Python examples

The quick start covers creation and verification. Use Metainfo.from_bytes for contiguous buffers and Metainfo.read for direct path I/O. Parsed raw values remain bytes, while optional text views return None when UTF-8 decoding is not lossless.

from btpc import UNCHANGED, Metainfo

torrent = Metainfo.read("payload.torrent")
reviewed = torrent.edit(comment="reviewed", source=UNCHANGED)
reviewed.write("payload-reviewed.torrent")

Top-level edits preserve info hashes; info-dictionary edits change them. write() preserves the edited object’s encoding and publishes atomically. Pass overwrite=True to replace an existing destination. Pass canonical=True to normalize bencoding, which can change info hashes for noncanonical input.

Reuse creation results directly:

from btpc import create_bytes

result = create_bytes("payload")
print(result.metainfo.magnet())
assert result.metainfo.verify("payload").is_valid

Copy a UTF-8 comment to another torrent without replacement decoding:

from btpc import Metainfo

source = Metainfo.read("source.torrent")
destination = Metainfo.read("destination.torrent")
comment = source.comment_text
if source.comment is not None and comment is None:
    raise ValueError("source comment is not UTF-8")
destination.edit(comment=comment).write("destination-reviewed.torrent")

Inspect an immutable extension value with ordinary collection operations:

from btpc import BencodeDictionary, BencodeList

values = BencodeList((1, b"raw"))
extension = BencodeDictionary(((b"values", values),))
assert values[1:] == BencodeList((b"raw",))
assert extension[b"values"] == values
assert dict(extension) == {b"values": values}