[reportlab-users] isinstance(val, file)

[Carl Karsten]

Andy Robinson wrote:

> On 14/11/2007, Carl Karsten <carl at personnelware.com> wrote:

>> This is not really a reportlab problem, but close enough.

>>

>> How can I test that the file to be passed to canvas.Canvas(buffer) is really a

>> file type object that can be written to?  I am trying to work with a wrapper

>> that looks like this:

> 

> 

> The traditional python approach would be...

> 

>   if hasattr(val, 'file'):

>       #treat it like a file

>   else:

>       #treat it like a string

> 

> i.e. if it walks like a duck and quacks like a duck...


except this does not apply to the animal that gets passed to
     p = canvas.Canvas(val)

 >>> import StringIO
 >>> val=StringIO.StringIO()
 >>> hasattr(val,'file')
False
 >>> import os
 >>> os.path.split(val)
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
   File "/usr/lib/python2.5/posixpath.py", line 77, in split
     i = p.rfind('/') + 1
AttributeError: StringIO instance has no attribute 'rfind'

Carl K