m, "DeclareLength", id, length)
+	ret0, _ := ret[0].(error)
+	return ret0
+}
+
+func (_mr *_MockFullDataStoreRecorder) DeclareLength(arg0, arg1 interface{}) *gomock.Call {
+	return _mr.mock.ctrl.RecordCall(_mr.mock, "DeclareLength", arg0, arg1)
+}
+
 // Mock of Locker interface
 type MockLocker struct {
 	ctrl     *gomock.Controller

head_test.go

@@ -81,4 +81,52 @@ func TestHead(t *testing.T) {
 			t.Errorf("Expected empty body for failed HEAD request")
 		}
 	})
+
+	SubTest(t, "DeferLengthHeader", func(t *testing.T, store *MockFullDataStore) {
+		store.EXPECT().GetInfo("yes").Return(FileInfo{
+			SizeIsDeferred: true,
+			Size: 0,
+		}, nil)
+
+		handler, _ := NewHandler(Config{
+			DataStore: store,
+		})
+
+		(&httpTest{
+			Method: "HEAD",
+			URL:    "yes",
+			ReqHeader: map[string]string{
+				"Tus-Resumable": "1.0.0",
+			},
+			Code: http.StatusOK,
+			ResHeader: map[string]string{
+				"Upload-Defer-Length": "1",
+			},
+		}).Run(handler, t)
+	})
+
+	SubTest(t, "NoDeferLengthHeader", func(t *testing.T, store *MockFullDataStore) {
+		gomock.InOrder(
+			store.EXPECT().GetInfo("yes").Return(FileInfo{
+				SizeIsDeferred: false,
+				Size: 10,
+			}, nil),
+		)
+
+		handler, _ := NewHandler(Config{
+			DataStore: store,
+		})
+
+		(&httpTest{
+			Method: "HEAD",
+			URL:    "yes",
+			ReqHeader: map[string]string{
+				"Tus-Resumable": "1.0.0",
+			},
+			Code: http.StatusOK,
+			ResHeader: map[string]string{
+				"Upload-Defer-Length": "",
+			},
+		}).Run(handler, t)
+	})
 }

patch_test.go

@@ -257,6 +257,132 @@ func TestPatch(t *testing.T) {
 		}).Run(handler, t)
 	})
 
+	SubTest(t, "DeclareLengthOnFinalChunk", func(t *testing.T, store *MockFullDataStore) {
+		gomock.InOrder(
+			store.EXPECT().GetInfo("yes").Return(FileInfo{
+				ID:             "yes",
+				Offset:         5,
+				Size:           0,
+				SizeIsDeferred: true,
+			}, nil),
+			store.EXPECT().DeclareLength("yes", int64(20)),
+			store.EXPECT().WriteChunk("yes", int64(5), NewReaderMatcher("hellothisismore")).Return(int64(15), nil),
+			store.EXPECT().FinishUpload("yes"),
+		)
+
+		handler, _ := NewHandler(Config{
+			DataStore: store,
+			MaxSize:   20,
+		})
+
+		body := strings.NewReader("hellothisismore")
+
+		(&httpTest{
+			Method: "PATCH",
+			URL:    "yes",
+			ReqHeader: map[string]string{
+				"Tus-Resumable": "1.0.0",
+				"Content-Type":  "application/offset+octet-stream",
+				"Upload-Offset": "5",
+				"Upload-Length": "20",
+			},
+			ReqBody: body,
+			Code:    http.StatusNoContent,
+			ResHeader: map[string]string{
+				"Upload-Offset": "20",
+			},
+		}).Run(handler, t)
+	})
+
+	SubTest(t, "DeclareLengthAfterFinalChunk", func(t *testing.T, store *MockFullDataStore) {
+		gomock.InOrder(
+			store.EXPECT().GetInfo("yes").Return(FileInfo{
+				ID:             "yes",
+				Offset:         20,
+				Size:           0,
+				SizeIsDeferred: true,
+			}, nil),
+			store.EXPECT().DeclareLength("yes", int64(20)),
+			store.EXPECT().FinishUpload("yes"),
+		)
+
+		handler, _ := NewHandler(Config{
+			DataStore: store,
+			MaxSize:   20,
+		})
+
+		(&httpTest{
+			Method: "PATCH",
+			URL:    "yes",
+			ReqHeader: map[string]string{
+				"Tus-Resumable": "1.0.0",
+				"Content-Type":  "application/offset+octet-stream",
+				"Upload-Offset": "20",
+				"Upload-Length": "20",
+			},
+			ReqBody:   nil,
+			Code:      http.StatusNoContent,
+			ResHeader: map[string]string{},
+		}).Run(handler, t)
+	})
+
+	SubTest(t, "DeclareLengthOnNonFinalChunk", func(t *testing.T, store *MockFullDataStore) {
+		gomock.InOrder(
+			store.EXPECT().GetInfo("yes").Return(FileInfo{
+				ID:             "yes",
+				Offset:         5,
+				Size:           0,
+				SizeIsDeferred: true,
+			}, nil),
+			store.EXPECT().DeclareLength("yes", int64(20)),
+			store.EXPECT().WriteChunk("yes", int64(5), NewReaderMatcher("hello")).Return(int64(5), nil),
+			store.EXPECT().GetInfo("yes").Return(FileInfo{
+				ID:             "yes",
+				Offset:         10,
+				Size:           20,
+				SizeIsDeferred: false,
+			}, nil),
+			store.EXPECT().WriteChunk("yes", int64(10), NewReaderMatcher("thisismore")).Return(int64(10), nil),
+			store.EXPECT().FinishUpload("yes"),
+		)
+
+		handler, _ := NewHandler(Config{
+			DataStore: store,
+			MaxSize:   20,
+		})
+
+		(&httpTest{
+			Method: "PATCH",
+			URL:    "yes",
+			ReqHeader: map[string]string{
+				"Tus-Resumable": "1.0.0",
+				"Content-Type":  "application/offset+octet-stream",
+				"Upload-Offset": "5",
+				"Upload-Length": "20",
+			},
+			ReqBody: strings.NewReader("hello"),
+			Code:    http.StatusNoContent,
+			ResHeader: map[string]string{
+				"Upload-Offset": "10",
+			},
+		}).Run(handler, t)
+
+		(&httpTest{
+			Method: "PATCH",
+			URL:    "yes",
+			ReqHeader: map[string]string{
+				"Tus-Resumable": "1.0.0",
+				"Content-Type":  "application/offset+octet-stream",
+				"Upload-Offset": "10",
+			},
+			ReqBody: strings.NewReader("thisismore"),
+			Code:    http.StatusNoContent,
+			ResHeader: map[string]string{
+				"Upload-Offset": "20",
+			},
+		}).Run(handler, t)
+	})
+
 	SubTest(t, "Locker", func(t *testing.T, store *MockFullDataStore) {
 		ctrl := gomock.NewController(t)
 		defer ctrl.Finish()

post_test.go

@@ -123,6 +123,54 @@ func TestPost(t *testing.T) {
 		}).Run(handler, t)
 	})
 
+	SubTest(t, "UploadLengthAndUploadDeferLengthFail", func(t *testing.T, store *MockFullDataStore) {
+		handler, _ := NewHandler(Config{
+			DataStore: store,
+		})
+
+		(&httpTest{
+			Method: "POST",
+			URL:    "",
+			ReqHeader: map[string]string{
+				"Tus-Resumable":       "1.0.0",
+				"Upload-Length":       "10",
+				"Upload-Defer-Length": "1",
+			},
+			Code: http.StatusBadRequest,
+		}).Run(handler, t)
+	})
+
+	SubTest(t, "NeitherUploadLengthNorUploadDeferLengthFail", func(t *testing.T, store *MockFullDataStore) {
+		handler, _ := NewHandler(Config{
+			DataStore: store,
+		})
+
+		(&httpTest{
+			Method: "POST",
+			URL:    "",
+			ReqHeader: map[string]string{
+				"Tus-Resumable":       "1.0.0",
+			},
+			Code: http.StatusBadRequest,
+		}).Run(handler, t)
+	})
+
+	SubTest(t, "InvalidUploadDeferLengthFail", func(t *testing.T, store *MockFullDataStore) {
+		handler, _ := NewHandler(Config{
+			DataStore: store,
+		})
+
+		(&httpTest{
+			Method: "POST",
+			URL:    "",
+			ReqHeader: map[string]string{
+				"Tus-Resumable":       "1.0.0",
+				"Upload-Defer-Length": "bad",
+			},
+			Code: http.StatusBadRequest,
+		}).Run(handler, t)
+	})
+
 	SubTest(t, "ForwardHeaders", func(t *testing.T, store *MockFullDataStore) {
 		SubTest(t, "IgnoreXForwarded", func(t *testing.T, store *MockFullDataStore) {
 			store.EXPECT().NewUpload(FileInfo{

s3store/s3store.go

@@ -271,6 +271,7 @@ func (store S3Store) WriteChunk(id string, offset int64, src io.Reader) (int64,
 			return bytesUploaded, nil
 		}
 
+		if !info.SizeIsDeferred {
 			if (size - offset) <= optimalPartSize {
 				if (size - offset) != n {
 					return bytesUploaded, nil
@@ -278,6 +279,7 @@ func (store S3Store) WriteChunk(id string, offset int64, src io.Reader) (int64,
 			} else if n < optimalPartSize {
 				return bytesUploaded, nil
 			}
+		}
 
 		// Seek to the beginning of the file
 		file.Seek(0, 0)

s3store/s3store_test.go

@@ -52,8 +52,8 @@ func TestNewUpload(t *testing.T) {
 		s3obj.EXPECT().PutObject(&s3.PutObjectInput{
 			Bucket:        aws.String("bucket"),
 			Key:           aws.String("uploadId.info"),
-			Body:          bytes.NewReader([]byte(`{"ID":"uploadId+multipartId","Size":500,"Offset":0,"MetaData":{"bar":"menü","foo":"hello"},"IsPartial":false,"IsFinal":false,"PartialUploads":null}`)),
+			Body:          bytes.NewReader([]byte(`{"ID":"uploadId+multipartId","Size":500,"SizeIsDeferred":false,"Offset":0,"MetaData":{"bar":"menü","foo":"hello"},"IsPartial":false,"IsFinal":false,"PartialUploads":null}`)),
-			ContentLength: aws.Int64(int64(148)),
+			ContentLength: aws.Int64(int64(171)),
 		}),
 	)
 

unrouted_handler.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"io"
 	"log"
+	"math"
 	"net"
 	"net/http"
 	"os"
@@ -15,6 +16,8 @@ import (
 	"time"
 )
 
+const UploadLengthDeferred = "1"
+
 var (
 	reExtractFileID  = regexp.MustCompile(`([^/]+)\/?$`)
 	reForwardedHost  = regexp.MustCompile(`host=([^,]+)`)
@@ -60,6 +63,8 @@ var (
 	ErrUploadNotFinished                = NewHTTPError(errors.New("one of the partial uploads is not finished"), http.StatusBadRequest)
 	ErrInvalidConcat                    = NewHTTPError(errors.New("invalid Upload-Concat header"), http.StatusBadRequest)
 	ErrModifyFinal                      = NewHTTPError(errors.New("modifying a final upload is not allowed"), http.StatusForbidden)
+	ErrUploadLengthAndUploadDeferLength = NewHTTPError(errors.New("provided both Upload-Length and Upload-Defer-Length"), http.StatusBadRequest)
+	ErrInvalidUploadDeferLength         = NewHTTPError(errors.New("invalid Upload-Defer-Length header"), http.StatusBadRequest)
 )
 
 // UnroutedHandler exposes methods to handle requests as part of the tus protocol,
@@ -122,6 +127,9 @@ func NewUnroutedHandler(config Config) (*UnroutedHandler, error) {
 	if config.StoreComposer.UsesConcater {
 		extensions += ",concatenation"
 	}
+	if config.StoreComposer.UsesLengthDeferrer {
+		extensions += ",creation-defer-length"
+	}
 
 	handler := &UnroutedHandler{
 		config:            config,
@@ -241,6 +249,7 @@ func (handler *UnroutedHandler) PostFile(w http.ResponseWriter, r *http.Request)
 	// uploads the size is sum of all sizes of these files (no need for
 	// Upload-Length header)
 	var size int64
+	var sizeIsDeferred bool
 	if isFinal {
 		// A final upload must not contain a chunk within the creation request
 		if containsChunk {
@@ -254,9 +263,11 @@ func (handler *UnroutedHandler) PostFile(w http.ResponseWriter, r *http.Request)
 			return
 		}
 	} else {
-		size, err = strconv.ParseInt(r.Header.Get("Upload-Length"), 10, 64)
+		uploadLengthHeader := r.Header.Get("Upload-Length")
-		if err != nil || size < 0 {
+		uploadDeferLengthHeader := r.Header.Get("Upload-Defer-Length")
-			handler.sendError(w, r, ErrInvalidUploadLength)
+		size, sizeIsDeferred, err = handler.validateNewUploadLengthHeaders(uploadLengthHeader, uploadDeferLengthHeader)
+		if err != nil {
+			handler.sendError(w, r, err)
 			return
 		}
 	}
@@ -272,6 +283,7 @@ func (handler *UnroutedHandler) PostFile(w http.ResponseWriter, r *http.Request)
 
 	info := FileInfo{
 		Size:           size,
+		SizeIsDeferred: sizeIsDeferred,
 		MetaData:       meta,
 		IsPartial:      isPartial,
 		IsFinal:        isFinal,
@@ -325,7 +337,7 @@ func (handler *UnroutedHandler) PostFile(w http.ResponseWriter, r *http.Request)
 			handler.sendError(w, r, err)
 			return
 		}
-	} else if size == 0 {
+	} else if !sizeIsDeferred && size == 0 {
 		// Directly finish the upload if the upload is empty (i.e. has a size of 0).
 		// This statement is in an else-if block to avoid causing duplicate calls
 		// to finishUploadIfComplete if an upload is empty and contains a chunk.
@@ -380,8 +392,13 @@ func (handler *UnroutedHandler) HeadFile(w http.ResponseWriter, r *http.Request)
 		w.Header().Set("Upload-Metadata", SerializeMetadataHeader(info.MetaData))
 	}
 
-	w.Header().Set("Cache-Control", "no-store")
+	if info.SizeIsDeferred {
+		w.Header().Set("Upload-Defer-Length", UploadLengthDeferred)
+	} else {
 		w.Header().Set("Upload-Length", strconv.FormatInt(info.Size, 10))
+	}
+
+	w.Header().Set("Cache-Control", "no-store")
 	w.Header().Set("Upload-Offset", strconv.FormatInt(info.Offset, 10))
 	handler.sendResp(w, r, http.StatusOK)
 }
@@ -437,12 +454,35 @@ func (handler *UnroutedHandler) PatchFile(w http.ResponseWriter, r *http.Request
 	}
 
 	// Do not proxy the call to the data store if the upload is already completed
-	if info.Offset == info.Size {
+	if !info.SizeIsDeferred && info.Offset == info.Size {
 		w.Header().Set("Upload-Offset", strconv.FormatInt(offset, 10))
 		handler.sendResp(w, r, http.StatusNoContent)
 		return
 	}
 
+	if r.Header.Get("Upload-Length") != "" {
+		if handler.composer.UsesLengthDeferrer {
+			if info.SizeIsDeferred {
+				uploadLength, err := strconv.ParseInt(r.Header.Get("Upload-Length"), 10, 64)
+				if err != nil || uploadLength < 0 || uploadLength < info.Offset || uploadLength > handler.config.MaxSize {
+					handler.sendError(w, r, ErrInvalidUploadLength)
+					return
+				}
+
+				info.Size = uploadLength
+				info.SizeIsDeferred = false
+				if err := handler.composer.LengthDeferrer.DeclareLength(id, info.Size); err != nil {
+					handler.sendError(w, r, err)
+					return
+				}
+			} else {
+				handler.sendError(w, r, ErrInvalidUploadLength)
+			}
+		} else {
+			handler.sendError(w, r, ErrNotImplemented)
+		}
+	}
+
 	if err := handler.writeChunk(id, info, w, r); err != nil {
 		handler.sendError(w, r, err)
 		return
@@ -460,11 +500,23 @@ func (handler *UnroutedHandler) writeChunk(id string, info FileInfo, w http.Resp
 	offset := info.Offset
 
 	// Test if this upload fits into the file's size
-	if offset+length > info.Size {
+	if !info.SizeIsDeferred && offset+length > info.Size {
 		return ErrSizeExceeded
 	}
 
 	maxSize := info.Size - offset
+	// If the upload's length is deferred and the PATCH request does not contain the Content-Length
+	// header (which is allowed if 'Transfer-Encoding: chunked' is used), we still need to set limits for
+	// the body size.
+	if info.SizeIsDeferred {
+		if handler.config.MaxSize > 0 {
+			// Ensure that the upload does not exceed the maximum upload size
+			maxSize = handler.config.MaxSize - offset
+		} else {
+			// If no upload limit is given, we allow arbitrary sizes
+			maxSize = math.MaxInt64
+		}
+	}
 	if length > 0 {
 		maxSize = length
 	}
@@ -507,7 +559,7 @@ func (handler *UnroutedHandler) writeChunk(id string, info FileInfo, w http.Resp
 // function and send the necessary message on the CompleteUpload channel.
 func (handler *UnroutedHandler) finishUploadIfComplete(info FileInfo) error {
 	// If the upload is completed, ...
-	if info.Offset == info.Size {
+	if !info.SizeIsDeferred && info.Offset == info.Size {
 		// ... allow custom mechanism to finish and cleanup the upload
 		if handler.composer.UsesFinisher {
 			if err := handler.composer.Finisher.FinishUpload(info.ID); err != nil {
@@ -836,7 +888,7 @@ func (handler *UnroutedHandler) sizeOfUploads(ids []string) (size int64, err err
 			return size, err
 		}
 
-		if info.Offset != info.Size {
+		if info.SizeIsDeferred || info.Offset != info.Size {
 			err = ErrUploadNotFinished
 			return size, err
 		}
@@ -847,6 +899,31 @@ func (handler *UnroutedHandler) sizeOfUploads(ids []string) (size int64, err err
 	return
 }
 
+// Verify that the Upload-Length and Upload-Defer-Length headers are acceptable for creating a
+// new upload
+func (handler *UnroutedHandler) validateNewUploadLengthHeaders(uploadLengthHeader string, uploadDeferLengthHeader string) (uploadLength int64, uploadLengthDeferred bool, err error) {
+	haveBothLengthHeaders := uploadLengthHeader != "" && uploadDeferLengthHeader != ""
+	haveInvalidDeferHeader := uploadDeferLengthHeader != "" && uploadDeferLengthHeader != UploadLengthDeferred
+	lengthIsDeferred := uploadDeferLengthHeader == UploadLengthDeferred
+
+	if lengthIsDeferred && !handler.composer.UsesLengthDeferrer {
+		err = ErrNotImplemented
+	} else if haveBothLengthHeaders {
+		err = ErrUploadLengthAndUploadDeferLength
+	} else if haveInvalidDeferHeader {
+		err = ErrInvalidUploadDeferLength
+	} else if lengthIsDeferred {
+		uploadLengthDeferred = true
+	} else {
+		uploadLength, err = strconv.ParseInt(uploadLengthHeader, 10, 64)
+		if err != nil || uploadLength < 0 {
+			err = ErrInvalidUploadLength
+		}
+	}
+
+	return
+}
+
 // ParseMetadataHeader parses the Upload-Metadata header as defined in the
 // File Creation extension.
 // e.g. Upload-Metadata: name bHVucmpzLnBuZw==,type aW1hZ2UvcG5n

utils_test.go

@@ -27,6 +27,7 @@ type FullDataStore interface {
 	tusd.ConcaterDataStore
 	tusd.GetReaderDataStore
 	tusd.FinisherDataStore
+	tusd.LengthDeferrerDataStore
 }
 
 type Locker interface {