API Proxy Server Documentation

Overview

This is a Cloudflare Worker script functioning as a proxy server for various AI models and APIs. It acts as a gateway between clients and different AI providers, offering features like caching, rate limiting, and security.

Configuration

Constants

• API_HOST: Main API host
• POLLINATIONS_HOST: Pollinations.ai service host
• GITHUB_HOST: GitHub Pages host for static contents
• MODEL_ID: Default model ID for Cloudflare AI
• MAX_CONTENT_LENGTH: Max request size (50KB)
• CUSTOM_MAX_LENGTH: Extended max size for certain endpoints (100KB)
• CACHE_CONTROL: Caching policy (4 hours)
• CACHE_FOREVER: Permanent caching (1 year)
• CORS_HEADERS: Cross-Origin Resource Sharing headers configuration

Main Functions

1. API Endpoint Handling

The server handles various routes:

• /api/[provider]/ - API calls for specific providers
• /ai/[query] - Simplified AI query interface
• /media/, /files/, /search/ - Media and file handling
• /dist/ - Static content
• /backend-api/ - Backend API routes

2. Supported AI Providers

const models = {
  "nvidia", "openrouter", "deepinfra", "groq", "ollama",
  "azure", "grok", "x.ai", "gemini", "typegpt", "pollinations",
  "api.airforce", "gpt4free.pro", "nectar", "audio", "perplexity",
  "huggingface", "puter"
}

3. Security Features

• Rate Limiting: Limits requests (1 per 10 seconds for API paths)
• Content-Length Validation: Checks request size limits
• CORS Handling: Manages cross-origin requests
• API Key Rotation: Randomly selects from multiple API keys
• Content-Type Validation: Protects against unwanted content types

Key Functions

handleRequest(request, env, ctx)

Main function that processes all incoming requests:

1. OPTIONS requests: Handles CORS preflight
2. Model list endpoints: Returns available models
3. Caching: Caches GET/HEAD responses
4. Rate limiting: Protects against abuse
5. Content validation: Enforces request size limit
6. Routing: Forwards requests to appropriate providers

forwardApi(request, newUrl, liteRequest, ctx, cache_control)

Forwards API requests with caching and CORS support.

forwardWorker(env, request, liteRequest, pathname, ctx)

Special handling for Cloudflare AI worker endpoints.

shield(url, options)

Performs safety checks:

• Content-Type validation
• Error handling standardization
• Removing sensitive headers
• Adding CORS headers

retrieveCache(request, liteRequest, pathname, ctx, host, cache_control)

Caching mechanism for repeated requests.

Caching Strategy

• Static contents: Forever cache (1 year)
• API responses: Time-limited cache (4 hours)
• Media/Files: Cache-based distribution

Error Handling

• Structured JSON error responses
• Rate limit errors with Retry-After header
• Content-Length errors
• Provider-specific error handling

Special Features

• Auto-Model Selection: Random provider selection
• JSON response formatting: Automatic JSON formatting
• Audio support: Text-to-Speech integration
• Image Generation: Pollinations.ai integration
• Documentation Generation: Dynamic docs creation

Deployment

This code is optimized for Cloudflare Workers with:

• Environment variables for API keys
• Cloudflare KV for rate limiting
• Cloudflare AI for local models
• Cloudflare cache for performance

This proxy server provides a robust, scalable API gateway that enhances security, performance, and flexibility for integrating various AI services.