NBT 1.4.1

Named Binary Tag Reader/Writer

This is a Named Binary Tag parser based upon the specification by Markus Persson.

From The spec:

“NBT (Named Binary Tag) is a tag based binary format designed to carry large

amounts of binary data with smaller amounts of additional data. An NBT file consists of a single GZIPped Named Tag of type TAG_Compound.”

read the full spec at http://www.minecraft.net/docs/NBT.txt

Usage:

1. Reading files.

The easiest way to read an nbt file is to instantiate an NBTFile object e.g.

>>> import nbt
>>> nbtfile = nbt.NBTFile("bigtest.nbt",'rb')
>>> nbtfile.name
u'Level'
>>> nbtfile["nested compound test"].tag_info()
TAG_Compound("nested compound test"): 2 Entries
>>> for tag in nbtfile["nested compound test"]["ham"].tags:
...     print(tag.tag_info())
...
TAG_String("name"): Hampus
TAG_Float("value"): 0.75
>>> [tag.value for tag in nbtfile["listTest (long)"].value]
[11, 12, 13, 14, 15]

Files can also be read from a fileobj (file-like object that contains a compressed stream) or a buffer (file-like object that contains an uncompressed stream of NBT Tags) which can be accomplished thusly:

>>> import nbt
>>> nbtfile = NBTFile(fileobj=previously_opened_file)
# or....
>>> nbtfile = NBTFile(buffer=net_socket.makefile())

2. Writing files.

Writing files is easy too! if you have a NBTFile object, simply call it’s write_file() method. If the NBTFile was instantiated with a filename, then write_file needs no extra arguments. It just works. If however you created a new file object from scratch (or even if you just want to save it somewhere else) call write_file(‘pathtonewfile.nbt’)

>>> import nbt
>>> nbtfile = nbt.NBTFile("bigtest.nbt",'rb')
>>> nbtfile["listTest (compound)"].tags[0]["name"].value = "Different name"
>>> nbtfile.write_file("newnbtfile.nbt")

It is also possible to write to a buffer or fileobj using the same keyword args.

>>> nbtfile.write_file(fileobj = my_file) #compressed
>>> nbtfile.write_file(buffer = sock.makefile()) #uncompressed

3. Creating files

Creating files is trickier but ultimately should give you no issue, as long as you have read the NBT spec (hint.. it’s very short). Also be sure to note that the NBTFile object is actually a TAG_Compound with some wrapper features, so you can use all the standard tag features

>>> from nbt import *
>>> nbtfile = NBTFile()

first, don’t forget to name the top level tag

>>> nbtfile.name = "My Top Level Tag"
>>> nbtfile.tags.append(TAG_Float(name="My Float Name", value=3.152987593947))
>>> mylist = TAG_List(name="TestList", type=TAG_Long) #type needs to be pre-declared!
>>> mylist.tags.append(TAG_Long(100))
>>> mylist.tags.extend([TAG_Long(120),TAG_Long(320),TAG_Long(19)])
>>> nbtfile.tags.append(mylist)
>>> print(nbtfile.pretty_tree())
TAG_Compound("My Top Level Tag"): 2 Entries
{
    TAG_Float("My Float Name"): 3.15298759395
    TAG_List("TestList"): 4 entries of type TAG_Long
    {
        TAG_Long: 100
        TAG_Long: 120
        TAG_Long: 320
        TAG_Long: 19
    }
}
>>> nbtfile["TestList"].tags.sort(key = lambda tag: tag.value)
>>> print(nbtfile.pretty_tree())
TAG_Compound("My Top Level Tag"): 2 Entries
{
    TAG_Float("My FloatName"): 3.15298759395
    TAG_List("TestList"): 4 entries of type TAG_Long
    {
        TAG_Long: 19
        TAG_Long: 100
        TAG_Long: 120
        TAG_Long: 320
    }
}
>>> nbtfile.write_file("mynbt.dat")