Hilt - OkHttp & Interceptor - How to update Singleton with auth token - kotlin

Question

The app starts out not authenticated. When the user is logged in I need to send a auth token to my interceptor and notify my OkHttp Singleton about the change.
My OkHttp Singleton:
#Provides
#Singleton
fun provideOkHttp(interceptor: AuthInterceptor): OkHttpClient {
return OkHttpClient
.Builder()
.addInterceptor(interceptor)
.build()
}
My AuthInterceptor Singleton:
#Provides
#Singleton
fun provideAuthInterceptor(): AuthInterceptor = AuthInterceptor()
My AuthInterceptor Class: (I got it from here: https://github.com/apollographql/apollo-kotlin/issues/2030#issuecomment-596131870 not sure if I'm using it correctly)
class AuthInterceptor() : Interceptor {
// You can change authorization here
#get:Synchronized
#set:Synchronized
var tokenString: String? = null
override fun intercept(chain: Interceptor.Chain): Response {
return chain.proceed(chain.request().newBuilder()
.addHeader("Authorization", tokenString ?: "")
.build())
}
}
So I was hoping that I can simply call authInterceptor.tokenString = token in my repository before sending requests to my server but the OkHttp singleton doesn't care about that lol.
The Interceptor and OkHttp Instances gets created at app start and tokenString is and remains NULL.
Pretty new to Hilt, OkHttp and Interceptors so maybe a pretty obvious mistake.
P.S I'm using Apollo Android + MVVM + Clean Architecture
How can I pass the token to my Interceptor and OkHttp Singleton?

Answer 1

In my app I'm not using a singleton for the Interceptor, instead I have a class WebService that contains my OkHttpClient and ApolloClient, and an interceptor variable
Singleton:
#Singleton
#Provides
fun provideWebService(tokenStorage: TokenStorage) = WebService(tokenStorage)
WebService:
class WebService(tokenStorage: TokenStorage) {
// the Auth Interceptor
// if tokenStorage (basically encrypted shared preferences) has a token already, create an interceptor, otherwise it will be null
var interceptor: OkHttpAuthorizationInterceptor? = if (tokenStorage.activeToken != null) OkHttpAuthorizationInterceptor(tokenStorage.activeToken!!) else null
var okHttpClient = OkHttpClient.Builder().apply {
if (interceptor != null) {
this.addNetworkInterceptor(interceptor!!) // add the interceptor only if it's not null
}
}.build()
var apolloClient = ApolloClient
.Builder()
.serverUrl(Constant.ANILIST_URL)
.okHttpClient(okHttpClient) // add the OkHttpClient to ApolloClient
.build()
}
I've ran into the same problem and came up with the following solution: In my WebService class I created a method that rebuilds the clients with a new interceptor. I call this method when I need to change the token like when logging in or switching accounts
fun switchToken(token: String) {
// rebuild the OkHttpClient
okHttpClient = okHttpClient.newBuilder().apply {
networkInterceptors().removeAll {
it is OkHttpAuthorizationInterceptor // remove the interceptor from client if it already exists (useful for changing tokens)
}
interceptor = OkHttpAuthorizationInterceptor(token) // assign a new interceptor to the interceptor variable with the given token
addNetworkInterceptor(interceptor!!) // add the new interceptor to the client
}.build()
// rebuild the ApolloClient
apolloClient = apolloClient.newBuilder().okHttpClient(okHttpClient).build()
}
And this is how my interceptor looks like (same as yours more or less):
class OkHttpAuthorizationInterceptor(private val token: String) : Interceptor {
override fun intercept(chain: Interceptor.Chain): Response = chain.run {
proceed(
request().newBuilder()
.addHeader("Authorization", token)
.build()
)
}
}
(Edit: changed the code of Singletons, as it turns out even with this method providing the Apollo/OkHttpClient as a singleton won't refresh them so injecting the WebService and accessing the clients from there, like webService.okHttpClient is the only option, unless there is a better way to do this altogether)