I wanted to try out the python BytesIO class.
As an experiment I tried writing to a zip file in memory, and then reading the bytes back out of that zip file. So instead of passing in a file-object to gzip
, I pass in a BytesIO
object. Here is the entire script:
from io import BytesIO import gzip # write bytes to zip file in memory myio = BytesIO() with gzip.GzipFile(fileobj=myio, mode='wb') as g: g.write(b"does it work") # read bytes from zip file in memory with gzip.GzipFile(fileobj=myio, mode='rb') as g: result = g.read() print(result)
But it is returning an empty bytes
object for result
. This happens in both Python 2.7 and 3.4. What am I missing?
Advertisement
Answer
You need to seek
back to the beginning of the file after writing the initial in memory file…
myio.seek(0)