expresspayments

v2.0.1

Published

5 months ago

ExpressPayments API wrapper

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ExpressPayments Node.js Library

The ExpressPayments Node library provides convenient access to the ExpressPayments API from applications written in server-side JavaScript.

For collecting customer and payment information in the browser, use ExpressPayments.js.

Documentation

See the expresspayments-node API docs for Node.js.

See video demonstrations covering how to use the library.

Requirements

Node 12 or higher.

Installation

Install the package with:

npm install expresspayments --save
# or
yarn add expresspayments

Usage

The package needs to be configured with your account's secret key, which is available in the ExpressPayments Dashboard. Require it with the key's value:

const expressPayments = require('expresspayments')('sk_test_...');

expressPayments.customers.create({
  email: '[email protected]',
})
  .then(customer => console.log(customer.id))
  .catch(error => console.error(error));

Or using ES modules and async/await:

import ExpressPayments from 'expresspayments';
const expressPayments = new ExpressPayments('sk_test_...');

const customer = await expressPayments.customers.create({
  email: '[email protected]',
});

console.log(customer.id);

Usage with TypeScript

As of 2.0.0, ExpressPayments maintains types for the latest API version.

Import ExpressPayments as a default import (not * as ExpressPayments, unlike the DefinitelyTyped version) and instantiate it as new ExpressPayments() with the latest API version.

import ExpressPayments from 'expresspayments';

const expressPayments = new ExpressPayments('sk_test_...', {
    apiVersion: '2023-11-01',
});

const createCustomer = async () => {
    const params: ExpressPayments.CustomerCreateParams = {
        description: 'test customer',
    };

    const customer: ExpressPayments.Customer = await expressPayments.customers.create(params);

    console.log(customer.id);
};
createCustomer();

You can find a full TS server example in expresspayments-samples.

Using old API versions with TypeScript

Types can change between API versions (e.g., ExpressPayments may have changed a field from a string to a hash), so our types only reflect the latest API version.

We therefore encourage upgrading your API version if you would like to take advantage of ExpressPayments' TypeScript definitions.

If you are on an older API version (e.g., 2023-11-01) and not able to upgrade, you may pass another version and use a comment like // @ts-ignore ep-Version-2023-11-01 to silence type errors here and anywhere the types differ between your API version and the latest. When you upgrade, you should remove these comments.

We also recommend using // @ts-ignore if you have access to a beta feature and need to send parameters beyond the type definitions.

Using `expand` with TypeScript

Expandable fields are typed as string | Foo, so you must cast them appropriately, e.g.,

const paymentIntent: ExpressPayments.PaymentIntent = await expressPayments.paymentIntents.retrieve(
  'pi_123456789',
  {
    expand: ['customer'],
  }
);
const customerEmail: string = (paymentIntent.customer as ExpressPayments.Customer).email;

Using Promises

Every method returns a chainable promise which can be used instead of a regular callback:

// Create a new customer and then create an invoice item then invoice it:
expressPayments.customers
  .create({
    email: '[email protected]',
  })
  .then((customer) => {
    // have access to the customer object
    return expressPayments.invoiceItems
      .create({
        customer: customer.id, // set the customer id
        amount: 2500, // 25
        currency: 'usd',
        description: 'One-time setup fee',
      })
      .then((invoiceItem) => {
        return expressPayments.invoices.create({
          collection_method: 'send_invoice',
          customer: invoiceItem.customer,
        });
      })
      .then((invoice) => {
        // New invoice created on a new customer
      })
      .catch((err) => {
        // Deal with an error
      });
  });

Usage with Deno

As of 11.16.0, expresspayments-node provides a deno export target. In your Deno project, import expresspayments-node using a npm specifier:

Import using npm specifiers:

import EP from 'npm:expresspayments';

Please see https://github.com/expresspayments-samples/expresspayments-node-deno-samples for more detailed examples and instructions on how to use expresspayments-node in Deno.

Configuration

Initialize with config object

The package can be initialized with several options:

import ProxyAgent from 'https-proxy-agent';

const expressPayments = ExpressPayments('sk_test_...', {
  apiVersion: '2023-11-01',
  maxNetworkRetries: 1,
  httpAgent: new ProxyAgent(process.env.http_proxy),
  timeout: 1000,
  host: 'api.example.com',
  port: 123,
  telemetry: true,
});

| Option | Default | Description | | ------------------- |---------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | apiVersion | null | ExpressPayments API version to be used. If not set, expresspayments-node will use the latest version at the time of release. | | maxNetworkRetries | 0 | The amount of times a request should be retried. | | httpAgent | null | Proxy agent to be used by the library. | | timeout | 80000 | Maximum time each request can take in ms. | | host | 'api.epayments.network' | Host that requests are made to. | | port | 443 | Port that requests are made to. | | protocol | 'https' | 'https' or 'http'. http is never appropriate for sending requests to ExpressPayments servers, and we strongly discourage http, even in local testing scenarios, as this can result in your credentials being transmitted over an insecure channel. | | telemetry | true | Allow ExpressPayments to send latency telemetry. |

Note Both maxNetworkRetries and timeout can be overridden on a per-request basis.

Configuring Timeout

Timeout can be set globally via the config object:

const expressPayments = ExpressPayments('sk_test_...', {
  timeout: 20 * 1000, // 20 seconds
});

And overridden on a per-request basis:

expressPayments.customers.create(
  {
    email: '[email protected]',
  },
  {
    timeout: 1000, // 1 second
  }
);

Configuring For Connect

A per-request EP-Account header for use with ExpressPayments Connect can be added to any method:

// List the balance transactions for a connected account:
expressPayments.balanceTransactions.list(
  {
    limit: 10,
  },
  {
    expressPaymentsAccount: 'acct_foo',
  }
);

Configuring a Proxy

To use expresspayments behind a proxy you can pass a https-proxy-agent on initialization:

if (process.env.http_proxy) {
  const ProxyAgent = require('https-proxy-agent');

  const expressPayments = ExpressPayments('sk_test_...', {
    httpAgent: new ProxyAgent(process.env.http_proxy),
  });
}

Network retries

Automatic network retries can be enabled with the maxNetworkRetries config option. This will retry requests n times with exponential backoff if they fail due to an intermittent network problem. Idempotency keys are added where appropriate to prevent duplication.

const expressPayments = ExpressPayments('sk_test_...', {
  maxNetworkRetries: 2, // Retry a request twice before giving up
});

Network retries can also be set on a per-request basis:

expressPayments.customers.create(
  {
    email: '[email protected]',
  },
  {
    maxNetworkRetries: 2, // Retry this specific request twice before giving up
  }
);

Examining Responses

Some information about the response which generated a resource is available with the lastResponse property:

customer.lastResponse.requestId; // see: https://docs.epayments.network/api/request_ids?lang=node
customer.lastResponse.statusCode;

`request` and `response` events

The ExpressPayments object emits request and response events. You can use them like this:

const expressPayments = require('expresspayments')('sk_test_...');

const onRequest = (request) => {
  // Do something.
};

// Add the event handler function:
expressPayments.on('request', onRequest);

// Remove the event handler function:
expressPayments.off('request', onRequest);

`request` object

{
  api_version: 'latest',
  account: 'acct_TEST',              // Only present if provided
  idempotency_key: 'abc123',         // Only present if provided
  method: 'POST',
  path: '/v1/customers',
  request_start_time: 1565125303932  // Unix timestamp in milliseconds
}

`response` object

{
  api_version: 'latest',
  account: 'acct_TEST',              // Only present if provided
  idempotency_key: 'abc123',         // Only present if provided
  method: 'POST',
  path: '/v1/customers',
  status: 402,
  request_id: 'req_Ghc9r26ts73DRf',
  elapsed: 445,                      // Elapsed time in milliseconds
  request_start_time: 1565125303932, // Unix timestamp in milliseconds
  request_end_time: 1565125304377    // Unix timestamp in milliseconds
}

Webhook signing

ExpressPayments can optionally sign the webhook events it sends to your endpoint, allowing you to validate that they were not sent by a third party. You can read more about it here.

Please note that you must pass the raw request body, exactly as received from ExpressPayments, to the constructEvent() function; this will not work with a parsed (i.e., JSON) request body.

You can find an example of how to use this with various JavaScript frameworks in examples/webhook-signing folder, but here's what it looks like:

const event = expressPayments.webhooks.constructEvent(
  webhookRawBody,
  webhookExpressPaymentsSignatureHeader,
  webhookSecret
);

Testing Webhook signing

You can use expresspayments.webhooks.generateTestHeaderString to mock webhook events that come from ExpressPayments:

const payload = {
  id: 'evt_test_webhook',
  object: 'event',
};

const payloadString = JSON.stringify(payload, null, 2);
const secret = 'whsec_test_secret';

const header = expressPayments.webhooks.generateTestHeaderString({
  payload: payloadString,
  secret,
});

const event = expressPayments.webhooks.constructEvent(payloadString, header, secret);

// Do something with mocked signed event
expect(event.id).to.equal(payload.id);

Writing a Plugin

If you're writing a plugin that uses the library, we'd appreciate it if you instantiated your expresspayments client with appInfo, eg;

const expressPayments = require('expresspayments')('sk_test_...', {
  appInfo: {
    name: 'MyAwesomePlugin',
    version: '1.2.34', // Optional
    url: 'https://myawesomeplugin.info', // Optional
  }
});

Or using ES modules or TypeScript:

const expressPayments = new ExpressPayments(apiKey, {
  appInfo: {
    name: 'MyAwesomePlugin',
    version: '1.2.34', // Optional
    url: 'https://myawesomeplugin.info', // Optional
  }
});

This information is passed along when the library makes calls to the ExpressPayments API.

Auto-pagination

We provide a few different APIs for this to aid with a variety of node versions and styles.

Async iterators (`for-await-of`)

If you are in a Node environment that has support for async iteration, such as Node 10+ or babel, the following will auto-paginate:

for await (const customer of expressPayments.customers.list()) {
  doSomething(customer);
  if (shouldStop()) {
    break;
  }
}

`autoPagingEach`

If you are in a Node environment that has support for await, such as Node 7.9 and greater, you may pass an async function to .autoPagingEach:

await expressPayments.customers.list().autoPagingEach(async (customer) => {
  await doSomething(customer);
  if (shouldBreak()) {
    return false;
  }
});
console.log('Done iterating.');

Equivalently, without await, you may return a Promise, which can resolve to false to break:

expressPayments.customers
  .list()
  .autoPagingEach((customer) => {
    return doSomething(customer).then(() => {
      if (shouldBreak()) {
        return false;
      }
    });
  })
  .then(() => {
    console.log('Done iterating.');
  })
  .catch(handleError);

`autoPagingToArray`

This is a convenience for cases where you expect the number of items to be relatively small; accordingly, you must pass a limit option to prevent runaway list growth from consuming too much memory.

Returns a promise of an array of all items across pages for a list request.

const allNewCustomers = await expressPayments.customers
  .list({created: {gt: lastMonth}})
  .autoPagingToArray({limit: 10000});

Request latency telemetry

By default, the library sends request latency telemetry to ExpressPayments. These numbers help expressPayments improve the overall latency of its API for all users.

You can disable this behavior if you prefer:

const expressPayments = new expressPayments('sk_test_...', {
  telemetry: false,
});

Beta SDKs

ExpressPayments has features in the beta phase that can be accessed via the beta version of this package. We would love for you to try these and share feedback with us before these features reach the stable phase. The beta versions can be installed in one of two ways

To install the latest beta version, run the command npm install expresspayments@beta --save
To install a specific beta version, replace the term "beta" in the above command with the version number like npm install [email protected] --save

Note There can be breaking changes between beta versions. Therefore, we recommend pinning the package version to a specific beta version in your package.json file. This way you can install the same version each time without breaking changes unless you are intentionally looking for the latest beta version.

We highly recommend keeping an eye on when the beta feature you are interested in goes from beta to stable so that you can move from using a beta version of the SDK to the stable version.

The versions tab on the expresspayments page on npm lists the current tags in use. The beta tag here corresponds to the latest beta version of the package.

If your beta feature requires a EP-Version header to be sent, use the apiVersion property of config object to set it:

const expressPayments = new ExpressPayments('sk_test_...', {
  apiVersion: '2023-11-01; feature_beta=v3',
});

Support

New features and bug fixes are released on the latest major version of the expresspayments package. If you are on an older major version, we recommend that you upgrade to the latest in order to use the new features and bug fixes including those for security vulnerabilities. Older major versions of the package will continue to be available for use, but will not be receiving any updates.

More Information

Development

Run all tests:

$ yarn install
$ yarn test

If you do not have yarn installed, you can get it with npm install --global yarn.

The tests also depends on expresspayments-expresspayments, so make sure to fetch and run it from a background terminal (expresspayments-mock's README also contains instructions for installing via Homebrew and other methods):

go get -u github.com/expresspayments/expresspayments-mock
expresspayments-mock

Run a single test suite without a coverage report:

$ yarn mocha-only test/Error.spec.ts

Run a single test (case-sensitive) in watch mode:

$ yarn mocha-only test/Error.spec.ts --grep 'Populates with type' --watch

If you wish, you may run tests using your EP_Test_API key by setting the environment variable EP_Test_API_KEY before running the tests:

$ export EP_TEST_API_KEY='sk_test....'
$ yarn test

Run prettier:

Add an editor integration or:

$ yarn fix