First, we have to arrange the Android challenge by putting in the required dependencies. These embrace Retrofit, OkHttp, and a JSON net token library. We will even configure the community request within the Android challenge utilizing Retrofit.

Right here is an instance of the best way to set up the Retrofit library in your construct.gradle file:

implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
implementation 'com.squareup.okhttp3:logging-interceptor:4.9.0'

And right here is an instance of the best way to arrange the Retrofit request:

val retrofit = Retrofit.Builder()
.baseUrl("https://api.instance.com/")
.addConverterFactory(GsonConverterFactory.create())
.construct()

Subsequent, we’ll create an OkHttp interceptor so as to add a token to the headers of our API requests.

class AuthInterceptor: Interceptor 
override enjoyable intercept(chain: Chain): Response 
val token = getFromStorage()
val request = chain.request()
if (token.isNullOrEmpty()) 
val newRequest = request
.newBuilder()
.header("Authorization", "Bearer $token")
.construct()
return chain.proceed(newRequest)

return chain.proceed(request)

Now, we’ll create an OkHttp shopper to which we’ll add this interceptor after which add it to our Retrofit generator.

non-public enjoyable getRetrofit(): Retrofit 
val authInterceptor = AuthInterceptor()
val okHttpClient = OkHttpClient.Builder()
.addInterceptor(authInterceptor)
.construct()
return Retrofit.Builder()
.baseUrl(BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.shopper(okHttpClient)
.construct()

Since we’ve got added tokens to every of our requests, it could be the case that the token will not be current or invalid and the request will fail with 401 standing code. In that case, we have to refresh the token, put it aside to native storage, and make the unique request once more.

class AuthInterceptor: Interceptor 
non-public enjoyable refreshToken():Response 
// make an API name to get new token
return if (response.isSuccessful) 
val token = response.physique()?.token
saveTokenToLocalStorage(token)
val newRequest = request
.newBuilder()
.header("Authorization", "Bearer $token")
.construct()
chain.proceed(newRequest)
 else 
chain.proceed(request)

override enjoyable intercept(chain: Chain): Response 
val token = getFromStorage()
val request = chain.request()
if (token.isNullOrEmpty()) 
val newRequest = request
.newBuilder()
.header("Authorization", "Bearer $token")
.construct()
val response = chain.proceed(newRequest)
return if (response.code() == 401) 
refreshToken()
 else 
response

 else 
refreshToken()

return chain.proceed(request)

updateToken() The perform will make a brand new API name to get a brand new token from the server after which it is going to be up to date in our native storage, after which we are able to make the unique request once more with the up to date token.

Refreshing JWT tokens in Android is essential to make sure the safety of your API calls. By utilizing OkHttp Interceptor, you may automate the method and make it easy. I hope this instance might help you perceive the implementation of the JWT token replace in Android and equip you with the required abilities to combine it into your individual tasks.

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