managarten/picture/apps/mobile/supabase/functions/process-generation

Process Generation Edge Function

Overview

This Edge Function contains the core Replicate API integration logic extracted from the original 667-line generate-image function. It can be imported as a module or called standalone for testing.

Purpose

• Handle actual Replicate API interaction for image generation
• Support 15+ different AI models with model-specific parameter handling
• Calculate aspect ratios and dimensions for each model
• Handle image-to-image (img2img) conversion
• Poll Replicate API until generation completes
• Return result URL when ready

Supported Models

FLUX Models

• FLUX Schnell: Fast generation with aspect ratio constraints
• FLUX Dev: Full control with img2img support
• FLUX Krea Dev: Enhanced version with img2img
• FLUX 1.1 Pro: Latest version with aspect ratio

SDXL Models

• SDXL: Full parameters with refiner and img2img
• SDXL Lightning: Ultra-fast 4-step generation with img2img

Other Models

• Ideogram V3 Turbo: Aspect ratio based
• Imagen 4 Fast: Google's model with aspect ratio
• Stable Diffusion 3.5: Latest SD with aspect ratio
• SeeDream 3/4: Advanced models with preset sizes
• Recraft V3: Both raster and SVG output
• Qwen Image: Specialized parameters

Usage

As a Module (Recommended)

import { processGeneration } from '../process-generation/index.ts';

const result = await processGeneration(
  {
    prompt: "A beautiful sunset over mountains",
    model_id: "black-forest-labs/flux-schnell",
    width: 1024,
    height: 1024,
    num_inference_steps: 30,
    guidance_scale: 7.5,
  },
  replicateApiToken
);

if (result.success) {
  console.log('Output URL:', result.output_url);
  console.log('Format:', result.format);
} else {
  console.error('Error:', result.error);
}

As Standalone Function (Testing)

curl -X POST https://your-project.supabase.co/functions/v1/process-generation \
  -H "Authorization: Bearer YOUR_ANON_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "A beautiful sunset",
    "model_id": "black-forest-labs/flux-schnell",
    "width": 1024,
    "height": 1024,
    "num_inference_steps": 30,
    "guidance_scale": 7.5
  }'

Parameters

Required

• prompt: Text description of desired image
• model_id: Replicate model ID (e.g., "black-forest-labs/flux-schnell")
• width: Image width in pixels
• height: Image height in pixels
• num_inference_steps: Number of denoising steps
• guidance_scale: How closely to follow prompt

Optional

• negative_prompt: What to avoid in image
• model_version: Specific model version hash
• seed: Random seed for reproducibility
• source_image_url: Source image for img2img
• strength: Transformation strength (0-1) for img2img

Return Value

interface GenerationResult {
  success: boolean;
  output_url?: string;           // URL to generated image
  format?: string;                // Image format (webp, png, jpeg, svg)
  width?: number;                 // Final image width
  height?: number;                // Final image height
  error?: string;                 // Error message if failed
  generation_time_seconds?: number; // Time taken
}

Model-Specific Logic

Aspect Ratio Handling

• FLUX Schnell: Only supports specific ratios (1:1, 16:9, etc.)
  • Automatically maps requested ratio to closest supported
  • Adjusts dimensions to maintain ratio
• Ideogram/Imagen: Use simplified aspect ratio string
• SDXL/Others: Use exact width/height

Image-to-Image Support

Models with img2img:

• FLUX Dev/Krea Dev
• SDXL and SDXL Lightning
• SeeDream 4

The function automatically:

1. Downloads source image
2. Converts to base64 data URI
3. Adds appropriate parameters for each model

Output Formats

• Default: WebP for efficiency
• Imagen 4: PNG
• Recraft SVG: Vector SVG format
• Auto-detected: From URL extension

Architecture

Main Function

processGeneration(params, apiToken) - Main entry point

Helper Functions

• simplifyAspectRatio() - Calculate simplified ratio (e.g., 16:9)
• convertImageToBase64() - Convert URL to data URI for img2img
• buildModelInput() - Create model-specific input parameters
• determineOutputFormat() - Detect output format from URL/model

Error Handling

• Validates required parameters
• Handles API errors with detailed messages
• Retries polling on transient failures
• Timeout after 10 minutes (120 polls × 2 seconds)
• Returns structured error in result object

Environment Variables

Required:

• REPLICATE_API_TOKEN or REPLICATE_API_KEY: Replicate API token

Development

Local Testing

# Serve locally
npx supabase functions serve process-generation

# Test with curl
curl -X POST http://localhost:54321/functions/v1/process-generation \
  -H "Authorization: Bearer YOUR_ANON_KEY" \
  -d '{"prompt":"test","model_id":"black-forest-labs/flux-schnell",...}'

Deploy

npx supabase functions deploy process-generation

Integration with Job Queue

This function is called by process-jobs worker for 'generate-image' jobs:

const result = await processGeneration(job.payload, apiToken);
if (result.success) {
  // Enqueue download-image job
  await enqueueJob('download-image', {
    output_url: result.output_url,
    ...
  });
}

Performance Notes

• Polls every 2 seconds (not resource-intensive)
• Max 10 minute timeout per generation
• Supports concurrent generations when imported
• Image-to-image conversion happens once, then cached in memory

Future Enhancements

• Add caching for model configurations
• Support batch generation (multiple images)
• Add progress callbacks for long generations
• Implement retry logic with exponential backoff
• Add telemetry/metrics collection