Feature Request: Modify Default CORS Hosts

[DAlba-sudo]

Feature Request

First and foremost, thanks for your work.

I have spent most of my time under a rock, and found myself going away from my usual frameworks/languages. This is truly a beautiful library you've written.

I am an avid chrome extension developer and I was hoping to use your library's simplified API Streaming library in conjunction with a chrome extension for a personal project. That said, it seems that the extension is not being allowed to connect. Here's a summary of the issue, what I've tried, and my hypothesis - for what it's worth.

Issue: Chrome extension websocket connection to an API endpoint is not connecting when the request is made from a different origin. Hypothesis: I believe this may be due to existing CORS policies, most likely due to the KTOR library (take with a grain of salt though, not well versed in either KTOR or Kobweb).

Potential Solutions

• I can see that there is a Server.class file that is being generated.

  @kotlinx.serialization.Serializable public final class Cors public constructor(hosts: kotlin.collections.List<com.varabyte.kobweb.project.conf.Server.Host> /* = compiled code */) {
      public companion object {
      }
  
      @kotlin.Deprecated public constructor(seen1: kotlin.Int, hosts: kotlin.collections.List<com.varabyte.kobweb.project.conf.Server.Host>?, serializationConstructorMarker: kotlinx.serialization.internal.SerializationConstructorMarker?) { /* compiled code */ }
  
      public final val hosts: kotlin.collections.List<com.varabyte.kobweb.project.conf.Server.Host> /* compiled code */
  
      @kotlin.Deprecated public object `$serializer` : kotlinx.serialization.internal.GeneratedSerializer<com.varabyte.kobweb.project.conf.Server.Cors> {
      }
  }

  If there was a way to publicly add hosts to whatever is being fed into the constructor of the Cors class, that would be amazing!

I am aware that Kobweb does not support websockets out of the box, in the sense that the Kobweb server will generate one websocket for all streams (at least the way that I understand it). I am able to create a websocket that interfaces with the API Stream and send/receive messages, from any site that has the same host (i.e., localhost:8080) by starting the websocket to the ws://localhost:8080/api/kobweb-streams endpoint and sending the proper data.

I would love to help out with this by the way - if you (or anyone that might know how to help) have a lot on your plate. Just need a bit of guidance as to where to start digging, and if this is a KTOR issue that can be configured by downloading the KTOR library.

[DAlba-sudo]

May be a duplicate #254.

[bitspittle]

Thank you for the nice comment. I'm glad you're finding the experience with Kobweb overall enjoyable.

CORS is a PITA. It is currently configurable in the .kobweb/conf.yaml file. Take a look at my blog post for a concrete example: https://bitspittle.dev/blog/2023/clouddeploy#configure-cors

For more details about the conf.yaml configuration values, see these related lines:

https://github.com/varabyte/kobweb/blob/0f0c6a48d68efadeda4236263a075329c5583446/common/kobweb-common/src/main/kotlin/com/varabyte/kobweb/project/conf/KobwebConf.kt#L127

https://github.com/varabyte/kobweb/blob/0f0c6a48d68efadeda4236263a075329c5583446/common/kobweb-common/src/main/kotlin/com/varabyte/kobweb/project/conf/KobwebConf.kt#L188

If it is a CORS issue, you should hopefully have access to your server logs to get more information about what's going on. They can be found in .kobweb/server/logs/kobweb-server.log. You may need to configure the logging level to TRACE (which I actually temporarily made the default in 0.13.9 but later learned that was the wrong call, and am going to move back to DEBUG in 0.13.10)