Checked with adopt-tapir's generated projects with ZIO and zio-http vs http4s server implementations, replacing Endpoints.scala with:

package com.softwaremill

import sttp.tapir._

import sttp.tapir.ztapir.ZServerEndpoint
import zio.ZIO
import sttp.model.Part
import sttp.tapir.generic.auto._

object Endpoints {
  case class UploadForm(file: Part[TapirFile])
  val helloEndpoint: PublicEndpoint[UploadForm, Unit, String, Any] = endpoint.post
    .in("hello")
    .in(multipartBody[UploadForm])
    .out(stringBody)
  val helloServerEndpoint: ZServerEndpoint[Any, Any] = helloEndpoint.serverLogicSuccess(user => ZIO.succeed(s"Hello $user"))

  val apiEndpoints: List[ZServerEndpoint[Any, Any]] = List(helloServerEndpoint)

  val all: List[ZServerEndpoint[Any, Any]] = apiEndpoints
}

the zio-http version hangs:

% curl -v http://localhost:8080/hello -X POST -F 'file=@build.sbt'
Note: Unnecessary use of -X or --request, POST is already inferred.
*   Trying 127.0.0.1:8080...
* Connected to localhost (127.0.0.1) port 8080 (#0)
> POST /hello HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.79.1
> Accept: */*
> Content-Length: 869
> Content-Type: multipart/form-data; boundary=------------------------446b122b8c71f149
> 
* We are completely uploaded and fine
* Empty reply from server
* Closing connection 0
curl: (52) Empty reply from server

while http4s version runs ok:

curl -v http://localhost:8080/hello -X POST -F 'file=@build.sbt'
Note: Unnecessary use of -X or --request, POST is already inferred.
*   Trying 127.0.0.1:8080...
* Connected to localhost (127.0.0.1) port 8080 (#0)
> POST /hello HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.79.1
> Accept: */*
> Content-Length: 995
> Content-Type: multipart/form-data; boundary=------------------------fe5f85d3ef7d8ac5
> 
* We are completely uploaded and fine
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Content-Type: text/plain; charset=UTF-8
< Date: Tue, 18 Oct 2022 22:15:40 GMT
< Content-Length: 245
< 
* Connection #0 to host localhost left intact
Hello UploadForm(Part(file,/var/folders/tn/grglkq4521sgkw60t257zmw00000gq/T/tapir12134154041590495837tmp,Map(filename -> build.sbt),List(Content-Disposition: form-data; name="file"; filename="build.sbt", Content-Type: application/octet-stream)))%       

That's probably because multipart isn't supported by the zio-http interpreter: https://github.com/softwaremill/tapir/blob/master/server/zio-http-server/src/main/scala/sttp/tapir/server/ziohttp/ZioHttpRequestBody.scala#L28

I think there was some missing functionality in zio-http which prevented us from implementing this, but maybe it's possible now. Either way, I'll change this to throw an exception instead of silently failing.

Exception is good as we can test for it in our test suites and know when support will be added :)

Thanks

It seems that ZIO-HTTP support for multipart is still work in progress - zio/zio-http#1617, so we will have to wait for now.

It seems that ZIO-HTTP supports multipart/form-data in 0.0.5. There is an example in zio/zio-http#2037

@akizminet Awesome :) Now we need somebody to volunteer to add multipart support to tapir+zio :)

I would like to volunteer:
feat: Add zio-http multipart body support #3690

Currently this PR is in Draft because:

1. I have yet to test my code
2. The PR does not have any tests (yet)

@seakayone Awesome! There are some multipart tests which can be enabled for the zio http interpreter: https://github.com/softwaremill/tapir/blob/master/server/zio-http-server/src/test/scala/sttp/tapir/server/ziohttp/ZioHttpServerTest.scala#L263, so this might give some guidance

Thanks @adamw I have activated the tests and am currently struggling with zio-http.

The incoming ServerRequest contains the multiple parts, but when calling zio.http.Request.body.[asMultipartFormStream|asMultiPartForm] they only ever return the single, first part. Will need to look into it further, might take some time.

@seakayone Any news on this perhaps?
This became relevant for me as well since I would like to switch from play http-server to zio-http.
do you need help maybe?

My PR for tapir cannot be merged as there is bug in zio-http zio/zio-http#2411 which I haven't been able to fix.