INFO1112 Computing 1B OS and Network Platforms - A1 - Just a friendly reminder
INFO1112 A1 - Just a friendly reminder
In this assignment, you'll be creating a basic application called "Jafr" (short for "Just a friendly reminder"). This application helps multiple users manage their tasks and meetings on a Unix-like OS (a popular choice of OS in industry where developers might share a computer system or host web applications).
Jafr is Unix-friendly. This means that
1. Users interact with Jafr by typing commands in a command-line interface.
2. Jafr assumes that all the tasks and meetings are stored in text files that are otherwise managed by users of the shared system. Users simply edit these files themselves when they want to make changes outside of Jafr.
You will implement Jafr in Python and write a simple start up script in Bash. You will then write I/O end to end tests for Jafr.
These specifications first describe each behaviour of Jafr. The final sections describe error handling, how to write tests for Jafr and provide some hints.
Overview
Jafr is designed to run whenever a user opens their terminal at the beginning of their day. Users can choose to view reminders that are relevant to the current day, or make changes. Changes can include sharing reminders with other users.
There are two kinds of reminders: tasks and meetings.
Setup
Jafr primarily relies on two text files for each user: tasks.md and meetings.md . These text files are placed inside a master directory of the user's choosing.
The user chooses their master directory inside a JSON file called
located at ~/.jafr/user-settings.json . You may consider
a 'hidden' directory,
for Jafr's internal use only.
user-settings.json
~/.jafr/
Hint
Notice that the hidden directory .jafr/ is inside a user's home directory which can be
symbolically referred to by ~ .
You can fetch the path referred to by ~ in Python by using os.path.expanduser('~')
user-settings.json has a single key value pair storing the absolute path to the master directory.
Sample user-settings.json :
{ }
"master": "/home/dailystuff"
Help! What's a JSON file?
JSON is a universal file format for easy data reading and writing. There are two kinds of
data structures possible to write in JSON: objects and arrays.
Curly braces are used to define an object: a collection of name/value pairs (exactly like
a dictionary in Python). Square brackets are used to define an array: an ordered list of
values (exactly like a list in Python).
You may use Python's json library in your implementation to read JSON files. See json.load()
Note
tasks.md and meetings.md for each user are given inside your scaffold. Assume the
user creates these themselves using their preferred text editor.
The ~/.jafr/ directory for each user is also given inside your scaffold. You do not
have to handle the case where ~/.jafr/user-settings.json is missing for any user.
Assume Jafr has some installation script that handles this, outside of the scope of your
assignment.
Text files containing reminders
The two text files inside the master directory for each user are as follows.
tasks.md
This text file contains dot pointed tasks with the following format. Dates follow DD/MM/YY, or more precisely the C standard format %d/%m/%y (see the datetime docs). You will only ever have to handle dates in the years 1969 - 2068 (inclusive).
- <task description> Due: <due date> <completion status> For example
- Complete INFO1112 A1 Due: 01/10/23 not complete
- Acquire Twitter Due: 30/10/23 complete
- Study linux namespaces Due: 30/09/23 not complete
Hint
Notice that a task must end with complete or not complete !
Moreover, the format implies that a task description should never contain the string
Due: . You do not have to handle the case where a user does this.
meetings.md
This text file contains dot pointed meetings with the following format. Times follow HH:mm, or more precisely the C standard format %H:%M (see the datetime docs).
- <meeting description> Scheduled: <scheduled time> <scheduled date> For example
- Michael Mai's welcome party Scheduled: 18:00 25/08/23
- A1 marking meeting Scheduled: 09:00 01/09/23
Hint
You do not have to handle the case where a user places Scheduled: inside the
meeting description.
Further, as suggested by the links above, it will be easiest to use datetime to handle
all dates/times!
Usage
Jafr runs when jafr.py is executed by the Python interpreter. There is one command line argument which will contain a path (absolute or relative) to a given passwd file. More on this below.
For example
python3 jafr.py passwd
Jafr first displays relevant reminders (tasks followed by meetings), before showing a menu.
The menu contains the following.
What would you like to do?
1. Complete tasks
2. Add a new meeting.
3. Share a task.
4. Share a meeting.
5. Change Jafr's master directory.
6. Exit
A user chooses one option only.
<menu num>
This invokes the relevant behaviour, described below. If the user enters 6 , Jafr exits. After completing a behaviour, Jafr returns to the menu.
For example
Just a friendly reminder! You have these tasks to finish today.
- Read INFO1112 A1 specs
- Fix bug 1 inside Jafr
- Study ELEC1601
These tasks need to be finished in the next three days!
- Shower by 03/08/23
- Organise paul's brithday by 03/08/23
You have the following meetings today!
- Michael Mai's welcome party at 18:00
- Resume writing workshop at 09:00
- Jafr dev meeting at 13:30
You have the following meetings scheduled over the next week!
- Barbenheimer marathon on 06/08/23 at 17:00
- Academic advice on 02/08/23 at 14:30
Displaying tasks
Jafr will write two views of tasks to standard output. The first is a view of all tasks that are due today that have not been completed. The second is a view of all tasks that are due in the upcoming three days that have not been completed.
Today's view has the following format.
For example
The upcoming three days' view has the following format.
For example
Just a friendly reminder! You have these tasks to finish today.
- <task description>
- <task description>
[...]
Just a friendly reminder! You have these tasks to finish today.
- Read INFO1112 A1 specs
- Fix bug 1 inside Jafr
- Study ELEC1601
These tasks need to be finished in the next three days!
- <task description> by <due date>
- <task description> by <due date>
[...]
These tasks need to be finished in the next three days!
- Shower by 03/08/23
- Organise paul's birthday by 04/08/23
- ELEC1601 group meeting on 03/08/23 at 11:00
What would you like to do?
1. Complete tasks
2. Add a new meeting.
3. Share a task.
4. Share a meeting.
5. Change Jafr's master directory.
6. Exit
Hint
The "upcoming" three days' view does not include the current day. Instead, "upcoming" implies the three days following the current day.
Displaying meetings
Jafr will write two views of meetings to standard output. The first is a view of all events that are scheduled today. The second is a view of all events that are scheduled in the upcoming 7 days.
Today's view has the following format.
For example
The upcoming 7 days' view has the following format.
For example
You have the following meetings today!
- <meeting description> at <scheduled time>
- <meeting description> at <scheduled time>
[...]
You have the following meetings today!
- Michael Mai's welcome party at 18:00
- Resume writing workshop at 09:00
- Jafr dev meeting at 13:30
You have the following meetings scheduled over the next week!
- <meeting description> on <scheduled date> at <scheduled time>
- <meeting description> on <scheduled date> at <scheduled time>
[...]
You have the following meetings scheduled over the next week!
- Barbenheimer marathon on 06/08/23 at 17:00
- Academic advice on 02/08/23 at 14:30
- ELEC1601 group meeting on 03/08/23 at 11:00
Note
Listed tasks are simply displayed in the order that they appear in tasks.md
Changing the user's master directory
Jafr allows the user to change their chosen master directory that contains tasks.md and meetings.md .
Which directory would you like Jafr to use?
The user enters an absolute path.
<absolute path>
Jafr should replace the master object in ~/.jafr/user-settings.json appropriately.
Jafr then writes a confirmation message to standard output.
Master directory changed to <absolute path>.
For example
Hint
See json.dump().
Which directory would you like Jafr to use?
/home/paul/atreides_work
Master directory changed to /home/paul/atreides_work.
Hint
Jafr does not move tasks.md or meetings.md when changing the master directory. You can assume the user handles this themselves. This also allows the user to have multiple directories containing reminders and have Jafr focus on one at a time.
Completing tasks
Jafr allows the user to mark tasks as completed. The user is first prompted for which task they would like to complete. All not complete tasks are shown and numbered, in the order they appear in tasks.md .
Note
Listed meetings are simply displayed in the order that they appear in meetings.md
The user then selects task(s) by their number, separated by whitespace.
<task num> [<task num> ... <task num>]
Jafr should modify tasks.md appropriately and write a message to standard output. Tasks
inside tasks.md are modified in place (in the same line). Marked as complete.
For example
Which task(s) would you like to mark as completed?
1. Shower by 26/07/23
2. Invite friend by 27/07/23
3. Read INFO1112 A1 specs by 28/07/23
13
Marked as complete.
If all tasks are already complete then Jafr just writes the following to standard output.
No tasks to complete!
Adding new meetings
Jafr allows users to add meetings. The user is first prompted for a meeting description, then a date, then a time.
Please enter a meeting description:
<meeting description>
Please enter a date:
<scheduled date>
Please enter a time:
<scheduled time>
Ok, I have added <meeting description> on <scheduled date> at <scheduled
time>.
Jafr should then modify meetings.md appropriately. A meeting is appended to the bottom of meetings.md as follows.
Which task(s) would you like to mark as completed?
1. <task description> by <due date:DD/MM/YY>
2. <task description> by <due date:DD/MM/YY>
[...]
##### added by you
- <meeting>
Would you like to share this meeting? [y/n]:
Who would you like to share with?
<user ID> <user name>
<user ID> <user name>
[...]
tasks.md meetings.md
Which task would you like to share?
1. <task description> by <due date>
2. <task description> by <due date>
[...]
<meeting description> on
<scheduled date> at <scheduled time>
<num>
Who would you like to share with?
<user ID> <user name>
<user ID> <user name>
[...]
<user ID> [<user ID> ... <user ID>]
tasks.md
meetings.md
The user is also prompted to optionally enter people to share the meeting with.
See more about sharing below.
Sharing tasks and meetings
Jafr allows users to share tasks or meetings from their own and files with other users.
The user is first prompted for which task (or meeting) they would like to share. They are shown all tasks (or meetings) regardless of completion or scheduled date.
The analogous meetings option contains numbered lines with .
The user then selects one task (or meeting) by its number in the shown list.
The user is then prompted for the user IDs with whom they would like to share their selection. They should not be shown their own user ID here.
The user then selects users by their user ID, separated by whitespace.
Jafr should then append the selected task or meeting to the other user's or appropriately, as follows.
A confirmation message is finally written to standard output ( or ).
For example
##### shared by <user name> - <task>
Hint
The above heading ##### shared by <user name> is always created, regardless of
previous sharing history! You may assume the user will clean up their text file in their
own time, after noticing added meetings.
This applies to Adding new meetings in your own meetings.md as above too.
Meeting
Task shared.
shared.
Which task would you like to share?
1. Fix bug 1 in Jafr by 08/08/23
2. Apply for research grant by 10/08/23
3. Shower by 03/08/23
1
Who would you like to share with?
0001 michaelmai
0002 hazemelalfy
0003 paulatreides
0004 prathampurohit
0001 0004
Task shared.
Note
Other users' and will be inside their own master directory, as
listed in their
.
tasks.md
meetings.md
~/.jafr/user-settings.json
user-settings.json
user-settings.json
passwd
How does Jafr find other users' home directories?
As you may have realised, in order for Jafr to append tasks/meetings to other users' .md files, it must be able to locate the of each user. However the location of depends on the current user's home directory! How will the application find other users' home directories?
All users' home directories will be contained inside a given file.
file
You will be given a passwd file (it is already present in your scaffold). This is a text file where each line denotes a different user on the shared computer system. Each line contains a user's username, hashed password, user ID, group ID, user ID info, home directory, and default shell.
Example passwd file:
<username>:<password>:<user ID>:<group ID>:<user ID info>:<home
directory>:<default shell>
michaelmai:x:0001:8888:staff user:/michael:/bin/bash
hazemelalfy:x:0002:8888:staff user:/hazem:/bin/bash
paulatreides:x:0003:1112:student user:/paul:/bin/bash
prathampurohit:x:0004:8888:staff user:/pratham:/bin/bash
Help! What's a passwd file?
passwd files are universal in Unix-like systems. They always contain the above information. This is how the OS remembers information about each user! However, usually the file is stored at /etc/passwd . Take a look at /etc/passwd on your own system!
You may notice that there is some unnecessary information in the passwd file. Jafr only requires the username, user ID and home directory.
Hint
You can find the current user's username using the environ object from the os
module. https://docs.python.org/3/library/os.html#os.environ
This a dictionary containing environment variables, exposed by the os module. You
can access the username as follows.
os.environ['USER']
Please use this method. Others have been found to not work correctly on Edstem.
Running Jafr when Bash is started
Jafr is designed to be run whenever a terminal running Bash is started. This section explains how this can be achieved.
passwd
Most Unix-like operating systems shipped with Bash allow users to customise a Bash script that is run whenever Bash is started. This script is called .bashrc and is stored inside the user's home directory (i.e. at ~/.bashrc ).
Once you have read the Usage section, have a go at modifying ~/.bashrc on your system so that it runs Jafr when bash is started. Your submission must include a .bashrc file that is able to do this.
You can check for the expected behaviour as follows. 1. Ensure your terminal runs bash.
2. Open a terminal window. On some systems you may need to run bash yourself (see Update below).
3. See if Jafr displays its views correctly.
Update
Some systems (which include Edstem's Arch and macOS) may not run .bashrc in
login shells. These are shells that are started upon logging in.
However, on any system you may start Bash again by simply executing bash . This will
be a "non-login" shell and will always run .bashrc .
You may provide comments inside a readme.md to your marker about any expectations you have for this to work correctly.
Hint
In order to be awarded this section of the assignment, you may assume jafr.py and passwd exists inside every user's home directory.
Remember .bashrc is a universal script. This means you can find plenty of help by looking this up online.
Error handling Setup
You do not have to handle a missing ~/.jafr directory or ~/.jafr/user-settings.json file for any user.
If either tasks.md or meetings.md are missing from the user's chosen master directory then Jafr does not display any reminders or show the menu. Jafr writes the following message to standard error before simply exiting.
If the user's chosen master directory does not exist, then Jafr does not display any reminders or show the menu. Jafr writes the following message to standard error before exiting.
Jafr's chosen master directory does not exist.
Text files
tasks.md and meetings.md can contain any amount of text, and not necessarily only tasks/meetings. A line is only considered a task or meeting if it is a dot point (the line starts with - ).
For example, suppose tasks.md contains
Note
Any amount of indentation is allowed before a dot point!
### School tasks
- Go to school Due: 01/08/23 not complete
- English homework Due: 02/08/23 not complete
- English homework introduction Due: 01/08/23 not complete
### Chores
- Take out trash Due: 01/08/23 not complete
##### shared by hazemelalfy
- Study linux namespaces Due: 04/08/23 not complete
Then there are five tasks recognisable by Jafr.
Help! Why do I have to parse these files for dot points?
Jafr is designed to rely on text files that are otherwise freely editable by users. Different
users may have different methods of organising their tasks or meetings. Think of Jafr
as a parser that adapts to each user's context.
The re module may be helpful here.
Missing tasks.md or meetings.md file.
Displaying tasks and meetings
Any malformed tasks or meetings are skipped when displaying them. No error message is given.
Menu
If the user enters an invalid <menu num> , then Jafr prompts them with a single-line explanation written to standard output, before allowing input again.
Completing tasks and adding new meetings
Any malformed tasks or meetings are skipped when displaying them. No error message is given.
If the user enters an invalid option at any point, Jafr prompts them with a single-line explanation written to standard output, before allowing input again.
Specifically, if the user enters an invalid;
<task num>
<meeting description>
<scheduled date>
<scheduled time> ,
then they are prompted with a single-line explanation.
