I'm working on a Dapp where users will buy tokens. Each token has a fixed price, let's say $100. Token holders will receive rewards in USN/USDT/USDC every X days.
What is the best way to implement it on Near Protocol? I mean the part of accepting payments from users and sending rewards back to them?
I guess the easiest way would be to use USN (Near-native Stablecoin), but I cannot find any information on how to use it in my smart contracts.
What about USDT, USDC, etc? Should I use some service to accept payments in those stablecoins?
Thanks!
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I uploaded and created a new smart contract. I sent 1000 units to this smart contract.
However when the contract is deployed the transferable is not equal to 1000.
And when I execute any function it also deducts the transferable.
Is there any way to prevent this. I want to deduct user token instead of the smart contract token. In Ethereum, the user token is deducted.
I want to deduct user token instead of the smart contract token. In Ethereum, the user token is deducted.
I think there is a misunderstanding here, you probably understood the deducted tokens as gas. But gas is deducted from the instantiating account (what you referred to as "user token"), same as in Ethereum.
The amount that is deducted from the contract here is state rent ‒ i.e. the contract has to regularly pay for the amount of state and code storage it uses. This is a concept which is currently used by the contracts pallet to reduce state bloat. I won't link to the documentation here though, since a new paradigm will be introduced soon, making it obsolete.
Is there a way to check the balance of Square gift cards through the API? I'm making an app on behalf of a merchant at a school who would like to facilitate mobile orders through the use of prepaid gift cards.
According to the user documentation, the receipt of a transaction received by the customer will display any remaining balance, but when I look at the API documentation no such information seems to be provided.
Any advice? Thanks.
You were right to check out the documentation. At this time there isn't an API for any giftcard functionality, including checking balances.
I want to integrate recurring payment using Payeezy in codeigniter. I have implement the single time payment using curl and now i want to recurring payment with acknowledgement to update my DB.
I created a WordPress plugin for Payeezy that also handles recurring. You should be able to use the underlying PHP code for CodeIgniter.
https://wordpress.org/plugins/wp-payeezy-pay/
I can explain the process that will get you the least PCI compliance issues, and that's the token-based API.
1. Generate Token in Payment Form
So basically you'll use the Javascript API to generate your authorize token. An authorize token doesn't charge the card. It's for validating the card and returning a token for better PCI compliance. This API source code and explanation is here:
https://github.com/payeezy/payeezy_js
2. Post Form To Your Server for the Curl Call to FirstData
Then, once you have this token, you post it back to your controller file with a standard form post, but remove the name attribute on your credit card number and credit card CVC fields so that these do not post to your server. Note that you'll need to store this data (but not card number and CVC) because on refunds (and subscription cancellations) you'll need to reply back with the last purchase token, cardholder name, card type, card expiration date, amount spent, and currency code. You may wonder why FirstData/PayEezy is asking you to store cardholder name, card type, and card expiration date. Well, there's a perfectly good explanation for that. Your call center may need that detail for troubleshooting an issue over the phone with a customer. Also, you need that for refunds. And, most importantly, if you're doing a recurring subscription payment, your code needs to look at the expiration date ahead of time before charging because the API call will fail if the card is past expiration. Last, because you're not storing the credit card number and credit card validation (CVC) code, you're going to be in stronger PCI compliance.
From there, since you are already familiar with the Curl process for a single-purchase, it's just a minor single field change (transaction_type becomes 'recurring') in the Curl to do the recurring. For anyone not familiar with the Curl process, it's explained here:
https://developer.payeezy.com/payeezy-api/apis/post/transactions-4
Also, for those unfamiliar people, you'll need to read up on how FirstData/PayEezy wants you to send in the Curl request with a special header that includes Content-Type: application/json, apikey, token, Authorization, nonce, and timestamp. You can see more detail about that here:
https://github.com/payeezy/payeezy_direct_API/blob/master/payeezy_php/example/src/Payeezy.php
(What I did to make that code simpler was intercept the Curl calls from that script into a log file so that I could make it much more straightforward in a single function instead of breaking it up into all these little functions. That made it far easier to understand what was going on.)
3. Switching Curl Call for Recurring Payments
So, as you discovered in your Curl call, you saw how to do a one-time purchase by setting the transaction_type to 'purchase'. For doing recurring, you set transaction_type to 'recurring'. You have to do that from the start. So, if I'm selling something for $29.99 monthly, the very first month charge needs to still be set to type 'recurring', as would any subsequent month.
4. Your Responsibilities for Recurring Payments
Now, this is where everyone gets hung up because it's poorly documented unless you check the PayEezy Developer Support Forum. For subscriptions, PayEezy doesn't have a system for setting payment plans with varying durations, nor setting up automatic (set-it-and-forget-it) subscriptions for you. (I think I read that they have something experimental on Apple Pay, but nothing else yet.) So, to achieve this, you have 2 choices:
Use Chargify.com. Unfortunately, though, this increases CPA (Cost Per Acquisition) of your product or service. You'll have to factor that in if you want to use that. This basically is a SaaS service that you send the transaction to and they handle the automatic subscription plan for you against FirstData/PayEezy.
Roll your own cron job solution. To do this, you basically take the Curl code for a single transaction, and change the transaction type from 'purchase' to 'recurring'. (Do that from the start -- don't start with 'purchase' on a recurring charge.) From there, it's up to you with your own cron job to check for product or service expiration terms, and then send the API call back off to FirstData/PayEezy for charging that card again with the 'recurring' transaction_type.
On either of those options, the customer never gets asked to enter in credit card data past the first time unless their card expires or unless you have some problem billing that card (like insufficient funds).
Of course, doing your own cron job route for the recurring payment has implications you'll need to prepare for:
Add some failsafe code so that you prevent the possibility of duplicate transactions, such as a database field.
Add some failsafe code such that if you have cancelled a subscription, you won't charge them again.
Add some failsafe code such that if they cancel their subscription, yet purchase it again as a subscription at a later time, that you do charge them again and don't block it from your other failsafe code.
Add some sort of grace period on your product or service such that even if you "say" that the term expired, you have like a 2 day grace period so that your API has a chance to do a renewal.
It's probably a good idea to email the customer before their renewal period so that they can make certain they have money in their account and have a way to cancel that charge (like call your office or call center, or have a link to click where you provide a way to cancel).
If their card has expired before the renewal, and you detect that in the warning email that comes before renewal, then you'll want to let them know this.
If their card has been declined for any reason at the point of renewal, then you'll want to let them know this and give them a link to go through the cart again to buy it again, or some other way to save that transaction in your code.
How To Do Subscription Cancellations / Stop Recurring Payments
To stop a recurring payment, you treat it just like a refund on a single purchase, but use the transaction ID of the last purchase. This is documented with this Curl example here:
https://developer.payeezy.com/payeezy-api/apis/post/transactions/%7Bid%7D-0
Look under "Refund" and choose Token.
I am currently in the process of planning & developing an integrated application using Stripe in addition to some other technologies (a combination of backbone & laravel). As a result I am using Stripejs in combination with the PHP stripe library.
I use stripejs to send Stripe their account info (for savings accounts I send country, routing and account numbers via stripes js lib, I then save off the created token in the response to the backend). I am attempting to transfer money to various recipients following charging accounts (so I have money in my stripe account) but I am a bit confused over exactly what approach to take.
My main questions are as follows.
If I am positive of the identities of the individual’s using the application, is verification required (5 – 10 people max will be using)?
If it is required what is the best approach to verifying the user using the current technique I am using (create a token, save off on the backend)?
From my experience with Stripe, you don't need to 'verify identities' each time you use a token, so long as a customer has been set up for recurring use. So as long as your application is properly secured so that only the 5-10 people can use it, and can only process payments for their own accounts, you are good to go. In other words, you obviously want to do your own user verification to make sure only valid people can use the application, but you don't need to do it as far as Stripe is concerned.
That said, if you are in essence transferring money between people, you might want to go the extra distance and make sure that the user has the correct card number or bank account number each time. In which case I would use something like:
Get user data using tokens stored in DB.
$cu = Stripe_Customer::retrieve("cus_4pn93XXXXXXXXXXX");
$card = $cu->cards->retrieve("card_14g7ZU4rLTyXXXXXXXXXXX");
If Stripe's returned data matches user-submitted data, you know you have the correct user. In particular, if the last 4 digits of the card and the expiry date match the last 4 returned by Stripe and the Stripe returned expiry date, you can be reasonably sure (albeit not certain) that the person actually possesses the card in question.
I'm coding a new website that will need users to enter their mobile phone number, the problem I'm facing is that I need to make sure that the user is in fact the owner of (or in this case, has access to) the mobile number.
The solution I've come up with is, upon number submission I send them a SMS with a token and ask the user to enter the token on my website, much like Google Calendar does. However I'm on a short budget and I need to make sure user A doesn't submit 100,000 mobile numbers, if that happens I'll be out of business in no time, since each SMS sent costs me about 0.10 USD.
So far, I've come up with the following solutions:
use a CAPTCHA (keeps some users away and it is still vulnerable to manual registrations)
limit the number of tokens a given IP address request (dynamic IPs, proxies, etc)
limit the number of tokens sent for a given mobile number (a user can request tokens for all the available numbers and when the real user tries to request a legitimate token, his number will be already blocked)
None of these solutions are perfect, how do you suggest I approach this problem?
In a recent project, we were associating SMS numbers with a user account. Each account needed a CAPTCHA and email activation. The user could activate SMS via token, like you are using.
You could rate limit IP addresses (not a total limit). No more than 10 requests from an IP within 5 minutes, or something like that.
And/or you could limit outstanding SMS requests. After an IP address requests a token for SMS, it must be submitted before that IP can request for another SMS number. Or no more than 10 outstanding SMS tokens per IP per day.
Also, like #Alan said, we put a cap on our SMS messages per month.
I would use a combination of CATPCHA and Limit the requests of a Given Mobile Number.
In addition you should be able to specify with your SMS aggregator a preset limit per month. After you reach that limit, service is shutoff. That way if you are a victim of an attack, you will only be liable for a limited amount of money.
Instead of SMS, you can make use of an automated service that calls a phone number speaks out a One Time Password (via Text 2 speech). These services are similar in pricing to SMS, and less likely to get spam abused, as there is more overhead.
Twilio cost $0.03 a minute, or in this case, $0.03 a call.
You could do what Twitter does, which is have the user text you the token (rather than you texting it to them).
This will require you to find a provider that let's you receive texts for free (or close to it), but that might be easier.
Why is SMS costing you a dime? Utilize the EMAIL address that is associated with every SMS system (at least here in the U.S).
http://www.sms411.net/2006/07/how-to-send-email-to-phone.html
If someone tries their best to abuse a system, they will more than likely find a way to do it.
Using a combination of the techniques you've already come up with is likely the best way to thwart most malicious users.
Limit what people can do (no more than 10 requests from 1 ip in 10 minutes, one phone number can only recieve 3 texts a week, captcha before number entry), but more importantly, if people have no control over the content of the message there's no real reason to exploit it.