Does anybody know a solution for this problem

Question

Does anybody know a solution for this problem <https stackoverflow com questions 54327143 how to create a dynamic proxy in kotlin common code>

gildor · Answer

You cannot This is jvm only feature

gildor · Answer

But you can use expect actual declaration and extract this code to jvm and implement in some different way in other platforms

addamsson · Answer

do you know about a library which does this

addamsson · Answer

Seems like that there is a proxy object in javascript as well

addamsson · Answer

Ema · Answer

< gildor> do you know if kapt based approaches are even possible Generating instead of reflecting code

Dico · Answer

You can generate code with kotlin dynamically on the jvm so yes It s a very powerful feature

Ema · Answer

how about generate code on KN

gildor · Answer

gt do you know about a library which does this Does what proxy It s platform specific API so should be done on platfrom specific code

gildor · Answer

< Ema> Kapt based on Java APT so it s JVM only API But you can use it to generate some Kotlin code that can be used on any platform It will be additional build step where you generate some common code than build it using MPP

addamsson · Answer

I think I ll try to reconcile javascript s proxy with java s proxy instead

addamsson · Answer

and provide a common api for it

addamsson · Answer

i don t really want to generate code

addamsson · Answer

or have my users bother with it

addamsson · Answer

thx for the ideas thumbsup

Davide Giuseppe Farella · Answer

< addamsson> I m in the same limbo here smile Actually I m using `Proxy` on Jvm and `TODO ` on KN amp JS since they aren t my priority actually and hoping in a better solution than code gen please keep in touch here on StackOF I ve starred your post just in case

addamsson · Answer

``` TODO ``` this literally made me laugh out loud smile

addamsson · Answer

thumbsup

Davide Giuseppe Farella · Answer

`TODO ` is the developers s 42 smile

gildor · Answer

just curious what is your use case for Proxy

Davide Giuseppe Farella · Answer

That s mine <https github com 4face studi0 Ermes> Tbh I m also curious about Adam

gildor · Answer

So Retrofit like use case Yeah I see

gildor · Answer

I don t think that it will be possible to implement something like this for MPP before Compiler Plugins API will be available

gildor · Answer

or some another approach like function delegation but it also requires language support

gildor · Answer

For now I just use ktor http client for this but also use interface to abstract it

Davide Giuseppe Farella · Answer

For now I m just exploring kotlin multiplatform and I m very happy to see at least the jvm part is working Then with time I ll see if something new will come to kotlin mp to help me on that or maybe choose a complete different approach

addamsson · Answer

< Davide Giuseppe Farella> I did some research

addamsson · Answer

I tried using javascript s `Proxy` as an `external` class

addamsson · Answer

addamsson · Answer

but it quickly turned out that javascript s proxy is not a real proxy

addamsson · Answer

when you careate a proxy for a `Foo` interface you get back a `Proxy` and not an object which implements `Foo`

addamsson · Answer

so I m kinda stuck with this idea

addamsson · Answer

while Java s proxy works as it is supposed to work javascript s proxy does not adhere to the proxy pattern

Davide Giuseppe Farella · Answer

So basically ``` interface Foo fun bar Int ``` become ``` class Proxy fun bar = 4 for instance ```

addamsson · Answer

no the whole point would have been to supply an interface

addamsson · Answer

and get a proxy instance back like

addamsson · Answer

``` val foo Foo = createProxyFrom Foo class ```

addamsson · Answer

this is the proxy pattern

addamsson · Answer

but javascript doesn t support it

Davide Giuseppe Farella · Answer

Yes I just didn t understand what that Js lib does instead of that

Davide Giuseppe Farella · Answer

I mean at runtime my `Foo` interface implementation become basically ``` class FooImpl Foo override fun bar = 4 ```

Davide Giuseppe Farella · Answer

What about that Proxy lib

addamsson · Answer

this is not a lib but a built in class in javascript

addamsson · Answer

what it does is that you give it an object

addamsson · Answer

it wraps the object

addamsson · Answer

and you use the proxy from that point like it was that object

addamsson · Answer

given javascript s dynamic nature it is not a problem that you get back a `Proxy` instead of a `Foo`

addamsson · Answer

but this is a problem in Kotlin since you can t cast a `Proxy` to a `Foo`

addamsson · Answer

I pasted a link to the docs above point up

Davide Giuseppe Farella · Answer

Ok so I get it right basically I ll have class FooImpl ~ Foo~

Davide Giuseppe Farella · Answer

I m taking a quick look at that

Davide Giuseppe Farella · Answer

Anyway maybe that could fit my usecase I ll need more valutations Thanks for now

addamsson · Answer

thumbsup