Een astrologie-app bouwen: complete gids voor ontwikkelaars

import express from 'express';
import { Astroway } from '@astroway/sdk';
import { z } from 'zod';

const app = express();
app.use(express.json());

const client = new Astroway({
  apiKey: process.env.ASTROWAY_API_KEY!,
});

const BirthInput = z.object({
  date: z.string(),
  time: z.string(),
  timezoneOffset: z.number(),
  latitude: z.number(),
  longitude: z.number(),
});

app.post('/api/chart', async (req, res) => {
  const parsed = BirthInput.safeParse(req.body);
  if (!parsed.success) return res.status(400).json({ error: parsed.error });

  try {
    const chart = await client.chart.compute({
      ...parsed.data,
      houseSystem: 'P',
    });
    res.json(chart);
  } catch (err) {
    res.status(500).json({ error: String(err) });
  }
});

app.listen(3000, () => console.log('http://localhost:3000'));

import { useState } from 'react';

type Chart = {
  planets: { name: string; longitude: number; isRetrograde: boolean }[];
  aspects: { planet1: string; planet2: string; type: { name: string }; orb: number }[];
};

// Planets come with ecliptic longitude, not a sign: the sign is that longitude
// divided by 30. Work it out on your side, it is cheaper than another call.
const SIGNS = ['Aries', 'Taurus', 'Gemini', 'Cancer', 'Leo', 'Virgo',
  'Libra', 'Scorpio', 'Sagittarius', 'Capricorn', 'Aquarius', 'Pisces'];
const signOf = (longitude: number) => SIGNS[Math.floor(longitude / 30) % 12];

export function NatalForm() {
  const [chart, setChart] = useState<Chart | null>(null);

  async function handleSubmit(formData: FormData) {
    const body = Object.fromEntries(formData.entries());
    const res = await fetch('/api/chart', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        date: body.date,
        time: body.time + ':00',
        timezoneOffset: Number(body.tz),
        latitude: Number(body.lat),
        longitude: Number(body.lng),
      }),
    });
    setChart(await res.json());
  }

  return (
    <div>
      <form action={handleSubmit}>
        <input name="date" type="date" required />
        <input name="time" type="time" required />
        <input name="tz" type="number" placeholder="Timezone offset (e.g. 3)" required />
        <input name="lat" type="number" step="0.0001" placeholder="Latitude" required />
        <input name="lng" type="number" step="0.0001" placeholder="Longitude" required />
        <button>Build chart</button>
      </form>

      {chart && (
        <div>
          <h2>Planets</h2>
          <ul>
            {chart.planets.map(p => (
              <li key={p.name}>{p.name}: {signOf(p.longitude)} {(p.longitude % 30).toFixed(2)}°{p.isRetrograde ? ' R' : ''}</li>
            ))}
          </ul>
          <h2>Aspects</h2>
          <ul>
            {chart.aspects.map((a, i) => (
              <li key={i}>{a.planet1} {a.type.name} {a.planet2} (orb {a.orb.toFixed(2)}°)</li>
            ))}
          </ul>
        </div>
      )}
    </div>
  );
}

const SynastryInput = z.object({
  chart1: BirthInput,
  chart2: BirthInput,
});

app.post('/api/synastry', async (req, res) => {
  const parsed = SynastryInput.safeParse(req.body);
  if (!parsed.success) return res.status(400).json({ error: parsed.error });

  const result = await client.synastry.compute(parsed.data);
  res.json({
    score: result.compatibility.score,
    label: result.compatibility.label,
    aspects: result.crossAspects,
  });
});

// The daily horoscope is keyed by sign and date, not by the birth chart.
const DailyInput = z.object({
  sign: z.enum(['aries', 'taurus', 'gemini', 'cancer', 'leo', 'virgo',
    'libra', 'scorpio', 'sagittarius', 'capricorn', 'aquarius', 'pisces']),
  date: z.string(),
});

app.post('/api/horoscope/daily', async (req, res) => {
  const parsed = DailyInput.safeParse(req.body);
  if (!parsed.success) return res.status(400).json({ error: parsed.error });

  const horoscope = await client.horoscope.daily({ ...parsed.data, language: 'uk' });
  res.json({
    text: horoscope.horoscope,
    disclaimer: horoscope.disclaimer, // must be shown in the UI!
  });
});

import { LRUCache } from 'lru-cache';

const cache = new LRUCache<string, any>({ max: 1000, ttl: 86400 * 1000 });

app.post('/api/horoscope/daily', async (req, res) => {
  const key = JSON.stringify(req.body);
  const cached = cache.get(key);
  if (cached) return res.json(cached);

  const horoscope = await client.horoscope.daily(req.body);
  cache.set(key, horoscope);
  res.json(horoscope);
});

credits/month = DAU × (avg_charts_per_user × 20
                     + avg_synastries × 50
                     + avg_horoscopes × 20) × 30

100 × (20 + 20 + 0.3 × 50) × 30 = 165,000 credits/month