cuioss/cui-http

CUI HTTP Skill

REFERENCE MODE: This skill provides reference material. Load specific standards on-demand based on current task.

CUI-specific HTTP client standards for projects using de.cuioss:cui-http. Covers HttpHandler, HttpResult sealed interface, and async-first adapters.

Enforcement

Execution mode: Reference library; load standards on-demand for HTTP client implementation tasks.

Prohibited actions:

• Do not use raw HttpClient or OkHttp directly; always use CUI HttpHandler abstraction
• Do not implement custom retry or error handling; use HttpResult sealed interface pattern matching
• Do not load all standards at once; load progressively based on current task

Constraints:

• All HTTP implementations must use de.cuioss:cui-http library
• Error handling must use HttpResult sealed interface (not exceptions)
• Async operations must use the async-first adapter pattern

Prerequisites

• de.cuioss:cui-http (HttpHandler, HttpResult, HttpAdapter)

Workflow

Step 1: Load HTTP Client Standards

CRITICAL: Load these standards for any HTTP client implementation work.

Read: standards/cui-http.md

This provides the foundational rules:

• MUST use HttpHandler builder for all HTTP client configuration
• MUST use HttpResult<T> sealed interface for result handling
• Async adapters with composable retry and caching

Step 2: Apply the Right Pattern (Based on Task)

Simple HTTP request — Use HttpHandler directly:

HttpHandler handler = HttpHandler.builder()
    .uri("https://api.example.com/data")
    .connectionTimeoutSeconds(10)
    .readTimeoutSeconds(30)
    .build();

Resilient HTTP with caching — Compose ETag + retry adapters:

HttpAdapter<String> adapter = ResilientHttpAdapter.wrap(
    ETagAwareHttpAdapter.<String>builder()
        .httpHandler(httpHandler)
        .responseConverter(StringContentConverter.identity())
        .build(),
    RetryConfig.defaults()
);

Result handling — Use pattern matching on HttpResult:

return switch (result) {
    case HttpResult.Success<ConfigData>(var config, var etag, var status) -> {
        updateCache(config, etag);
        yield true;
    }
    case HttpResult.Failure<ConfigData> failure -> {
        if (failure.fallbackContent() != null) {
            yield true;  // Graceful degradation
        }
        yield failure.isRetryable();
    }
};

Key Concepts

HttpResult Sealed Interface

Type-safe result handling with exhaustive pattern matching:

• HttpResult.Success<T> — Content with ETag and HTTP status
• HttpResult.Failure<T> — Error with optional fallback content and error category

HttpErrorCategory

| Category | Retryable | Examples | |----------|-----------|----------| | NETWORK_ERROR | Yes | Connection failures, timeouts | | SERVER_ERROR | Yes | 5xx responses | | CLIENT_ERROR | No | 4xx responses | | INVALID_CONTENT | No | Content conversion failures | | CONFIGURATION_ERROR | No | Setup/config issues |

Standards Reference

| Standard | Purpose | |----------|---------| | standards/cui-http.md | HttpHandler builder, HttpResult pattern matching, adapters, error categories |

Related Skills

• pm-dev-java:java-core — General Java patterns
• pm-dev-java-cui:cui-http-testing — HTTP testing with CUI MockWebServer