servant VS swagger-petstore

> do you really have to understand language extensions?

You do when your code doesn't compile and you're trying to figure out what the error message means, or when the library you want to use makes heavy use of it for even basic functionality.

> These days one just enables GHC2021

My experience was pre-GHC2021. I basically had to enable at a minimum 5-6 language extensions in every single file.

> Mostly they're just about removing unnecessary restrictions from the older standard.

Yeah, those ones are usually fine. I have zero objection to things like FlexibleInstances or DeriveFoldable.

> Could you give an example?

I believe I was trying to implement Central Authentication Service using Servant. However, that required returning a custom HTTP status code. There has been an open Github issue for this since 2017, but it seems to require basically rewriting the entire framework: https://github.com/haskell-servant/servant/issues/732

Looking back at it now Servant does have "ServerError", but that basically requires giving up all the advantages Servant claims to have and I believe it was not a viable option at the time. Looking at the timeline I was probably also on Servant 0.15, and there seems to have been a rewrite since then.

I vaguely recall running into a similar issue trying to interact with a database, but I can't remember the details of that.

If you don't like this style, the usual alternative is to change mkDualAuthHandler to take two additional arguments, Proxy tag0 and Proxy tag1 (as e.g. lots of Servant functions do, for historical reasons).

Dunno if this is helpful, but I found this github issue about ResourceT and servant https://github.com/haskell-servant/servant/issues/1345

And what about the cabal repl --with-compiler=doctest, which was added recently, in doctest v0.20? I recently submitted a PR for Servant to use this in place of GHC environment files, because it seems less finicky to me. Was this a bad idea?

I asked a somewhat relevant question recently. Maybe you'll find this discussion somewhat helpful: https://github.com/haskell-servant/servant/issues/1547; two packages were talked about. One of the folks from Well Typed replied, and said they tried it recently (and worked fine).

Hey, is it possible this could solve the quadratic compile times issue for Servant routes? I was under the impression the slowdown was related to GHC being slow processing giant types, so maybe breaking the API down into records is just the thing...

You'll actually have to use the unreleased servant-auth-server from master (see here for details). I need to push a release :-)

We use servant library that allows us to describe API at the type level and check during the compilation whether both the server handlers and the client functions use correct parameters of the required types and correspond to the current API version (if you forgot to change the client function at the frontend, it just won’t be built).

Since nobody has mentioned it yet, there is an outstanding issue about quadratic compile times in Servant.

Failed to create a client for Java. The generator imports Java's types instead of TeamCity's. There are bugs described for the Java client in both the Swagger generator and the OpenAPI generator. Let's see how the generator behaves when building a Kotlin client.

[swagger-codegen](https://github.com/swagger-api/swagger-codegen) generates code from an OpenAPI definition, and it supports Rust code output (client and/or server).

Swagger contains three greats tools to work with the specification: Swagger UI, Swagger Editor and Swagger Codegen. The Swagger UI renders OpenAPI specs as interactive API documentation, Swagger Editor is a browser-based editor where you can write OpenAPI specs and Swagger Codegen generates server stubs and client libraries from an OpenAPI spec like the OpenAPI generator.

We ran into some minor issues (#1201, #1210, #1355, #1356 and #1769) and fixed some stuff we stumbled upon along the way, although it didn't really bother us as well (#1451 and #1769).

I am interested in integrating a swagger-codegen generated Python server with an existing Flask application. swagger-codegen generates a Python implementation based on the Connexion library from a Swagger API specification.

Creating TS types/interfaces manually can be tedious. But, if you have JSON responses of your APIs, you can quickly convert those JSON responses to TS interfaces using VS Code extension Paste JSON as Code. Also, if your backend already uses Swagger for API, you can auto-generate all the TS types of your API models using swagger-codegen

git clone https://github.com/swagger-api/swagger-codegen cd swagger-codegen java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar generate \ -i https://petstore.swagger.io/v2/swagger.json \ -l spring \ -o samples/server/petstore/springboot

Specifically for automatically generating code like clients, check out https://github.com/swagger-api/swagger-codegen