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Use Dagger to inject different Retrofit and OkHttp object before and after login

I have my Retrofit and OkHttp instances injected. I am changing the headers of my OkHttp object using an Interceptor. In this Interceptor, I set information such as app name, version etc.
I am now adding a login and want to set an authToken to the headers. However, this only exists AFTER login, obviously. So what I want to do is be able to add a new header after login for authToken. However, I can't get access to my OkHttp object as its buried in my module, and I just get my RestClient object injected in my class, with everything else built.
I was thinking of copying all my provides... code and making duplicates for before an after Login. For example, wrap my RestClient in a class called "PreLoginApi" that doesn't have authToken, and then creating another wrapper class called "PostLoginApi" which has the authToken, but this won't work if Dagger creates the objects on app launch.
#Provides
#Singleton
#Named("HeaderInterceptor")
fun provideHeaderInterceptor(context: Context): Interceptor {
val headerMap = context.getHeaderMap()
return Interceptor { chain ->
val original = chain.request()
val builder = original.newBuilder()
headerMap.keys.forEach {
builder.addHeader(it, headerMap[it] ?: "")
}
val request = builder.build()
chain.proceed(request)
}
}
#Provides
fun providesOkHttpClient(
#Named("HeaderInterceptor") headerInterceptor: Interceptor,
): OkHttpClient {
val builder = OkHttpClient.Builder()
.connectTimeout(60, TimeUnit.SECONDS)
.readTimeout(60, TimeUnit.SECONDS)
.addInterceptor(headerInterceptor)
return builder.build()
}
You can see here where I call my extension function Context.getHeaderMap(). Inside this function, I'm retrieving the authToken from EncryptedSharedPreferences.
So ideally, I'd like to be able to tell Dagger to redo this initialisation once I login, because at this stage the authToken will be set. Is it possible to just re-initialise this one module or will I have to wrap my RestClient in another class, and maybe use Lazy loading to initialise the "PostLoginApi"?
Thanks.
EDIT:
I do similar for Firebase FCM token, where I pass in the headerMap during initialisation, like this:
private fun updateFirebaseToken(headerMap: HashMap<String, String>) {
FirebaseMessaging.getInstance().token.addOnCompleteListener(OnCompleteListener { task ->
if (!task.isSuccessful) {
return#OnCompleteListener
}
// Get new FCM registration token
task.result?.let { token ->
headerMap["FirebaseId"] = token
}
})
}
But I don't think I can do something like this for a SharedPrefs value.

Kotlin : Okhttpclient correct way of creating single instance? OkHttpClient doesn't go through server ip check?

I'm new at android kotlin development and currently trying to solve how to correctly create a single instance of OkHttpClient for app-wide usage. I've currently sort-of* created a single instance of client and using it to communicate with the server, however currently the back-end server is not using token/userid for validation but IP check. I can log in the user no problem, but after going to another activity trying to call api, I'm being blocked access by server because apparently IP is not the same. I've used POSTMAN as well as already created a same functioning iOS app that is working with no issue. So my question is am i creating the single instance of OkHttpClient wrong? Or is OkHttpClient not suitable for this kind of ipcheck system? Should i use other library, and if yes, any suggestion and examples?
Thanks in advance
Currently i tried creating it like this :
class MyApplication: Application(){
companion object{
lateinit var client: OkHttpClient
}
override fun onCreate(){
super.onCreate()
client = OkHttpClient()
}
}
Then i created a helper class for it :
class OkHttpRequest {
private var client : OkHttpClient = MyApplication.client
fun POST(url: String, parameters: HashMap<String, String>, callback: Callback): Call {
val builder = FormBody.Builder()
val it = parameters.entries.iterator()
while (it.hasNext()) {
val pair = it.next() as Map.Entry<*, *>
builder.add(pair.key.toString(), pair.value.toString())
}
val formBody = builder.build()
val request = Request.Builder()
.url(url)
.post(formBody)
.build()
val call = client.newCall(request)
call.enqueue(callback)
return call
}
fun GET(url: String, callback: Callback): Call {
val request = Request.Builder()
.url(url)
.build()
val call = client.newCall(request)
call.enqueue(callback)
return call
}
}
Finally I'm using it like this :
val loginUrl = MyApplication.postLoginUrl
var userIdValue = user_id_textfield.text.toString()
var passwordValue = password_textfield.text.toString()
val map: HashMap<String, String> = hashMapOf("email" to userIdValue, "password" to passwordValue)
var request = OkHttpRequest()
request.POST(loginUrl, map, object : Callback {
val responseData = response.body?.string()
// do something with response Data
}
And on another activity after user log in :
val getPaidTo = MyApplication.getPaidTo
var request = OkHttpRequest()
request.GET(getPaidTo, object: Callback{
//do something with data
}

First, don't use your OkHttpClient directly in every Activity or Fragment, use DI and move all of your business logic into Repository or some source of data.
Here I will share some easy way to make REST request with Retrofit, OkHttpClient and Koin, if you want use the same:
WebServiceModule:
val webServiceModule = module {
//Create HttpLoggingInterceptor
single { createLoggingInterceptor() }
//Create OkHttpClient
single { createOkHttpClient(get()) }
//Create WebServiceApi
single { createWebServiceApi(get()) }
}
/**
* Setup a Retrofit.Builder and create a WebServiceApi instance which will hold all HTTP requests
*
* #okHttpClient Factory for HTTP calls
*/
private fun createWebServiceApi(okHttpClient: OkHttpClient): WebServiceApi {
val retrofit = Retrofit.Builder()
.baseUrl(BuildConfig.REST_SERVICE_BASE_URL)
.client(okHttpClient)
.addCallAdapterFactory(CoroutineCallAdapterFactory())
.build()
return retrofit.create(WebServiceApi::class.java)
}
/**
* Create a OkHttpClient which is used to send HTTP requests and read their responses.
*
* #loggingInterceptor logging interceptor
*/
private fun createOkHttpClient(
loggingInterceptor: HttpLoggingInterceptor
): OkHttpClient {
return OkHttpClient.Builder()
.addInterceptor(loggingInterceptor)
.readTimeout(defaultTimeout, TimeUnit.SECONDS)
.connectTimeout(defaultTimeout, TimeUnit.SECONDS)
.build()
}
And now you can inject your WebServiceApi everywhere, but better inject it in your Repository and then use it from some ViewModel
ViewModelModule:
val viewModelModule = module {
//Create an instance of MyRepository
single { MyRepository(webServiceApi = get()) }
}
Hope this help somehow

Okay, after i check with the back-end developer, i figured out the problem wasn't the ip address(it stays the same) but that the cookie was not saved by okhttp, both POSTMan and xcode automatically save the token returned into cookie so i never noticed that was the problem. So after googling a-bit, the solution can be as easy as this:
class MyApplication : Application(){
override fun onCreate(){
val cookieJar = PersistentCookieJar(SetCookieCache(),SharedPrefsCookiePersistor(this))
client = OkHttpClient.Builder()
.cookieJar(cookieJar)
.build()
}
}
With adding persistentCookieJar to gradle.

Dynamic urls with Koin ans Retrofit

Using Retrofit for network calls and Koin for dependency injection in an Android app, how to support dynamic url change?
(while using the app, users can switch to another server)
EDIT: network module is declared like this:
fun networkModule(baseUrl: String) = module {
single<Api> {
Retrofit.Builder()
.baseUrl(baseUrl)
.client(OkHttpClient.Builder().readTimeout(30, TimeUnit.SECONDS)
.connectTimeout(30, TimeUnit.SECONDS)
.writeTimeout(30, TimeUnit.SECONDS)
.build())
.build().create(Api::class.java)
}
I am starting Koin in the Aplication class onCreate like this:
startKoin {
if (BuildConfig.DEBUG) AndroidLogger() else EmptyLogger()
androidContext(this#App)
modules(listOf(networkModule(TEST_API_BASE_URL), storageModule, integrationsModule, appModule))
}

I faced the same problem recently. The most convenient way is to use a Interceptor to change the baseUrl dynamically.
class HostSelectionInterceptor(defaultHost: String? = null, defaultPort: Int? = null) : Interceptor {
#Volatile var host: String? = null
#Volatile var port: Int? = null
init {
host = defaultHost
port = defaultPort
}
#Throws(IOException::class)
override fun intercept(chain: Interceptor.Chain): okhttp3.Response {
var request = chain.request()
this.host?.let {host->
val urlBuilder = request.url().newBuilder()
urlBuilder.host(host)
this.port?.let {
urlBuilder.port(it)
}
request = request.newBuilder().url(urlBuilder.build()).build()
}
return chain.proceed(request)
}
}
Initialize it with your default url.
single { HostSelectionInterceptor(HttpUrl.parse(AppModuleProperties.baseUrl)?.host()) }
single { createOkHttpClient(interceptors = listOf(get<HostSelectionInterceptor>()))}
And add this interceptor when creating your OkHttpClient.
val builder = OkHttpClient().newBuilder()
interceptors?.forEach { builder.addInterceptor(it) }
To change the url you only have to update the interceptors member.
fun baseUrlChanged(baseUrl: String) {
val hostSelectionInterceptor = get<HostSelectionInterceptor>()
hostSelectionInterceptor.host = baseUrl
}

I've tried with Koin loading/unloading modules..and for a short period of time it worked, but later, after a minimal change I wasn't able to make it reload again.
At the end, I solved it with wrapper object:
class DynamicRetrofit(private val gson: Gson) {
private fun buildClient() = OkHttpClient.Builder()
.build()
private var baseUrl = "https://etc..." //default url
private fun buildApi() = Retrofit.Builder()
.baseUrl(baseUrl)
.addConverterFactory(GsonConverterFactory.create(gson))
.client(buildClient())
.build().create(MyApi::class.java)
var api: MyApi = buildApi()
private set
fun setUrl(url: String) {
if (baseUrl != url)
baseUrl = url
api = buildApi()
}}
I declare it in within Koin module like this:
single<DynamicRetrofit>()
{
DynamicRetrofit(get(), get())
}
and use it in pretty standard way:
dynamicRetrofit.api.makeSomeRequest()
It was good solution for my case since I change baseUrl very rarely. If you need to make often and parallel calls to two different servers it will probably be inefficient since you this will recreate HTTP client often.

How to get Context inside an Object?

I am using retrofit to fetch some data and for that I am passing a token in Header for Authentication.
I want to fetch the token from the Shared Preferences in my Retrofit Client Object but I don't know how to?
I tried to get a context in the object using a function but then it gives me WARNING that
Do not place Android context classes in static fields (static reference to RetrofitClient which has field context pointing to Context); this is a memory leak (and also breaks Instant Run) less...
Also i tried to get context in my interface of retrofit and I got the context without warning but I don't know where to get Shared Preferences.
interface Api {
var context:Context;
#FormUrlEncoded
#POST("getMerchantProductsSlideContent")
fun getProductsForSlide(
//Don't know how to get value from shared refercne to this header
#Header("Authentication: Bearer ")
#Field("token") token:String,
#Field("deviceId") deviceId:String,
#Field("content_receiver") content_receiver:String,
#Field("content_type") content_type:String,
#Field("data") data:Array<String>
):Call<DefaultResponse>
fun getContext(mContext:Context){
context = mContext
}
}
This is retrofitClient.kt
object RetrofitClient {
private val AUTH = "Bearer $token"
private const val BASE_URL = "http://192.168.1.5/Projects/Sitapuriya/public/"
private val okHttpClient = OkHttpClient.Builder()
.addInterceptor { chain ->
val original = chain.request()
val requestBuilder = original.newBuilder()
.addHeader("Authorization", AUTH)
.method(original.method(), original.body())
val request = requestBuilder.build()
chain.proceed(request)
}.build()
val instance: Api by lazy{
val retrofit = Retrofit.Builder()
.baseUrl(BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.client(okHttpClient)
.build()
retrofit.create(Api::class.java)
}
}
This is my retrofit interface
interface Api {
#FormUrlEncoded
#POST("getMerchantProductsSlideContent")
fun getProductsForSlide(
#Field("token2") token2:String,
#Field("deviceId") deviceId:String,
#Field("content_receiver") content_receiver:String,
#Field("content_type") content_type:String,
#Field("data") data:Array<String>
):Call<DefaultResponse>
}
[UPDATED] This is my activity n which i am calling the retrofit
val data = arrayOf(merchantId)
RetrofitClient.instance.getContext(this)
RetrofitClient.instance.getProductsForSlide(
token,
deviceId,
"MERCHANT",
"MERCHANT_VIEW_BASIC",
data
).enqueue(object:Callback<DefaultResponse>{
override fun onFailure(call: Call<DefaultResponse>, t: Throwable) {
Toast.makeText(applicationContext,"ERROR: ${t.message}",Toast.LENGTH_LONG).show()
}
override fun onResponse(
call: Call<DefaultResponse>,
response: retrofit2.Response<DefaultResponse>
) {
Toast.makeText(applicationContext,"SUCCESS: ${response.body()?.content}",Toast.LENGTH_LONG).show()
}
})
I want to get the token from Shared Preferences and use it as a header for my request and I know to access Shared Preferences we need a context. How can I get the context in Object?
[UPDATE-2] Tried #Blundell answer
interface Api {
var token: String
#FormUrlEncoded
#POST("getMerchantProductsSlideContent")
fun getProductsForSlide(
#Header("Authentication: Bearer $token")
#Field("token") token:String,
#Field("deviceId") deviceId:String,
#Field("content_receiver") content_receiver:String,
#Field("content_type") content_type:String,
#Field("data") data:Array<String>
):Call<DefaultResponse>
fun setAuthHeader(token2:String){
token = token2
}
}
But it gives error: An annotation argument must be a compile-time constant

Try to get token in your activity (you can use activity's context and get token from shared preferences) and pass this token to your retrofit class.
Also try to read something about dependency injection, dagger2, koin etc to provide different dependencies to your classes
interface Api {
#FormUrlEncoded
#POST("getMerchantProductsSlideContent")
fun getProductsForSlide(
#Header("Authentication") token:String,
#Field("deviceId") deviceId:String,
#Field("content_receiver") content_receiver:String,
#Field("content_type") content_type:String,
#Field("data") data:Array<String>
):Call<DefaultResponse>
}
In your activity:
val prefToken = // get it from prefences
val token = "Bearer " + prefToken

Instead of trying to store the context in a singleton, store the header you want to send. Access the context & sharedpreferences in your Activity.
Change:
RetrofitClient.instance.getContext(this)
To something like
RetrofitClient.instance.setAuthHeader(getSharedPreferences().getString("Header"))

Recreate object in kotlin

I have simple issue: need recreate a object with other parameters.
Have this object:
object NetworkClient {
var BASE_URL = "http://google.ru" //we can take this from another class or Pref's
const val API_BASE_URL = "$BASE_URL/api/"
val httpClient = OkHttpClient.Builder()
val client: Client
var retrofit: Retrofit
init {
val builder = Retrofit.Builder()
.baseUrl(API_BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
retrofit = builder.client(httpClient.build()).build()
client = retrofit.create<PapaJobsClient>(Client::class.java)
}
}
In rare cases you need to change the BASE_URL on the fly to another String and recreate client and etc. I know how to make it, but my resolution so hard - need rework all places where i use this class but i want create this object with concrete parameter. How you think about this problem?

You need to make a separate class for that, since singletons (object in Kotlin) cannot have a constructor:
class NetworkClient(val baseUrl: String) {
const val API_BASE_URL = "$baseUrl/api/"
val httpClient = OkHttpClient.Builder()
val client: Client
var retrofit: Retrofit
init {
// ...
}
}
Use an object to have the current networkClient instance always at hand:
object NetworkClientProvider {
var networkClient = NetworkClient("http://google.ru")
}
Usage, if you need to create a new NetworkClient:
NetworkClientProvider.networkClient = NetworkClient("http://someOtherDomain.com")

You're misusing object here. This should be used if you really have a single instance of a class, it's the Kotlin built-in feature for applying the Singleton pattern.
Fix it by making it a regular class:
class NetworkClient(val baseurl: String) {
const val API_BASE_URL = "$baseurl/api/"
val httpClient = OkHttpClient.Builder()
//...
}
Then it’s possible to create objects with different baseurls as shown:
val russian = NetworkClient("http://google.ru")
val com = NetworkClient("http://google.com")