This is my project for computer networks course
Project description:
In this project you will develop a peer-to-peer (P2P) file sharing network application in Java with GUI1 . The application should allow users to share and download files from each other. In general, the system should work as follows. In the system, one designated machine, let’s call it FileTracker (FT), should always be on and waiting for others’ (peers) requests. FT should contain information about the files which are shared by online peers and information about the peers. If a peer A wants to download a file X, A asks FT to send information about the online peers that share X. If there exist peers that share X, FT sends information about these peers and files to A (Note that different files with the same name may exist (difference could be in size, type, etc.)). A connects to one of the peers that it has received from FT and may download from X that peer. The rest explains how the system should work in detail. See Figure 1 for illustration. • The IP address of FT and the port number on which the application is running should be public, i.e., users should know the IP address and port number of FT. • When a peer A connects to FT, A should automatically send information about its shared files (up to 5 files) as a list of records to FT in the following format: <file name, file type (e.g., text, jpg, etc), file size, file last modified date (DD/MM/YY), IP address, port number>. A should send “HELLO” and receive “HI” before sending the information. • If A does not send any file information to FT while joing the system, i.e., if A does not share any file, then FT should not accept A. FT should not respond to A. • Only accepted peers should be able to use the services offered by this system. • When A wants to download a file with the name “File Name”, A requests the file from FT by sending “SEARCH: ” + “File Name”. • When FT receives “SEARCH: ” + “File Name”, it tries to find the file in a hash table where ‘key’ is filename and ‘value’ is a list which contains records of this format: <file type, file size, file last modified date (DD/MM/YY), IP address, port number>. – If FT finds the file, it should send “FOUND: ” + list of records + corresponding peer scores. – If FT does not find the file, it should send “NOT FOUND”. • After receiving a list of records, A should choose one of the peers (records) from the list, say B, and connect to B (using IP and port number) to request and download the file. For that A should send “DOWNLOAD: ” + “FileName, type, size” to B. • When B receives a “DOWNLOAD” message, it should generate a random number 1 ≤ p ≤ 100, and if p < 50, then A sends “FILE: ”+file, otherwise sends “NO!”. In other words, as mentioned earlier, B may not send the requested file to A. This requirement is just to test the scoring method of this system. • The scoring method is used to evaluate peers trustworthiness. The method works as follows: FT keeps track of two variables - ‘NumOfRequests’ and ‘NumOfUploads’. Assume peer A requests a file from peer B. – If B sends the requested file to A, A will send “SCORE of ”+IP Addr of B+“ : 1” to FT. 1A sample Java program with GUI will be given on the course’s moodle page. 1 – If B does not send the requested file to A, A will send “SCORE of ”+IP Addr of B+“ : 0” to FT. – When FT receives “SCORE of ”+IP Addr of B+“ : n”, it increments ‘NumOfRequests’ by 1 and increments ‘NumOfUploads’ by n of B. • When A wants to leave the system, A should notify FT about this so that FT can update the hash table accordingly. A should send “BYE” to FT to do so. • FT should also store a list of all peers that have joined the system at least once. A peer in the list should include the following information: <IP address, score>. FT should keep the information about a peer even the peer leaves the system. You can use HashMap<String,Integer> for this.