689 CPSC Industrial Frameworks for Distributed Computing Spring 2003
Peer-2-Peer File Sharing System
Jeevan Joseph John (jeevanj@cs,tamu.edu) B S Kumar ([e-mail]) Praveen Pathiyil ([e-mail]) Subramonia Sarma ([e-mail])
Overview
Motivation
Familiarity and appreciation of utilities like Napster, Kazaa, Gnutella, LimeWire etc The concept includes enough issues to become a good distributed systems project
Challenges
Understand the concepts involved in a generic file sharing application To develop a system having components in different languages to run on different platforms and still be able to inter-operate
Technologies
Java, Linux C#, Forms, Windows MySQL JDBC Sockets XML
Approaches Discarded
Java RMI and C# Remoting In-compatible solutions CORBA ORBs for C# is not free Non-availability of documentation for trial versions Experience in integrating Java with C# and .NET, Ja.Net : Integration between Java and Microsoft .NET, Intrinsyc Software Inc.
Server Explained
Client
Conn instance
Server
Connect Request
Conn instance parseMesg
Client
Request Message Response Message
DB
processMesg processX
Server Explained
Multithread Server
No limits on the number of simultaneous client connections
DOM Parser
Transformer DocumentBuilder
JDBC for connecting to Database
A well defined set of APIs provide the interface
Messages & Formats
Interface between client and server Follows XML formats
register online / offline sinupdate / bulkupdate search / resumesearch
String based messages overcome in-compatibilities in serialization / marshalling Well defined format for XML parsing
Flexibility in keeping different fields in different messages
Messages Explained
register
Registers a new user
online / offline
To update the status of a client in DB Exceptions are caught and the state set, to account for broken connections
sinupdate / bulkupdate
Updates the file information at a client in DB `bulkupdate' for refresh at periodic intervals `sinupdate' for updates after successful downloads `bulkupdate' for refresh on foul play !
Messages Explained
search / resumesearch
`search' for searching a particular file (keyword searching is supported) Returns the locations of the file with their corresponding IP Address, exact file name, file size, user name, connection speed `resumesearch' for attempting to resume a download from a different location `resumesearch' is transparent to user
Example Message
<mesg> <mesgtype>search</mesgtype> <IPAddress>1.2.3.4</IPAddress> <uname>testuser</uname> <keyword>mp3</keyword> </mesg>
Example Message
<mesg> <mesgtype>bulkupdate</mesgtype> <IPAddress>1.2.3.4</IPAddress> <uname>testuser</uname> <file>
<filename>example1</filename> <filesize>1024</filesize>
</file> <file>
<filename>example2</filename> <filesize>2048</filesize>
</file> <....> ... </....> </mesg>
The Peer
The general User
Search for files that he needs Download them without Interruption
The Ideal User
Share own files Optimal Use of his Bandwidth
The Peer : Scenarios
Developer
Interact With Server, a look up for files Interact with Peer : Server, to download files Interact with Peer : Client, to upload files Interact with Front End, a GUI
Client Explained
Server File and Peer info Peer
Peer File Exchange Peer
Client
GUI
Peer
C#
Level of Abstraction for Network Programming Libraries for XML parsing Ease of GUI building New Technology Microsoft Technology for Windows Platform
Server Client Interaction
Runs in the Main Thread, Single Instance Message Passing through Xml
Register,online / offline,sinupdate / bulkupdate, search /resumesearch
Other Interactions subject to Server Connection being Alive
Interact with Peer : Server
Our Peer is Client Tries to Connect to Peer(server) based on search results Each interaction is a separate thread File Download in byte format of Acknowledgement each chunk of transfer (IKB)
Interact with Peer : Server
Constant Interaction with GUI to inform of status Pause/Resume Downloads Completion of broken downloads Inform the Server of new files on local machine
Interact with Peer: Client
Our Peer is Server Runs as Thread Listens on a Port(fixed) Each Connection to peer spawns a new thread Each new Thread uploads a file
Interact with Peer: Client
Maximum Number of uploads user defined Uploads hidden from user
Interact with Front End
Client is an instance in the FrontEnd FrontEnd provides information about local settings The Front End is informed about the Status of interaction with Peers. Provides a wrapper of Peer Functionalities to Front End
Database Explained
MySql database JDBC for connection between server and DB from MM MySQL Tables
ClientInfo ipaddress, flag, connection_speed, currentuser FileInfo ipaddress, filename, filesize Users Username, Password log clientip, username, msgtype, timestamp
Database Explained
Database Server Interface functions
Function Name do_register() do_login() do_logout() do_search()
Table read / written Users ClientInfo ClientInfo ClientInfo&FileInfo
Database Explained
Database Server Interface functions
Tables read / written ClientInfo&FileInfo FileInfo FileInfo log
Function Name do_resumesearch(ipaddress,fn) do_singleupdate(ipaddress,fileinfo) do_bulkupdate(ipaddress,fileinfo) log_request(clientip,username,msgtype,timestamp)
GUI Introduction
The `Face' of the application Use of Microsoft .NET framework with the components developed in Visual C# GUI communicates with both the user and the local client program Features a set of easily usable UI controls (ListView, ContextMenu,Toolbar,MainMenu etc) Seamless interaction between the controls and client
A GUI screenshot...
GUI Explained
GUI functionalities
Connection and disconnection to/from server User registration Customized Configuration of Peer-2-Peer Peer file search Download files from peers (***THE functionality***) Real time download status update Give users finer control over the download Easy access to the User Manual
GUI Features Explained
Compact and intuitive UI design Multiple options for same functionality eg:- Right-click context menu and also a toolbar button for file download Use of friendly messages Error Messages Status Messages Right amount of leverage given to the user
Configuration
Customized use...