Working with the SDK

Resources

Resource classes represent blocks of related API endpoints, as described in the API docs. Each resource class is accessible via Coinbase object and lazily initialized.

Here is an example of how to use user resource from CoinbaseSDK:

let userResource = coinbase.userResource

userResource.current { result in
    switch result {
    case .success(let user):
        // ...
    case .failure(let error):
        // ...
    }
}

Responses

All request methods expect completion closure parameter that takes result represented by a generic enum Result<Value> when the request is completed.

Most of the requests return Result containing only parsed model (Result<User>). But for endpoints returning an object list, data will be presented as full response model (e.g. Result<ResponseModel<[Address]>>) with additional information (see next section).

Response with pagination

All GET endpoints which return an object list support cursor based pagination with pagination information presented by a pagination object (more info here).

For this type of endpoints Result will be associated with ResponseModel<T> type. This type has a pagination field that contains a current page information (limit, previous and next item ids, order).

Request with pagination

Every paginated request has PaginationParameters. If not provided defaults are applied.

coinbase.accountResource.list { result in
    switch result {
    case .success(let responseModel):
        // array of accounts can be accessed as responseModel.data
        // ...
    case .failure(let error):
        // ...
    }
}

Otherwise, you might specify pagination parameters:

let paginationParameters = PaginationParameters(limit: 50,
                                                order: .asc)

coinbase.accountResource.list(page: paginationParameters) { result in
    // ...
}

It is possible to retrieve pagination parameters for next and previous pages from response Pagination object (order and limit will remain as they were set in original request):

if let nextPage = responseModel.pagination?.nextPage {
    coinbase.accountResource.list(page: nextPage) { result in
        // ...
    }
}

If you reach the last page nextPage will return nil.

The same applies for previousPage.

Handling error responses

In case of error Result.failure is passed to the request completion closure. This enum case has an associated error that caused the request to fail.

An associated error can be one of the next types:

• NetworkError
• OAuthError
• ResponseSerializationError
• DecodingError
• other error types.

API errors (server responded with the status code different from 2XX) are represented by OAuthError.responseError for TokenResource and NetworkError.responseError for other recources.

NetworkError.responseError case has an associated instance of ErrorResponse that contains an array of ErrorModel.

OAuthError.responseError case has an associated instace of OAuthErrorResponse that contains the error ID and human-readable error description.