PayPerUse validation incorrect

[r-brown]

According to the wiki page for the PayPerUse licensing model, a validation response will contain valid=true if the sum of quantity of all active licenses (given credits) is bigger than the sum of usedQuantity of these licenses (used credits).

In fact, valid=true is also returned (alongside remainingQuantity=0) if the numbers are equal.

valid=false is only returned if (in pre-payment mode) you issue a validation with reserveQuantity=N and N is greater than the number of remaining credits.
(Note: I have only tried issuing calls with reserveQuantity=1, and only get valid=false if there are no credits remaining. I don't know for sure what would happen if there were 10 credits remaining and you asked for 11.)

So if the current behaviour is intended, the documentation needs to be corrected.
But to say that a PayPerUse license is valid when there are no uses left seems a little strange to me.

source: Labs64/NetLicensingClient-csharp#29
requester: @HappyPathAB

[r-brown]

Just verified the described issue and got the following results (demo:demo account):

Post-payment scenario

Status before

• Quantity: 5
• Used Quantity: 3

Request

curl -X POST --header 'Content-Type: application/x-www-form-urlencoded' --header 'Accept: application/xml' --header 'Authorization: Basic ZGVtbzpkZW1v' -d 'productModuleNumber=M3-DEMO&usedQuantity=2' 'https://go.netlicensing.io/core/v2/rest/licensee/I3-DEMO/validate' | xmllint --format -

Response

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ns2:netlicensing xmlns="http://www.w3.org/2000/09/xmldsig#" xmlns:ns2="http://netlicensing.labs64.com/schema/context" ttl="2020-10-27T18:17:36.933Z">
  <ns2:infos/>
  <ns2:items>
    <ns2:item type="ProductModuleValidation">
      <ns2:property name="productModuleNumber">M3-DEMO</ns2:property>
      <ns2:property name="valid">false</ns2:property>
      <ns2:property name="remainingQuantity">0</ns2:property>
      <ns2:property name="productModuleName">Module using "Pay-per-Use" licensing model</ns2:property>
      <ns2:property name="licensingModel">PayPerUse</ns2:property>
    </ns2:item>
  </ns2:items>
</ns2:netlicensing>

Conclusion

• remainingQuantity is 0 after the validation call; accordingly, the valid flag set to false (no remaining credits available)
• sum of available credits 5 - 3 = 2 is not bigger than usedQuantity = 2 (as stated in the documentation)
  • possibly there is a confusion with the wording: bigger than vs. bigger than or equal