from memory import Memory
m = Memory()
r = m.alloc("xyz", 14)
print r
print m
r = m.alloc("abc", 12)
print r
print m
r = m.read("xyz", 4, 5)
print r
print m
r = m.deleteFile("xyz")
print r
print m
r = m.deleteFile("abc")
print r
print m
class Server:
backlog = 5
# this set will serve as a filesystem index
files = set()
def __init__(self, port):
# creates server object
global blocksize, n_blocks
path = ".storage"
try:
os.makedirs(path)
except OSError as exception:
shutil.rmtree(path)
os.makedirs(path)
host = ""
self.s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.s.bind((host, port))
self.port = port
self.memory = Memory(n_blocks, blocksize)
print "Block size is", blocksize
print "Number of blocks is", n_blocks
def process_line(self, client):
# recv's until \n
recieved = ""
while True:
cur = client.recv(1)
if cur == "\n":
break
elif not cur:
return cur
else:
recieved += cur
return recieved
def listen(self):
# Handles initial client connections and thread creation
self.s.listen(self.backlog)
print "Listening on port", self.port
while True:
client, address = self.s.accept()
print "Received incoming connection from", address[0]
cmd = self.process_line(client)
thread = threading.Thread(target=self.handler, args=(cmd, client))
thread.start()
# the following functions implement the server functionality requested
def store(self, client, args):
thread = str(threading.current_thread().ident)
if len(args) != 3:
client.send("ERROR: INVALID COMMAND.\n")
print "[thread", thread + "] Sent: ERROR: INVALID COMMAND."
return
args[2] = int(args[2])
if args[1] in self.files:
client.send("ERROR: FILE EXISTS.\n")
print "[thread", thread + "] Sent: ERROR: FILE EXISTS."
data = client.recv(args[2]) # can we assume data will be sent regardless of error?
return
response = self.memory.alloc(args[1], args[2])
if not response[0]:
client.send("ERROR: INSUFFICIENT DISK SPACE.\n")
print "[thread", thread + "] Sent: ERROR: INSUFFICIENT DISK SPACE."
data = client.recv(args[2]) # can we assume data will be sent regardless of error?
return
# actually do the storing stuff
data = client.recv(args[2])
f = open(".storage/" + args[1], "w")
f.write(data)
self.files.add(args[1])
print "[thread", thread + "] Stored file '%s' (%s bytes; %s blocks; %s" % response, (
"cluster" if response[3] == 1 else "cluster"
) + ")"
print "[thread", thread + "] Simulated Clustered Disk Space Allocation:"
print self.memory
client.send("ACK\n")
print "[thread", thread + "] Sent: ACK"
def read(self, client, args):
thread = str(threading.current_thread().ident)
if len(args) != 4:
client.send("ERROR: INVALID COMMAND.\n")
print "[thread", thread + "] Sent: ERROR: INVALID COMMAND."
return
if args[1] not in self.files:
client.send("ERROR: NO SUCH FILE.\n")
print "[thread", thread + "] Sent: ERROR: NO SUCH FILE."
return
args[2] = int(args[2])
args[3] = int(args[3])
data = open(".storage/" + args[1], "r").read()
if args[2] + args[3] > len(data) or args[2] < 0 or args[3] < 0:
client.send("ERROR: INVALID BYTE RANGE.\n")
print "[thread", thread + "] Sent: ERROR: INVALID BYTE RANGE."
return
# TODO: (1) Memory dump / print output
result = "ACK " + str(args[3]) + "\n" + data[args[2] : args[2] + args[3]]
print "[thread", thread + "] Sent: ACK", args[3]
client.send(result)
response = self.memory.read(args[1], args[2], args[3])
print "[thread", thread + "] Sent %s bytes (from %s '%s' blocks) from offset %s." % response
def delete(self, client, args):
thread = str(threading.current_thread().ident)
if len(args) != 2:
client.send("ERROR: INVALID COMMAND.\n")
print "[thread", thread + "] Sent: INVALID COMMAND."
return
if args[1] not in self.files:
client.send("ERROR: NO SUCH FILE.\n")
print "[thread", thread + "] Sent: ERROR: NO SUCH FILE."
return
os.remove(".storage/" + args[1])
self.files.remove(args[1])
response = self.memory.deleteFile(args[1])
client.send("ACK\n")
print "[thread", thread + "] Deleted", args[1], "file '%s' (deallocated %s blocks)" % response
print "[thread", thread + "] Simulated Clustered Disk Space Allocation:"
print self.memory
print "[thread", thread + "] Sent: ACK"
def dir(self, client):
thread = str(threading.current_thread().ident)
files_sorted = sorted(self.files, key=str.lower)
result = str(len(self.files)) + "\n"
for f in files_sorted:
result += f + "\n"
print "[thread", thread + "] Sent list of %d" % len(self.files), (
"file" if len(self.files) == 1 else "files"
) + "."
client.send(result)
def handler(self, cmd, client):
# Handles specific client connections until they close
thread = str(threading.current_thread().ident)
while cmd:
print "[thread", thread + "] Rcvd:", cmd
args = cmd.split(" ")
args[0] = args[0].strip()
if args[0] == "STORE":
self.store(client, args)
elif args[0] == "READ":
self.read(client, args)
elif args[0] == "DELETE":
self.delete(client, args)
elif args[0] == "DIR":
self.dir(client)
else:
client.send("ERROR: INVALID COMMAND.\n")
print "[thread", thread + "] Sent: ERROR: INVALID COMMAND."
cmd = self.process_line(client).strip()
print "[thread", thread + "] Client closed its socket....terminating."
client.close()
