stripe-erlang: stripe client. erlang flavored.

Status

stripe-erlang is a minimal stripe client. Currently we support these operations:

• turning a credit card into an opaque token
• turning a bank account into an opaque token
• creating a customer with a token
• charging a customer
• charging in any supported currency
• charging a token
• creating a pay-out recipient
• updating details of a recipient
• transferring money to a recipient
• updating a subscription
• canceling a subscription
• retrieving customers, events, and invoiceitems

If you need refunds or transaction management, use the delightful stripe.com admin interface for now.

Usage

Quick Start

Eshell V5.9.3.1  (abort with ^G)
1> inets:start().
ok
2> ssl:start().
ok
3> application:start(stripe), application:set_env(stripe, auth_token, "vtUQeOtUnYr7PGCLQ96Ul4zqpDUO4sOE").
ok
4> rr(stripe).
[stripe_card,stripe_charge,stripe_customer,stripe_error,
 stripe_event,stripe_invoiceitem,stripe_plan,
 stripe_subscription,stripe_token]
5> #stripe_token{id = Token} = stripe:token_create("4242424242424242", 12, 2021, 123, [], [], [], [], [], []).
#stripe_token{id = <<"tok_1Lok1HEM0RJlE5">>,
              currency = 'Not Returned by API',used = false,
              amount = <<"Not Returned by API">>,livemode = false,
              card = #stripe_card{last4 = <<"4242">>,exp_year = 2021,
                                  exp_month = 12,type = <<"Visa">>,
                                  cvc_check = 'Not Returned by API',
                                  address_line1_check = 'Not Returned by API',
                                  address_zip_check = 'Not Returned by API',
                                  country = <<"US">>}}
6> stripe:charge_card(5000, usd, Token, "Mah Money").
#stripe_charge{id = <<"ch_1Lok7sGzzioHBA">>,
               created = 1361721296,amount = 5000,fee = 175,currency = usd,
               description = <<"Mah Money">>,livemode = false,paid = true,
               refunded = false,customer = null,
               card = #stripe_card{last4 = <<"4242">>,exp_year = 2021,
                               exp_month = 12,type = <<"Visa">>,cvc_check = pass,
                               address_line1_check = null,address_zip_check = null,
                               country = <<"US">>}}

Configuration

You must start inets and ssl before using stripe.

By default, erlang-stripe uses the global stripe API test token. You must change this to your private API key before you can receive payments:

inets:start(),
ssl:start(),
application:start(stripe),
application:set_env(stripe, auth_token, "sk_test_BQokikJOvBiI2HlWgH4olfQ2").

Branch Naming Policy

All Stripe API endpoints begin with /v1/ and when I built this application, Stripe was much younger and didn't have huge API changes yet. Crazy me thought by naming their API endpoint /v1/ they would rev the version number for changes.

Instead, Stripe decided to use date-based versions. So, the Stripe API for your account is /v1/ combined with the most recent YYYY-MM-DD API revision you've used.

If this were a better organized project, we'd have branches or tags against each individual API change. But, we're not that well organized.

For now, we aim to always support the most recent Stripe API release defined at their API upgrades page. If the most recent Stripe API has drifted from our implementation here, please file an issue or make a pull request so we can keep everything working.

Currencies

Stripe added multiple currency support, but how do you figure out your prices in all the different currencies?

The stripe_currency module supports reading a JSON format of currency abbreviation to exchange rates. You can get a currency JSON by signing up for free at open exchange rates.

Their free plan allow 1,000 complete exchange rate retrievals every month. You can easily cache their exchange rate output to stay under their monthly free limit.

For easier ingestion of the currency JSON, use the currencies script in priv/ to download the the JSON and format it correctly.

You can load your currency file by putting the file path in an app environment variable for stripe called currency_json or you can load the file directly with stripe_currency:load(Filename). Loading the currency JSON will cache it in the app as well.

You can convert prices using the stripe_price/4 function: stripe_currency:stripe_price(usd, eur, 500) would convert 5.00 USD into EUR. Remember, Stripe prices are in cents — unless — the currency has no cent denomination like the Yen. In that case, we can convert to a zero cent currency, but not from one for the time being.

Note: The stripe_price function automatically adds 2% to the final converted price to cover the additional fee charged by Stripe for all non-native currency transactions.

Building

    rebar get-deps
    rebar compile

Testing

    rebar eunit skip_deps=true suite=stripe

The tests automatically use valid Stripe public dev test tokens, so you don't need to enter any information for the tests to complete successfully.

Sometimes Stripe changes their API behavior. Changes in API behavior can cause our tests to fail. If you find failing tests, check their latest API changes at API Upgrades then fix the code and/or tests to compensate.

Next Steps

In no specific order:

• Flesh out remaining stripe API
  • Adding a new API feature requires adding: exported user function, request wrapper, result to record extractor.
  • Add support for the card fingerprint element in relevant places.
  • Add support for the fee_details structure.
  • Add support for the disputed flag.
  • Add support for the failure_message note.
  • Add support for multi-valued properties (cards, subscriptions, ...).
• Add tests for error conditions
• Move from env-specified auth token to something more call specific
  • Options:
    • Per-call auth token (stripe:charge_card(AuthToken, ...))
    • Leave env, but add per-auth token options

Contributions

Want to help? Patches welcome.

• Add a missing API call
  • Add the record with type info in include/stripe.hrl
  • Add the exported function in src/stripe.erl
  • Add the request_* wrapper function
  • Add a new json_to_record result extractor
  • Add positive and negative tests in test/stripe_tests.erl
• Find a bug. Fix a bug.

Contributors

• Thanks to @stefanrusek for fixing a failing test and expanding functionality
• Thanks to @michaelpellon for fixing an interface due to the API changing out from under us