Generate http client from interface

[zZHorizonZz]

Describe the feature

I was wondering if it would be useful to have Vert.x codegen support for generating HTTP client implementations from interfaces. For example, you could define something like this:

@VertxGen
@HttpClient
public interface PetStoreApi {
    @Path(path = "/pets", method = HttpMethod.GET)
    Future<List<Pet>> listAllPets(@QueryParam("page") int page, @QueryParam("limit") int limit);
    
    @Path(path = "/pets/{id}", method = HttpMethod.GET)
    Future<JsonObject> getPetData(@PathParam("id") String id);
}

The generated implementation would:

• Take an HttpClient as a constructor argument
• Support primitive types, JsonObject, and data objects as request parameters
• Support JsonObject and data objects as response types
• Automatically handle path parameters, query parameters, and request/response serialization

This would provide a declarative way to define HTTP client interfaces similar to JAX-RS or Spring's @FeignClient, reducing boilerplate code for REST API consumption in Vert.x applications.

Contribution

I'm willing to contribute this

[tsegismont]

From my perspective, it could be an interesting Reactiverse project

[vietj]

I think the Retrofit integration should be updated and perhaps moved to vertx or reactiverse. https://github.com/vietj/retrofit-vertx

…

On Fri, Sep 19, 2025 at 12:20 PM Daniel Fiala ***@***.***> wrote: *zZHorizonZz* created an issue (eclipse-vertx/vert.x#5729) <#5729> Describe the feature I was wondering if it would be useful to have Vert.x codegen support for generating HTTP client implementations from interfaces. For example, you could define something like this: @***@***.*** interface PetStoreApi { @path(path = "/pets", method = HttpMethod.GET) Future<List<Pet>> ***@***.***("page") int page, @QueryParam("limit") int limit); @path(path = "/pets/{id}", method = HttpMethod.GET) Future<JsonObject> ***@***.***("id") String id); } The generated implementation would: - Take an HttpClient as a constructor argument - Support primitive types, JsonObject, and data objects as request parameters - Support JsonObject and data objects as response types - Automatically handle path parameters, query parameters, and request/response serialization This would provide a declarative way to define HTTP client interfaces similar to JAX-RS or Spring's @FeignClient, reducing boilerplate code for REST API consumption in Vert.x applications. Contribution I'm willing to contribute this — Reply to this email directly, view it on GitHub <#5729>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABXDCW54WDT7IVJ2PMH77T3TPKGPAVCNFSM6AAAAACG6QVVYCVHI2DSMVQWIX3LMV43ASLTON2WKOZTGQZTGNZZGQ2TINI> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[zZHorizonZz]

https://github.com/vietj/retrofit-vertx

That is cool, I think it would be nice thing to have.

From my perspective, it could be an interesting Reactiverse project

I don't have an issue with it being a Reactiverse project, but at the same time I think some Vert.x libraries might benefit from this as well, for example, the Consul client. In that case, I think it might be weird if the Vert.x project depends on retrofit-vertx, which would be part of Reactiverse.

[vietj]

I don't think we need to use this for consul client since the code is already written and works well enough.

…

On Sat, Sep 20, 2025 at 9:45 AM Daniel Fiala ***@***.***> wrote: *zZHorizonZz* left a comment (eclipse-vertx/vert.x#5729) <#5729 (comment)> https://github.com/vietj/retrofit-vertx That is cool, I think it would be nice thing to have. From my perspective, it could be an interesting Reactiverse project I don't have an issue with it being a Reactiverse project, but at the same time I think some Vert.x libraries might benefit from this as well, for example, the Consul client. In that case, I think it might be weird if the Vert.x project depends on retrofit-vertx, which would be part of Reactiverse. — Reply to this email directly, view it on GitHub <#5729 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABXDCTJO2Y5F6NSZJPQAFT3TUAZTAVCNFSM6AAAAACG6QVVYCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTGMJUG42DIMJTGY> . You are receiving this because you commented.Message ID: ***@***.***>

[zZHorizonZz]

Consul client was just a example, but in any case I could take a look at updating your lib to the newer version, then we can decide what to do with it?

[re-thc]

Not sure if it's a good idea. Retrofit has moved on to Kotlin. The latest version has a transitive dependency on it.

[zZHorizonZz]

Hmm, interesting. I see that might be an issue. @vietj, any thoughts?

[vietj]

I think it is fine if that is in reactiverse, perhaps there are alternatives to that client ?

[zZHorizonZz]

Now that you mention it, I have no idea why I didn't research that sooner (probably laziness). Feign actually has first-party integration of Vert.x: https://github.com/OpenFeign/feign/tree/master/vertx