For anyone interested in http4k-connect.. https://kotlinlang.slack.com/archives/C0BJ0GTE2/p1612803153161600

Hi! I'm working with http4-connect (which is really great btw) and I'm facing an issue. In our organization, there is an on-premise S3 installation on an internal domain. I noticed that http4k-aws and http4k-connect have

<http://amazonaws.com|amazonaws.com>

domain hardcoded. When I change the domain with

ClientFilters.SetHostFrom

, the signature process seems to fail: I get an AccessDenied response, even if the request is correct. By trying the same request with Postman and its included AWS Signature feature, I got a different

SignedHeaders

: • Postman:

SignedHeaders=host;x-amz-content-sha256;x-amz-date,

• Http4k-connect:

SignedHeaders=host;x-amz-date,

So I think there are those two possibilities, either the signature is wrong due to a late host change, or the signature needs to sign

x-amz-content-sha256

too. Either way, it would be nice to be able to set the base domain.

Hello. I’m loving http4k but I noticed I’m not having luck with exception handling. Normally, when you have an uncaught exception, it will eventually get logged. That doesn’t seem to be happening. I’m using Undertow as my server, but I’m not sure that matters. I saw the

CatchAll

filter, but I it looks like that logs the stacktrace to the response, which is not what I would expect or want. I want a 500 status returned on uncaught exception, but I also want a log with the stacktrace. Sure, I can implement this myself with a filter, but I just feel like I’m missing some important piece of the puzzle. Please advise on how to approach exceptions (there will always be exceptions we don’t anticipate, and I want to make sure that these get logged so that in a production system, I can see the stacktrace).

As far as I know http4k doesn't do any logging by itself, because it doesn't have dependencies on logging frameworks, and in any case, it doesn't know how you might want to log stuff, or even if you want to. Many people have moved far away from log4j and the like, and instead emit structured events when things happen, just to stdout, that are collected by fluentd or similar. There are a few examples of structured logging in the cookbook https://www.http4k.org/cookbook/structured_logging_with_events/ If you would like to log lines with log4j, slf4j, java logging or whatever its easy to add a filter that uses your local logging library natively. I think there are some examples in https://www.http4k.org/cookbook/monitoring/

You can also see structured logging in use in the http4k-by-example repo 🙃. https://github.com/http4k/http4k-by-example/blob/68a56c96cdacaf4567bba74ec910f41b2e44a1af/src/main/kotlin/verysecuresystems/SecuritySystem.kt#L37

If you use Body.auto() with Gson, and send the JSON literal "null" as body, you get a null out of the lens even though it promises not to return nulls in its contract. Should this be validated by the lens or is it application logic?

I am not sure whether it is a bug or feature - consider having lens

<http://Query.int|Query.int>().required("minValue", "Required minimal value")

This will nicely generate OpenApi description with

integer

definition. This seems to be the result of

IntegerParam

in

mapWithNewMeta(StringBiDiMappings.long(), IntegerParam)

. However, when using

.multi

, this doesn't change, the OpenApi definition stays at

integer

. I can se ParamMeta contains also

ArrayParam

, so I guess this should ideally result in somehting like

integer array

? If I understand correctly, the

ArrayParam

is not used for .

multi

and I am not sure how this should be done properly?

Hello, Would anyone have any examples around for implementing micrometer's stackdriver library with http4k? I found the SimpleMeterRegistry to be straight forward but struggling to get the Stackdriver plugin setup. (I apologize if this is trivial, pretty new to Kotlin and the JVM ecosystem..) Thanks!

Hi guys, any examples of using a custom Configuration with a templating engine? I am using freemarker, however the default usage logs a severe error on every call (it's because http4k uses

Configuration(Configuration.getVersion())

instead of a specific version:

Configuration(Configuration.VERSION_2_3_30)

)... but I am striking out when trying to provide a custom Configuration. Also useful for providing custom string formats, equality checks, etc.

@dave Is it possible to add the

OpenApiExtension

for the

paths

in OpenApi spec through http4k-contract? My scenario is that I want to be able to add a custom attribute with a value to every path in my OpenApi Spec. I was able to add a custom attribute block using OpenApiExtension to the

extensions

field in

OpenApi3

. But I am not sure how to do it for each of my path object

apiBaseUrl bind contract {
      renderer = OpenApi3(
        ApiInfo(apiName, apiVersion, apiName),
        WdsHttpJackson,
        listOf(XApiDefinitionExtension),
        OpenApi3ApiRenderer(WdsHttpJackson)
      )
      descriptionPath = swaggerJsonPath
      routes += contractRoutes
    }

This is a feature of the code that is processing the request body. Assuming you are using json and Jackson, you can do this by making the relevant field not-nullable, or by setting the relevant options in jackson.

I created a basic Hello World app using the http4k generator. I can do a gradle clean build and a jar file is generated. When I try to run the jar file, I get an error that the jar is missing a manifest file. I added a jar tag with a manifest attribute but now I'm getting class loading errors. Anyone know what I'm missing?

Hi, in a contractRoute I use an object that contains a list of map. the OAS specification declares the map as a SingletonMap but that reference does not exist. there is a JS error in the swagger because of that.

Hi, does http4k client support receiving SSE? If so, is there any information on how to implement that? I can't seem to find any info on that on the project site (only the server side or so it looks for me)...

@Razvan omg. It's a total nightmare. The latest was this morning when we discovered that the new BOM was no longer compatible with any of our projects because of gradle magic. Of course we only found that out today because it took 12 hours for the artifacts to actually make their way into maven central after publishing them.

@Saša Šijak you can find react and hotwire examples in the example repo : https://github.com/http4k/examples

Hi, about using lenses with

result4k

if I got a lens declared as:

Body.auto<T>().toLens().asResult()

I can only use

extract

lens function I can’t use

inject

to it, so. what’s best practice ?

val requestLens = Body.auto<T>().toLens()
val responseLens = responseLens.asResult()

Sure. PR away! 😉

I'd recommend you can write a small test class which you can run to generate the contract JSON. As a general rule, we also keep the JSON in Git so that we know when it changes (and we have an approval test to manually approve the changes before it gets committed)

Hi, I submitted a small addition to the docs, regarding regex pattern matchers in URLs. Thanks. https://github.com/http4k/http4k/pull/589

Is there a way to create and manage a session in http4k?

@dave Is there a way to add the

servers

object section to openapi specs using the http4k contracts?

Hello everyone, does one of you have a tip what else might be needed to get the live templates running? https://github.com/http4k/intellij-settings I followed the instructions and the repository seems to be added, but unfortunately it seems to not work yet: Thanks in advance!

No, it doesn’t

Heyo, I'm having the same issue as this when using Spring https://github.com/http4k/http4k/issues/320, however with slightly different versions: • spring-boot: 2.3.3 • jackson-module-kotlin: 2.11.2 • http4k: 4.3.5.4 Is there any easy way to check which to downgrade?

Out of curiosity, @MrNiamh, how are you using http4k with Spring?

Spring allows to add a server section in the OpenApi output: This allows calling the endpoint on given server and also the path is visible. Is this feasible with http4k?

What do you guys recommend as JSON library when one wants to build a native executable with GraalVM? I wanted to try out Moshi, but

val socketLens = Body.auto<Set<Socket>>().toLens()

just throws

No JsonAdapter for class java.util.LinkedHashSet, you should probably use Set instead of LinkedHashSet (Moshi only supports the collection interfaces by default) or else register a custom JsonAdapter.

and I'm not sure if I really want to add all of that: https://pulseadvancedmedia.co.uk/java/moshi-adapters-for-platform-types-like-arraylist-and-linkedlist/ Any tips what I'm missing? What are you guys using? I'm just used to Jackson, but it makes use of reflection, so I rather not use it for GraalVM I guess. Thanks in advance!

Is there a way to route to a single static file? eg:

routes(
    "/docs/swagger-ui/swagger-ui.css" bind static(Classpath("/swagger-ui/swagger-ui.css")), // read from src/main/resources
    "/docs" bind static(Classpath("META-INF/resources/webjars/swagger-ui/3.25.2"))

basically I want to override the single

swagger-ui.css

file and leave the rest of swagger tools as default. with the example above, the file is ignored and only content from the swagger-ui webjars is served.