Issue 26299: wsgiref.util FileWrapper raises ValueError: I/O operation on closed file.

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This issue has been migrated to GitHub: https://github.com/python/cpython/issues/70487

classification

Title:	wsgiref.util FileWrapper raises ValueError: I/O operation on closed file.
Type:		Stage:
Components:	Library (Lib)	Versions:	Python 3.6, Python 2.7

process

Status:	open	Resolution:
Dependencies:		Superseder:
Assigned To:		Nosy List:	pje, samwyse
Priority:	normal	Keywords:

Created on 2016-02-05 18:40 by samwyse, last changed 2022-04-11 14:58 by admin.

Files
File name	Uploaded	Description	Edit
wsgitest.py	samwyse, 2016-02-05 18:40	demonstrates the issue

Messages (1)
msg259685 - (view)	Author: Samwyse (samwyse) *	Date: 2016-02-05 18:40
While developing, I am using wsgiref.simple_server. Using to serve static content isn't working. The attached program demonstrates the issue. Run it and connect to http://127.0.0.1:8000/. You will see three buttons. Clicking on 'wsgi.filewrapper' causes the FileWrapper class found in wsgiref.util to be used, while clicking on 'PEP 0333' uses code suggested in PEP 0333 (https://www.python.org/dev/peps/pep-0333/#id36). Both of these fail. Clicking on 'slurp' causes the entire file to loaded and returned in a list. This works. When an application returns an instance of environ['wsgi.file_wrapper'], or creates it's own iterator, an error is raised during the initial read of the file. Reading the entire file and returning a single-element list (the 'slurp' technique) works, but is impractical for larger files. I've tested this with both Python 2.7.9 and 3.4.3 under Windows 7 (my laptop) and 3.4.3 under Alpine Linux (a Docker instance).

msg259685 - (view)

Author: Samwyse (samwyse) *

Date: 2016-02-05 18:40

While developing, I am using wsgiref.simple_server.  Using to serve static content isn't working.  The attached program demonstrates the issue.  Run it and connect to http://127.0.0.1:8000/.  You will see three buttons.  Clicking on 'wsgi.filewrapper' causes the FileWrapper class found in wsgiref.util to be used, while clicking on 'PEP 0333' uses code suggested in PEP 0333 (https://www.python.org/dev/peps/pep-0333/#id36).  Both of these fail.  Clicking on 'slurp' causes the entire file to loaded and returned in a list.  This works.

When an application returns an instance of environ['wsgi.file_wrapper'], or creates it's own iterator, an error is raised during the initial read of the file.  Reading the entire file and returning a single-element list (the 'slurp' technique) works, but is impractical for larger files.

I've tested this with both Python 2.7.9 and 3.4.3 under Windows 7 (my laptop) and 3.4.3 under Alpine Linux (a Docker instance).

History
Date	User	Action	Args
2022-04-11 14:58:27	admin	set	github: 70487
2016-02-07 11:21:48	SilentGhost	set	nosy: + pje versions: + Python 3.6, - Python 3.4
2016-02-05 18:40:05	samwyse	create