basic captcha generator

helpers/captcha.js

@@ -0,0 +1,41 @@
+const gm = require('@tohru/gm')
+	, crypto = require('crypto')
+	, fs = require('fs')
+	, rr = (min, max) => Math.floor(Math.random() * (max-min + 1) + min)
+	, width = 200
+	, height = 80;
+
+function getShape() {
+	const x1 = rr(width * 0.1, width * 0.9)
+		, y1 = rr(height * 0.1, height * 0.9)
+		, size = rr(15, 30)
+		, x2 = rr(x1, x1 + size)
+		, y2 = rr(y1, y1 + size);
+	return { x1, x2, y1, y2 };
+}
+
+module.exports = () => {
+	return new Promise((resolve, reject) => {
+		const text = crypto.randomBytes(20).toString('hex').substring(0,6).split('')
+		const x = gm(200, 80, '#fff')
+		.fill('#000')
+		.fontSize(80)
+		for (let i = 0; i <6; i++) {
+			x.drawText(i*30, 55+rr(0,10), text[i])
+		}
+		for (let i = 0; i <4; i++) {
+			const shape = getShape();
+			x.strokeWidth(rr(3, 5))
+			x.drawCircle(shape.x1, shape.y1, shape.x2, shape.y1)
+		}
+		x.wave(10, rr(50,80))
+		.blur(1, 2)
+		.crop(200, 80, 0, 0)
+		.write('./static/img/captcha.jpg', (err) => {
+			if (err) {
+				return reject();
+			}
+			return resolve();
+		});
+	})
+}