New Captcha Package added

2026-07-25 13:38:18 +05:30
parent d0aded0392
commit 8b728a3e5d
157 changed files with 12092 additions and 1913 deletions
@@ -0,0 +1,112 @@
+import { describe, expect, test } from "bun:test";
+import {
+  CAPTCHA_CONCRETE_IMAGE_STYLES,
+  CAPTCHA_IMAGE_STYLES,
+  normalizeCaptchaImageStyleList,
+  resolveCaptchaImageStyle,
+} from "../src/challenges/styles.ts";
+import { renderTextChallenge } from "../src/challenges/visual.ts";
+import type {
+  CaptchaConcreteImageStyle,
+  CaptchaGeneratorContext,
+} from "../src/types.ts";
+
+function random(seedValue = 17) {
+  let seed = seedValue >>> 0;
+  const next = () => {
+    seed = (seed * 1664525 + 1013904223) >>> 0;
+    return seed;
+  };
+  return {
+    int(min: number, max: number) {
+      return min + (next() % (max - min + 1));
+    },
+    float() {
+      return next() / 0xffff_ffff;
+    },
+  };
+}
+
+function context(style: CaptchaConcreteImageStyle): CaptchaGeneratorContext {
+  const source = random(CAPTCHA_CONCRETE_IMAGE_STYLES.indexOf(style) + 101);
+  return {
+    difficulty: "normal",
+    disturbance: 50,
+    imageStyle: style,
+    requestedImageStyle: style,
+    imageStylePool: [style],
+    locale: "en",
+    length: 6,
+    caseSensitive: false,
+    minCompletionMs: 800,
+    randomInt: source.int,
+    randomFloat: source.float,
+    randomId: (bytes = 18) => `${style}-${bytes}`,
+  };
+}
+
+function decodeDataUri(uri: string): Uint8Array {
+  const encoded = uri.slice(uri.indexOf(",") + 1);
+  return Uint8Array.from(atob(encoded), (character) => character.charCodeAt(0));
+}
+
+describe("CAPTCHA image renderer styles", () => {
+  test("publishes the complete renderer catalog", () => {
+    expect(CAPTCHA_IMAGE_STYLES).toContain("random");
+    expect(CAPTCHA_CONCRETE_IMAGE_STYLES).toHaveLength(18);
+    expect(CAPTCHA_CONCRETE_IMAGE_STYLES).toEqual([
+      "classic",
+      "collision",
+      "snow",
+      "corrosion",
+      "spiderweb",
+      "cross-shadow",
+      "split",
+      "split2",
+      "cut",
+      "darts",
+      "distortion",
+      "stitch",
+      "striped",
+      "wave",
+      "grid-noise",
+      "scribble",
+      "pixel",
+      "broken-lines",
+    ]);
+  });
+
+  test("renders a valid PNG for every concrete style", () => {
+    const images = new Set<string>();
+    for (const style of CAPTCHA_CONCRETE_IMAGE_STYLES) {
+      const image = renderTextChallenge("A7K93P", context(style));
+      expect(image.startsWith("data:image/png;base64,")).toBe(true);
+      const bytes = decodeDataUri(image);
+      expect([...bytes.slice(0, 8)]).toEqual([137, 80, 78, 71, 13, 10, 26, 10]);
+      expect(bytes.byteLength).toBeGreaterThan(1_000);
+      images.add(image);
+    }
+    expect(images.size).toBe(CAPTCHA_CONCRETE_IMAGE_STYLES.length);
+  });
+
+  test("normalizes comma-separated renderer pools", () => {
+    expect(normalizeCaptchaImageStyleList("snow, wave, snow", "allowedStyles")).toEqual([
+      "snow",
+      "wave",
+    ]);
+    expect(() => normalizeCaptchaImageStyleList("snow,unknown", "allowedStyles")).toThrow(
+      "allowedStyles contains an unknown image style",
+    );
+  });
+
+  test("selects random styles only from the active pool", () => {
+    const resolved = resolveCaptchaImageStyle({
+      imageStyle: "random",
+      allowedStyles: ["classic", "snow", "wave"],
+      excludedStyles: ["snow"],
+      randomInt: () => 1,
+    });
+    expect(resolved.pool).toEqual(["classic", "wave"]);
+    expect(resolved.resolved).toBe("wave");
+  });
+});