def doGet(filename, clientSocket):
RRQpackage = generatePackage(type=OPCODE['RRQ'], filename=filename)
clientSocket.sendto(RRQpackage, (HOST, PORT))
fileData = getterHandler(clientSocket, BLOCK_SIZE)
if (fileData is not None):
writeFileBytes(filename, fileData)
serviceMsg(f'Successfully wrote data to {filename}')
printMessage(f"File {filename} is successfully received.")
return
else:
return
def writeFile(data, address):
writeSocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
writeSocket.bind((HOST, randint(1024, 65535)))
writeSocket.settimeout(TIMEOUT)
filename = str(data).split('\\x')[2][2:]
if checkFile(data):
serviceMsg(f'File already exists.')
ERRpackage = generatePackage(type=OPCODE['ERROR'], errorCode=6)
writeSocket.sendto(ERRpackage, address)
serviceMsg(f'Sent error to client: {address}. Raw data: {ERRpackage}')
return
else:
ACKpackage = generatePackage(type=OPCODE['ACK'], blockNumber=0)
writeSocket.sendto(ACKpackage, address)
serviceMsg(f'Sent ACK after WRQ to client: {address}. Raw data: {ACKpackage}. Block number: {0}')
fileData = getterHandler(writeSocket, BLOCK_SIZE)
if (fileData is not None):
writeFileBytes(f'f/{filename}', fileData)
serviceMsg(f'Successfully wrote data to f/{filename}')
writeSocket.close()
return
else:
return
def main():
serverSocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
serverSocket.bind((HOST, PORT))
print(f"Listening on port {PORT}...")
while True:
data, address = serverSocket.recvfrom(BLOCK_SIZE)
if (data[1] == OPCODE['RRQ']):
serviceMsg(f'Received RRQ from {address}. Raw data: {data}')
sendFile(data, address)
elif (data[1] == OPCODE['WRQ']):
serviceMsg(f'Received WRQ from {address}. Raw data: {data}')
writeFile(data, address)
def getterHandler(getterSocket, BLOCK_SIZE):
currentBlock = 0
receivedBefore = 0
fileData = b''
while True:
currentBlock = currentBlock + 1
try:
data, address = getterSocket.recvfrom(BLOCK_SIZE +
4) # expecting DATA
except socket.timeout:
serviceMsg(f'Did not receive data')
continue
if (data[1] == OPCODE['DATA']):
# https://coderwall.com/p/x6xtxq/convert-bytes-to-int-or-int-to-bytes-in-python
receivedBlockNumber = 256 * data[2] + data[3]
serviceMsg(
f'Received DATA from {address}. Received block number: {receivedBlockNumber}. Block len: {len(data)}'
)
ACKpackage = generatePackage(type=OPCODE['ACK'],
blockNumber=receivedBlockNumber)
getterSocket.sendto(ACKpackage, address)
serviceMsg(
f'Sent ACK after DATA to server: {address}. Raw data: {ACKpackage}. Block number: {currentBlock}'
)
if (receivedBlockNumber != receivedBefore):
fileData += data[4:]
if (len(data) < BLOCK_SIZE):
return fileData
receivedBefore = receivedBlockNumber
elif (data[1] == OPCODE['ERROR']):
printError(f'Error on the server: {ERROR[data[3]]}')
return None
def sendFile(data, address):
blocksToSend = []
sendSocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sendSocket.bind((HOST, randint(1024, 65535)))
sendSocket.settimeout(TIMEOUT)
filename = str(data).split('\\x')[2][2:]
try:
with open(f'f/{filename}', 'rb') as f:
for byte in iter(lambda: f.read(BLOCK_SIZE), b''):
blocksToSend.append(byte)
except FileNotFoundError:
serviceMsg(f'File doesn\'t exist.')
ERRpackage = generatePackage(type=OPCODE['ERROR'], errorCode=1)
sendSocket.sendto(ERRpackage, address)
serviceMsg(f'Sent error to client: {address}. Raw data: {ERRpackage}')
return
currentBlock = 1
receivedACKblockNum = 1
numberOfBlocks = len(blocksToSend)
serviceMsg(f"Number of blocks to send: {numberOfBlocks}")
DATApackage = generatePackage(type=OPCODE['DATA'], blockNumber=currentBlock,
fileData=blocksToSend[currentBlock - 1])
sendSocket.sendto(DATApackage, address)
while True:
try:
# expecting ACK after DATA
data, server = sendSocket.recvfrom(BLOCK_SIZE + 4)
except socket.timeout:
serviceMsg(f'Did not receive ACK after DATA. Resending DATA.')
DATApackage = generatePackage(type=OPCODE['DATA'], blockNumber=receivedACKblockNum + 1,
fileData=blocksToSend[receivedACKblockNum + 1])
sendSocket.sendto(DATApackage, server)
serviceMsg(f'Re-sent block #{currentBlock}')
continue
except ConnectionResetError:
serviceMsg(f'Lost connection')
return
if (data[1] == OPCODE['ACK']):
# https://coderwall.com/p/x6xtxq/convert-bytes-to-int-or-int-to-bytes-in-python
receivedACKblockNum = 256 * data[2] + data[3]
serviceMsg(f'Received ACK from client. Raw data: {data}. Block number: {receivedACKblockNum}')
# sending data
try:
DATApackage = generatePackage(type=OPCODE['DATA'], blockNumber=receivedACKblockNum + 1,
fileData=blocksToSend[receivedACKblockNum])
except:
serviceMsg(f'All blocks sent.')
sendSocket.close()
return
sendSocket.sendto(DATApackage, server)
serviceMsg(f'Sent block #{receivedACKblockNum + 1}')
currentBlock = currentBlock + 1
elif (data[1] == OPCODE['ERROR']):
serviceMsg(f'Received ERROR from client: {ERROR[data[3]]}')
return
def doSend(filename, clientSocket):
blocksToSend = []
try:
with open(filename, 'rb') as f:
for byte in iter(lambda: f.read(BLOCK_SIZE), b''):
blocksToSend.append(byte)
except FileNotFoundError:
printError("Error: this file does't exist. Try again.")
return
WRQpackage = generatePackage(type=OPCODE['WRQ'], filename=filename)
clientSocket.sendto(WRQpackage, (HOST, PORT))
serviceMsg(f'Sent WRQ to server. Raw data: {WRQpackage}')
currentBlock = 0
numberOfBlocks = len(blocksToSend)
serviceMsg(f"Number of blocks to send: {numberOfBlocks}")
while True:
try:
# expecting ACK after DATA
data, server = clientSocket.recvfrom(BLOCK_SIZE + 4)
except socket.timeout:
if (currentBlock == 0):
serviceMsg(f'Did not receive ACK after WRQ.')
printError("Unexpected error: try to re-send file")
return
else:
serviceMsg(f'Did not receive ACK after DATA. Resending DATA.')
DATApackage = generatePackage(type=OPCODE['DATA'], blockNumber=receivedACKblockNum + 1,
fileData=blocksToSend[receivedACKblockNum + 1])
clientSocket.sendto(DATApackage, server)
serviceMsg(f'Re-sent block #{currentBlock}')
continue
except ConnectionResetError:
printError(f'Error: server is unreachable. Try again later or restart the server.')
return
if (data[1] == OPCODE['ACK']):
# https://coderwall.com/p/x6xtxq/convert-bytes-to-int-or-int-to-bytes-in-python
receivedACKblockNum = 256 * data[2] + data[3]
serviceMsg(f'Received ACK from server. Raw data: {data}. Block number: {receivedACKblockNum}')
# sending data
try:
DATApackage = generatePackage(type=OPCODE['DATA'], blockNumber=receivedACKblockNum + 1,
fileData=blocksToSend[receivedACKblockNum])
except:
serviceMsg(f'All blocks sent.')
printMessage("File is sent successfully.")
return
clientSocket.sendto(DATApackage, server)
serviceMsg(f'Sent block #{receivedACKblockNum + 1}')
currentBlock = currentBlock + 1
elif (data[1] == OPCODE['ERROR']):
serviceMsg(f'Received ERROR from server. Raw data: {data}')
printError(f'Error on the server: {ERROR[data[3]]}')
return