Error out if source provides less data than expected (#606)

* Adds end-to-end test that reproduces the issue

* Error out if the source provides less data than specified

* Remove impossible test

* Clean up tests

---------

Co-authored-by: Marius Kleidl <marius@transloadit.com>

lib/browser/sources/FileSource.js

@@ -17,7 +17,8 @@ export default class FileSource {
     }
 
     const value = this._file.slice(start, end)
-    return Promise.resolve({ value })
+    const done = end >= this.size
+    return Promise.resolve({ value, done })
   }
 
   close() {

lib/node/sources/BufferSource.js

@@ -7,7 +7,8 @@ export default class BufferSource {
   slice(start, end) {
     const value = this._buffer.slice(start, end)
     value.size = value.length
-    return Promise.resolve({ value })
+    const done = end >= this.size
+    return Promise.resolve({ value, done })
   }
 
   close() {}

lib/node/sources/FileSource.js

@@ -46,8 +46,9 @@ class FileSource {
       end: offset + end - 1,
       autoClose: true,
     })
-    stream.size = end - start
-    return Promise.resolve({ value: stream })
+    stream.size = Math.min(end - start, this.size)
+    const done = stream.size >= this.size
+    return Promise.resolve({ value: stream, done })
   }
 
   close() {

lib/upload.js

@@ -782,14 +782,30 @@ class BaseUpload {
     }
 
     return this._source.slice(start, end).then(({ value, done }) => {
+      const valueSize = value && value.size ? value.size : 0
+
       // If the upload length is deferred, the upload size was not specified during
       // upload creation. So, if the file reader is done reading, we know the total
       // upload size and can tell the tus server.
       if (this.options.uploadLengthDeferred && done) {
-        this._size = this._offset + (value && value.size ? value.size : 0)
+        this._size = this._offset + valueSize
         req.setHeader('Upload-Length', this._size)
       }
 
+      // The specified uploadSize might not match the actual amount of data that a source
+      // provides. In these cases, we cannot successfully complete the upload, so we
+      // rather error out and let the user know. If not, tus-js-client will be stuck
+      // in a loop of repeating empty PATCH requests.
+      // See https://community.transloadit.com/t/how-to-abort-hanging-companion-uploads/16488/13
+      const newSize = this._offset + valueSize
+      if (!this.options.uploadLengthDeferred && done && newSize !== this._size) {
+        return Promise.reject(
+          new Error(
+            `upload was configured with a size of ${this._size} bytes, but the source is done after ${newSize} bytes`
+          )
+        )
+      }
+
       if (value === null) {
         return this._sendRequest(req)
       }

test/spec/test-browser-specific.js

@@ -658,6 +658,51 @@ describe('tus', () => {
 
         await options.onSuccess.toBeCalled
       })
+
+      it('should throw an error if the source provides less data than uploadSize', async () => {
+        const reader = makeReader('hello world')
+
+        const testStack = new TestHttpStack()
+        const options = {
+          httpStack: testStack,
+          uploadSize: 100,
+          chunkSize: 100,
+          endpoint: 'http://tus.io/uploads',
+          retryDelays: [],
+          onError: waitableFunction('onError'),
+        }
+
+        const upload = new tus.Upload(reader, options)
+        upload.start()
+        let req = await testStack.nextRequest()
+        expect(req.url).toBe('http://tus.io/uploads')
+        expect(req.method).toBe('POST')
+        expect(req.requestHeaders['Tus-Resumable']).toBe('1.0.0')
+
+        req.respondWith({
+          status: 204,
+          responseHeaders: {
+            Location: 'http://tus.io/uploads/foo',
+          },
+        })
+
+        req = await testStack.nextRequest()
+        expect(req.url).toBe('http://tus.io/uploads/foo')
+        expect(req.method).toBe('PATCH')
+
+        req.respondWith({
+          status: 204,
+          responseHeaders: {
+            'Upload-Offset': 11,
+          },
+        })
+
+        const err = await options.onError.toBeCalled
+
+        expect(err.message).toBe(
+          'tus: failed to upload chunk at offset 11, caused by Error: upload was configured with a size of 100 bytes, but the source is done after 11 bytes, originated from request (method: PATCH, url: http://tus.io/uploads/foo, response code: n/a, response text: n/a, request id: n/a)'
+        )
+      })
     })
 
     describe('resolving of URIs', () => {

test/spec/test-common.js

@@ -763,6 +763,38 @@ describe('tus', () => {
       )
     })
 
+    it('should throw an error if the source provides less data than uploadSize', async () => {
+      const testStack = new TestHttpStack()
+      const file = getBlob('hello world')
+      const options = {
+        httpStack: testStack,
+        uploadSize: 100,
+        endpoint: 'http://tus.io/uploads',
+        retryDelays: [],
+        onError: waitableFunction('onError'),
+      }
+
+      const upload = new tus.Upload(file, options)
+      upload.start()
+
+      const req = await testStack.nextRequest()
+      expect(req.url).toBe('http://tus.io/uploads')
+      expect(req.method).toBe('POST')
+      expect(req.requestHeaders['Tus-Resumable']).toBe('1.0.0')
+
+      req.respondWith({
+        status: 204,
+        responseHeaders: {
+          Location: 'http://tus.io/uploads/foo',
+        },
+      })
+
+      const err = await options.onError.toBeCalled
+      expect(err.message).toBe(
+        'tus: failed to upload chunk at offset 0, caused by Error: upload was configured with a size of 100 bytes, but the source is done after 11 bytes, originated from request (method: PATCH, url: http://tus.io/uploads/foo, response code: n/a, response text: n/a, request id: n/a)'
+      )
+    })
+
     it('should throw if retryDelays is not an array', () => {
       const file = getBlob('hello world')
       const upload = new tus.Upload(file, {