Problem

The method _BlitzGateway.createOriginalFileFromFileObj in src/omero/gateway/__init__.py line 4075 reads the entire file into memory to compute the SHA1 hash:

h.update(fo.read())  # Reads entire file into memory

This causes out-of-memory errors for files larger than available RAM.

Suggested Fix

Use chunked reading for SHA1 computation, similar to the upload logic that already uses 10KB chunks (lines 4093-4101):

h = sha1()
chunk_size = 10000
fo.seek(0)
while True:
    chunk = fo.read(chunk_size)
    if not chunk:
        break
    h.update(chunk)

Impact

Files larger than RAM cannot be uploaded through this method.