Google Play In-app Billing Validation

This (simple) gem validates In-app Billing transactions. Pass your base64 encoded public key, the transaction data (json) and the base64 encoded signature and it will return a boolean value telling you whether or not your transaction is valid.

##Installation

$ gem install play_billing_validator

##Requirements

A public key for your Android app's in app billing. Get it from the Google Play Developer Console.

##Usage

Implement the In-app Billing in your Android app:

String data = data.getStringExtra(RESPONSE_INAPP_PURCHASE_DATA);
String signature = data.getStringExtra(RESPONSE_INAPP_SIGNATURE);

Then send the data and signature to your server and validate like this:

data = params[:data]
signature = params[:signature]
if (PlayBilling::Transaction.valid(public_key, data, signature))
    # success. save the transaction, give away cookies and so on.
else
    # booo. bad transaction data. reprimand the crook or give them a cookie anyway.
end

I recommend keeping a record of valid transactions in your database to prevent malicious users from replaying them for free loot.

Details

Need more detail on how all of this works (especially the Android implementation)? Read Google's In-app Billing Docs.

Thanks

Thanks to Walt Schlender for his answer to this StackOverflow question. This gem is based on that post.

##Copyrights and License

• Copyright (c) 2013 Amro Mousa. This gem is licensed under the MIT license. See LICENSE.txt for details.