Refresh token handling using retrofit in android java-CodePudding

i am using jwt Authentication in android . i am able to get access token and expire time and using interceptors i am sending in headers . here everything works fine . but when token expires i am not able to handle the case.

i am using single ton retrofit class and i have the refresh token api . but i don't know how to call the refresh token api when the token expires .

i have 2 suggestions

i have to call the refresh token api before the access token expires or else whenever the 401 error occurs it should automatically call the refresh token api

CodePudding user response：

Here are a couple of ways you can handle token expiration in your Android app:

You can check the expiration time of the token before it expires and call the refresh token API in advance. This way, you always have a valid token.

You can use an interceptor that automatically calls the refresh token API whenever a 401 error occurs. This way, if the token expires while the user is using the app, the interceptor will refresh it automatically.

Remember to handle the case where the refresh token itself expires or is invalid and prompt the user to log in again. Also, it is important to clear the token from local storage after refresh.

CodePudding user response：

Here's an example of how you might implement the second approach I mentioned, using an interceptor to automatically refresh the token when a 401 error occurs:

public class TokenRefreshInterceptor implements Interceptor {
    private TokenStore tokenStore;

    public TokenRefreshInterceptor(TokenStore tokenStore) {
        this.tokenStore = tokenStore;
    }

    @Override
    public Response intercept(Chain chain) throws IOException {
        Request request = chain.request();
        Response response = chain.proceed(request);

        if (response.code() == 401) {
            // Attempt to refresh the token
            TokenResponse tokenResponse = refreshToken();

            if (tokenResponse != null) {
                // Replace the old token with the new one
                tokenStore.saveToken(tokenResponse.getAccessToken(), tokenResponse.getExpiration());

                // Add the new token to the request header
                request = request.newBuilder()
                    .header("Authorization", "Bearer "   tokenResponse.getAccessToken())
                    .build();

                // Retry the request with the new token
                return chain.proceed(request);
            } else {
                // Token refresh failed, prompt user to log in again
                // redirect to login page
            }
        }

        return response;
    }

    private TokenResponse refreshToken() {
        // Implement your refresh token logic here
        // Make a refresh token API call and parse the response to get the new token and expiration
        // Return the TokenResponse object containing the new token and expiration
    }
}

You can then add the interceptor to your Retrofit client:

Retrofit retrofit = new Retrofit.Builder()
    .baseUrl(API_BASE_URL)
    .addConverterFactory(GsonConverterFactory.create())
    .client(new OkHttpClient.Builder()
        .addInterceptor(new TokenRefreshInterceptor(tokenStore))
        .build())
    .build();

Here, TokenStore is a class that holds the current access token and expiration time and should have methods such as saveToken(token, expiration), getToken(), getExpiration(), etc.