PayPal Client (for Haskell)
This library allows you to connect with PayPal's REST API V1 through Haskell.
Warning Regarding Stability
During releases under 1.0.0, please use exact version numbers as bug fixes may require breaking changes while this library is unstable.
What Can It Do?
Currently implemented API resources include:
- OAuth 2
- Create a payment
- Execute approved PayPal payment
- Show payment details
- List payments
Documentation and Usage Examples
Documentation can be found at the page for paypal-rest-client in Hackage.
The PayPal Monad and Session
PayPal's API uses OAuth 2 and therefore provides access tokens which expire.
When this happens, the access token must be renewed. This problem is solved by
PayPalOperations monad. This monad can chain PayPal actions together which
will be executed consecutively by
execPayPal. If the token expires before an
action is executed, the token is first renewed.
Suppose you need to create a new payment, then get that payment ID back as well as a list of all payment IDs. You could write this:
import Network.Payments.PayPal import Network.Payments.PayPal.Payments myOperations :: PayPalOperations (PaymentID, [PaymentID]) myOperations = do cRes <- createPayment $ CreateRequest ... lRes <- listPayments Nothing return (createResPayId cRes, map createResPayId $ listResPayments lRes)
Then, given you have a
Config module with the credentials, you can execute the
monad and get your results like so
import Config import Network.Payments.PayPal main :: IO () main = do payPalResult <- execPayPal sandboxUrl Config.clientId Config.secret myOperations case payPalResult of Left err -> show err Right (newId, allIds) -> do putStrLn ("The new ID is: " ++ show newId) putStrLn ("All IDs are: " ++ show allIds)
The monad does not need to take error handling into account. If an error occurs,
the monad receives a short circuit and the rest of the code is not executed. The
error is simply returned to be handled. In the example, this means if
listPayments will never run.