WeChat QR Code ID Verification

I need a small, self-contained module that lets me verify a person’s identity by having them scan a WeChat-generated QR code. When the code is scanned, WeChat should return a secure callback confirming the user’s OpenID (or UnionID) so I can treat the scan as proof of identity... (Budget: $10 - $30 USD, Jobs: Android, API Development, Java, Node.js, PHP, Python, Software Architecture, Web Development)