Special Considerations and Big Picture Questions

[tylerthedeveloper]

STELLAR SDK

• multiple currency payment a single transation takes a list of operations and if any fails, the whole transaction fails

  • (= https://www.stellar.org/developers/guides/concepts/transactions.html)
  • (example here: https://hackernoon.com/exploring-stellar-lumens-development-tutorial-cdf6d09a0e87)

• managing offers: - This we will have to see if it is needed for us, or if finding the path (below) is sufficient

• path finding: send the equivalent of x in y (pathfinder for between currencies a .. B … c => a … c) my understanding is to find the best path from a->c, then if it exists, make a payment following that path (= pathfinder, https://www.stellar.org/developers/horizon/reference/endpoints/path-finding.html) (= make path payment https://www.stellar.org/developers/guides/concepts/list-of-operations.html#path-payment)

• mock transaction (this might not be needed if we find the best path above)

CHECKOUT Design

• Preferred Currency: radio buttons (proceed to checkout)

• Other Checkout Options (expandable / accordion like experience)

  • Checkout with multiple currencies: A [ % ] = X A coins B [ % ] = X B Coins (continue to checkout )

Experience

• default to latest
• “this price at this time stamp for X minutes”
  • auto refresh X minutes

SECURITY

• Displayed values are consistent with DB and up to date with changes made
  • when to update the quantity
• guard against injection attacks changing transaction verification / authorization *** move to microservice
• Ensure transaction completes to protect against buying without paying
• Block form resubmission to prevent double spending

CART:

• batching and atomicity ??? --> (handled on batch transaction)
• what is a failure??? (if not failure on batch transaction, and not failure on DB updates, should be a success)
• buying something from multiple sellers… (create payment ops per operation)
• percentages??? (see checkout section)
• multi currency and multi seller -> (see above: add operations per combination)

Random Notes Slippage and who to protect and how

• set max on payment
  • set timeout window for price displayed (option to refresh OR auto re-fresh)
  • find paths to display what the conversion (and potential) slippage will be