Programming computer science project

Programming computer science project

just follow the instructions of the description.

CSCI 204 Introduction to Computer Science II

Fall 2018 1 Project 1

CSCI       204         – Introduction   to            Computer           Science II

Project 1 – E-Commerce Inventory

Assigned: Monday, 09/03/2018

First phase due: 09/14/2018

Second phase due: 09/21/2018

1 Academic         Integrity

The project falls under the Homework and Projects in the course collaboration policy. Make sure you

follow these policies.

2 Objective

The main objective of this project is to master the design and implementation of objects and classes with

inheritance.

3 Problem Statement

You are just hired by Samszone, a start-up e-commerce company to help them implement their on-line

inventory system. The company plans to sell various items over the web. The types of goods the company

is planning to sell can be divided into books, CDs and vinyls, collectables, and eBay items. Each type of

the items contains different types of sales information, e.g., a book would have a title and author(s),

among other information while a fashion item would have a product name and the manufacturer. The

information about these items are stored in a collection of CSV files (Common-Separated Values).

Your tasks are to first design a Python class hierarchy that properly reflects the nature of these items, then

you are to write Python programs that can manage these items over the web that allows a user to search

for a particular item, to query other information such as total value of the inventory, or to print the

information of a collection of item based on their class, e.g., all books or all collectables.

4 Your   Tasks

You are given a set of CSV files that contain information for all items for sale. You are also given a

collection of test programs to run in Linux command line, or to run within IDLE. You will design and

implement the programs such that these test programs will run properly. This will be your first phase of

the project. Once these test programs run properly, which means your class implementation is most likely

correct, you will extend your programs to run over the web. This will be your second phase of the

project. You are also given a set of sample web server-client program to demonstrate how a set of Python

programs can interact over the web.

4.1 Phase             One:      Design  and        Implement         the         Inventory            Class

You are given a set of test programs and data files. You can copy the files from this link, or from the

following Linux directory using the command, assuming you are in your working project directory

CSCI 204 Introduction to Computer Science II

Fall 2018 2 Project 1

cp –r ~csci204/2018-fall/student/project/p1/ .

If you are not in the proper working directory yet, please make and change into the directory by the

following commands before issuing the copy command above.

cd ~/csci204

mkdir p1

cd p1

You should see a set of files copied to your directory. Let’s concentrate on the CSV files first.

The following set of CSV files are given, followed by a brief description. Note that we have a total of four

general classes of items in the database, Books, CD/Vinyl, Collectibles, and eBay items. The eBay items

are divided into three sub-classes, Electronics, Fashion, and Home/Garden items.

File name Content

book.csv A collection of 10 books with title, publishing date, publisher, author, unit price,

ISBN, and quantity or count in the database.

cd_vinyl.csv A collection of 10 CDs or vinyls with title, artist(s), label, ASIN, date, unit price, and

quantity.

collectible.csv A list of seven collectibles with title, unit price, data, owner, and quantity.

electronics.csv A collection of nine items with name, unit price, data, manufacturer, and quantity.

fashion.csv Same type of information as in the ‘electronics.csv.’

home_garden.csv Same type of information as in the ‘electronics.csv.’

Table 1: Description of the CSV files

These are the data files you will work with. Note that the amount of data is very small. But your programs

should work correctly with data of any size, the logic is the same.

You should also see a few Python programs. You will need the programs simple_web_server.py and

test_inventory_web.py in the second phase of the project. Examine the program

test_inventory.py first. From the test_inventory.py program you can tell that your Inventory

class need to have the following public interface that is the methods that a public program can use.

Method name Description

__init__() Constructor

check_type() Return the type of object, using isinstance()

compute_inventory() Compute the total value of the inventory

print_inventory() Print the information of the inventory

print_category() Print information by categories of the items

search_item() Search items whose name contain the given pattern

Table 2: Methods of the Inventory class that are accessible by the public

The text file output.txt is the direct result of executing test_inventory.py. Your programs, when

completed, should generate a similar, if not identical result.

Design your Inventory class, Item class, and subclasses of the Item class

CSCI 204 Introduction to Computer Science II

Fall 2018 3 Project 1

Now that you have a sense how a user may use the class through programs such as

test_inventory.py, you are asked to design and implement the Inventory class. While object-oriented

programs and design are not the concentration of this course (you will see it in CSCI 205), you are asked

to follow some basic approaches.

First, draw a diagram of class indicating the relations among the classes and subclasses. Remember the

key feature in this design is to minimize the redundancy and to facilitate the future expansion of the class.

Follow the pattern you learned in your lab work. Draw the diagram either using a graphics tool such as

xfig on Linux or Paint on Windows. Figure 1 is the Counter class hierarchy we saw in our lab.

Figure 1: The Counter class hierarchy used in the lab

While the Inventory itself might not need any subclasses, consider the items that are in an inventory. Read

the CSV files and their descriptions in Table 1. Identify what are the common features in these items that

should be included in a base class. Specific features in items such as Book, Collectible and others indicate

that they may belong to a subclass of the Item class.

Implement your classes

Once the classes are designed, implement them in Python. You are asked to implement the Inventory

class, an Item class, and all subclasses of the Item class. Put all the implementation in one file. Name the

file inventory.py to make our testing and grading easier.

You may have the certain degrees of freedom how to design and implement these classes. You do have to

pay attention to the following notes.

1 All inventory items should be maintained as one Python list within the Inventory class.

2 While you can read any CSV files and parse them into Python lists using Python file structure we

learned before, it may be easier to use the existing Python package named csv (yes, the exact

same name as the type of the CSV files.) In the files you copied for this project, you should see

one named csv2list.py which reads a CSV file and converts the contents into a list of lists.

Use the component in this example, you can write a method for your Inventory class to read all

the CSV data files.

3 Python has a function named isinstance() that returns True if a variable belongs to a given

class. You should use this function to implement your check_type() method.

CSCI 204 Introduction to Computer Science II

Fall 2018 4 Project 1

4 When implementing class methods, make sure they are cohesive and loosely-coupled. Cohesive

means only relevant and closely related actions should be put in one method; loosely-coupled

means reduce or eliminate inter-dependency between methods. Don’t make any methods too

long. If an action needs many steps to complete, consider splitting it into multiple methods.

Test your implementations

Test your implementations often. You should test at each step after completing a method or an object.

You can comment out sections of code in test_inventory.py to test one component at a time. For

example, comment everything out except the constructor part

invent = Inventory()

that allows you to test if you constructor works. Of course, when completed, you must run the

original given test program test_inventory.py to show that everything works fine.

4.2Phase              Two:      Make    Your       Inventory            Accessible           through                the         Web

Now that your program works fine at the command line, or through the IDLE, you are to make the

inventory accessible through the web like any real e-Commerce website! Through a web interface

that you will implement, a user is able to issue all the commands that you implemented in Phase One

of the project. For example, one can query the total value of the inventory, search the names of the

items by name, or print a category of items. Figures 2, 3 and 4 show some sample screen shots that

illustrate the idea.

Figure 2: Home page of Samszone website with the list option shown

CSCI 204 Introduction to Computer Science II

Fall 2018 5 Project 1

Figure 3: Search result for key phrase “garm” in names

Figure 4: Partial result of listing operation

How to tackle the problem

Python provides easy-to-use, yet very powerful libraries for programming over the web. The basic

idea is that a server program runs on the background (from command line or IDLE) that supports the

logic of the program. The server program takes input from any web browser, processes the request,

produces the results, formats the results as a web page, then sends page back to the web browser for

display. While the details of web programming is not necessary the focus of this project, we provide

you with a sample Python server program. From the examples, you can easily figure out what takes

place in web programming and you can implement your own logic for your task of creating a website

for Samszone.

CSCI 204 Introduction to Computer Science II

Fall 2018 6 Project 1

Try out the given server program

Among the files you copied for this project, you should see a Python web server program named

simple_web_server.py. In addition, you should have two HTML files, home.html and

form.html. Now at the Linux command line, or in your IDLE, run the program

simple_web_server.py. You should see something similar to the following on your terminal

window or your IDLE window.

[bash abc@host]$ ./simple_web_server.py

Sun Aug 13 10:23:55 2017 Server Starts – :8080

Starting httpd…

Figure 5: Start the simple web server from Linux command line

Now go to your favorite browser, and visit the page using the URL http://localhost:8080, you should

see a web page similar to the following shown in Figure 6.

Figure 7: Home page with inputs already typed in

What happened was that the simple web server is running on the computer named localhost at the

port 8080. The browser, e.g., Google Chrome or Mozilla Firefox, contacts the server through the

HTTP protocol that both understand. The figure shows the screen shot that the user (you) has typed

the some inputs, but not yet click the submit button yet. Once the Submit button is clicked, the

information that was typed is sent to the server that is running on the Linux command line. After

receiving this collection of information, the server can parse and process the information, then sends

any responses back to the browser. Figure 8 shows the responses that the simple_web_server.py

sends back, it simply echo what the user typed in.

CSCI 204 Introduction to Computer Science II

Fall 2018 7 Project 1

Figure 8: The response page generated by the server

One can see from the figure that the information typed in by the user such as “one liner” or the

click box or the pulldown menu are sent back by the server and displayed in the web page.

Study how the interaction was generated

Run the program multiple times with different inputs so you have a sense what happens. Now let’s

study the logic behind the program simple_web_server.py. Starting from the bottom of the file,

you will see that the program starts by the line run(port=HOSTPORT) which calls the function

run(). Basically the server starts running and waits for input from a client which can be any program

that sends requests to this server. In our case, the client will be any web browser. You can then start a

web browser, and point the URL to be something like http://localhost:8080, see Figure 7. Once you

type the information similar to that in Figure 7 and click the Submit button, the browser sends all the

information you typed to the server through the internet. The server program

(simple_web_server.py) handles the request from the client, in our case, the browser using the

following default functions.

Function do_GET()

The function do_GET() is automatically called when the user hits the Return key with the URL

http://localhost:8080 in the browser. Read the code in the function, what the server does is to send

back a home page to the browser for it to display. The home page is a text in HTML format. The

content of the home page is stored in two text files, home.html and form.html. The functions

generate_home_page() and generate_form() read these two files and store the contents in two

variables home_page and form_text for other functions to use. Note that the content of the

form_text, when displayed on a browser gives the user a form to fill out. Among other information,

the form contains a Submit button specified by the <input type=”submit” /> HTML phrase.

When the user click this submit button, the content of the form is sent from the browser to the server.

The server will process the information using its do_POST() function.

Function do_POST()

The function do_POST() is called when the information sent from the browser contains an HTML

phrase <form name=”main” method=”post”>. What the function does is to extract the

CSCI 204 Introduction to Computer Science II

Fall 2018 8 Project 1

information from the form data, process it, and send the result back to the browser. Read the code

do_POST() you will find that after reading the content of the form, the function calls another

function convert_code() to convert HTML data into plain text. When the information is sent from

a browser to a web server, some special texts are coded as hexadecimal or other special character to

avoid confusion. For example, the space character ‘ ‘ is coded as a ‘+’, and the character ‘+’ itself is

coded as hex 2B proceeded by a ‘%’, that is the HTML code ‘%2B’ represents the plus sign ‘+’. See

the website at http://www.ascii.cl/htmlcodes.htm for a complete list. In the

simple_web_server.py program, the function do_POST() simply returns the content of the form

after being parsed out to the browser.

Your tasks

Your work will modify the functions do_GET() and do_POST() to make them behave as you

needed for the Samszone website. In the given do_POST() function, we simply return the parsed data

to the browser. What you need to do is to parse out the data, find out what the user wants to do, for

example, list the inventory, or compute the inventory value, perform these computation, format the

result, and send them back to the browser. We have given you the ways to parse out the data and

determine what the user wants. You have written the code to perform the actual tasks in your Phase

One code. What you need to do now is to format the data and send back to the browser.

An easier way of accomplishing these tasks is to make a copy of your Phase One code. Revise the

code such that instead of printing the results to the screen as Phase One required, you now revise the

code such that the contents will be formatted as an HTML string and returned to the caller. For

example, in your Phase One code, you may have a function called ‘print_inventory()’ that

prints the inventory to the screen. You now need to revise this function such that it will return the

string formatted as HTML text. Your do_POST() function then can return this formatted text directly

to the browser.

If you are not familiar with HTML code, you can consult any of the information on the web, for

example, https://www.w3schools.com/ but in this part of the project, the one you will use most is

probably HTML list, which can be found here in this website:

https://www.w3schools.com/html/html_lists.asp

5 Submission for the Two Phases

Make sure you test all your programs before submission. You are required to submit two phases

separately by the respective deadlines. All submissions are to the course Moodle site. You must

submit all the relevant files in a zipped file such that your programs will run in their own folder.

Create the zipped file using the following command at your Linux command line, assuming you have

followed instructions in the project description in creating the project folder named p1 under your

csci204 directory.

cd ~/csci204/

zip -r p1.zip p1/

The above commands creates a file named p1.zip in your csci204 directory. You can submit the

zip file to the course Moodle site. In Phase One submission, you must submit all files that will make

CSCI 204 Introduction to Computer Science II

Fall 2018 9 Project 1

the test program test_inventory.py run directly from its own folder. In Phase Two, you must

submit all relevant files that will make the program samszone_web_server.py correctly.

Submission of a README file

Submit a plain text file named README for each of the two phases. Name the file README.p1 for

phase one and README.p2 for phase two. The README file should contain a couple of paragraphs

describing one or two points in your program that you like most, and one or two points that you had

the most challenges. The README files should not be longer than a page.

6 Grading Rubrics

Normal requirements for programming work apply, including correctness, style, and organization.

Specifically the following grading rubrics will be used for the two phases.

Phase One rubrics [60 pts]

[10 pts] Proper design of the Inventory class and Item class along with its subclasses.

[10 pts] Reading CSV file and creating the Python list(s) according.

[25 pts] Correct implementation of the designed classes, including constructors, string methods, and

all methods needed to make the programs work.

[10 pts] Using good programming style, including naming, spacing, and others.

[5 pts] Overall program quality, including any features that stand out.

Phase Two rubrics [40 pts]

[20 pts] Implementing the server properly, including handling of forms.

[8 pts] Converting results from plain text to HTML for the server to use.

[8 pts] Using good programming style, including naming, spacing, and others.

[4 pts] Overall program quality, including any features that stand out.