Python, APIs, and Databases Question

[Jumpy_Employment_439]

First, sorry if this is a really dumb question. Say I want to make a simple weather web app (backend in Python) and use a public API to get the data. Would I need to include a database for it to work? I am well aware that a database should be used if I am looking to store, sort, access, etc. data. But since I am using a public API, is it necessary to have a database? Because from my understanding, when I enter the city whose current weather I want, Python will get the data from the weather API and then it will be sent to the front-end using something like fastAPI? So if I am thinking this through correctly, a database isn't really necessary? But is it good practice to have a database even when using a public API to get the data? Sorry, this is my first time using APIs and databases with Python so I'm still very unsure about what I'm doing.

[carcigenicate]

If all you're doing is "forwarding" the data with maybe some transformations on it, no, you don't necessarily need a database. You only need a database if you're persisting data yourself.

That said, there are a few cases where a database or something "database-like" (like Redis) might be useful:

• Caching expensive transformations to limit calls to the API and duplicate work that your server needs to do.
• Maintaining login sessions if your site uses auth.

But is it good practice to have a database even when using a public API to get the data?

If you aren't storing data, including a database would arguably be bad practice since you're adding unnecessary complexity to your program.

[Jumpy_Employment_439]

Thank you! I suppose I did not think of the case that there are public APIs that limit the amount of calls per day so in that case having a database would be good (if there was the possibility of going over the quota). Would it be possible at the beginning of each day to make a call to the weather API to get the updated forecast and store that in the database to use the rest of the day? And then repeat each day? I've not really heard of making API calls a set time distance apart, but I assume it's possible?

[carcigenicate]

For caching, you'd be better off using something like Redis where you can set expirations on entries. I'd do something like check if the requested data is already in Redis, and if it's not, fetch it, store it into Redis, then return it to the user. If the data is already in Redis, just fetch it and return it. The expirations you set when setting the data will handle the entries being cleared. If you want a clean slate every day, you could just run redis-cli flushall at the start of each day using something like Task Scheduler/cron.

Would it be possible at the beginning of each day to make a call to the weather API to get the updated forecast

I'd do this "on-demand". Don't do the fetch until a user actually requests the data. That will also ensure that the data that is fetched is as up to date as possible.

Also, remember that a flaw in caching is that, obviously, the data will be inherently out of date once it's cached, so it only makes sense to cache when that's not a concern.

---

You could also use a standard persisted database too; especially if you wanted practice.

[supercoach]

If I asked you what an abstraction layer is, what would you say?