title: API Services Overview description: Comprehensive documentation of all backend integrations, API endpoints, and service communication in p2d2 quality: completeness: 80 accuracy: 75 reviewed: false reviewer: 'KI (Gemini)' reviewDate: null

API Services - Overview

Status: ✅ Fully documented

Introduction

The p2d2 application integrates multiple backend services and APIs for professional geodata processing. These services form the technical foundation for the entire data infrastructure, enabling real-time access to geodata, automatic synchronization, and robust error handling.

Service Architecture

Overview of Backend Integrations

Main Service Categories

🗺️ Geodata Services

• GeoServer Integration - Professional WMS/WFS Services
• WFS Transaction Management - Write access to geodatabase
• WMS Layer Management - Raster data and basemaps

🔄 Synchronization Services

• Overpass API Integration - OSM data retrieval with load balancing
• Polygon Sync Engine - Automatic data synchronization
• WFS-T Client - Transaction-based data persistence

🔐 Security & Proxy Services

• WFS Proxy API - Secure CORS circumvention and authentication
• Credential Management - Secure handling of service credentials
• Input Validation - Robust input validation

Service Properties

1. Robustness & Error Handling

All services implement comprehensive error handling:

// Retry mechanism with exponential backoff
async function resilientOperation(operation: string, fn: () => Promise<any>) {
  for (let attempt = 0; attempt <= maxRetries; attempt++) {
    try {
      return await fn();
    } catch (error) {
      if (attempt === maxRetries) throw error;
      await sleep(retryDelay * Math.pow(2, attempt)); // Exponential backoff
    }
  }
}

2. Performance Optimizations

• Layer Caching - Reuse of loaded geodata
• Request Batching - Efficient batch processing
• Connection Pooling - Reuse of HTTP connections

3. Security Features

• Host Validation - Only trusted endpoints
• Credential Encryption - Secure storage of credentials
• Input Sanitization - Protection against injection attacks

Usage Examples

Complete Service Integration

import { wfsAuthClient } from '../utils/wfs-auth';
import { syncKommunePolygons } from '../utils/polygon-wfst-sync';
import WFSLayerManager from '../utils/wfs-layer-manager';

// 1. Display WFS layer
const wfsManager = new WFSLayerManager(map);
await wfsManager.displayLayer(kommune, 'administrative');

// 2. Polygon synchronization
const syncResult = await syncKommunePolygons('koeln', ['admin_boundary']);
console.log('Sync successful:', syncResult.success);

// 3. Fetch WFS features
const features = await wfsAuthClient.getFeatures('p2d2_containers', {
  CQL_FILTER: "wp_name='Köln'"
});

Error Handling in Practice

try {
  // Service operation with fallback
  const data = await loadGeodataWithFallback(kommune, category);
} catch (error) {
  // Comprehensive logging
  logger.error('Service operation failed', error, {
    kommune: kommune.slug,
    category: category,
    timestamp: new Date().toISOString()
  });
  
  // User-friendly error message
  showUserNotification({
    type: 'error',
    message: 'Service temporarily unavailable',
    action: 'retry'
  });
}

Monitoring & Debugging

Performance Metrics

interface ServiceMetrics {
  requestCount: number;
  successRate: number;
  averageResponseTime: number;
  errorDistribution: Record<string, number>;
  cacheHitRate: number;
}

// Automatic monitoring
const metrics = serviceMonitor.getMetrics();
console.log('Service Performance:', {
  successRate: metrics.successRate,
  avgResponseTime: `${metrics.averageResponseTime}ms`,
  cacheEfficiency: metrics.cacheHitRate
});

Debug Logging

// Detailed debug logging
if (process.env.DEBUG) {
  console.debug('WFS-Request Details:', {
    url: wfsUrl,
    params: requestParams,
    timestamp: new Date().toISOString(),
    userAgent: navigator.userAgent
  });
}

Configuration

Environment Variables

# WFS Services
WFS_USERNAME="p2d2_wfs_user"
WFS_PASSWORD="eif1nu4ao9Loh0oobeev"
WFST_ENDPOINT="https://wfs.data-dna.eu/geoserver/ows"

# Performance
WFS_TIMEOUT=30000
WFS_MAX_RETRIES=3
CACHE_TTL=300000

# Debugging
DEBUG="true"
LOG_LEVEL="info"

Service Configuration

const SERVICE_CONFIG = {
  wfs: {
    endpoints: {
      development: "https://wfs.data-dna.eu/geoserver/ows",
      production: "https://wfs.data-dna.eu/geoserver/Verwaltungsdaten/ows"
    },
    timeout: 30000,
    maxRetries: 3
  },
  overpass: {
    endpoints: [
      "https://overpass-api.de/api/interpreter",
      "https://overpass.kumi.systems/api/interpreter"
    ],
    timeout: 180,
    maxSize: 1073741824
  },
  caching: {
    layerTtl: 5 * 60 * 1000, // 5 minutes
    featureTtl: 30 * 60 * 1000 // 30 minutes
  }
};

Best Practices

1. Service Design

// ✅ Correct - Clear service interfaces
interface GeodataService {
  loadFeatures(kommune: KommuneData, category: string): Promise<FeatureCollection>;
  syncPolygons(slug: string, categories: string[]): Promise<SyncResult>;
  getLayerStats(): ServiceMetrics;
}

// ❌ Avoid - Unstructured service calls
// Direct fetch calls without abstraction

2. Error Handling

// ✅ Correct - Comprehensive error handling
async function loadDataWithRetry() {
  try {
    return await resilientOperation('data-load', () => 
      geodataService.loadFeatures(kommune, category)
    );
  } catch (error) {
    if (error instanceof NetworkError) {
      return getCachedData(kommune, category);
    }
    throw error;
  }
}

// ❌ Avoid - Unhandled errors
const data = geodataService.loadFeatures(kommune, category);

3. Performance

// ✅ Correct - Efficient service usage
const [features, statistics] = await Promise.all([
  wfsManager.getFeatures(kommune, 'administrative'),
  wfsManager.getLayerStats()
]);

// ❌ Avoid - Inefficient sequential calls
const features = await wfsManager.getFeatures(kommune, 'administrative');
const statistics = await wfsManager.getLayerStats(); // Blocking

Further Documentation

• Astro API Endpoints - Backend API Integrations
• WFS Transaction Management - WFS-T and GeoServer
• Overpass API Integration - OSM Data Retrieval
• GeoServer Integration - WMS/WFS Services

Changelog

v1.0.0 (2024-12-19)

• ✅ Complete documentation of all API Services
• ✅ Robust error handling implementations
• ✅ Performance optimizations with caching
• ✅ Comprehensive security features
• ✅ Monitoring and debugging tools

These API Services form the technical backbone of p2d2, ensuring reliable access to geodata with professional error handling and performance optimizations.