From bf711ceeb51d16e3911ccaf68a39ba4baccd77e2 Mon Sep 17 00:00:00 2001
From: Paul Vincent Craven <paul@cravenfamily.com>
Date: Thu, 14 Mar 2019 19:24:15 -0500
Subject: [PATCH] Update big message code.

---
 tcp_receive_big_message.py | 31 +++++++++++++++++++++++++++----
 tcp_send_big_message.py    | 33 +++++++++++++++++++--------------
 2 files changed, 46 insertions(+), 18 deletions(-)

diff --git a/tcp_receive_big_message.py b/tcp_receive_big_message.py
index cc14185..ce90e32 100644
--- a/tcp_receive_big_message.py
+++ b/tcp_receive_big_message.py
@@ -1,11 +1,26 @@
 import socket
+import time
 
+# This is your buffer size.
+# You can't receive anything more than the buffer size at one time.
 BUFFER_SIZE = 65535
 
+# This should be the IP address of the computer you run this
+# code on (the server). It should be the SAME IP address that
+# the client hooks up to.
+# Note: If you use '127.0.0.1' you can only receive connections
+# from the same computer. Outside computers cannot connect to a
+# computer listening to 127.0.0.1.
 my_ip_address = '127.0.0.1'
 my_ip_port = 10000
 
-# Our full message
+# We will loop until we get a connection or we get data. We don't want
+# to check thousands of times per second for these because that would
+# max our CPU. If we have nothing to do, how long we wait before we
+# check again.
+DELAY = 0.1
+
+# Our full message. Starts empty.
 full_message = b""
 
 # We need to build a "state machine" that keeps
@@ -22,7 +37,9 @@
 my_socket.settimeout(0.0)
 
 # Tell the socket it will be listening on my_ip_address, and my_port.
-my_socket.bind((my_ip_address, my_ip_port))
+# Note that Python expects ip and port as a list
+listen_to = (my_ip_address, my_ip_port)
+my_socket.bind(listen_to)
 
 # We are going to be listening as a server, not connecting as a client.
 # The "1" specifies the size of the backlog of connections we allow before
@@ -31,6 +48,9 @@
 
 done = False
 chunks = 0
+connection = None
+client_ip = None
+client_port = None
 
 while not done:
 
@@ -40,6 +60,8 @@
             # Get a connection, and the address that hooked up to us.
             # The 'client address' is an array that has the IP and the port.
             connection, client_address = my_socket.accept()
+            client_ip = client_address[0]
+            client_port = client_address[1]
             state = CONNECTED
         except BlockingIOError:
             pass
@@ -52,7 +74,7 @@
             chunks += 1
 
             if len(data) > 0:
-                print("Data from {}:{} \"{}\"".format(client_address[0], client_address[1], data))
+                print(f"Data from {client_ip}:{client_port} '{data}'")
 
             # Append this chunk to the full message
             full_message += data
@@ -70,4 +92,5 @@
 # Close the socket. No socket operations can happen after this.
 my_socket.close()
 
-print("Done receiving message. Processed {} bytes in {} chunks.".format(len(full_message), chunks))
\ No newline at end of file
+print(f"Done receiving message.")
+print(f"Processed {len(full_message)} bytes in {chunks} chunks.")
\ No newline at end of file
diff --git a/tcp_send_big_message.py b/tcp_send_big_message.py
index 4064731..082f106 100644
--- a/tcp_send_big_message.py
+++ b/tcp_send_big_message.py
@@ -6,27 +6,32 @@
 
 # Size of our message.
 # Must be at least 1
-message_size_in_bytes = 300000
+message_size_in_bytes = 600000
 
-# Message as a byte array. (Hence the b at the front.)
-# Send a bunch of x's, and an "END"
+# Create a message as a byte array.
+# Use multiplication to quickly create an array of n-1 bytes.
+# Add a \n at the end which we will use to detect end-of-message.
 my_message = b"X" * (message_size_in_bytes - 1) + b"\n"
 
 try:
-  # Open a socket
-  my_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    # Create a socket for IPv4 (AF_INET), TCP stream (SOCK_STREAM)
+    my_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 
-  # Connect to this server, and this port.
-  my_socket.connect((server_ip_address, server_ip_port))
+    # Connect to this specified server and port
+    # Note that Python expects ip and port as a list
+    destination = (server_ip_address, server_ip_port)
+    my_socket.connect(destination)
 
-  # Send the message
-  my_socket.sendall(my_message)
+    # Send the message
+    my_socket.sendall(my_message)
 
-  # Close the socket
-  my_socket.close()
+    # Close the socket
+    my_socket.close()
 
-except:
-  # Something bad happened.
-  print("Unable to send the message.")
+except ConnectionRefusedError:
+    print("Client refused to accept the connection.")
+
+except Exception as e:
+    print("Error: ", e)
 
 print("Done")
\ No newline at end of file