[RaihanSharif]

Learners, PR Template

Self checklist

• I have titled my PR with Region | Cohort | FirstName LastName | Sprint | Assignment Title
• My changes meet the requirements of the task
• I have tested my changes
• My changes follow the style guide

Task code

CYF-1162

Changelist

Created a live updating chat app that allows client to use either long polling or short polling.

• Users can add new message

• User is notified whenever a new message is created by another user

• User can like or dislike a message

• User is notified when a message is liked/disliked

backend: https://z4k2yzxetkpevkwf6zy9ea37.trainees.hosting.cyf.academy/messages
frontend: https://qhdyqohwxffxraktvwh1e0ys.trainees.hosting.cyf.academy/

[RaihanSharif]

Update: I have now created the two separate apps, one polling and one Websocket. Both try to reuse as much code as possible, both in the frontend and backend.

Backend:

• pollingApp.js
• websocketApp.js
• All other files are common between the two, such as the model, helper functions etc.

Frontend:

• pollingScript.js
• websocketScript.js
• common.js -- contains the common files between the two.

Application uses HTTP post to create new messages and reactions and event streaming through either long polling or websocket to read new events.

Has some functionality to avoid race conditions by using even cursor per client.

[LonMcGregor]

Good work building this app, you've organised the files neatly and used classes where appropriate. I can also see places where you've given consideration to how you could extend with new functionality later.

I have spotted a few areas where you could improve, or where you could answer my questions to check your understanding of the code.

[LonMcGregor]

What is the difference between a "waiter" and a "subscriber"?

[RaihanSharif]

In this code waiters are the polling requests, and subscribers are WebSocket connections.

I was going to create a more general "subscriber" interface so that both WebSocket and HTTP, but I didn't have the time to get it done.

I've added some comments to make this clearer.

[LonMcGregor]

That makes sense. Adding comments is a good way to reduce ambiguity, thanks for adding them. If you encounter this again, another approach could be to change the variable names themselves to make the distinction more clear

[LonMcGregor]

Thanks for answering my questions, this is complete now