473,587 Members | 2,227 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

Bad magic no. in python zipfile

I've been experimenting with the python zipfile module, and have run
into a snag.

I'm able to create a new zipfile with the module's ZipFile class and
add files to it. After closing the file, I'm able to view the contents
of it with WinZip. I can also confirm that it is a python zip file by
using the is_zipfile() method. All good so far. However, under some
circumstances, I am unable to later read the file and extract its
contents. As soon as a I attempt to instantiate a new ZipFile
instance, I receive an error regarding Bad Magic number. In the past,
I've seen that when trying to use a .pyc module, created with one
Python version, using another Python version. But in this case, I
created the zip file under Python 2.4.2 and tried to open it under
Python 2.4.2 as well. Any ideas on what to do? (apart from giving up
on Python and using winzip?)

On a separate topic, zipfile wasn't available under Python 1.5.2. I
need to create zip files using that old version, since it's the only
one installed on a remote server. Any suggestions on what to do?

thanks
S

Oct 13 '05 #1
2 4147
st************* **@gmail.com wrote:
\> I'm able to create a new zipfile with the module's ZipFile class and
add files to it. After closing the file, I'm able to view the contents
of it with WinZip. I can also confirm that it is a python zip file by
using the is_zipfile() method. All good so far. However, under some
circumstances, I am unable to later read the file and extract its
contents. As soon as a I attempt to instantiate a new ZipFile
instance, I receive an error regarding Bad Magic number. In the past,
I've seen that when trying to use a .pyc module, created with one
Python version, using another Python version. But in this case, I
created the zip file under Python 2.4.2 and tried to open it under
Python 2.4.2 as well. Any ideas on what to do?


Maybe try posting the full traceback so we can see the "Bad Magic
Number" error you are getting...

-Peter
Oct 13 '05 #2
okay, I've figured out the problem - the zip file was being mangled by
a file transfer. I was fetching a remote python-generated zip file in
8k chunks, and then writing those chunks to a file. At first I was
using an array to store the data in, and had the 'bad magic number'
problem. This may have been due to writing the chunks out to a local
file as strings, which would definitely have corrupted the file; I also
noticed that the local copy was several kb larger, probably due to the
line endings being added. When I took care to write the file as a
binary file, all was well. case closed.

BTW, regarding using zipfile under Python 1.5.2... I found zipfile.py
in Python 1.6, but it wouldn't run. You need to build Python 1.5 with
the binascii.c and zlibmodule.c from Python 1.6, since a CRC32 method
has been added to those modules. This was more trouble than it was
worth, in the end.

S

Oct 14 '05 #3

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

24
2499
by: huy | last post by:
Hi, Just wondering if there were any plans (or existing projects) similar to Java webstart for Python. I think this would be a boon for python. I would love to start my new project using Python but the deployment (and long term upgrading) factor is a major itch which pyfreeze and py2exe just doesn't scratch properly. Thanks
1
1697
by: deejaay | last post by:
Hello, I following an example on how to zip files from the www.devshed.com site. I can create a zip package, however I am not getting any compression. 120M file stays 120M within the zip package. I need to know how to set or activate the compression values. here is the code I'm using: >import zipfile >zip =...
2
1287
by: Andy Dingley | last post by:
I run build processes for a Java shop using Python (and some Ant). Would anyone care to suggest favoured tools for manipulating the innards of JARs? Or do I just treat them as plain zipfiles and get stuck right in there? Mainly I'm trying to query lists of classes and their embedded versions and do some library dependency reporting....
0
312
by: Kurt B. Kaiser | last post by:
Patch / Bug Summary ___________________ Patches : 408 open ( -9) / 3585 closed (+20) / 3993 total (+11) Bugs : 968 open ( +8) / 6505 closed ( +7) / 7473 total (+15) RFE : 267 open ( +1) / 251 closed ( +0) / 518 total ( +1) New / Reopened Patches ______________________
9
2029
by: alf | last post by:
Hi, I have a small app which consist of a few .py files. Is there any way to distribute it in jar like fashion as a single file I can just run python on. I obviously look for platform independent solution. Thx in advance, A.
0
1661
by: Rocky Zhou | last post by:
python unzip At first, I tried to use 'os.popen3("unzip ...") like this: fin, fout, ferr = os.popen3("unzip -o -d %s %s" % (dest, zipfile)) strerr = ferr.read() # This makes the program hanging up if strerr: print >sys.stderr, strerr outlog.error(strerr)
2
17895
by: fartknuckle | last post by:
When I try to build and install python from source It configures and makes fine but upon 'make install' I always get to this point: Listing /usr/local/lib/python2.5/xml/sax ... Compiling /usr/local/lib/python2.5/xml/sax/__init__.py ... Compiling /usr/local/lib/python2.5/xml/sax/_exceptions.py ... Compiling...
10
38577
by: Bertsche | last post by:
I'm relatively new to python, and am trying to zip a directory containing several levels of files and folders. I can use the walk function to name each file in my directory, and I can use zipfile to zip a flat number of files in one folder, but I am having heck of a time trying to zip the whole directory. I want to zip it all to a file called...
0
7843
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language...
0
8205
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. ...
0
8339
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that...
1
7967
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For...
0
8220
tracyyun
by: tracyyun | last post by:
Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the...
0
6619
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then...
1
5712
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules. He will explain when you may want to use classes...
0
5392
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert...
1
2347
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.