about rpm module in python

Question

I looked for some informations,the rpm module can only use for search installed rpm package Information.I want to use the python rpm module to search *.rpm files in the folder and know their information,like release or version.Is this possible using the rpm module?

Answer 1

In case someone still ends up here while searching for an answer, here is how you can do it with python-rpm:

import os
import rpm

fdno = os.open(PATH_TO_RPM_FILE, os.O_RDONLY)
ts = rpm.ts()
hdr = ts.hdrFromFdno(fdno)
os.close(fdno)

(Note the call to os.close())

Now hdr holds the RPM header information. You can access individual attributes in dict style using RPMTAG_* values as keys, for example:

arch = hdr[rpm.RPMTAG_ARCH]

You can try reverse engineering all possible RPMTAG_* values using dir():

import rpm
print '\n'.join(filter(lambda x: x.startswith('RPMTAG'), dir(rpm)))

You can also call keys() on hdr, but it will return the possible keys as integers, which might not be as friendly.

I have found that using python-rpm instead of invoking the command line tool as a subprocess gives a significant performance boost when a large number of RPM files are to be handled.

For further information, see http://rpm5.org/docs/api/classRpmhdr.html