Project Malcolm

Authors: Ubadah Jafry, Hamza Ijaz

Overview

Project Malcolm is divided into two parts:

• A multi-threaded client that can download from multiple servers
• A server that start virtual servers that listen on multiple ports

Working

The whole system works in the following manner

• Server are launched using the server.py which launches the virtual servers that are set on the port given in the arguments
• The ports for virtual servers are verified if they are correct or not and will be removed from before starting them
• Client is launched using the client.py where the parameters for launched servers are passed
• The client tries to connect with server and receives a checksum from all the server
• The checksum is generated from the file which is going to be downloaded by the client and will only connect to the server which have the same checksum in majority. This is a initial corruption check done by the client
• Now the client will request the file size from one of the server instead of all of them since the same checksum guaretee same size as well
• After receiving the size of file, the client divides them into equal parts (such that they are integers) and send argument to the server
• The argument contains offset and bytes to transfer, which will be parsed by server and the specified part of the file will be sent
• The client after receiving the file will generate combine them and generate a checksum and compare to the original checksum. In case, this fails the client will restart the process
• Once the file is checked, the connection is terminated by the client

Files

server.py

Executable file that launches multiple virtual servers and display there status after certain interval

Arguments

• -i --interval Time interval in seconds between server status reporting in seconds
• -n --number Total number of virtual server
• -f --file Path to the file (either absolute or relative)
• -p --port List of ports that must be equal to number of virtual servers
• -c --color-printing Enables color printing in the console

Examples

$ ./server.py --help
usage: server.py [-h] -i INTERVAL -n NUMBER -f FILE -p [PORT [PORT ...]]

Launches multiple virtual servers and display there status after certain interval

optional arguments:
  -h, --help            show this help message and exit
  -i INTERVAL, --interval INTERVAL
                        Time interval in seconds between server status reporting in seconds
  -n NUMBER, --number NUMBER
                        Total number of virtual server
  -f FILE, --file FILE  Path to the file (either absolute or relative)
  -p [PORT [PORT ...]], --port [PORT [PORT ...]]
                        List of ports that must be equal to number of virtual servers

$ ./server.py -f data.mp4 -n 4 -i 1 -p 10001 10002 10003 10004

$ python server.py --file data.mp4 --number 4 --interval 1 --port 10001 10002 10003 10004

client.py

Executable file that launches a client that can connect to multiple servers that includes error handling and file verification

Arguments

• -i --interval Time interval in seconds between server status reporting in seconds
• -o --output Path to the output directory (either absolute or relative)
• -a --address The ip address of the server
• -p --port List of ports that must be equal to number of virtual servers
• -r --resume Flag that tells the client whether to resume the existing download in progress
• -c --color-printing Enables color printing in the console

Examples

$ ./client.py --help
usage: client.py [-h] -i INTERVAL -o OUTPUT -a ADDRESS -p [PORT [PORT ...]] [-r] [-c]

Launches a client that can connect to multiple servers that includes error handling and file verification

optional arguments:
  -h, --help            show this help message and exit
  -i INTERVAL, --interval INTERVAL
                        Time interval in seconds between server status reporting in seconds
  -o OUTPUT, --output OUTPUT
                        Path to the output directory (either absolute or relative)
  -a ADDRESS, --address ADDRESS
                        The ip address of the server
  -p [PORT [PORT ...]], --port [PORT [PORT ...]]
                        List of ports that must be equal to number of virtual servers
  -r, --resume          Flag that tells the client whether to resume the existing download in progress
  -c, --color-printing  Enables color printing in the console

$ ./client.py -o . -a 127.0.0.1 -i 1 -r -p 10001 10002 10003 10004

$ python client.py --output . --address 127.0.0.1 --interval 1 --resume --port 10001 10002 10003 10004