Square SDK is unusable in Cloudflare Workers

[Jen Garcia]

Describe the bug
Attempting to use the Square SDK in a Cloudflare Workers environment will throw the following error:

TypeError: adapter is not a function
    at module.exports (C:\Users\Jen\Dev\hive23.com\node_modules\axios\lib\core\dispatchRequest.js:53:10)
    at Axios.request (C:\Users\Jen\Dev\hive23.com\node_modules\axios\lib\core\Axios.js:108:15)
    at HttpClient2._axiosInstance (C:\Users\Jen\Dev\hive23.com\node_modules\axios\lib\helpers\bind.js:9:15)
    at HttpClient2.<anonymous> (C:\Users\Jen\Dev\hive23.com\node_modules\@apimatic\core\es\http\httpClient.js:189:20)
    at step (C:\Users\Jen\Dev\hive23.com\node_modules\@apimatic\core\node_modules\tslib\tslib.js:144:27)
    at Object.next (C:\Users\Jen\Dev\hive23.com\node_modules\@apimatic\core\node_modules\tslib\tslib.js:125:57)
    at C:\Users\Jen\Dev\hive23.com\node_modules\@apimatic\core\node_modules\tslib\tslib.js:118:75
    at new Promise (<anonymous>)
    at __awaiter (C:\Users\Jen\Dev\hive23.com\node_modules\@apimatic\core\node_modules\tslib\tslib.js:114:16)
    at HttpClient2.executeRequest (C:\Users\Jen\Dev\hive23.com\node_modules\@apimatic\core\es\http\httpClient.js:159:12)

The root cause of this error is that the Axios library does not use fetch for network requests (which is required for Cloudflare Workers and other ServiceWorker-compatible environments). There is a feature request in Axios that has been open for a few years related to this: axios/axios#1219

The error says adapter is not a function which is because the XMLHTTPRequest adapter is not available in a Cloudflare Workers environment. It might be possible to fix this bug by allowing users to pass their own adapter to Axios. Example of a fetch adapter for Axios: https://github.com/vespaiach/axios-fetch-adapter

Expected behavior
Square SDK is able to access payment APIs in a Cloudflare Workers environment.

To Reproduce
Steps to reproduce the bug:

1. Create a Cloudflare Workers function that initializes a Square SDK client
2. Call createPayment (or some other Square API) when the function is called
3. Error is thrown

Square SDK version
For example: 24.0.0

Additional context

• Here's a Contentful.js bug caused by the same Axios issue: contentful/contentful.js#395
• Users that want to create Progressive Web Apps will also be affected by this bug, since PWAs use ServiceWorkers to fetch content.

[Jen Garcia]

From reviewing the SDK code I've realized that the unstable_httpClientOptions parameter for the Square Client is passed directly to the axios.create() function. This allows me to pass a fetch adapter like this:

const client = new Client({
  accessToken,
  environment,
  unstable_httpClientOptions: { adapter: fetchAdapter }
});

Unfortunately the fetch adapter provided by vespaiach/axios-fetch-adapter imports utilities directly from axios, which causes errors in a Cloudflare Worker. To fix this, I've made an alternate version without the axios dependency: @haverstack/axios-fetch-adapter.

Since it is possible to supply an adapter to the Square SDK, this issue can be closed.