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# Hermes
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### Statement
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Hermes is a multi-client chat program akin to IRC written in Racket. Building
Hermes is interesting as it exposes us to various design problems namely networking,
synchronization, scheduling, and GUI design.
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### Analysis
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> Will you use data abstraction? How?
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TCP communication will be abstracted away, so that we deal with Hermes
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definition of a message.
We will try to encrypt the messages passed around. The encryption will be
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abstracted away, so we only have to think about it once during implementation.
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> Will you use recursion? How?
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The server will continually loop waiting for connections from clients.
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The GUI will continually loop to handle input from the user, and to and fro
the server.
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> Will you use map/filter/reduce? How?
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Map will be used for dealing with input area of clients, and iterating over a list
of open ports to send messages.
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> Will you use object-orientation? How?
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Keeping count of the number of clients will require an object of some sort.
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With procedures to increment and decrement the number of users.
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> Will you use functional approaches to processing your data? How?
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The communication part of Hermes is over tcp which uses a lot of functional
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approaches e.g. you start a listener which you can call tcp-accept on.
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The result of tcp accept are two pairs of ports which we can then bind to some
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variables.
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> Will you use state-modification approaches? How? (If so, this should be encapsulated within objects. `set!` pretty much should only exist inside an object.)
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State-modification will be used e.g. keeping count of logged in users requires
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state modification via set! to maintain the true user account.
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> Will you build an expression evaluator, like we did in the symbolic differentatior and the metacircular evaluator?
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Users will type their input into a text field from the GUI. We will retrieve
the command and evaluate it to see if its a message, or a command to change
GUI state. We will do something that resembles the metacircular evaluator.
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### Deliverable and Demonstration
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There are two big deliverables for this project. Code for the server
, and the clients which not only has code for interacting with Hermes,
but also a GUI for interactivity with a user.
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We plan to demonstrate Hermes by running the server code on a remote machine.
We will connect to the server via our PCs running client code. We will ssh into
the remote machine to see the server running. Since Hermes is a multichat anyone
can join in the demonstration by connecting their computers to the remote
machine!
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### Evaluation of Results
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Evaluating Hermes is very simple. Can at least two clients hold a meaningful
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conversation remotely? If Client A speaks at 11:01 am, and client B does so at
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11:01 plus a few seconds, Hermes has to convey this state correctly. Is the GUI
intuitive for current irc users? When we can successfully answer this questions
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satisfactorily we would have met our goals.
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## Architecture Diagram
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#### Preliminary design
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![Architecture ](https://github.com/oplS17projects/Hermes/blob/master/ext/arch_diagram.png )
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#### The Game plan
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![Diagram ](https://github.com/oplS17projects/Hermes/blob/master/ext/architecture_diagram.png )
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## Schedule
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The first step in our project will be to setup a system to get data from one machine to another. What data exactly isn't directly important and the other machine doesn't really need to display it in a pretty manner, it just needs to relay that it has recieved the correct information.
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Next we need to create a user interface that looks nice. Some way to control the connection and display information in a convient and readable format.
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After we have finished the user interface and connecting the machines, we will need to merge them together and begin expanding the utility if time permits.
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### First Milestone (Sun Apr 9)
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Get two different machines to relay information meaningfully.
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### Second Milestone (Sun Apr 16)
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Get a GUI that looks professional and uses the correct format.
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### Public Presentation (Mon Apr 24, Wed Apr 26, or Fri Apr 28 [your date to be determined later])
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Merging the GUI and information relay together into one program. If time permits we also plan on adding additional features.
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## Group Responsibilities
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### Douglas Richardson @Doug-Richardson
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Will write the GUI code. This should allow the user to access different
aspects of our program in a clean easy to use interface. Most of
how the program responds to user input will be filtered through the gui.
If time permits I will also be writing code to encrypt and decrypt the information
going from the server to the clients.
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### Ibrahim Mkusa @iskm
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Will write the networking code i.e. code that allows communication between
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clients through server. I will also write scheduling code responsible for queueing
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fairly and orderly the client messages and broadcasting to the rest of connected
clients. If time permits, i will also be responsible for authenticating users
via a backend database.