From 5bfad661efa7ae5219061a8c642c9dbebbb6c555 Mon Sep 17 00:00:00 2001
From: b1ek <me@blek.codes>
Date: Sat, 24 Jun 2023 02:14:01 +1000
Subject: [PATCH] init: parameters

---
 index.js          |  8 +++++--
 package.json      |  3 ++-
 public/index.html | 12 +++++++++-
 routes.js         | 56 +++++++++++++++++++++++++++++++++++++----------
 4 files changed, 63 insertions(+), 16 deletions(-)

diff --git a/index.js b/index.js
index cf55f1b..2fa8035 100644
--- a/index.js
+++ b/index.js
@@ -1,5 +1,5 @@
 require('dotenv').config();
-const { APP_DEBUG } = process.env;
+const { APP_DEBUG, SCRIPT_PROD } = process.env;
 
 const fastify = require('fastify')({ logger: APP_DEBUG == 'true' });
 const path = require('path');
@@ -11,7 +11,11 @@ fastify.register(require('@fastify/static'), {
 
 // load routes from routes.js
 require('./routes')(fastify);
-console.log('Starting up')
+console.log('Starting up');
+
+if (SCRIPT_PROD == 'true' && APP_DEBUG == 'true') {
+    console.warn('\x1b[33mYou are running a production script with APP_DEBUG=true. App will run \x1b[1;31min development mode.\x1b[0m');
+}
 
 fastify.listen({ port: process.env.APP_PORT ?? 8000 }, (err, address) => {
     if (err) throw err;
diff --git a/package.json b/package.json
index ec5a051..e52bf66 100644
--- a/package.json
+++ b/package.json
@@ -13,6 +13,7 @@
     "sharp": "^0.32.1"
   },
   "scripts": {
-    "dev": "gulp dev"
+    "dev": "gulp dev",
+    "prod": "SCRIPT_PROD=true node index.js"
   }
 }
diff --git a/public/index.html b/public/index.html
index 4af8b86..67caa4a 100644
--- a/public/index.html
+++ b/public/index.html
@@ -11,7 +11,17 @@
         <p>
             Send a GET to <b>/catpcha/v{version}/{text}</b>, where
             <b>version</b> - captcha version, and
-            <b>text</b> is the text of your captcha
+            <b>text</b> is the text of your captcha.
+        </p>
+        <p>
+            Also you can pass additional props in the query. Supported props are:<br/>
+            <ul>
+                <li><b>width</b> - ratio width (default 3)</li>
+                <li><b>height</b> - ratio height (default 1)</li>
+                <li><b>padding</b> - padding of the image (default 20)</li>
+                <li><b>format</b> - output format of the image (not supported) (default png)</li>
+                <li><b>dpi</b> - dots per inch, basically text scale (default 250)</li>
+            </ul>
         </p>
 
         <hr/>
diff --git a/routes.js b/routes.js
index bff81cf..c6e8ae0 100644
--- a/routes.js
+++ b/routes.js
@@ -1,21 +1,54 @@
 const sharp = require('sharp');
 const canvas = require('canvas');
-const crypto = require('crypto')
+const crypto = require('crypto');
+const randint = (min, max) => { return crypto.randomInt(max) + min };
+
+/** @param {import('fastify').FastifyRequest} req */
+const getSettings = (req) => {
+    const q = req.query;
+    const settings = {
+        // Width and height are ratio numbers; actual width & height is calculated from text length & padding
+        width: q.width ?? 3,
+        height: q.height ?? 1,
+        padding: q.padding ?? 20,
+        format: q.format ?? 'png',
+        dpi: q.dpi ?? 250
+    };
+    for (const key in settings) {
+        if (['format'].indexOf(key) !== -1) continue;
+        settings[key] = parseInt(settings[key]);
+    }
+    return settings;
+}
+
+const get_size = (ratio, dpi, txtlen, padding) => {
+    return {
+        width: Math.floor((ratio[0] * dpi * 0.12) + (txtlen * dpi * 0.08)) + (padding * 2),
+        height: Math.floor(ratio[1] * dpi * 0.2) + (padding * 2)
+    }
+}
 
 /** @param {import('fastify').FastifyInstance} fastify */
 module.exports = (fastify) => {
     fastify.get('/captcha/v1/:text', async (req, res) => {
 
+        const text = req.params.text;
+
+        const settings = getSettings(req);
+        const size = get_size([settings.width, settings.height], settings.dpi, text.length, settings.padding);
+
+        console.log(size)
+        console.log(settings)
+
         let pic = (await sharp({
             create: {
-                width: 150,
-                height: 50,
+                width: size.width,
+                height: size.height,
                 channels: 4,
                 background: { r: 0, g: 0, b: 0, alpha: 0 }
             }
         }));
 
-        const text = req.params.text;
 
         pic.composite([
             {
@@ -23,11 +56,12 @@ module.exports = (fastify) => {
                     text: {
                         text: text,
                         font: 'Arial',
-                        dpi: crypto.randomInt(150, 200),
+                        dpi: settings.dpi,
                         rgba: true
                     }
                 },
-                blend: 'over'
+                blend: 'over',
+                gravity: 0
             }
         ]);
 
@@ -36,17 +70,15 @@ module.exports = (fastify) => {
             .toFormat('png', { compressionLevel: 6 })
             .toBuffer();
 
-        const draw = canvas.createCanvas(150, 50);
+        const draw = canvas.createCanvas(size.width, size.height);
         const ctx = draw.getContext('2d');
-        ctx.drawImage(await canvas.loadImage(textpic), 0, 0, 150, 50);
+        ctx.drawImage(await canvas.loadImage(textpic), 0, 0, size.width, size.height);
 
-        const randint = (min, max) => { return crypto.randomInt(max) + min };
-
-        const strokes = randint(25, 50);
+        const strokes = randint(25, 40);
         for (let i = 0; i != strokes; i++) {
             ctx.strokeStyle = `rgba(0,0,0,${10})`;
             ctx.beginPath();
-            ctx.bezierCurveTo(randint(0, 150), randint(0, 50), randint(0, 150), randint(0, 50), randint(0, 150), randint(0, 50));
+            ctx.bezierCurveTo(randint(0, size.width), randint(0, size.height), randint(0, size.width), randint(0, size.height), randint(0, size.width), randint(0, size.height));
             ctx.stroke();
         }