Introduction

NZB is an XML-based file format for retrieving posts from NNTP (Usenet) servers. Since NZB is XML-based, it's relatively easy to build one-off parsers to parse NZB files. This project is an attempt to consolidate those many one-off NZB parsers into one simple interface.

This package includes three implementations: one based on expat, another based on ElementTree, and a final implementation based on lxml. The order in which they were listed is in order of compatibility. The expat version should work on all versions of Python > 2.0, the lxml one will work on all versions > 2.5, and lxml will only work if you have lxml installed.

A Note on Installing lxml

While lxml is not a requirement, I have had a hard time installing lxml in the past. I have found this set of commands to work perfectly:

STATIC_DEPS=true easy_install 'lxml>=2.2beta4'
STATIC_DEPS=true sudo easy_install 'lxml>=2.2beta4'

API Documentation

Accessing the Default Parser

Simply import nzb_parser from the pynzb package. It's an instantiated version of the fastest available parser that your system can support.

Other Parser Locations

ExpatNZBParser:

Available in the pynzb.expat_nzb namespace.

ETreeNZBParser:

Available in the pynzb.etree_nzb namespace.

LXMLNZBParser:

Available in the pynzb.lxml_nzb namespace.

Using the NZB Parser

If you're using a specific parser, like the ETreeNZBParser, you will first have to instantiate it:

nzb_parser = ETreeNZBParser()

Otherwise, you can just import the default parser for your system:

from pynzb import nzb_parser

Then, simply call the parse method, giving it the xml string as the only argument:

files = nzb_parser.parse('<?xml ... my nzb file here ... </nzb>')

This will return a list of NZBFiles for you to use. You can then pass this list (or a list of NZBFiles populated by any other code) to one of two writeto methods:

nzb_parser.writetofile(files, 'C:\\output.nzb')

...which will write out an NZB file or:

nzbstring = nzb_parser.writetostring(files)

...which will return the NZB-formatted XML as a string.

NZBFile Objects

All of the parsers return NZBFile objects, which are objects with the following properties:

poster:

The name of the user who posted the file to the newsgroup.

date:

A datetime.date representation of when the server first saw the file.

subject:

The subject used when the user posted the file to the newsgroup.

groups:

A list of strings representing the newsgroups in which this file may be found.

segments:

A list of NZBSegment objects talking about where to get the contents of this file.

NZBSegment Objects

Each NZBFile has a list of NZBSegment objects, which include information on how to retrieve a part of a file. Here's what you can find on an NZBSegment object:

number:

The number of the segment in the list of files.

bytes:

The size of the segment, in bytes.

message_id:

The Message-ID of the segment (useful for retrieving the full contents)

Example

In this example, we will grab an Ubuntu NZB and parse the file, print out some information about each file and its segments, and write it back out:

from pynzb import nzb_parser
from urllib2 import urlopen

# Grab a sample Ubuntu NZB
ubuntu_nzb = urlopen('http://media.eflorenzano.com/misc/sample-ubuntu-nzb.nzb').read()

# Parse the NZB into files
files = nzb_parser.parse(ubuntu_nzb)

# Print out each file's subject and the first two segment message ids
for nzb_file in files:
    print nzb_file.subject
    for segment in nzb_file.segments[:2]:
        print '    ' + segment.message_id
    if len(nzb_file.segments) > 2:
        print '    ...'

#Write the NZB to the hard-drive:
nzb_parser.writetofile(files, 'C:\\sample-ubuntu-nzb.nzb')