MCS-177 Project 10: Facebook

Start: Monday 12/09; Due: Friday 12/13, by the beginning of class

Overview

In this project, you will continue to experiment with building your own Python classes. Many of you log into Facebook and interact with your friends. You will build classes to represent a text-version of Facebook.

This project is out of 20 points and offers up to 7 extra credit points once the project is complete. You can skip anything shown in blue and come back to finish it later for more credits.

We stongly encourage you to work on this project with a partner.

Example

>>> TextFacebook = Facebook()
>>> TextFacebook.registerUser('Bob', 'bob@gmail.com')
>>> TextFacebook.registerUser('Alice', 'alice@gac.edu')
>>> TextFacebook.registerUser('Charles', 'charlie@hotmail.com')
>>> TextFacebook.login('Bob')
>>> TextFacebook.addFriend('Alice')
>>> TextFacebook.postStatus('is working on Project 10!')
>>> TextFacebook.viewStatus()
(0) Bob is working on Project 10!
>>> TextFacebook.logout()
>>> TextFacebook.login('Charles')
>>> TextFacebook.addFriend('Alice')
>>> TextFacebook.postStatus('is going to watch Star Trek Into Darkness.')
>>> TextFacebook.viewStatus()
(1) Charles is going to watch Star Trek Into Darkness.
>>> TextFacebook.logout()
>>> TextFacebook.login('Alice')
>>> TextFacebook.viewProfile()
Alice (alice@gac.edu)
Friends: Bob and Charles
>>> TextFacebook.viewStatus()
(0) Bob is working on Project 10!
(1) Charles is going to watch Star Trek Into Darkness.
>>> TextFacebook.likeStatus(1)
>>> TextFacebook.viewStatus()
(0) Bob is working on Project 10!
(1) Charles is going to watch Star Trek Into Darkness.
Alice likes this.
>>> TextFacebook.commentOnStatus(0, 'Poor you... Have a cookie!')
>>> TextFacebook.viewStatus()
(0) Bob is working on Project 10!
Alice: Poor you... Have a cookie!
(1) Charles is going to watch Star Trek Into Darkness.
Alice likes this.
>>> TextFacebook.logout()
>>> TextFacebook.login('Bob')
>>> TextFacebook.viewStatus()
(0) Bob is working on Project 10!
Alice: Poor you... Have a cookie!
>>> TextFacebook.commentOnStatus(0, "It's all right. The project is a lot of fun!")
>>> TextFacebook.postStatus("finished working on Project 10! Woohoo!")
>>> TextFacebook.logout()
>>> TextFacebook.login('Alice')
>>> TextFacebook.viewStatus()
(0) Bob is working on Project 10
Alice: Poor you... Have a cookie!
Bob: It's all right. The project is a lot of fun!
(1) Charles is going to watch Star Trek Into Darkness.
Alice likes this.
(2) Bob finished working on Project 10! Woohoo!

Specific tasks

1. Implement the Comment class in comment.py such that:
   • Each comment consists of the name of the commentor and the content.
   • The Comment class provides accessor and mutator methods for all instance variables.
   • Make sure to check for valid inputs for mutator methods. For example, a string with only whitespaces should not be allowed for instance variables that store strings. When given invalid inputs, mutator methods must print an error messsage and not modify the corresponding instance variable.

   • The __str__ method of the Comment class returns a string that shows the name and the content separated by a colon. For example, Inigo Montoya's comment "I do not think it means what you think it means." should return a string shown below.

     'Inigo Montoya: I do not think it means what you think it means.'
     

2. Implement the Status class in status.py such that:
   • Each status consists of the name of the person who posted the status, the status message, names of those who liked the status, and comment objects associated with the status.
   • The Status class provides accessor and mutator methods for all instance variables.
   • Make sure to check for valid inputs for mutator methods. For example, a string with only whitespaces should not be allowed for instance variables that store strings. When given invalid inputs, mutator methods must print an error messsage and not modify the corresponding instance variable.

   • The Status class provides the following methods:
     • A method addLike which takes a name and adds the name to those who like the status.
     • A method addComment which takes a Comment object and adds the given comment.

   • The __str__ method of the Status class returns a string with the poster's name, the status message, the names of those who like the status and commments afterwards. The string should not have a newline character (\n) at the end. If multiple users liked the status, they should be comma separated. For example, if Alice and Bob liked the status, "Alice, Bob like this."

     The following string is returned by a Status object whose poster is Ben Franklin and status message is 'signed the declaration of independence today. Booyah, England!'. France liked this Status object, and there are four Comment objects for the status.

     'Ben Franklin signed the declaration of independence today. Booyah, England!\nFrance like this.\nJohn Adams: Bring it, bra.\nBen Franklin: You redcoats don't stand a chance.\nJohn Hancock: Does this mean we get to sign more? Cuz that was fun.\nBen Franklin: So we gathered.'
     

     The output below shows when the above string is printed.

     Ben Franklin signed the declaration of independence today. Booyah, England!
     France like this.
     John Adams: Bring it, bra.
     Ben Franklin: You redcoats don't stand a chance.
     John Hancock: Does this mean we get to sign more? Cuz that was fun.
     Ben Franklin: So we gathered.
     

     For more credit, make the line with people who like the status gramatically correct. For example, "France likes this." and "France and Bob like this." and "France, Bob and Daniel like this."

3. Implement the User class in user.py such that:
   • Each user consists of his/her name, e-mail address and list of friends (User objects). Only the name and e-mail address are required to create a User object.
   • The User class provides accessor and mutator methods for all instance variables.
   • Make sure to check for valid inputs for mutator methods. For example, a string with only whitespaces should not be allowed for instance variables that store strings. When given invalid inputs, mutator methods must print an error messsage and not modify the corresponding instance variable.

   • The User class provides the following methods:
     • A method addFriend which takes a User object and makes both users friends of each other.
     • A method isFriend which takes a User object and returns True if the given user is a friend and False otherwise.

   • The __str__ method of the User class returns a string containg the name, e-mail address and the names of all friends. For example, if you print a user whose name is Jim Halpert, whose e-mail address is jim@office.com and whose only friend is Pam Beesley, the string should look as shown below.

     'Jim Halpert (jim@office.com)\nFriends: Pam Beesley'
     

     The output below shows when the above string is printed.

     Jim Halpert (jim@office.com)
     Friends: Pam Beesley
     

     If one has no friends, the output should be as shown below.

     Chazz Michael Michaels (lonewolf@icerink)
     Friends: None
     

     If one has more than one friend, the names of all the friends should belong to the same line as shown below.

     Bob (bob@gmail.com)
     Friends: Alice, Charles, Daniel
     

     For more credit, upgrade the format of the list of friends as shown below.

     Bob (bob@gmail.com)
     Friends: Alice, Charles and Daniel
     
     Alice (alice@gmail.com)
     Friends: Bob and Charles
     

4. Implement the Facebook class in facebook.py such that:
   • Start the facebook.py file with the following import

     from comment import *
     from status import *
     from user import *
     

   • Facebook keeps track of all the users and their statuses and the currently logged-in user. Facebook object also keeps track of unique IDs for statuses. For the purpose of this project, only one user is allowed to use the Facebook at a time. When a Facebook object is created, it does not have any users or statuses.
   • Use a dict-of-string:user, where the keys are names and the values are user objects, to keep track of users in the Facebook class.
   • Use a list-of-status, where the positions in the list are status IDs and the values are status objects, to keep track of statuses in the Facebook class.
   • Use a string (the name of the current user) to keep track of who's currently using your Facebook.

   • You do NOT have to implement any accessors and mutators for the instance variables in the Facebook class.
   • You do NOT have to implement the __str__ method in the Facebook class.
   • For examples of outputs from the following methods, refer the the example at the top of this page. None of the following methods returns any value; all output is printed
   • The Facebook class provides a method called registerUser which takes a name and an e-mail address. This method adds a new user to Facebook. It should return an error if there is already a user with the same name.
   • The Facebook class provides a method called login which takes a name. This method allows a person to log into Facebook with the user associated with the given name. If another user is logged in already, it should print out an error message saying that the other user needs to log off first.
   • The Facebook class provides a method called logout. This method allows the currently logged-in user to log out from Facebook. It should print out an error message if there is no user logged in at the time.
   • The Facebook class provides a method called addFriend that takes a name. This method allows the currently logged-in user to befriend the user with the given name. This should make both users friends of each other. It should print out an error message if there is no user logged in at the time; or if there is no other user with the given name.
   • The Facebook class provides a method called viewProfile. This method allows the currently logged-in user to view his/her profile that includes his/her name and email address along with the list of his/her friends.
   • The Facebook class provides a method called postStatus. This method allows the currently logged-in user to post a new status. Facebook should add this new status. It should print out an error message if there is no user logged in at the time.
   • The Facebook class provides a method called viewStatus. This method allows the currently logged-in user to view statuses of the user and his/her friends. If there is no user logged in at the time, it should not print any statuses and print out an error message saying that a user need to be logged in. The selected statuses should be printed in order of status ID number.
   • The Facebook class provides a method called likeStatus which takes a status ID number. This method allows the currently logged-in user to like his/her status or his/her friend's status. If there is no user logged in at the time, it should print out an error message. If the status the user tries to "like" is not his/hers or his/her friend's, it should also print out an error message.
   • The Facebook class provides a method called commentOnStatus which takes a status identification number and a comment (string). This method allows the currently logged-in user to comment on his/her status or his/her friend's status. If there is no user logged in at the time, it should print out an error message. If the status the user tries to "comment" is not his/hers or his/her friend's, it should also print out an error message.

Note

• Remember not to print anything in the __str__ method. You should accumulate ONE string that contains all the information and return it.

Submitting your work

You will be submitting your code using Moodle; click on the following link for instructions on submitting code using Moodle. For this project, you will need to submit the following files:

• comment.py, which contains all implementation and documentation for the Comment class.
• status.py, which contains all implementation and documentation for the Status class.
• user.py, which contains all implementation and documentation for the User class.
• facebook.py, which contains all implementation and documentation for the Facebook class.

Grading

You will earn one point for each of the following accomplishments: (Project 10 is still out of 20 points. In other words, you may earn up to 7 points of extra credits in this project.)

1. You have all the instance variables necessary for the Comment class.
2. You have all the accessor and mutator methods for all the instance variables in the Comment class.
3. The mutator methods in the Comment class accept only valid values and prints an error message for invalid values.
4. The __str__ method in the Comment formats the code correctly.
5. You have all the instance variables necessary for the Status class.
6. You have all the accessor and mutator methods for all the instance variables in the Status class.
7. The mutator methods in the Status class accept only valid values and prints an error message for invalid values.
8. The __str__ method in the Status class formats the code correctly.
9. The addLike and addComment methods are implemented correctly.
10. You have all the instance variables necessary for the User class.
11. You have all the accessor and mutator methods for all the instance variables in the User class.
12. The mutator methods in the User class accept only valid values and prints an error message for invalid values.
13. The __str__ method in the User class formats the code correctly.
14. The addFriend method links two users as friends correctly in the User class.
15. The isFriend method checks if the given user is a friend or not correctly.
16. You have all the instance variables necessary for the Facebook class.
17. The registerUser method adds a new user to Facebook correctly.
18. The login and logout methods log in and out a user correctly and prints out an error message when appropriate.
19. The addFriend method correctly links two users as friends in the Facebook class.
20. The viewProfile method displays the information about the current user correctly.
21. The viewStatus method displays only the status of the currently logged-in user and his/her friends.
22. The viewStatus method formats the statuses correctly and prints out an error message when appropriate.
23. The postStatus method adds a new post by the user correctly. It prints out an error message when appropriate.
24. The likeStatus and commentOnStatus methods behave correctly. They print out an error message when appropriate.
25. Your code is not unnecessarily complex.
26. The __str__ method of the status class uses the grammatically correct format.
27. The __str__ method of the user class uses the grammatically correct format.