lbry-sdk/lbrynet/lbryfile/StreamDescriptor.py

import binascii
import logging
from lbrynet.core.cryptoutils import get_lbry_hash_obj
from lbrynet.cryptstream.CryptBlob import CryptBlobInfo
from twisted.internet import defer
from lbrynet.core.Error import DuplicateStreamHashError, InvalidStreamDescriptorError


log = logging.getLogger(__name__)


LBRYFileStreamType = "lbryfile"


def save_sd_info(stream_info_manager, sd_info, ignore_duplicate=False):
    log.debug("Saving info for %s", str(sd_info['stream_name']))
    hex_stream_name = sd_info['stream_name']
    key = sd_info['key']
    stream_hash = sd_info['stream_hash']
    raw_blobs = sd_info['blobs']
    suggested_file_name = sd_info['suggested_file_name']
    crypt_blobs = []
    for blob in raw_blobs:
        length = blob['length']
        if length != 0:
            blob_hash = blob['blob_hash']
        else:
            blob_hash = None
        blob_num = blob['blob_num']
        iv = blob['iv']
        crypt_blobs.append(CryptBlobInfo(blob_hash, blob_num, length, iv))
    log.debug("Trying to save stream info for %s", str(hex_stream_name))
    d = stream_info_manager.save_stream(stream_hash, hex_stream_name, key,
                                        suggested_file_name, crypt_blobs)

    def check_if_duplicate(err):
        if ignore_duplicate is True:
            err.trap(DuplicateStreamHashError)

    d.addErrback(check_if_duplicate)

    d.addCallback(lambda _: stream_hash)
    return d


def get_sd_info(stream_info_manager, stream_hash, include_blobs):
    d = stream_info_manager.get_stream_info(stream_hash)

    def format_info(stream_info):
        fields = {}
        fields['stream_type'] = LBRYFileStreamType
        fields['stream_name'] = stream_info[1]
        fields['key'] = stream_info[0]
        fields['suggested_file_name'] = stream_info[2]
        fields['stream_hash'] = stream_hash

        def format_blobs(blobs):
            formatted_blobs = []
            for blob_hash, blob_num, iv, length in blobs:
                blob = {}
                if length != 0:
                    blob['blob_hash'] = blob_hash
                blob['blob_num'] = blob_num
                blob['iv'] = iv
                blob['length'] = length
                formatted_blobs.append(blob)
            fields['blobs'] = formatted_blobs
            return fields

        if include_blobs is True:
            d = stream_info_manager.get_blobs_for_stream(stream_hash)
        else:
            d = defer.succeed([])
        d.addCallback(format_blobs)
        return d

    d.addCallback(format_info)
    return d


class LBRYFileStreamDescriptorValidator(object):
    def __init__(self, raw_info):
        self.raw_info = raw_info

    def validate(self):
        log.debug("Trying to validate stream descriptor for %s", str(self.raw_info['stream_name']))
        try:
            hex_stream_name = self.raw_info['stream_name']
            key = self.raw_info['key']
            hex_suggested_file_name = self.raw_info['suggested_file_name']
            stream_hash = self.raw_info['stream_hash']
            blobs = self.raw_info['blobs']
        except KeyError as e:
            raise InvalidStreamDescriptorError("Missing '%s'" % (e.args[0]))
        for c in hex_suggested_file_name:
            if c not in '0123456789abcdef':
                raise InvalidStreamDescriptorError("Suggested file name is not a hex-encoded string")
        h = get_lbry_hash_obj()
        h.update(hex_stream_name)
        h.update(key)
        h.update(hex_suggested_file_name)

        def get_blob_hashsum(b):
            length = b['length']
            if length != 0:
                blob_hash = b['blob_hash']
            else:
                blob_hash = None
            blob_num = b['blob_num']
            iv = b['iv']
            blob_hashsum = get_lbry_hash_obj()
            if length != 0:
                blob_hashsum.update(blob_hash)
            blob_hashsum.update(str(blob_num))
            blob_hashsum.update(iv)
            blob_hashsum.update(str(length))
            return blob_hashsum.digest()

        blobs_hashsum = get_lbry_hash_obj()
        for blob in blobs:
            blobs_hashsum.update(get_blob_hashsum(blob))
        if blobs[-1]['length'] != 0:
            raise InvalidStreamDescriptorError("Does not end with a zero-length blob.")
        h.update(blobs_hashsum.digest())
        if h.hexdigest() != stream_hash:
            raise InvalidStreamDescriptorError("Stream hash does not match stream metadata")
        log.debug("It is validated")
        return defer.succeed(True)

    def info_to_show(self):
        info = []
        info.append(("stream_name", binascii.unhexlify(self.raw_info.get("stream_name"))))
        size_so_far = 0
        for blob_info in self.raw_info.get("blobs", []):
            size_so_far += int(blob_info['length'])
        info.append(("stream_size", str(self.get_length_of_stream())))
        suggested_file_name = self.raw_info.get("suggested_file_name", None)
        if suggested_file_name is not None:
            suggested_file_name = binascii.unhexlify(suggested_file_name)
        info.append(("suggested_file_name", suggested_file_name))
        return info

    def get_length_of_stream(self):
        size_so_far = 0
        for blob_info in self.raw_info.get("blobs", []):
            size_so_far += int(blob_info['length'])
        return size_so_far