TokenAuthenticationProvider.java

package com.leansoft.nanorest.auth;

import com.leansoft.nanorest.client.BaseRestClient;

import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.preference.PreferenceManager;
import android.text.TextUtils;

public class TokenAuthenticationProvider implements AuthenticationProvider {

    private static final String TOKEN_KEY = "api_key";

    private static TokenAuthenticationProvider account;
    private final Context context;
    private String token;

    /**
     * <b> this object will be using a Reference to the application context via
     * getApplicationContext() NOT the Activity context</b> Recommended to be initialized at the
     * application startup or by initializing in your own class extending application
     * <p>
     * <b> Don't forget to set the password on first init </b>
     * 
     * @param context it is only used into the first time init of the singleton, its reference is
     *        stored so the singleton is alive during the application lifecycle.
     * @return
     */
    public static synchronized TokenAuthenticationProvider getInstance() {
        if (account == null) {
            throw new RuntimeException("Initialize the Provider first");
        }
        return account;
    }

    public static synchronized void init(Context context) {
        if (account == null) {
            account = new TokenAuthenticationProvider(context);
        }
    }

    private TokenAuthenticationProvider(final Context context) {
        this.context = context.getApplicationContext();
        initializeToken();
    }

    @Override
    public void authenticateRequest(BaseRestClient client) {
        if (TextUtils.isEmpty(token)) {
            return;
        }
        client.addHeader("Authorization", "OAuth " + token);
    }

    public String getToken() {
        return token;
    }

    public void setToken(String token) {
        this.token = token;
        saveApiKey(token);
    }

    public boolean isTokenValid() {
        return !TextUtils.isEmpty(token);
    }

    public boolean clearAuth() {
        Editor editor = PreferenceManager.getDefaultSharedPreferences(context).edit();
        editor.remove(TOKEN_KEY);
        boolean commit = editor.commit();
        return commit;
    }

    /**
     * Use as an alternative for saving the token to accounts (Note that using the account manager
     * is a preferred and safer method)
     * 
     * @param apiKey the token aqured from chute auth
     * @param context
     * @return if the save was successful
     */
    private boolean saveApiKey(final String apiKey) {
        Editor editor = PreferenceManager.getDefaultSharedPreferences(context).edit();
        editor.putString(TOKEN_KEY, apiKey);
        boolean commit = editor.commit();
        return commit;
    }

    private String restoreApiKey() {
        SharedPreferences savedSession = PreferenceManager.getDefaultSharedPreferences(context);
        return savedSession.getString(TOKEN_KEY, "");
    }

    private void initializeToken() {
        String apiKey = restoreApiKey();
        if (!TextUtils.isEmpty(apiKey)) {
            this.setToken(apiKey);
            return;
        }
        // Set a manual token for testing
        // this.setPassword("46e580a90085912ed11c565084f1f2465f28630bd58fa80cc98432f3078fc5ac");
    }
}