Fix: evaluate sha256 for resource from fd (#279)

Author: rakovskij-stanislav

karton/core/resource.py

@@ -39,6 +39,7 @@ def __init__(
         bucket: Optional[str] = None,
         metadata: Optional[Dict[str, Any]] = None,
         sha256: Optional[str] = None,
+        fd: Optional[IO[bytes]] = None,
         _uid: Optional[str] = None,
         _size: Optional[int] = None,
         _flags: Optional[List[str]] = None,
@@ -66,6 +67,16 @@ def __init__(
                     for byte_block in iter(lambda: f.read(4096), b""):
                         sha256_hash.update(byte_block)
                 sha256 = sha256_hash.hexdigest()
+        elif fd is not None:
+            if calculate_hash:
+                # we need to calculate the whole hash and return pos as it was
+                sha256_hash = hashlib.sha256()
+                last_position = fd.tell()
+                fd.seek(0)
+                for byte_block in iter(lambda: fd.read(4096), b""):
+                    sha256_hash.update(byte_block)
+                sha256 = sha256_hash.hexdigest()
+                fd.seek(last_position)
         elif content:
             if isinstance(content, str):
                 self._content = content.encode()
@@ -190,6 +201,7 @@ def __init__(
             bucket=bucket,
             metadata=metadata,
             sha256=sha256,
+            fd=fd,
             _uid=uid,
             _flags=_flags,
         )