Lab 4: Grade API program

Please try to work through Tasks 0 and 1 ahead of your lab time on Monday. Your team and TA can help you during the lab if you had any trouble, so don't worry if you don't get through Task 1 before lab. There will also be some time to do this as your TA helps everyone get into teams.

Task 0: Fork and clone this repo

1. As with the previous lab activities, start by making a fork of this repo and cloning it.

Task 1: Your API Token (token)

In order to use the Grade API, you will need to sign up a new username, and obtain an API token. To sign up a username, we are going to make a simple request to the Grade API.

1. Go to https://hoppscotch.io. This is a tool like Postman, which can be used to quickly interact with APIs.
2. Beside the word GET, replace https://echo.hoppscotch.io/ with http://vm003.teach.cs.toronto.edu:20112/signUp.

Next, we need to specify the username which we want to use. To do this, we add a parameter.

3. In the Parameters tab, choose + Add new and set the parameter name to username.
4. For its value, choose whatever username you want to use. Make note of the name you choose, as you'll use it during the lab. (Don't worry, you can repeat this process with a new username if you need to later!)
5. Press the Send button to make the request. You may receive an error that the request didn't go through. Scroll down and select proxy as the middleware and press Send again. You should now see the result of the request.
6. If the username had been used before, you will see a response indicating that. Choose a new username and send the request again.
7. If the request is successfully sent, you will see a response that contains a status_code of value 200. In this response, you will get two important fields: token and environment_variables, whose values you will need later on in the activity.

You can also refer to the Grade API Postman Workspace for the documentation of all API requests related to the Grade API. Specifically, to learn more about the SignUp API request, refer to this section of the workspace.

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Alternative to the above: Enter http://vm003.teach.cs.toronto.edu:20112/signUp?username=USERNAME in any web browser with USERNAME replaced with the username you want to use. Note, we are introducing you to tools like hoppscotch.io and postman above, since we'll later see API requests which can't be made through your web browser.

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7. Create a new file called token.txt in the root directory of your project and copy / paste the value you found for the token field in that file. This file is indicated in the .gitignore for your project, so its name will appear yellow in IntelliJ to indicate that git will ignore the file (it won't be version controlled). This can be useful to ensure that you don't accidentally share private information (like personal API tokens) or configurations specific to your local environment when working on a team project.

Now that you have your API token, the last step is to get your program to use it. To do so, we are going to set an environment variable in the run configuration.

Note: at this point you should be able to run the program, but it is possible that the Maven project didn't automatically build. If you have errors which won't let you run the code in the next step, you may need to reload the Maven project. You can do this by right-clicking on the pom.xml file in your project. In the context menu, choose Maven -> reload project. This should resolve any errors. You may also need to go to Project Structure... and select your project JDK.

Important: make sure not to commit any changes to the .idea/misc.xml file, as it will store which specific JDK you are using, which likely isn't the same as the rest of your team when you collaborate on the coding task later in this lab.

8. Try running the main application (src/main/java/app/gui/Application). When you start the program, you will see that it says your token is null (since we didn't set it yet). Stop the program and go to Run -> Edit Configurations....

9. Open the Run Configuration for Application and find the Environment Variables: field.

   • Note: If you don't see this Run Configuration listed:
     • create a new Run Configuration of type Application (use the + in the top left corner of the window).
     • where it says "Main class", type app.gui.Application.

10. In that field, paste the text you copied from environment_variables when you sign up an account. Your token should also be in token.txt. Example: token=6SgDAt8XpnQYTDPt4vHcPCCKJ2ppLg1C.

11. Click Apply and then OK.

12. Now, rerun the program and you should see your token displayed.

13. Click on the Log Grade button and in the next screen, enter 207 as the course, enter a valid grade for this course, and click Log. You should see a popup telling you that your grade was successfully entered. You can then check your grade by using the Get Grade menu and specifying your username and 207 for the course.

You are now ready to use the program! The following task will be completed with your team during the lab. First, make sure everyone has successfully completed the steps above.

Task 2: Forming a team

As a team-building exercise, you will now work together to form a team using this application. Team members in this program are able to view the grades of other team members.

1. Choose a team name. Make it something unique to your team, as other teams will also be picking team names and duplicate names aren't allowed.

2. Have one member of your team form a team with the name your team chose by clicking the Form a team button, entering the team name in the text field, and pressing Submit.

3. Each other member of the team should then join the team using the Join a team menu. Make sure you see the popup confirming that you successfully joined the team.

4. Try looking up the grade another team member entered for 207 using the Get a Grade menu.

Now that you are all on the team, there are a couple coding tasks for your team to work on.

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Note: If your team finds it convenient to work on parts of this lab on a common machine, you can create different run configurations (copy an existing one) which each use a different token environment variable. Then you can run multiple instances of the program and enter requests as different users!

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Note: Your team can choose how you want to work on the following two tasks, but below is our suggestion.

Suggested logistics: One of you should invite the others to collaborate on their fork of the original repo on GitHub. You can do this in your repo on GitHub under Settings -> Collaborators. This will allow you to push branches to a common repo and then use pull requests to contribute your code and review. To prevent others from pushing directly to the main branch, we recommend you set branch protection rules on GitHub. Below are how the settings might look if you add branch protection rules:

We recommend splitting your team into two halves with one half working on task 3 and the other on task 4. You can work on separate branches and merge the code together when you are done. Note that successful completion of task 3 is a pre-requisite for task 4 as the getMyTeam() method is used in both the features, but you can still write the code for task 4 so that it is ready to run once task 3 is complete.

Task 3: Coding the Get Average Grade feature

While this program has some useful core functionality which is provided by the Grade API, there are certain things which the Grade API can't currently do for us.

1. Go to My Team menu, enter the course name as 207 and click on Get average grade. You will notice that the functionality for Get Average Grade isn't implemented yet — it will just display Average Grade: 0.0.
2. As a team, your goal is to work together to implement this feature and confirm that it works.
3. Follow the flow from the getAverage button defined in the UI layer (app/gui/Application.java) to reach until the GetAverageGradeUseCase in the usecase layer. You can do this by setting a breakpoint and running the program in debug mode.
4. You will need to finish implementing the logic of calculating the average grade (Task 3a in the code) in the GetAverageGradeUseCase class. The logic is partly implemented, but what is written depends on the getMyTeam method (Task 3b in the code), which needs to be implemented. Follow the hints provided in this method to complete its implementation. Note the API response will be in json format which you learned how to parse last lab.

You can run the provided tests to check if your "Task 3a" GetAverageGradeUseCase logic is implemented correctly, before you finish implementing the "Task 3b" MongoGradeDataBase.getMyTeam method in Task 3. These tests make use of the technique of mocking (or stubbing), where instead of calling the actual API we use fake data instead. This is possible because of how the program is designed, with the GradeDataBase interface allowing us to replace any variable with reference type GradeDataBase with our own dummy implementation.

Task 4: Coding the Get Top Grade feature

In this task, you are required to build a feature that will allow the user to get the top grade on their team for a given course.

1. Similar to Get Average Grade, you will need to implement the Get Top Grade feature.
2. However, in this feature, the Get Top Grade usecase is already implemented in the GetTopGradeUseCase class.
3. You will need to implement the UI layer for this feature by adding a button Get Top Grade in the My Team menu. You can draw inspiration from the Get Average Grade button.

Task 5 Bonus

If your team finishes the above tasks and has extra time, we encourage you to think of an additional use case that can be implemented using this Grade API. Implement this use case end-to-end, from the UI layer to the UseCase layer, and see if you can get it working. This will be good practice for when your team starts developing your own course project where you will also be using an API endpoint.

Note about authentication

3. We are using a very simple authentication method, by passing our API token in the request headers. When you use other real-world APIs in the future, you will see some more sophisticated authentication techniques.