![Purchase State Changed
JSON
{ "nonce" : 1836535032137741465,
"orders" :
[{ "notificationId" : "android.test.purchased",
"orderId" : "transactionId.android.test.purchased",
"packageName" : "com.example.dungeons",
"productId" : "android.test.purchased",
"developerPayload" : "bGoa+V7g/yqDXvKRq",
"purchaseTime" : 1290114783411,
"purchaseState" : 0,
"purchaseToken" : "rojeslcdyyiapnqcynkjyyjh" }]
}](https://image.slidesharecdn.com/androidin-appbillinggoogledevfest-121109042153-phpapp01/85/Android-in-app-billing-Google-DevFest-Barcelona-2012-29-320.jpg)
![Set Configuration
public void onCreate() {
super.onCreate();
BillingController.setDebug(true);
BillingController.setConfiguration(new BillingController.IConfiguration() {
@Override
public byte[] getObfuscationSalt() {
return new byte[] {41, -90, -116, -41, 66, -53, 122, -110, -127, -96, -88, 77, 127
}
@Override
public String getPublicKey() {
return "your public key here";
}
});
}](https://image.slidesharecdn.com/androidin-appbillinggoogledevfest-121109042153-phpapp01/85/Android-in-app-billing-Google-DevFest-Barcelona-2012-54-320.jpg)
Android in-app billing @ Google DevFest Barcelona 2012
- 1. @hpique
- 2. Android In-app Billing Demystified Hermés Piqué @hpique
- 3. Agenda • In-app Billing Overview • Google Play Billing Service • Android Billing Library • Security Best Practices
- 4. Top Grossing is dominated by IAB
- 5. Freemium Digital goods Virtual currency Subscriptions
- 7. In-app billing terms • Powered by Google Wallet • 30% of the sale price • No refunds (kinda) • Only for digital goods • Flexible pricing (unlike iOS)
- 8. Agenda • In-app Billing Overview • Google Play Billing Service • Android Billing Library • Security Best Practices
- 9. Google Play Billing Service • Google Play only • Android 1.6 upwards (API level 4) • Now at version 2 with subscriptions support
- 10. Product types • In-app products • Managed (per user account): premium, digital content • Unmanaged: virtual currency, consumable virtual goods • Subscriptions • Monthly & yearly with free trials support
- 11. Pre-requisites • Services • AIDL • BroadcastReceiver • PendingIntent
- 12. Wait, there’s more • SQLite • Obfuscation • Signature validation • 57 pages of doc!
- 13. Architecture overview app Android IAB Market requests Server
- 14. IAB requests • CHECK_BILLING_SUPPORTED • REQUEST_PURCHASE • GET_PURCHASE_INFORMATION • CONFIRM_NOTIFICATIONS • RESTORE_TRANSACTIONS
- 15. IAB requests • MarketBillingService interface defined in an Android Interface Definition Language file (IMarketBillingService.aidl) • IAB requests sent by single IPC method (sendBillingRequest()) of the interface • Request type and parameters are sent as a Bundle
- 16. Binding to MarketBillingService try { boolean bindResult = mContext.bindService( new Intent("com.android.vending.billing.MarketBillingService.BIND"), this, Context.BIND_AUTO_CREATE); if (bindResult) { Log.i(TAG, "Service bind successful."); } else { Log.e(TAG, "Could not bind to the MarketBillingService."); } } catch (SecurityException e) { Log.e(TAG, "Security exception: " + e); } public void onServiceConnected(ComponentName name, IBinder service) { Log.i(TAG, "MarketBillingService connected."); mService = IMarketBillingService.Stub.asInterface(service); }
- 17. Request bundle parameters • Shared • BILLING_REQUEST: request type • API_VERSION: “1” for in-app products, “2” for subscriptions • PACKAGE_NAME: app package • Specific • ITEM_ID, ITEM_TYPE, NONCE, NOTIFY_ID, DEVELOPER_PAYLOAD
- 18. Request bundle protected Bundle makeRequestBundle(String method) { Bundle request = new Bundle(); request.putString(BILLING_REQUEST, method); request.putInt(API_VERSION, 1); request.putString(PACKAGE_NAME, getPackageName()); return request; }
- 19. Making a request Bundle request = makeRequestBundle("REQUEST_PURCHASE"); request.putString(ITEM_ID, mProductId); Bundle response = mService.sendBillingRequest(request);
- 20. IAB responses • The IAB service responds to every request with a synchronous response • Followed by 0..N asynchronous responses depending of the request type
- 21. Synchronous responses • RESPONSE_CODE: status information and error information about a request • REQUEST_ID: used to match asynchronous responses with requests • PURCHASE_INTENT: PendingIntent, which you use to launch the checkout activity • REQUEST_PURCHASE only
- 22. Asynchronous responses • Broadcast intents: • RESPONSE_CODE • IN_APP_NOTIFY • PURCHASE_STATE_CHANGED
- 23. Receiving async responses public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (ACTION_PURCHASE_STATE_CHANGED.equals(action)) { String signedData = intent.getStringExtra(INAPP_SIGNED_DATA); String signature = intent.getStringExtra(INAPP_SIGNATURE); // Do something with the signedData and the signature. } else if (ACTION_NOTIFY.equals(action)) { String notifyId = intent.getStringExtra(NOTIFICATION_ID); // Do something with the notifyId. } else if (ACTION_RESPONSE_CODE.equals(action)) { long requestId = intent.getLongExtra(INAPP_REQUEST_ID, -1); int responseCodeIndex = intent.getIntExtra(INAPP_RESPONSE_CODE, ResponseCode.RESULT_ERROR.ordinal()); // Do something with the requestId and the responseCodeIndex. } else { Log.w(TAG, "unexpected action: " + action); } }
- 25. Check Billing Supported Parameters Shared Sync response keys RESPONSE_CODE RESULT_OK RESULT_BILLING_UNAVAILABLE Response codes RESULT_ERROR RESULT_DEVELOPER_ERROR Async response RESPONSE_CODE
- 26. Request Purchase
- 27. Request Purchase Shared ITEM_ID Parameters ITEM_TYPE DEVELOPER_PAYLOAD RESPONSE_CODE Sync response keys PURCHASE_INTENT REQUEST_ID RESULT_OK Response codes RESULT_ERROR RESULT_DEVELOPER_ERROR RESPONSE_CODE Async response IN_APP_NOTIFY
- 28. Get Purchase Information Shared Parameters NONCE NOTIFY_IDS RESPONSE_CODE Sync response keys REQUEST_ID RESULT_OK Response codes RESULT_ERROR RESULT_DEVELOPER_ERROR RESPONSE_CODE Async response PURCHASE_STATE_CHANGED
- 29. Purchase State Changed JSON { "nonce" : 1836535032137741465, "orders" : [{ "notificationId" : "android.test.purchased", "orderId" : "transactionId.android.test.purchased", "packageName" : "com.example.dungeons", "productId" : "android.test.purchased", "developerPayload" : "bGoa+V7g/yqDXvKRq", "purchaseTime" : 1290114783411, "purchaseState" : 0, "purchaseToken" : "rojeslcdyyiapnqcynkjyyjh" }] }
- 30. JSON fields (1) • nonce: to verify the integrity of the message • notificationId: to match with IN_APP_NOTIFY • orderId: Google Wallet order id • packageName: your app package
- 31. JSON fields (2) • productId: set in the Developer Console • purchaseTime: time of purchase • purchaseState: purchased, cancelled, refunded or expired • purchaseToken: subscriptionId • developerPayload: optional value provided in REQUEST_PURCHASE
- 32. Purchase states • Purchased (0) • Cancelled (1) • Refunded (2) • Expired (3): subscriptions only
- 33. Confirm Notifications Shared Parameters NONCE NOTIFY_IDS RESPONSE_CODE Sync response keys REQUEST_ID RESULT_OK Response codes RESULT_ERROR RESULT_DEVELOPER_ERROR Async response RESPONSE_CODE
- 34. Unsolicited In-app Notify • Purchase when app is running in various devices • Refunds • Subscription expired (?)
- 35. Unsolicited In-app Notify
- 37. Restore Transactions Basic Parameters NONCE RESPONSE_CODE Sync response keys REQUEST_ID RESULT_OK Response codes RESULT_ERROR RESULT_DEVELOPER_ERROR RESPONSE_CODE Async response PURCHASE_STATE_CHANGED
- 38. Security Controls • Signed purchase data • In-app notify nonces
- 39. Purchase State Changed Extras • inapp_signed_data: Signed JSON string (unencrypted) • inapp_signature: Use the Google Play public key to validate
- 41. IAB limitations • No API for product details & price • To fully test you need to pay for real • Sometimes async messages are really async
- 42. Obligatory image of Justin Bieber to wake you up
- 43. Agenda • In-app Billing Overview • Google Play Billing Service • Android Billing Library • Security Best Practices
- 45. Android Billing Library tiny.cc/android-billing • Open-source on github • “Better than starting from scratch”™
- 46. Features • Full Android IAB Service implementation • Auto-confirmations • Obfuscated purchase database • Implements security best practices • Half-decent unit testing coverage
- 47. Overview • BillingController • IBillingObserver • BillingController.IConfiguration • ISignatureValidator
- 48. Overview
- 49. Check Billing Supported " @Override " public void onCreate(Bundle savedInstanceState) { " " // ... " " BillingController.registerObserver(mBillingObserver); " " BillingController.checkBillingSupported(this); " " // ... " } " public void onBillingChecked(boolean supported) { " " if (!supported) { " " " showDialog(DIALOG_BILLING_NOT_SUPPORTED_ID); " " } " }
- 50. Request Purchase BillingController.requestPurchase(this, productId); @Override public void onPurchaseIntent(String itemId, PendingIntent purchaseIntent) { BillingController.startPurchaseIntent(activity, purchaseIntent, null); } @Override public void onRequestPurchaseResponse(String itemId, ResponseCode response) { } @Override public void onPurchaseStateChanged(String itemId, Order order) { }
- 51. Restore Transactions if (!mBillingObserver.isTransactionsRestored()) { BillingController.restoreTransactions(this); Toast.makeText(this, R.string.restoring_transactions, Toast.LENGTH_LONG).show(); } @Override public void onTransactionsRestored() { final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(activity); final Editor editor = preferences.edit(); editor.putBoolean(KEY_TRANSACTIONS_RESTORED, true); editor.commit(); }
- 53. AndroidManifest.xml <!-- Add this permission to your manifest --> <uses-permission android:name="com.android.vending.BILLING" /> <application> <!-- Add this service and receiver to your application --> <service android:name="net.robotmedia.billing.BillingService" /> <receiver android:name="net.robotmedia.billing.BillingReceiver"> <intent-filter> <action android:name="com.android.vending.billing.IN_APP_NOTIFY" /> <action android:name="com.android.vending.billing.RESPONSE_CODE" /> <action android:name="com.android.vending.billing.PURCHASE_STATE_CHANGED" /> </intent-filter> </receiver> </application>
- 54. Set Configuration public void onCreate() { super.onCreate(); BillingController.setDebug(true); BillingController.setConfiguration(new BillingController.IConfiguration() { @Override public byte[] getObfuscationSalt() { return new byte[] {41, -90, -116, -41, 66, -53, 122, -110, -127, -96, -88, 77, 127 } @Override public String getPublicKey() { return "your public key here"; } }); }
- 55. Agenda • In-app Billing Overview • Google Play Billing Service • Android Billing Library • Security Best Practices
- 56. Best Practices • Random nonces • Obfuscate purchase data • Embedding public key • Code obfuscation • Server-side signature validation
- 57. Random nonces • Sent with GET_PURCHASE_INFORMATION and RESTORE_TRANSACTION requests • Handled by ABL • Server-side nonce generation & verification not supported by ABL (but really?)
- 58. Obfuscate purchase data • Do not store purchase data plainly • Handled by ABL • Uses salt, installation id, device id and app id to perform obfuscation
- 59. Embedding public key • Do not embed the public key plainly • Only embed the public key if you can’t perform server-side signature validation
- 60. Code obfuscation • Obfuscate your app code to make it harder to hack • Problem: ABL is open-source! • Use ProGuard and consider making changes to the ABL code
- 61. Server-side validation • Perform the signature validation on a server • Supported by ABL • Provide your own ISignatureValidator; validation is performed with AsyncTask • Return null on IConfiguration.getKey
- 62. Thanks!
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