/
client.py
149 lines (132 loc) · 4.86 KB
/
client.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
import datetime
from xmlrpc.server import SimpleXMLRPCServer, SimpleXMLRPCRequestHandler
import xmlrpc.client
import socket
import sys
from threading import Thread
import multiprocessing
import random
import json
import socketserver
key_value_store = dict()
servers = dict()
my_port = ""
timestamp = 1
class AsyncXMLRPCServer(socketserver.ThreadingMixIn,SimpleXMLRPCServer): pass
def connect_to_server(port):
if(port == my_port):
return "Not a valid server port"
proxy = xmlrpc.client.ServerProxy("http://localhost:"+port+"/")
try:
proxy._() # Call a fictive method.
except xmlrpc.client.Fault:
servers[port] = proxy
except socket.error:
# Not connected ; socket error mean that the service is unreachable.
return
def disconnect_server(port):
if(port in servers):
#print ("disconnect_server from client: ", port)
servers.pop(port,None)
return ""
def today():
today = datetime.datetime.today()
return xmlrpc.client.DateTime(today)
def get(key):
global timestamp
if len(servers) == 0:
return "No server is connected"
serv = random.randint(0,len(servers)-1)
li = list(servers.values())
val, server_timestamp = json.loads(li[serv].request("get "+str(key) + " " + str(timestamp)))
#print("getting value from server: "+str(li[serv]))
#print("got: "+str(val))
old_timestamp = timestamp
timestamp = max(timestamp, server_timestamp) + 1
if val[0] == "ERR_KEY":
# server thinks it doesn't have this key - did we ask for it before?
if key in key_value_store:
# we asked for it before so return "ERR_DEP"
return "ERR_DEP"
else:
# we did not ask for it before, so we can return "ERR_KEY"
return "ERR_KEY"
else:
# server had the key, did we previously know about this key?
if key in key_value_store:
# we knew about this key already, so check the timestamp
if key_value_store[key][1] > val[1] or (key_value_store[key][1] == val[1] and key_value_store[key][2] > val[2]):
# timestamp from the server is less than the timestamp
# we previously knew, so return ERR_DEP
return "ERR_DEP"
else:
# timestamp is newer, so update our memory of k-v pairs
# and return value from server
key_value_store[key] = val
return val[0]
else:
# we learned about a new key, so update our memory of k-v pairs
# and return value from server
key_value_store[key] = val
# print("val: "+val[0])
return val[0]
def put_value(key,value):
global timestamp
if len(servers) == 0:
return "No server is connected"
serv = random.randint(0,len(servers)-1)
li = list(servers.values())
val, server_timestamp = json.loads(li[serv].request("put "+str(key)+" "+str(value) + " " + str(timestamp)))
#print("putting value to server: "+str(li[serv]))
# remember the value and timestamp of what the server put
# print("value from server: "+str(val))
timestamp = max(timestamp, int(server_timestamp)) + 1
key_value_store[key] = val
#parsing commands
# valid commands
# - put key value
# - get key
# - connect_to_client client_port
# - disconnect_client client_port
def parse_req(command):
words = command.rstrip().split(" ")
if("put" in words[0]):
val = put_value(words[1],words[2])
return ""+str(val)
else:
return ""+str(globals()[words[0]](words[1]))
def threaded_function(arg) :
arg.serve_forever()
def start(id,queue):
global my_port
try:
my_port = id
port = int(id)
except:
print("Give appropriate port number")
sys.exit(-1)
client = AsyncXMLRPCServer(("localhost", port),SimpleXMLRPCRequestHandler, logRequests=False)
#print("Listening on port "+str(port))
client.register_function(today, "today")
client.register_function(get, "get")
client.register_function(put_value, "put_value")
client.register_function(connect_to_server, "connect_to_server")
client.register_function(disconnect_server, "disconnect_server")
client.register_function(parse_req, "request")
queue.put("Done")
client.serve_forever()
if __name__== "__main__":
try:
port = int(sys.argv[1])
my_port = str(port)
except:
print("Give appropriate port number")
sys.exit(-1)
server = SimpleXMLRPCServer(("localhost", port))
print("Listening on port "+str(port))
server.register_function(get, "get")
server.register_function(put_value, "put_value")
server.register_function(connect_to_server, "connect_to_server")
server.register_function(disconnect_server, "disconnect_server")
server.register_function(parse_req, "request")
server.serve_forever()