How to verify in app purchases for google play? [duplicate]

This question is an exact duplicate of:

• How can I verify IAP purchases on my RESTAPI with googles server?

How can I verify google in app purchases on my separate server (using PHP)? I am using google's IAHelper class, what should I do after I receive the purchase object?

How can I use googles API to validate a receipt on my RESTAPI? I seen many threads similar to this, all of which are either:

• Outdated.
• Not answered at all.
• Do not provide a clear 2017 answer with how to implement.

The main purpose I need for verification is to:

• Stop IAP crackers.

• Provide a secure way only a valid receipt can trigger a MySQL query to run giving digital content to the user (and one would surly just decompile my app, strip the IAP code out and use my RESTAPI for there advantage sending fake receipts without verification)

I would really prefer a PHP way to do this, but I can do node.js as a last option.

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