Base32 encoded SHA1 (Gnutella)

[sjehuda]

An argument --gnutella to combine arguments --base32 --sha1 be useful.

URN of Magnet Link URI is SHA1.

magnet:?xl={filesize}&dn={filebase}&xt=urn:sha1:{filehash_gnutella}

[rhash]

Use as a workaround the --printf option:

rhash --printf "magnet:?xl=%s&dn=%uf&xt=urn:sha1:%bh" FILES...

[sjehuda]

Thank you for that information.

[sjehuda]

This is how I utilize it with the Python module of RHash.

    @staticmethod
    def file_id_of_gnutella(filepath):
        """Compute Gnutella SHA1 hash (base32-encoded)."""
        function_name = sys._getframe().f_code.co_name
        logger.debug(f"{function_name}\t\tStart")
        sha1_hex = rhash.hash_file(filepath, rhash.SHA1)
        sha1_bytes = bytes.fromhex(sha1_hex)
        return base64.b32encode(sha1_bytes).decode("ascii")

Previous function.

    @staticmethod
    def _file_id_of_gnutella(filepath):
        """Compute Gnutella SHA1 hash (base32-encoded)."""
        function_name = sys._getframe().f_code.co_name
        logger.debug(f"{function_name}\t\tStart")
        sha1 = hashlib.sha1()
        with open(filepath, "rb") as f:
            while True:
                block = f.read(8192)
                if not block:
                    break
                sha1.update(block)
        return base64.b32encode(sha1.digest()).decode("ascii")

Reference: https://git.xmpp-it.net/sch/Rivista/commit/874f1bea511e51801ea99a33ba43e8041e6c74c5