On Tue, 19 Nov 2013 16:30:46 -0800, Victor Hooi wrote:
> Hi,
>
> Is either approach (try-excepts, or using libmagic) considered more
> idiomatic? What would you guys prefer yourselves?
Specifically in the case of file types, I consider it better to use
libmagic. But as a general technique, using try...except is a reasonable
approach in many situations.
> Also, is it possible to use either approach with a context manager
> ("with"), without duplicating lots of code?
>
> For example:
>
> try:
> with gzip.open('blah.txt', 'rb') as f:
> for line in f:
> print(line)
> except IOError as e:
> with open('blah.txt', 'rb') as f:
> for line in f:
> print(line)
>
> I'm not sure of how to do this without needing to duplicating the
> processing lines (everything inside the with)?
Write a helper function:
def process(opener):
with opener('blah.txt', 'rb') as f:
for line in f:
print(line)
try:
process(gzip.open)
except IOError:
process(open)
If you have many different things to try:
for opener in [gzip.open, open, ...]:
try:
process(opener)
except IOError:
continue
else:
break
[...]
> Also, on another note, python-magic will return a string as a result,
> e.g.:
>
> gzip compressed data, was "blah.txt", from Unix, last modified: Wed Nov
> 20 10:48:35 2013
>
> I suppose it's enough to just do a?
>
> if "gzip compressed data" in results:
>
> or is there a better way?
*shrug*
Read the docs of python-magic. Do they offer a programmable API? If not,
that kinda sucks.
--
Steven
--
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