Add size attribute to UploadFile

docs/requests.md

@@ -123,6 +123,7 @@ multidict, containing both file uploads and text input. File upload items are re
 * `content_type`: A `str` with the content type (MIME type / media type) (e.g. `image/jpeg`).
 * `file`: A <a href="https://docs.python.org/3/library/tempfile.html#tempfile.SpooledTemporaryFile" target="_blank">`SpooledTemporaryFile`</a> (a <a href="https://docs.python.org/3/glossary.html#term-file-like-object" target="_blank">file-like</a> object). This is the actual Python file that you can pass directly to other functions or libraries that expect a "file-like" object.
 * `headers`: A `Headers` object. Often this will only be the `Content-Type` header, but if additional headers were included in the multipart field they will be included here. Note that these headers have no relationship with the headers in `Request.headers`.
+* `size`: An `int` with file's size in bytes.
 
 `UploadFile` has the following `async` methods. They all call the corresponding file methods underneath (using the internal `SpooledTemporaryFile`).
 

starlette/datastructures.py

@@ -416,7 +416,10 @@ class UploadFile:
 
     spool_max_size = 1024 * 1024
     file: typing.BinaryIO
+    filename: str
+    content_type: str
     headers: "Headers"
+    size: int
 
     def __init__(
         self,
@@ -430,16 +433,26 @@ def __init__(
         self.content_type = content_type
         if file is None:
             self.file = tempfile.SpooledTemporaryFile(max_size=self.spool_max_size)  # type: ignore  # noqa: E501
+            self.size = 0
         else:
             self.file = file
+            self.size = self._get_file_size(file)
         self.headers = headers or Headers()
 
+    def _get_file_size(self, file: typing.BinaryIO):
+        self.file.seek(0, 2)  # Seek end of file
+        size = self.file.tell()
+        self.file.seek(0, 0)
+        return size
+
     @property
     def _in_memory(self) -> bool:
         rolled_to_disk = getattr(self.file, "_rolled", True)
         return not rolled_to_disk
 
     async def write(self, data: bytes) -> None:
+        self.size += len(data)
+
         if self._in_memory:
             self.file.write(data)  # type: ignore
         else:

tests/test_datastructures.py

@@ -224,6 +224,7 @@ async def test_upload_file():
     await big_file.write(b"big-data")
     await big_file.seek(0)
     assert await big_file.read(1024) == b"big-data" * 128
+    assert big_file.size == 4104
     await big_file.close()
 
 
@@ -232,9 +233,11 @@ async def test_upload_file_file_input():
     """Test passing file/stream into the UploadFile constructor"""
     stream = io.BytesIO(b"data")
     file = UploadFile(filename="file", file=stream)
+    assert file.size == 4
     assert await file.read() == b"data"
     await file.write(b" and more data!")
     assert await file.read() == b""
+    assert file.size == 19
     await file.seek(0)
     assert await file.read() == b"data and more data!"