【自動化】Gemini Imagen APIでブログのeyecatch画像を自動生成してR2にアップロードする

Absolutely no text, no words, no letters, no labels, no numbers, no characters.
Pure visual abstract art only.

const CATEGORY_COLORS = {
  'トラブルシューティング': 'warm orange, burnt sienna, cream, dark brown. Beige background.',
  '設定・環境構築': 'deep navy blue, steel blue, lavender, soft peach. Navy blue background.',
  '実装': 'emerald green, teal, sage, dark forest green. Soft mint background.',
  '設計': 'deep indigo, slate blue, dusty rose, warm taupe. Light gray background.',
  '学習メモ': 'golden yellow, amber, warm brown, mustard. Cream background.',
  '技術': 'cool gray, steel blue, ice blue, charcoal. Light silver background.',
};

Abstract geometric composition with overlapping translucent circles,
arcs and curved shapes. Matte paper-like texture. Flat design,
minimal, modern. 16:9.

function callImagen(prompt) {
  return new Promise((resolve, reject) => {
    const url = `https://generativelanguage.googleapis.com/v1beta/models/imagen-4.0-fast-generate-001:predict?key=${API_KEY}`;
    const body = JSON.stringify({
      instances: [{ prompt }],
      parameters: { sampleCount: 1, aspectRatio: '16:9' },
    });
    // HTTPS POSTリクエスト
    // レスポンスのpredictions[0].bytesBase64Encodedがbase64画像データ
  });
}

{
  "predictions": [{
    "bytesBase64Encoded": "iVBORw0KGgo...",
    "mimeType": "image/png"
  }]
}

import { S3Client, PutObjectCommand } from '@aws-sdk/client-s3';

const s3 = new S3Client({
  region: 'auto',
  endpoint: process.env.R2_ENDPOINT,
  credentials: {
    accessKeyId: process.env.R2_ACCESS_KEY,
    secretAccessKey: process.env.R2_SECRET_KEY,
  },
});

async function uploadToR2(buffer, filename) {
  const key = `images/eyecatch/${filename}`;
  await s3.send(new PutObjectCommand({
    Bucket: 'microcms-image',
    Key: key,
    Body: buffer,
    ContentType: 'image/png',
  }));
  return `${BUCKET_URL}/${key}`;
}

async function updateNotionEyecatch(pageId, imageUrl) {
  await notion.pages.update({
    page_id: pageId,
    properties: {
      Eyecatch: { url: imageUrl },
    },
    cover: {
      type: 'external',
      external: { url: imageUrl },
    },
  });
}

// 各記事の処理後に15秒待機
await new Promise(r => setTimeout(r, 15000));