Timeline for answer to How do I mitigate a scenario where a user goes to pay, but the price is changed mid-request? by cjs
Current License: CC BY-SA 4.0
Post Revisions
15 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Feb 20, 2020 at 21:05 | audit | First posts | |||
| Feb 20, 2020 at 21:05 | |||||
| Jan 25, 2020 at 11:24 | comment | added | cjs | @Jasen On most shopping sites you do not contract to purchase until after you've entered your card information. See, e.g., Amazon.com. | |
| Jan 25, 2020 at 9:39 | comment | added | Jasen | A: "Buy $10" Server: "price $10 enter card" B: "price now $20" A:"card xxxx-xxxx-xxxx-xxxx", Sever: "Alice, here is product. Bob, here is $10" B: "WTF?" | |
| Jan 25, 2020 at 5:17 | comment | added | cjs | @Loren That goes back to the core confusion here. The transaction did not start when the seller posted his offer. The transaction started when the seller received an acceptance of the offer. If that acceptance was received after the seller revoked the offer, clearly there can be no transaction. | |
| Jan 25, 2020 at 5:14 | comment | added | Loren Pechtel | @MartinSmith Only if you're willing to reject the transaction because the price changed in the middle. | |
| Jan 24, 2020 at 21:52 | comment | added | cjs | @Loren Or to put it in another way, it's pefectly fine to trust user data when the user data is, "I am willing to pay up to $10 for one of these, but I will not purchase it if it's more than that." | |
| Jan 24, 2020 at 8:31 | comment | added | Martin Smith |
@LorenPechtel - this answer doesn't require trusting user data. If Alice sends a message for Purchase item for $0.01 or even Purchase item for -$10. the Server will just respond with Item not available for that price; current price is $x.
|
|
| Jan 24, 2020 at 5:19 | comment | added | Loren Pechtel | This means trusting user data--a very big no-no. | |
| Jan 23, 2020 at 16:24 | comment | added | Cruncher | @JosefsaysReinstateMonica Which matters for something high volume. But when selling a thing or a service on a website, the negotiation is very local and is surely possible to only have 1 bidder. In this case they control the entire "market" | |
| Jan 23, 2020 at 16:15 | comment | added | Josef | @0x5453 only if all of them work together. Because a market order means to buy at the lowest available price. | |
| Jan 23, 2020 at 14:22 | comment | added | 0x5453 | There could be abuse for a website like this where there are not regulating bodies in place to prevent such. For example, sellers could repeatedly flash between a reasonable offer and some insane number, hoping that a few users will use market orders without paying attention to the price updates during "checkout". | |
| Jan 23, 2020 at 14:11 | comment | added | cjs | @0x5453 Yes, those are known as "market" and "limit" orders. I was trading cash-settled options on futures of an index, and market orders were almost never used. (I certainly never used them.) There's no "abuse" in changing your orders frequently; it's quite normal to cancel old orders before they've been filled. The only limit is on how fast you can send your orders to the exchange, which can easily be several dozen per second. | |
| Jan 23, 2020 at 13:45 | comment | added | 0x5453 | Going along with the exchange example, an alternative solution would be to present different order types to the customer. Let them choose "just give me the current market price, I'll pay whatever it is" vs "I will pay $x or better, and I'm ok if my order isn't executed right away." (Though make sure to take precautions to prevent the first option from being abused, such as limiting the frequency of price updates from the seller.) | |
| Jan 23, 2020 at 12:32 | history | edited | cjs | CC BY-SA 4.0 |
added 356 characters in body
|
| Jan 23, 2020 at 5:18 | history | answered | cjs | CC BY-SA 4.0 |