Fiber: 🚀 add configuration option for key in cache mw

[marcusti]

Currently the cache middleware uses a hard coded c.Path() as cache key.

Sometimes a more complicated cache key is required, so please add a configuration option to support a custom cache key function.

https://github.com/gofiber/fiber/blob/master/middleware/cache/cache.go#L126

[welcome[bot]]

Thanks for opening your first issue here! 🎉 Be sure to follow the issue template! If you need help or want to chat with us, join us on Discord https://gofiber.io/discord

[Fenny]

Hi @marcusti, could you elaborate an use case on why c.Path() is not the best identifier? Just curious ^^

[marcusti]

Hey @Fenny, I have an API where the path references a resource. Example: /news gives a list of articles.

Then I use query parameters on GET requests as resource filters. Example: /news?limit=5 gives 5 articles. Etc...

Since c.Path() does not include query parameters, I get wrong cache hits. c.OriginalURL() would be a solution.

[hi019]

I agree this is a flaw in our implementation. I'll make a pr later today.

[Fenny]

I think a similar approach like https://github.com/gofiber/fiber/blob/master/middleware/limiter/limiter.go#L36 would be valid, I currently don't have time to make the PR myself but will accept one using the above implementation 👍