def test_full_name(self):
data = Data()
data.wireDecode(codedData)
# Check the full name format.
self.assertEqual(data.getFullName().size(), data.getName().size() + 1)
self.assertEqual(data.getName(), data.getFullName().getPrefix(-1))
self.assertEqual(data.getFullName().get(-1).getValue().size(), 32)
# Check the independent digest calculation.
sha256 = hashes.Hash(hashes.SHA256(), backend=default_backend())
sha256.update(Blob(codedData).toBytes())
newDigest = Blob(bytearray(sha256.finalize()), False)
self.assertTrue(newDigest.equals(
data.getFullName().get(-1).getValue()))
# Check the expected URI.
self.assertEqual(
data.getFullName().toUri(), "/ndn/abc/sha256digest=" +
"96556d685dcb1af04be4ae57f0e7223457d4055ea9b3d07c0d337bef4a8b3ee9")
# Changing the Data packet should change the full name.
saveFullName = Name(data.getFullName())
data.setContent(Blob())
self.assertNotEqual(data.getFullName().get(-1), saveFullName.get(-1))
def test_full_name(self):
data = Data()
data.wireDecode(codedData)
# Check the full name format.
self.assertEqual(data.getFullName().size(), data.getName().size() + 1)
self.assertEqual(data.getName(), data.getFullName().getPrefix(-1))
self.assertEqual(data.getFullName().get(-1).getValue().size(), 32)
# Check the independent digest calculation.
sha256 = hashes.Hash(hashes.SHA256(), backend=default_backend())
sha256.update(Blob(codedData).toBytes())
newDigest = Blob(bytearray(sha256.finalize()), False)
self.assertTrue(newDigest.equals(data.getFullName().get(-1).getValue()))
# Check the expected URI.
self.assertEqual(
data.getFullName().toUri(), "/ndn/abc/sha256digest=" +
"96556d685dcb1af04be4ae57f0e7223457d4055ea9b3d07c0d337bef4a8b3ee9")
# Changing the Data packet should change the full name.
saveFullName = Name(data.getFullName())
data.setContent(Blob())
self.assertNotEqual(data.getFullName().get(-1), saveFullName.get(-1))
def readDataAndCreateManifests(self, filename, groupSize, keepData):
if groupSize < 1:
raise RuntimeError("Group size cannot be less than 1")
self.allChunks = [
] # for holding the generated data packets, including unsigned manifests
self.allManifests = [
] # for storing first unsigned manifest packets, which are then signed in-place
self.rawDataCount = 0
self.ndnChunkCount = 0
seqNo = 0 # sequence number of data packets
chunkNo = 0 # number of the chunk in the group
with open(filename, 'rb') as f:
# prepare space to store all manifests of the group (last manifest will not use all the space)
def allocateBufferForDigests():
return bytearray(groupSize * SHA256_DIGEST_SIZE)
digests = allocateBufferForDigests()
while f.readable():
chunkPayload = f.read(self._maxSegmentPayloadLength)
if len(chunkPayload) == 0:
break
self.rawDataCount = self.rawDataCount + len(chunkPayload)
chunk = Data(
Name("/icn2019/test/data").appendSequenceNumber(seqNo))
seqNo = seqNo + 1
chunk.setContent(chunkPayload)
digestSignature = DigestSha256Signature()
digestSignature.setSignature(
Blob(bytearray(SHA256_DIGEST_SIZE))
) # not real a valid signature, but ok for the experiment
chunk.setSignature(digestSignature)
if keepData:
self.allChunks.append(chunk)
# only data chunks; manifest sizes counted separatedly, as they are signed
self.ndnChunkCount = self.ndnChunkCount + chunk.wireEncode(
).size()
# For storing data packet to a file
# with open(writepath + "-1.txt", "wb") as dataf
# dataf.write(dpacket_bytes)
implicitDigest = chunk.getFullName()[-1].getValue()
offset = chunkNo * SHA256_DIGEST_SIZE
digests[offset:offset +
SHA256_DIGEST_SIZE] = implicitDigest.toBytes()[:]
chunkNo = chunkNo + 1
if chunkNo == groupSize:
manifest = self._createManifest(
Name("/icn2019/test/data").appendSequenceNumber(seqNo),
digests, groupSize) # full group
seqNo = seqNo + 1
self.allChunks.append(manifest)
self.allManifests.append(manifest)
chunkNo = 0
digests = allocateBufferForDigests()
if chunkNo != 0:
manifest = self._createManifest(
Name("/icn2019/test/data").appendSequenceNumber(seqNo),
digests, groupSize) # partial group
self.allChunks.append(manifest)
self.allManifests.append(manifest)
self.nDataChunks = seqNo - len(
self.allManifests
) # number of data packets, excluding the manifests
def setObject(self, namespace, obj, useSignatureManifest=False):
"""
Segment the object and create child segment packets of the given Namespace.
:param Namespace namespace: The Namespace to append segment packets to.
This ignores the Namespace from setNamespace().
:param Blob obj: The object to segment.
:param bool useSignatureManifest: (optional) If True, only use a
DigestSha256Signature on the segment packets and create a signed
_manifest packet as a child of the given Namespace. If omitted or
False, sign each segment packet individually.
"""
keyChain = namespace._getKeyChain()
if keyChain == None:
raise RuntimeError(
"SegmentStreamHandler.setObject: There is no KeyChain")
# Get the final block ID.
finalSegment = 0
# Instead of a brute calculation, imitate the loop we will use below.
segment = 0
offset = 0
while offset < obj.size():
finalSegment = segment
segment += 1
offset += self._maxSegmentPayloadLength
finalBlockId = Name().appendSegment(finalSegment)[0]
SHA256_DIGEST_SIZE = 32
if useSignatureManifest:
# Get ready to save the segment implicit digests.
manifestContent = bytearray(
(finalSegment + 1) * SHA256_DIGEST_SIZE)
# Use a DigestSha256Signature with all zeros.
digestSignature = DigestSha256Signature()
digestSignature.setSignature(Blob(bytearray(SHA256_DIGEST_SIZE)))
segment = 0
offset = 0
while offset < obj.size():
payloadLength = self._maxSegmentPayloadLength
if offset + payloadLength > obj.size():
payloadLength = obj.size() - offset
# Make the Data packet.
segmentNamespace = namespace[Name.Component.fromSegment(segment)]
data = Data(segmentNamespace.getName())
metaInfo = namespace._getNewDataMetaInfo()
if metaInfo != None:
# Start with a copy of the provided MetaInfo.
data.setMetaInfo(metaInfo)
data.getMetaInfo().setFinalBlockId(finalBlockId)
data.setContent(obj.toBytes()[offset:offset + payloadLength])
if useSignatureManifest:
data.setSignature(digestSignature)
# Append the implicit digest to the manifestContent.
implicitDigest = data.getFullName()[-1].getValue()
digestOffset = segment * SHA256_DIGEST_SIZE
manifestContent[digestOffset:digestOffset + SHA256_DIGEST_SIZE] = \
implicitDigest.toBytes()[:]
else:
keyChain.sign(data)
segmentNamespace.setData(data)
segment += 1
offset += self._maxSegmentPayloadLength
if useSignatureManifest:
# Create the _manifest data packet.
namespace[self.NAME_COMPONENT_MANIFEST].serializeObject(
Blob(manifestContent))
# TODO: Do this in a canSerialize callback from Namespace.serializeObject?
namespace._setObject(obj)
