panta82/comments_service

Comments microservice

Comments service

Based on: https://www.youtube.com/watch?v=CnailTcJV_U

Requirements

Create a comment

POST /api/comments

Need to include:

• Author
• Text
• PostId

Can also include:

• Reply to id (for nested comments)

After creation, it's also filled with:

• id
• createdAt
• modifiedAt
• hash
• published (set to true if there are no bad words, otherwise to false)
• source:
  • ip
  • user agent

The bad words are checked on some api called "content moderator" https://contentmoderator.cognitive.microsoft.com/

Get comment

Return a comment with all its child comments, available as array under replies.

Change comment text

PATCH /api/comments/:id

Can only change text

Delete a comment

DELETE /api/comments/:id

Returns:

• Deleted count
• Whether it was soft delete

If comment has children, the comment is "soft deleted", meaning:

• author is set to deleted
• text is set to placeholder

If all comments in a chain are soft deleted, they are then actually deleted.

Thoughts

• Async/await is still annoying to use with a debugger. Keep with Promises for now.

• 2 layer architecture (imperative shell, service layer) feels right. 3rd layer could be extracted from private mongo-based methods into some kind of DAL layer. But it feels a lot of these methods would really just be private methods of CommentManager (needlessly) living in a different service, so I didn't go for that. An ORM/OOM on its own could have been the third layer.

• Using pure classes for services is annoying. Writing this.app.x gets old quick. Closure factory is still a better choice for long lived services.

• Models with base class still the best choice. No idea how to prevent base class from balooning in complexity.

• Express with Promise wrapper good.

• Debug logger better than winston, but I miss the ability to log different events at different levels. Maybe those could too be tags? Had some problems configuring it properly, I wish these libraries didn't insist on screwing with global env-s.

• Dotenv based config serviceable in a small app, but I'd stil prefer yaml that maps precisely to the settings structure.

• Extracted all settings into one class, instead of each service declaring its own. Works fine for this small app, might become unwieldy in a real monolith.

• Does this arch make sense in a microservice? Seems like most code ended up in one file (comment_manager.js). Will it always be that? Should I break it apart? How?

• Api-tester.http is a JetBrains testing system, replacement for Postman and Insomnia. A bit better once you get used to it, but I found it annoying having to click between my debug and run window. I wish they'd have made results of requests appear in a side-window to the http file editor.

• Controllers as function work fine. No need for full service class ceremony.

• Missing features: validation, a bunch of consistency checks.

• Mongo's ObjectID is the most annoying part of dealing with mongo. I keep having to think which parts of my models need to be casted into and out of ID-s. I wish they could have just used a string (I guess that's why you use ODM?).

• Mongo is generally annoying.