req VS uri-bytestring

req

• How to implement a disk cache plugin for Elixir's Req HTTP client?
  5 projects | news.ycombinator.com | 17 Aug 2023

  > no error checking at all (I assume it just panics or exception?)

  In Elixir, bang functions per convention will raise on error. `get/2` will return error tuples allowing you to handle errors. In fact, get!/2 just calls get/2 and raises for you[^1].

  > no mention of JSON at all

  Req is the most "batteries included" Elixir HTTP lib out there. I can't speak for Wojtek, but I believe the goal was to make Req extremely easy to use in scripting or things like LiveBook without having to do much work. That being said, the automatic decoding is mentioned in the readme[^2] and the docs[^3].

  > if "body" is JSON, how do you even get the raw body, or can you?

  Per the docs[^3], you can either skip with a `:raw` option, or just build your own request using only the steps you want.

  > just seems over engineered/over fitted whatever you want to call it.

  Fair, but again, this library is designed to be on that end of the spectrum. There are plenty of other libraries further down the stack that you can use. I am partial to Finch[^4], upon which Req is built.

  To address the sibling comment about "Let it Crash", the language allows you to easily recover from crashes, but that is for resiliency, not error handling. In practice you would use the non-bang get/2, pattern match on the response, handle any errors, perhaps use Kernel.get_in/2 to safely traverse the map, etc. The example provided by the author is not "production ready".

  [^1]: https://github.com/wojtekmach/req/blob/v0.3.11/lib/req.ex#L3...

  5 projects | news.ycombinator.com | 17 Aug 2023

  > no error checking at all

  Functions that raise always end in `!` in Elixir, or at least they should. Most have alternatives that return error tuples instead which you can pattern match on (this is what I recommend). You can read the docs for `get/2` (as opposed to `get!/2` which raises) here: https://hexdocs.pm/req/Req.html#get/2.

  A common pattern is for the `!` version to call the version that doesn't raise, check the result, and raise on error, which is the case here: https://github.com/wojtekmach/req/blob/9de30de0df481ee557ccc...

  > and if "body" is JSON, how do you even get the raw body, or can you?

  You would set `decode: false` when calling `get!/2: https://hexdocs.pm/req/Req.html#new/1. You can also set this as configuration with https://hexdocs.pm/req/Req.html#default_options/1.

  As a closing note I'll mention that Req is intended to be a very high-level, scripting-friendly requests library, similar to Requests in Python. If you don't want conveniences like Req provides, you can either turn them off or use something different, like Finch (which Req is based on, https://github.com/sneako/finch). Other than Req and Finch I'm personally only familiar with HTTPoison, which is significantly older than all of the libraries derived from Mint (like Finch and Req, https://github.com/elixir-mint/mint) but still works. There are many others though, like Gun and Tesla and such.

uri-bytestring

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Tracking mentions began in Dec 2020.