Retrofit Interceptor not adding query param to URL

Question

I'm trying to add apikey in the URL using custom interceptor but it's not adding the params in the URL so response body is null.

CustomInterceptor

class CustomInterceptor : Interceptor {

    override fun intercept(chain: Interceptor.Chain): Response {

        val url = chain.request().url().newBuilder()
            .addQueryParameter("apiKey", API_KEY)
            .build()

        val request = chain.request().newBuilder()
            .url(url)
            .build()

        return chain.proceed(request)
    }
}

Client

class Client {

    companion object {

        const val API_KEY = "123123"
        private const val apiUrl = "https://www.omdbapi.com/"

        fun <T> create(service: Class<T>): T {
            val client = OkHttpClient.Builder()
                .addInterceptor(CustomInterceptor())
                .build()

            return Retrofit.Builder()
                .baseUrl(apiUrl)
                .addConverterFactory(GsonConverterFactory.create())
                .client(client)
                .build()
                .create(service)
        }
    }
}

IMovie

interface IMovie {

    @GET("/")
    fun searchMovie(@Query("s") query: String): Call<SearchResult>
}

After sending the request the response body is null and this is the

Actual URL:- https://www.omdbapi.com/?s=Man

Expected URL:- https://www.omdbapi.com/?s=Man&apikey=123123

Answer 1

First create a new httpUrl instance from the existing request adding your query parameter and value:

var request = chain.request()

val httpUrl = request.url().newBuilder().addQueryParameter("token", authToken).build()

Then update the request:

request = request.newBuilder().url(httpUrl).build()

and proceed with it:

return chain.proceed(request)

• When you recall the request from the chain (the one you proceed with after manipulation) you are getting the unmodified request again.