Hi, in Ktor-client, how do I set path parameter if I have a url template like `<https://foo.com/{id}...

# ktor

[Sourabh Rawat]

Hi, in Ktor-client, how do I set path parameter if I have a url template like <https://foo.com/{id}/car/{bar}> ?
I need to set the values of id and bar
Thanks in advance.

[Matteo Mirk]

I don’t think ktor-client has a built-in facility, but you could just use string templates:

fun urlTemplate(id: String, bar: String) = "<https://foo.com/${id}/car/${bar}>"

urlTemplate("1", "foo") // <https://foo.com/1/car/foo>

[christophsturm]

you need to be really careful with string templates because they are not really type safe. if you change the type of id or bar to something else kotlin will automatically call toString

[christophsturm]

which is not a problem when you encapsulate it in a type safe method like in this example. (or have good code coverage)

[Sourabh Rawat]

The issue is that we store endpoints in application.yaml so I am not sure how can I use urlTemplate for that.

[christophsturm]

how do you add the parameters to them currently?

[Matteo Mirk]

Instead of a yaml file, store them in a kotlin file, each one in its own function: that way you can call them lazily in your client code. The advantage is that this kind of configuration is still code, checked by the compiler, instead of a semi-structured text file with all the problems that YAML brings along 😉

[Matteo Mirk]

Hey @Sourabh Rawat, inspired by your problem I wrote this, maybe it could be useful: https://kotlinlang.slack.com/archives/C0BJ0GTE2/p1634286003392100