AttributeError: 'cStringIO.StringO' object has no attribute 'len'

[anonymous]

Attaching files doesn't seem to work correctly anymore. This is Trac 0.10.2 and Python 2.5.

Python Traceback

Traceback (most recent call last):
  File "/usr/lib64/python2.5/site-packages/trac/web/main.py", line 387, in dispatch_request
    dispatcher.dispatch(req)
  File "/usr/lib64/python2.5/site-packages/trac/web/main.py", line 238, in dispatch
    resp = chosen_handler.process_request(req)
  File "/usr/lib64/python2.5/site-packages/trac/attachment.py", line 361, in process_request
    self._do_save(req, attachment)
  File "/usr/lib64/python2.5/site-packages/trac/attachment.py", line 449, in _do_save
    size = upload.file.len
AttributeError: 'cStringIO.StringO' object has no attribute 'len'

[ThurnerRupert]

what platform are you on?

[anonymous]

Linux 2.6.18, x86_64, SuSE.

[eblot]

Replying to anonymous:

Attaching files doesn't seem to work correctly anymore. This is Trac 0.10.2 and Python 2.5.

I don't think this is related to this very issue, but Trac 0.10 is known to have issues when run with Python 2.5, due to issues w/ ClearSilver.

[mgood]

Which web frontend are you using? FastCGI, mod_python, CGI, etc.? Which web server?

[stepan@…]

No fastcgi afaik

apache2-2.2.3-20 apache2-mod_python-3.2.10-27 python-2.5-19

what else do you need to know?

[mgood]

Hmm, Python 2.5 changed the cgi module to use cStringIO for files if it's available, which unlike the StringIO object doesn't support reading the length. I guess we need to find another way to check the size of the uploaded file.

[Stefan Reinauer <stepan@…>]

My oh my.. I am not becoming a python fan. After wasting about 5h with wild guesses and restarting apache I found the following workaround seems to do it for my small test file. Don't know if it is worth anything.

if hasattr(upload.file, 'fileno'):

size = os.fstat(upload.file.fileno())[6]

else:

fstr = StringIO.StringIO(upload.file) size = fstr.len

[anonymous]

I found the same error and observed that the error comes up, if the size of the uploaded file is smaller than 1kByte (approx.) Maybe this helps to find the reason.

[mgood]

This is not specific to mod_python. The problem is due to the change in the Python cgi module which is used by Trac for parsing POSTs on all frontends.

[thatch]

I think using the file-like interface ought to work since StringIO and cStringIO both provide it. This is constant time for both modules.

Tested on Python 2.4 and it works. Analysis of 2.5's source for cStringIO shows it should work too.

trac/attachment.py

@@ -448 +448 @@
         if hasattr(upload.file, 'fileno'):
             size = os.fstat(upload.file.fileno())[6]
         else:
-            size = upload.file.len
+            upload.file.seek(0, 2)
+            size = upload.file.tell()
+            upload.file.seek(0)
         if size == 0:
             raise TracError("Can't upload empty file")

[mgood]

Replying to thatch:

I think using the file-like interface ought to work since StringIO and cStringIO both provide it. This is constant time for both modules.

Aha, yes I figured there should be some other way to check the size, but I missed that seek() supported seeking relative to the end of the file. That should do the trick.

[mgood]

Fixed in r4459 and r4460. Thanks for the patch.

[demarco@…]

This bug is triggered by attempting to upload a vCard / vcf. These keywords should help others avoid submitting duplicate bugs.

[mgood]

Replying to demarco@maya.com:

This bug is triggered by attempting to upload a vCard / vcf. These keywords should help others avoid submitting duplicate bugs.

The problem is not dependent on the file type. It was an issue with an internal API that changed in Python 2.5.

[kap4020@…]

Yup, I have this problem too:

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=7.04
DISTRIB_CODENAME=feisty
DISTRIB_DESCRIPTION="Ubuntu 7.04"

But, the patch fixed things for me. =)

[Didactylos]

I am experiencing this bug in Trac 0.10.4 when trying to attach a file to a template.

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/trac/web/main.py", line 406, in dispatch_request
    dispatcher.dispatch(req)
  File "/usr/lib/python2.5/site-packages/trac/web/main.py", line 237, in dispatch
    resp = chosen_handler.process_request(req)
  File "build/bdist.linux-i686/egg/WikiTemplates/attachment.py", line 363, in process_request
    self._do_save(req, attachment)
  File "build/bdist.linux-i686/egg/WikiTemplates/attachment.py", line 455, in _do_save
    size = upload.file.len
AttributeError: 'cStringIO.StringO' object has no attribute 'len'

[cboos]

Well, as you could see by following the link to r4459, that size = upload.file.len line has been replaced for 0.10.4. So if you're having that line in your backtrace, you're not running 0.10.4 (and installing Trac as an egg is not supported for versions before 0.11dev).

[Didactylos]

Look again: this is when attaching a file to a template. I'm a Trac user, not an administrator - so I'm just reporting the bug. I know nothing of eggs. If the bug needs to go elsewhere, or is a separate issue, then please do what needs doing. I'm reporting it here because it is an identical bug to the previously fixed bug - just in a different place.

[cboos]

Ok, my bad, but that bug should be reported on http://wikitemplates.ufsoft.org/, where the WikiTemplates? plugin is developed.

Closing again the ticket, as the problem is fixed in Trac itself.

[Alexo]

You should also patch this line

size = f.len

with

f.seek(0, 2) size = f.tell() f.seek(0)

For newer cStringIO.

Cheers.

Alexo

[anonymous]

Well, -as you could see by following the link to r4459, that size = upload.file.len line has been replaced for 0.10.4. So if you're having that line in your backtrace, you're not running 0.10.4 (and installing Trac as an egg is not supported for versions before 0.11dev).