111 lines
4.9 KiB
Markdown
111 lines
4.9 KiB
Markdown
# Hermes
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### Statement
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Hermes is a multi-client chat program akin to IRC written in Racket. Building
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Hermes was interesting as it exposed us to various design problems namely networking,
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synchronization, scheduling, GUI design, and component design.
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### Analysis
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> Will you use data abstraction? How?
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TCP communication has been abstracted away, so that we deal with Hermes
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definition of a message.
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> Will you use recursion? How?
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The server continually loops waiting for connections from clients. The clients
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are always on standby to receive input.
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The GUI continually loops to handle input from the user,
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as well as to keep the canvas it writes the messages on updated.
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> Will you use map/filter/reduce? How?
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Map was used for dealing with input area of clients, and iterating over a list
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of open ports to send messages. Filter was used to find the recipient of
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a whisper.
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> Will you use object-orientation? How?
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Keeping count of the number of clients required working with objects that are able to
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increment and decrement the number of users. We handled a list of connection
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ports, messages similarly.
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We also keep the GUI in an object so the many moving parts of the
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user interface are packaged in one place.
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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. Functional approaches are exemplied in most of the code base.
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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 was used e.g. keeping count of logged in users requires
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state modification via set! to maintain the true user account, managing the list
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of open connections and messages required state-modification.
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The user interface also needs a few states that it needs to keep up to date.
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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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We allowed the use of a few commands through the user interface. The most notable ones
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are the /whisper to send private messages to a user, /list count and /list users
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to view user statistics , and the /color command to allow
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the user to change the color of their text.
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### Deliverable and Demonstration
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There are two big deliverables for this project. Code for the server
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, and the clients which not only has code for interacting with Hermes,
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but also a GUI for interactivity with a user.
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We are going to demonstrate Hermes by running the server code on a remote machine.
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We will connect to the server via our PCs running client code. We will ssh into
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the remote machine to see the server running. Since Hermes is a multichat anyone
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can join in the demonstration by connecting their computers to the remote
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machine!
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### Evaluation of Results
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Evaluating Hermes was 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
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intuitive for current irc users? We successfully met these questions, and more.
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## Architecture Diagram
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#### Completed design
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## Schedule
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The first step in our project was to setup a system to get data from one machine to another. What data exactly wasn't directly important and the other machine didn't really need to display it in a pretty manner, it just needed to relay that it has recieved the correct information.
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Next we needed to create a user interface that looked nice. Some way to control the connection and display information in a convient and readable format.
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After we finished the user interface and connecting the machines, we needed 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)
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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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I have written the code for the GUI.
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It presents the user with a simple readable format for displaying the information
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that the server provides. For the most part the program only interacts with the user
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through the GUI.
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### Ibrahim Mkusa @iskm
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I wrote the networking code i.e. code that allows communication between
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clients through server. I wrote scheduling code responsible for queueing
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fairly the client messages and broadcasting to the rest of connected
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clients. I also implemented the logic for handling /list, /whisper commands.
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