Added createCaptcha.cjs

src/utils/createCaptcha.cjs

@@ -0,0 +1,199 @@
+const shuffle = require(`../util/lodash/shuffle.js`);
+const random = require(`../util/crypto/random.js`);
+
+/**
+ * Asynchronously Generates a CAPTCHA.
+ * @param {Number} [length=6] The Text Length of the CAPTCHA. Defaults to 6.
+ * @param {String} [blacklist=""] A List of Characters to Exclude from the CAPTCHA.
+ * @returns {CaptchaImageData} The CAPTCHA Image Data.
+ */
+
+module.exports = async function createCaptcha(length = 6, blacklist = "") {
+
+    // Check to see if Canvas is installed.
+    try {
+        require("canvas")
+    } catch { throw new Error("Captcha Generation Error: Automatic CAPTCHA Creation requires the 'canvas' library to be installed.\n You can follow these instructions to install Canvas: https://github.com/AdamT20054/DJSCaptcha/tree/Interactions#presenting-a-captcha-to-a-member-with-built-in-captcha-creation") }
+    const { Canvas } = require("canvas");
+
+    // Validate length param
+    if (Number.isNaN(length)) throw new Error("Captcha Generation Error: Length must be a Number.");
+    if (length < 1) throw new Error("Captcha Generation Error: The CAPTCHA Length must be at least 1 character.\nNeed help? Open an issue at https://github.com/AdamT20054/DJSCaptcha/issues");
+
+    // Validate blacklist param
+    if (typeof blacklist !== "string") throw new Error("Captcha Generation Error: The blacklist parameter must be a string.\nNeed help? Open an issue at https://github.com/AdamT20054/DJSCaptcha/issues");
+    if (blacklist.match(/[^a-zA-Z0-9]/)) throw new Error("Captcha Generation Error: The blacklist parameter must only contain alphanumeric characters.\nNeed help? Open an issue at https://github.com/AdamT20054/DJSCaptcha/issues");
+
+    chars.splice(0, chars.length, ...chars.filter(c => !blacklist.includes(c)));
+    chars = await shuffle(chars);
+
+    let chars = [
+        "a",
+        "b",
+        "c",
+        "d",
+        "e",
+        "f",
+        "g",
+        "h",
+        "i",
+        "j",
+        "k",
+        "l",
+        "m",
+        "n",
+        "o",
+        "p",
+        "q",
+        "r",
+        "s",
+        "t",
+        "u",
+        "v",
+        "w",
+        "x",
+        "y",
+        "z",
+        "A",
+        "B",
+        "C",
+        "D",
+        "E",
+        "F",
+        "G",
+        "H",
+        "I",
+        "J",
+        "K",
+        "L",
+        "M",
+        "N",
+        "O",
+        "P",
+        "Q",
+        "R",
+        "S",
+        "T",
+        "U",
+        "V",
+        "W",
+        "X",
+        "Y",
+        "Z",
+        "0",
+        "1",
+        "2",
+        "3",
+        "4",
+        "5",
+        "6",
+        "7",
+        "8",
+        "9"
+    ];
+
+
+    // Remove blacklisted characters from the character list
+    chars.splice(0, chars.length, ...chars.filter(c => !blacklist.includes(c)));
+    chars = await shuffle(chars);
+
+    const canvas = new Canvas(400, 250);
+    const ctx = canvas.getContext("2d");
+
+    // Set background color
+    ctx.globalAlpha = 1;
+    ctx.fillStyle = "white";
+    ctx.beginPath();
+    ctx.fillRect(0, 0, 400, 250);
+    ctx.save();
+
+    // Set style for lines
+    ctx.strokeStyle = "#000";
+    ctx.lineWidth = 4;
+
+    // Draw lines
+    ctx.beginPath();
+
+    const coords = [];
+
+    for (let i = 0; i < 4; i++) {
+        if (!coords[i])
+            coords[i] = [];
+        for (let j = 0; j < 5; j++)
+            coords[i][j] = Math.round(await random() * 80) + j * 80;
+        if (!(i % 2))
+            coords[i] = await shuffle(coords[i]);
+    }
+
+    for (let i = 0; i < coords.length; i++) {
+        if (!(i % 2)) {
+            for (let j = 0; j < coords[i].length; j++) {
+                if (!i) {
+                    ctx.moveTo(coords[i][j], 0);
+                    ctx.lineTo(coords[i + 1][j], 400);
+                }
+                else {
+                    ctx.moveTo(0, coords[i][j]);
+                    ctx.lineTo(400, coords[i + 1][j]);
+                }
+            }
+        }
+    }
+
+    ctx.stroke();
+
+    // Set style for circles
+    ctx.fillStyle = "#000";
+    ctx.line400 = 0;
+
+    // Draw circles
+    for (let i = 0; i < 200; i++) {
+        ctx.beginPath();
+        ctx.arc(Math.round(await random() * 360) + 20, Math.round(await random() * 360) + 20, Math.round(await random() * 7) + 1, 0, Math.PI * 2);
+        ctx.fill();
+    }
+
+    // generate text
+    let text = "";
+    for (let i = 0; i < length; i++) text += chars[Math.floor(await random() * chars.length)];
+
+
+    // Set style for text based on length param
+    ctx.font = `${length > 6 ? (80 / (length / 7.5)) : 80}px Sans`;
+    ctx.fillStyle = "#000";
+
+
+    // Set position for text
+    ctx.textAlign = "center";
+    ctx.textBaseline = "top";
+    ctx.translate(0, 250);
+    ctx.translate(Math.round(await random() * 100 - 50) + 200, -1 * Math.round(await random() * (250 / 4) - 250 / 8) - 250 / 2);
+    ctx.rotate(await random() - 0.5);
+
+    // Set text value and print it to canvas
+    ctx.beginPath();
+    ctx.fillText(text, 0, 0);
+
+    // Draw foreground noise
+    ctx.restore();
+
+    for (let i = 0; i < 5000; i++) {
+
+        ctx.beginPath();
+
+        let color = "#";
+        while (color.length < 7) {
+            color += Math.round(await random() * 16).toString(16);
+        }
+
+        color += "a0";
+        ctx.fillStyle = color;
+        ctx.arc(Math.round(await random() * 400), Math.round(await random() * 250), await random() * 2, 0, Math.PI * 2);
+        ctx.fill();
+    }
+
+    return {
+        image: canvas.toBuffer(),
+        text: text
+    };
+}