Batch Request Adapter

The batch request adapter bridges a list of public requests to the validation client. It maps the incoming requests to the provider's batch DTO using the batch request mapper, then forwards it to the same typed HttpClient used by the singular pipeline. Implement IBatchApiRequestAdapter<TRequest, TApiResponse>.

[SuppressMessage("Performance", "CA1812:Avoid uninstantiated internal classes", Justification = "Instantiated by DI container")]
internal sealed class BatchApiRequestAdapter : IBatchApiRequestAdapter<MyAddressValidationRequest, ApiResponse>
{
    private readonly MyAddressValidationClient _client;

    private readonly IBatchApiRequestMapper<MyAddressValidationRequest, ApiRequest> _requestMapper;

    public BatchApiRequestAdapter(MyAddressValidationClient client,
                                  IBatchApiRequestMapper<MyAddressValidationRequest, ApiRequest> requestMapper)
    {
        _client = client ?? throw new ArgumentNullException(nameof(client));
        _requestMapper = requestMapper ?? throw new ArgumentNullException(nameof(requestMapper));
    }

    public Task<ApiResponse?> ExecuteAsync(IReadOnlyList<MyAddressValidationRequest> requests, CancellationToken cancellationToken)
    {
        ApiRequest apiRequest = _requestMapper.Map(requests);
        return _client.ValidateAddressAsync(apiRequest, cancellationToken);
    }
}

Note

Batch support needs no new authentication or HTTP infrastructure. The adapter reuses the same validation client and, transitively, the same BearerTokenDelegatingHandler<TClient> and resilience pipeline configured for the singular pipeline. If the provider's batch endpoint uses a different URL or request shape than the single-address endpoint, add a second method to the existing validation client, instead of creating a separate typed HttpClient.

public Task<ApiResponse?> ValidateAddressesAsync(ApiRequest request, CancellationToken cancellationToken = default)
{
    ArgumentNullException.ThrowIfNull(request);
    return ValidateAddressesInternalAsync(request, cancellationToken);
}

private async Task<ApiResponse?> ValidateAddressesInternalAsync(ApiRequest request, CancellationToken cancellationToken)
{
    Uri requestUri = new(_options.Value.EndpointUri, "/v1/address/validate-batch");

    using HttpRequestMessage httpRequest = new(HttpMethod.Post, requestUri);
    httpRequest.Content = JsonContent.Create(request, MyApiRequestJsonSerializerContext.Default.ApiRequest);

    using HttpResponseMessage response = await _httpClient.SendAsync(httpRequest, cancellationToken).ConfigureAwait(false);
    if ( response.IsSuccessStatusCode )
    {
        return await response.Content.ReadFromJsonAsync(MyApiResponseJsonSerializerContext.Default.ApiResponse, cancellationToken)
                                     .ConfigureAwait(false);
    }

    ApiErrorResponse? errorResponse = await response.Content.ReadFromJsonAsync(MyApiResponseJsonSerializerContext.Default.ApiErrorResponse, cancellationToken)
                                                             .ConfigureAwait(false);
    return errorResponse is not null ? new ApiResponse { ErrorResponse = errorResponse } : null;
}

Note

Mark the batch request adapter internal. This reduces the public API surface if you redistribute the integration as a library.