Question

I’m trying to create a temporary file from an entry in my database. I have done a print(filedata['data']) and I can see that the data is being retrieved properly but even with the temp_h.flush() I never see any data saved to the file. When I go to retrieve it, the file is empty. Could someone please explain to me what’s causing this and if there’s a better way to do what I’m trying to do with PIL, I’d love to learn that too. I’m running this on a Linux system with an EXT3 File system

def main():
    '''Main'''

    for nohisto in thestash.stash.get_files():
       fileid = str(nohisto['_id'])
       filedata = openstash(fileid)
       temp_h = tempfile.TemporaryFile(mode='r+')
       temp_h.write(filedata['data'])
       temp_h.flush()
       time.sleep(3)
       myhisto = Image.open(temp_h).histogram()

Answer 1

Try mode='w+', then after writing, seek(0) to put the i/o pointer back to the file beginnning. You can also create in-memory file-like objects using the StringIO module.