*added API to check for fingerprint authentication availability

*checking for availability before showing auth dialog
*throwing authentication error if not available

Author: Matthew Wheatley

README.md

@@ -1,5 +1,5 @@
 #Installation
-`meteor add cordova:cordova-plugin-android-fingerprint-auth@0.0.1`
+`meteor add cordova:cordova-plugin-android-fingerprint-auth`
 
 #Setup
 Add preferences to mobile-config.js
@@ -15,14 +15,15 @@ buildToolsVersion "23.0.2"
 ```
 
 #API
+##FingerprintAuth.show
 ```
 FingerprintAuth.show({
             clientId: "myAppName",
             clientSecret: "a_very_secret_encryption_key"
         }, successCallback, errorCallback);
 
 /**
- * @return {withFingerprint:base64EncodedString, withPassword:String}
+ * @return {withFingerprint:base64EncodedString, withPassword:boolean}
  */
 function successCallback(result) {
     console.log("successCallback(): " + JSON.stringify(result));
@@ -34,9 +35,35 @@ function successCallback(result) {
 }
 
 function errorCallback(error) {
-    console.log("errorCallback(): " + error);
+    console.log(error); // "Fingerprint authentication not available"
 }
 
 ```
 Opens a native dialog fragment to use the device hardware fingerprint scanner to authenticate against fingerprints
-registered for the device.
+registered for the device.
+
+##FingerprintAuth.isAvailable
+```
+FingerprintAuth.isAvailable(isAvailableSuccess, isAvailableError);
+
+/**
+ * @return {
+ *      isAvailable:boolean,
+ *      isHardwareDetected:boolean,
+ *      hasEnrolledFingerprints:boolean
+ *   }
+ */
+function isAvailableSuccess(isAvailable) {
+    console.log("FingerprintAuth available: " + JSON.stringify(isAvailable)); // { isAvailable: true }
+    if (isAvailable) {
+        FingerprintAuth.show({
+                    clientId: "myAppName",
+                    clientSecret: "a_very_secret_encryption_key"
+                }, successCallback, errorCallback);
+    }
+}
+
+function isAvailableError(message) {
+    console.log("isAvailableError(): " + message);
+}
+```

package.json

@@ -1,6 +1,6 @@
 {
   "name": "cordova-plugin-android-fingerprint-auth",
-  "version": "0.0.1",
+  "version": "0.0.2",
   "description": "Cordova plugin to use Android fingerprint authentication API",
   "cordova": {
     "id": "cordova-plugin-android-fingerprint-auth",

plugin.xml

@@ -2,7 +2,7 @@
 <plugin xmlns="http://apache.org/cordova/ns/plugins/1.0"
         xmlns:android="http://schemas.android.com/apk/res/android"
         id="cordova-plugin-android-fingerprint-auth"
-        version="0.0.1">
+        version="0.0.2">
     <name>FingerprintAuth</name>
     <description>Cordova plugin to use Android fingerprint authentication API</description>
     <license>Apache 2.0</license>

src/android/FingerprintAuth.java

@@ -50,6 +50,7 @@ public class FingerprintAuth extends CordovaPlugin {
 	public static KeyStore mKeyStore;
 	public static KeyGenerator mKeyGenerator;
 	public static Cipher mCipher;
+	private FingerprintManager mFingerPrintManager;
 
 	public static CallbackContext mCallbackContext;
 	public static PluginResult mPluginResult;
@@ -82,6 +83,9 @@ public void initialize(CordovaInterface cordova, CordovaWebView webView) {
 		mKeyguardManager = cordova.getActivity().getSystemService(KeyguardManager.class);
 		mPluginResult = new PluginResult(PluginResult.Status.NO_RESULT);
 
+		mFingerPrintManager = cordova.getActivity().getApplicationContext()
+				.getSystemService(FingerprintManager.class);
+
 		try {
 			mKeyGenerator = KeyGenerator.getInstance(
 					KeyProperties.KEY_ALGORITHM_AES, ANDROID_KEY_STORE);
@@ -118,45 +122,66 @@ public boolean execute(final String action,
 						   JSONArray args,
 						   CallbackContext callbackContext) throws JSONException {
 		mCallbackContext = callbackContext;
-		Log.v(TAG, "FingerprintAuth action:" + action);
+		Log.v(TAG, "FingerprintAuth action: " + action);
 
 		JSONObject arg_object = args.getJSONObject(0);
-		mClientId = arg_object.getString("clientId");
-		mClientSecret = arg_object.getString("clientSecret");
 
 		if (action.equals("authenticate")) {
-			createKey();
-			cordova.getActivity().runOnUiThread(new Runnable() {
-				public void run() {
-					// Set up the crypto object for later. The object will be authenticated by use
-					// of the fingerprint.
-					if (initCipher()) {
+		    mClientId = arg_object.getString("clientId");
+        	mClientSecret = arg_object.getString("clientSecret");
+			if (isFingerprintAuthAvailable()) {
+				createKey();
+				cordova.getActivity().runOnUiThread(new Runnable() {
+					public void run() {
+						// Set up the crypto object for later. The object will be authenticated by use
+						// of the fingerprint.
+						if (initCipher()) {
 
-						mFragment = new FingerprintAuthenticationDialogFragment();
-						mFragment.setCancelable(false);
-						// Show the fingerprint dialog. The user has the option to use the fingerprint with
-						// crypto, or you can fall back to using a server-side verified password.
-						mFragment.setCryptoObject(new FingerprintManager.CryptoObject(mCipher));
-						mFragment.show(cordova.getActivity().getFragmentManager(), DIALOG_FRAGMENT_TAG);
-					} else {
-						// This happens if the lock screen has been disabled or or a fingerprint got
-						// enrolled. Thus show the dialog to authenticate with their password first
-						// and ask the user if they want to authenticate with fingerprints in the
-						// future
-						mFragment.setCryptoObject(new FingerprintManager.CryptoObject(mCipher));
-						mFragment.setStage(
-								FingerprintAuthenticationDialogFragment.Stage.NEW_FINGERPRINT_ENROLLED);
-						mFragment.show(cordova.getActivity().getFragmentManager(), DIALOG_FRAGMENT_TAG);
+							mFragment = new FingerprintAuthenticationDialogFragment();
+							mFragment.setCancelable(false);
+							// Show the fingerprint dialog. The user has the option to use the fingerprint with
+							// crypto, or you can fall back to using a server-side verified password.
+							mFragment.setCryptoObject(new FingerprintManager.CryptoObject(mCipher));
+							mFragment.show(cordova.getActivity().getFragmentManager(), DIALOG_FRAGMENT_TAG);
+						} else {
+							// This happens if the lock screen has been disabled or or a fingerprint got
+							// enrolled. Thus show the dialog to authenticate with their password first
+							// and ask the user if they want to authenticate with fingerprints in the
+							// future
+							mFragment.setCryptoObject(new FingerprintManager.CryptoObject(mCipher));
+							mFragment.setStage(
+									FingerprintAuthenticationDialogFragment.Stage.NEW_FINGERPRINT_ENROLLED);
+							mFragment.show(cordova.getActivity().getFragmentManager(), DIALOG_FRAGMENT_TAG);
+						}
 					}
-				}
-			});
-			mPluginResult.setKeepCallback(true);
+				});
+				mPluginResult.setKeepCallback(true);
+				mCallbackContext.sendPluginResult(mPluginResult);
+
+			} else {
+				mPluginResult = new PluginResult(PluginResult.Status.ERROR);
+				mCallbackContext.error("Fingerprint authentication not available");
+				mCallbackContext.sendPluginResult(mPluginResult);
+			}
+			return true;
+		} else if (action.equals("availability")) {
+			JSONObject resultJson = new JSONObject();
+			resultJson.put("isAvailable", isFingerprintAuthAvailable());
+			resultJson.put("isHardwareDetected", mFingerPrintManager.isHardwareDetected());
+			resultJson.put("hasEnrolledFingerprints", mFingerPrintManager.hasEnrolledFingerprints())
+			mPluginResult = new PluginResult(PluginResult.Status.OK);
+			mCallbackContext.success(resultJson);
 			mCallbackContext.sendPluginResult(mPluginResult);
 			return true;
 		}
 		return false;
 	}
 
+	private boolean isFingerprintAuthAvailable() {
+		return mFingerPrintManager.isHardwareDetected()
+				&& mFingerPrintManager.hasEnrolledFingerprints();
+	}
+
 	/**
 	 * Initialize the {@link Cipher} instance with the created key in the {@link #createKey()}
 	 * method.

www/FingerprintAuth.js

@@ -16,5 +16,15 @@ FingerprintAuth.prototype.show = function (params, successCallback, errorCallbac
     );
 }
 
+FingerprintAuth.prototype.isAvailable = function (successCallback, errorCallback) {
+    cordova.exec(
+        successCallback,
+        errorCallback,
+        "FingerprintAuth",  // Java Class
+        "availability", // action
+        [{}]
+    );
+}
+
 FingerprintAuth = new FingerprintAuth();
 module.exports = FingerprintAuth;