NWEN 241 Assignment 5 Network Server Program

NWEN 241 Assignment 5
Network Server Program

In this assignment, you will implement a network server program given
a set of specifications and guidelines which are outlined in the tasks. Unlike the past four assignments, code framework and test codes will not be
provided. You are free to design the program in any way you want and
implement it in either pure C or C++.
Full marks is 100.
Instructions and Submission Guidelines:
• You should provide appropriate comments to make your source code
readable. If your code does not work and there are no comments,
you may lose all the marks. See the marking criteria at the end of this
document for details about the marks for commenting.
• You should follow a consistent coding style when writing your source
code. See the marking criteria at the end of this document for details
about the marks for coding style.
• Submit the required files to the Assessment System (https://apps.
ecs.vuw.ac.nz/submit/NWEN241/Programming_Assignment_
5) on or before the submission deadline.
• Late submissions (up to 48 hours from the submission deadline) will
be accepted but will be penalized. No submissions will be accepted
48 hours after the submission deadline.
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NWEN 241 2019-T1 Network Server Program Assignment 5
Program Specifications
Upon execution, the program should perform the following:
1. Load the CSV database file scifi.csv which contains the 25 greatest science fiction films of all time. You can use any data structure for
holding the records in memory. Note that scifi.csv is provided
under the files directory.
2. Perform required socket operations to create and bind a socket.
3. Listen for clients at TCP port 12345. (During testing, you may need
to use a different port number to avoid conflicts with other students
running tests in the same server.)
4. When a client successfully establishes connection, send a message
with contents HELLO.
5. Wait for a message from the client.
6. Perform the following based on the received message from the client:
(a) If the message has the contents BYE (case-insensitive), close the
connection to the client and go back to step 3.
(b) If the message has the contents GET (case-insensitive), send a
message back to the client containing the entire database. You
may format the content in any way you want, but all the fields
of every record must be printed. Go back to step 5.
(c) If the message has the contents GET (case-insensitive) followed
by a number (example: GET 12), treat the number as the row
number of the record to be fetched. That is, send a message back
to the client containing the record at the specified row number.
You may format the content in any way you want, but all the
fields of the record must be printed. If the specified row number
does not exist, send back a message containing ERROR. Go back
to step 5.
Testing
As you are using the Linux socket() and fork() system calls, you will
need to test your program in any of the computers inside CO246. Alternatively, you can perform remote testing following the procedures in https:
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NWEN 241 2019-T1 Network Server Program Assignment 5
//ecs.victoria.ac.nz/foswiki/pub/Courses/NWEN241_2019T1/
LectureSchedule/NWEN241-Week02-Lab.pdf. For remote testing you
can connect to any of the following Linux-based ECS servers:
• barretts.ecs.vuw.ac.nz
• embassy.ecs.vuw.ac.nz
• greta-pt.ecs.vuw.ac.nz
• regent.ecs.vuw.ac.nz
You do not need to write a client program to test your server program. You
can use the Linux program nc to receive and send messages to your server
program. To do this (assuming you are in CO246):
1. Open a terminal. Compile and run your program.
2. Open another terminal. Run nc localhost 12345 to establish a
connection with your server program. You may need to replace 12345
with the actual port number that you specified in your code. Once nc
is connected to the server program: whatever you type in this terminal will be sent to the server program, and whatever is sent by the
server program will shown in this terminal.
If you are performing the test remotely, you will need to open 2 ssh/putty
connections to the same server machine. In one ssh/putty terminal, you
compile and run your program. In the other ssh/putty terminal, you run
nc localhost 12345 to establish a connection with your server program. You may need to replace 12345 with the actual port number that
you specified in your code.
Task 1.
Basics [40 Marks]
Design the header file(s) to be used by your program. You can use any
name for your header file(s), but their extension must either be .h (for pure
C) or .hh for (C++).
Task 2.
Completion [30 Marks]
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NWEN 241 2019-T1 Network Server Program Assignment 5
Provide an implementation (C/C++ source files) of the server program as
specified in the Program Specifications above. You can use any name for
your source file(s), but their extension must either be .c (for pure C) or .cc
for (C++).
Task 3.
Completion [10 Marks]
Provide a Makefile to automatically build your program. The Makefile
should have at least 2 rules:
1. dbserver: This rule should compile the server program that you
have implemented in Task 2.
2. clean: This rule should delete any compiled file (object and executable files).
Important: If you opt not to perform this task, you must provide instructions on how to compile your code. Write these instructions in a text file
named README.
Task 4.
Challenge [20 Marks]
One of the drawbacks of the server program specified in the Program Specifications above is that when a client is connected with the server, no other
client can connect to the server.
Provide an enhancement of the server program by using the fork() system call as follows: At step 4, when a client successfully establishes connection, fork a child process. Upon successful fork, the parent process should
go back to step 3. Whereas, the child process should perform the following:
1. Send a message to the client with contents HELLO.
2. Wait for a message from the client.
3. Perform the following based on the received message from the client:
(a) If the message has the contents BYE (case-insensitive), close the
connection to the client and exit the process.
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NWEN 241 2019-T1 Network Server Program Assignment 5
(b) If the message has the contents GET (case-insensitive), send a
message back to the client containing the entire database. You
may format the content in any way you want, but all the fields
of every record must be printed. Go back to Step 2.
(c) If the message has the contents GET (case-insensitive) followed
by a number (example: GET 12), treat the number as the row
number of the record to be fetched. That is, send a message back
to the client containing the record at the specified row number.
You may format the content in any way you want, but all the
fields of the record must be printed. If the specified row number
does not exist, send back a message containing ERROR. Go back
to Step 2.
If the fork is not successful, the process should perform steps 4 and 5 (in
the original Program Specifications).
Important: Provide instructions on how to compile your code for this task.
Write these instructions in a text file named README. Alternatively, you can
create a rule in the Makefile in Task 3.
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NWEN 241 2019-T1 Network Server Program Assignment 5
Marking Criteria for Task 1:
Criteria Weight Expectations for Full Marks
Commenting 10% Source code contains sufficient and appropriate
comments
Coding Style 10% Source code is formatted, readable and uses a
coding style consistently
Correctness 80% Uses syntax in the declarations and/or definitions
100%
Marking Criteria for Tasks 2 and 4:
Criteria Weight Expectations for Full Marks
“Compilability” 10% Source code compiles without warnings
Commenting 10% Source code contains sufficient and appropriate
comments
Coding Style 10% Source code is formatted, readable and uses a
coding style consistently
Correctness 70% Implements all specifications correctly and
handles all possible cases correctly
100%
Marking Criteria for Task 3:
Criteria Weight Expectations for Full Marks
Correctness 70% Rules result in correct behaviour
Completeness 30% All dependencies are included in the rules
100%
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