n8n DrawThings

For my workflow I have integrated DrawThings, the diagram of it looks like:

Steps to reproduce:

• Assuming n8n is in Docker and DrawThings are on the host URL, it should be http://host.docker.internal:7860/sdapi/v1/txt2img. We need to use JSON, not fields, because n8n converts them to strings, and n8n has problems with interpretation. In my case, it’s:

{
    "height": 576,
    "width": 1024,
    "seed": -1,
    "prompt": "{{ $json.output.replaceAll('"', '\'').replaceAll('\n', '') }}",
    "batch_size": 1
}

• Next, we need to move the Base64 string to the file using the field images[0] and put it in the data field.
• We save PNG as e.g. /tmp/{{ $now.format('yyyy-MM-dd_HH-mm-ss') }}.png
• For conversion to WebP, we use a simple script and the SharpJS library executed as: npm run convert -- {{ $json.fileName }}

// convert.js
const fs = require('fs');
const sharp = require('sharp');

async function convertPngToJpeg(filePath) {
    const outputPath = filePath.replace(/\.png$/i, '.webp');
    const input = fs.readFileSync(filePath);

    const output = await sharp(input).webp().toBuffer();

    fs.writeFileSync(outputPath, output);
    console.log(`Converted: ${outputPath} end.`);
}

const inputPath = process.argv[2];
if (!inputPath) {
    console.error('Usage: node convert.js <path-to-png>');
    process.exit(1);
}

convertPngToJpeg(inputPath);

• The next thing is to get the filename from stdout.: {{ $json.stdout.match(/Converted: (.*) end./)[1] }} and pass it as filename
• The last link is to read WebP, for example, sending it to WordPress (using the filename from the previous step).

Hope it helps or inspires someone to use different tools 🙂