Hi Folks,
I'm having some issues with an small socket based server I'm writing,
and I was hoping I could get some help.
My code (attached below) us supposed to read an HTTP Post message
coming from a power meter, parse it, and return a proper HTTP 200 Ok
message. The problem is that the socket fails to send the entire
message as one message, creating a fragmented message which the power
meter then fails to read and accept.
Is there any way to force the socket to send the entire message at
once? Am I doing anything wrong? Is there an easier way to implement
this functionality?
Thanks,
Guy Davidson
Code:
# server application to read data from power meter
# listens on port 80
# receives HTTP POST messages
# author: Maria Kazandjieva <mariakaz@cs.st anford.edu>, Guy Davidson
<gudyav2002@yah oo.com>
# updated: July 7th, 2008: staring to add database writing
functionality
import time
import datetime #datetime for response message
from socket import * #socket module
import DataPacket #local file with data packet class
import library
import MySQLdb
#formats a proper response message
myHost = ""
myPort = 80
#response = "HTTP/1.1 200 OK\r\nDate: Fri, 20 June 2008 20:40:34 GMT\r
\nServer:SING\r \nX-Powered-By: maria\r\nConten t-Length: 7\r
\nConnection:cl ose\r\nContent-Type: text/html\r\n\r\n[0!:20]\n"
#initializing the socket:
s = socket(AF_INET, SOCK_STREAM) # create a TCP socket
s.setsockopt(SO L_SOCKET, SO_REUSEADDR, 1) # allow port reuse? I hope
s.bind((myHost, myPort)) # bind it to the server port
s.listen(50) # allow 50 simultaneous
pending connections
print('Socket initialized')
#intializing the database
db = MySQLdb.connect (host='localhos t', user='powernet' ,
passwd='jplicks ', db='test')
cursor = db.cursor()
print('Database cursor intialized')
while 1:
print('In while 1')
connection, address = s.accept() # connection is a new socket
print('Accepted a connection')
# TODO:
# verify connection is from powernet so we don't get random
connections to port 80
# best way to get the data would be:
# read until we get all the headers
# parse Content header to get length of data
# read for that many additional bytes
while 1:
print('In while 1 2')
data = connection.recv (4096) # receive up to 4K bytes
print('First set of data receieved:')
#print(data)
'''
if data:
print data
#connection.sen d(response) #send response; OK 200 HTTP message
else:
break
'''
if data:
# second read should recieve the rest of the packet
# finding how long the content is
length = data.find('Cont ent-Length: ')
print('Index of "Content-Length" = ' + str(length))
length = int(data[length+16:lengt h+18])
# adding the bytes from the "Content-Type section:"
length += 51
data += connection.recv (length)
print('Second set of data received:')
print(data)
if data:
#print('Found data:')
#print data #print the string data
packet = DataPacket.Data Packet(data) #use the string data to
create a DataPacket object
print(packet) #print the contents of the object, I hope :)
#we have a packet, let's write it to the mysql DB
packet.mysql_in sert(cursor)
#connection.sen d(response) #send response; OK 200 HTTP
message
print('Sending response')
response = library.respons e_message() #get the response message
totalsent = 0 #initialize a variable to track how much we've sent
so far
while totalsent < len(response): #while we haven't sent everything
sent = connection.send (response[totalsent:]) #send whatever we
can starting where we stopped
totalsent += sent #increment the count of how much we've sent.
else:
print('No data')
break
else:
print('No data')
break
I'm having some issues with an small socket based server I'm writing,
and I was hoping I could get some help.
My code (attached below) us supposed to read an HTTP Post message
coming from a power meter, parse it, and return a proper HTTP 200 Ok
message. The problem is that the socket fails to send the entire
message as one message, creating a fragmented message which the power
meter then fails to read and accept.
Is there any way to force the socket to send the entire message at
once? Am I doing anything wrong? Is there an easier way to implement
this functionality?
Thanks,
Guy Davidson
Code:
# server application to read data from power meter
# listens on port 80
# receives HTTP POST messages
# author: Maria Kazandjieva <mariakaz@cs.st anford.edu>, Guy Davidson
<gudyav2002@yah oo.com>
# updated: July 7th, 2008: staring to add database writing
functionality
import time
import datetime #datetime for response message
from socket import * #socket module
import DataPacket #local file with data packet class
import library
import MySQLdb
#formats a proper response message
myHost = ""
myPort = 80
#response = "HTTP/1.1 200 OK\r\nDate: Fri, 20 June 2008 20:40:34 GMT\r
\nServer:SING\r \nX-Powered-By: maria\r\nConten t-Length: 7\r
\nConnection:cl ose\r\nContent-Type: text/html\r\n\r\n[0!:20]\n"
#initializing the socket:
s = socket(AF_INET, SOCK_STREAM) # create a TCP socket
s.setsockopt(SO L_SOCKET, SO_REUSEADDR, 1) # allow port reuse? I hope
s.bind((myHost, myPort)) # bind it to the server port
s.listen(50) # allow 50 simultaneous
pending connections
print('Socket initialized')
#intializing the database
db = MySQLdb.connect (host='localhos t', user='powernet' ,
passwd='jplicks ', db='test')
cursor = db.cursor()
print('Database cursor intialized')
while 1:
print('In while 1')
connection, address = s.accept() # connection is a new socket
print('Accepted a connection')
# TODO:
# verify connection is from powernet so we don't get random
connections to port 80
# best way to get the data would be:
# read until we get all the headers
# parse Content header to get length of data
# read for that many additional bytes
while 1:
print('In while 1 2')
data = connection.recv (4096) # receive up to 4K bytes
print('First set of data receieved:')
#print(data)
'''
if data:
print data
#connection.sen d(response) #send response; OK 200 HTTP message
else:
break
'''
if data:
# second read should recieve the rest of the packet
# finding how long the content is
length = data.find('Cont ent-Length: ')
print('Index of "Content-Length" = ' + str(length))
length = int(data[length+16:lengt h+18])
# adding the bytes from the "Content-Type section:"
length += 51
data += connection.recv (length)
print('Second set of data received:')
print(data)
if data:
#print('Found data:')
#print data #print the string data
packet = DataPacket.Data Packet(data) #use the string data to
create a DataPacket object
print(packet) #print the contents of the object, I hope :)
#we have a packet, let's write it to the mysql DB
packet.mysql_in sert(cursor)
#connection.sen d(response) #send response; OK 200 HTTP
message
print('Sending response')
response = library.respons e_message() #get the response message
totalsent = 0 #initialize a variable to track how much we've sent
so far
while totalsent < len(response): #while we haven't sent everything
sent = connection.send (response[totalsent:]) #send whatever we
can starting where we stopped
totalsent += sent #increment the count of how much we've sent.
else:
print('No data')
break
else:
print('No data')
break
Comment