PayTrace: 400 Bad Request For Declined Payment

TLDR:  post IS successful.  PayTrace, by design, returns a 400 error, which sets off exceptions in httpresponse.  Solution: catch the exception and then continue deserializing your response.

I coded a few weeks ago a .NET post to the PayTrace API which helps me demo and test payment by credit card using client side encryption.  The process more or less went like this:

  • Create demo account as a merchant on Paytrace
  • Download PEM key
  • On submit of form with credit card information, an imported PayTraceJS library encrypts the card number and csc code
  • Use the demo account’s username and password to submit a request for a token
  • Submit transaction (which includes encrypted info as well as other required fields) using token and await response

A successful http response returns a status code of 200.  I read it via stream, deserialize it using json into my CardResponse object (both successful and failure responses have the same design).  Everything went great until I began testing rejected cards.

.NET Core with PayTrace (Mime Type Fix)

This year I am re-writing my previous payment solution (from PHP to .NET) and first on the project list is credit cards.  We are using PayTrace and their client-side encryption as to not have to worry about PCI Compliance.

I’m to the point where I have a Pre-Payment model with all the fields needed to send via JSON.  I also have a method to request a token for sending (uses demo username and pass) and a test PEM file I downloaded from the PayTrace site.  I also got the webpage scanning credit cards, and I hit submit and.. I get this:

XML Parsing Error: no element found

This is appearing in the console of Inspector in Firefox.  Turns out this a generic error Firefox throws out when it’s expending a file but gets nothing.

My path’s are correct, but the “public_key.pem” file is not attaching to my post.   The problem?  MIME-type.…