yeeehaooo/create-api-adapter

Create API Adapter

Purpose

Create adapter structure for integrating third-party APIs.

Scope

Applies to:

• Infrastructure Layer
• External service integration
• HTTP-based API integrations

Rules

• Interface defined in Application layer
• Implementation in Infrastructure layer
• Use HttpClient for HTTP calls
• Return Result pattern for error handling
• Register in DI container
• Use retry policy for transient failures

Template Structure

Interface (Application Layer):

public interface I{ProviderName}Service
{
    Task<Result<{ResponseType}>> ExecuteAsync({RequestType} request, CancellationToken ct = default);
}

Implementation (Infrastructure Layer):

public class {ProviderName}Service : I{ProviderName}Service
{
    private readonly HttpClient _httpClient;
    private readonly IRetryPolicy _retryPolicy;
    private readonly ILogger<{ProviderName}Service> _logger;

    public {ProviderName}Service(
        HttpClient httpClient,
        IRetryPolicy retryPolicy,
        ILogger<{ProviderName}Service> logger)
    {
        _httpClient = httpClient;
        _retryPolicy = retryPolicy;
        _logger = logger;
    }

    public async Task<Result<{ResponseType}>> ExecuteAsync({RequestType} request, CancellationToken ct = default)
    {
        return await _retryPolicy.ExecuteAsync(async () =>
        {
            var response = await _httpClient.PostAsJsonAsync("endpoint", request, ct);
            response.EnsureSuccessStatusCode();
            var content = await response.Content.ReadFromJsonAsync<{ResponseType}>(ct);
            return Result<{ResponseType}>.Success(content!);
        }, ct);
    }
}

DI Registration:

services.AddHttpClient<I{ProviderName}Service, {ProviderName}Service>(client =>
{
    client.BaseAddress = new Uri(configuration["{ProviderName}:BaseUrl"]);
    client.Timeout = TimeSpan.FromSeconds(30);
});

Anti-Patterns

• Using HttpClient directly in Application layer
• Calling third-party API from Controller
• No error handling
• Hard-coded endpoints
• No retry policy for transient failures

Notes

• Use typed HttpClient for better configuration
• Implement retry policy for resilience
• Use Result pattern for error handling
• Log API calls for observability