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SkillRack Math Captcha Solver

Solves Math Captcha on the SkillRack website using Tesseract.js.

当前为 2024-11-21 提交的版本，查看 最新版本。

  1. // ==UserScript==
  2. // @name         SkillRack Math Captcha Solver
  3. // @namespace    http://tampermonkey.net/
  4. // @version      0.4
  5. // @description  Solves Math Captcha on the SkillRack website using Tesseract.js.
  6. // @author       Bit-Blazer
  7. // @license      GNU GPLv3
  8. // @match        https://www.skillrack.com/faces/candidate/codeprogram.xhtml
  9. // @match        https://www.skillrack.com/faces/candidate/tutorprogram.xhtml
  10. // @icon         https://envs.sh/GiG.png
  11. // @require      https://cdn.jsdelivr.net/npm/tesseract.js@5/dist/tesseract.min.js
  12. // @grant        none
  13. // ==/UserScript==
  14.  
  15. (function () {
  16.   "use strict";
  17.  
  18.   // Define the IDs of the captcha image, input field, and proceed button
  19.   const CAPTCHA_INPUT = "capval";
  20.   const PROCEED_BTN = "proceedbtn";
  21.  
  22.   /**
  23.    * Inverts the colors of the Captcha Image for better OCR results.
  24.    * This is useful for enhancing the text recognition capability of Tesseract.js.
  25.    * @param {HTMLImageElement} image - The image to be inverted.
  26.    * @returns {string} - Base64 encoded data URL of the inverted image.
  27.    */
  28.   function invertColors(image) {
  29.     const canvas = document.createElement("canvas");
  30.     const ctx = canvas.getContext("2d");
  31.     canvas.width = image.width;
  32.     canvas.height = image.height;
  33.     ctx.drawImage(image, 0, 0);
  34.     ctx.globalCompositeOperation = "difference"; // Invert colors
  35.     ctx.fillStyle = "white"; // Set background to white
  36.     ctx.fillRect(0, 0, canvas.width, canvas.height); // Fill the canvas
  37.     return canvas.toDataURL(); // Return the inverted image as a data URL
  38.   }
  39.  
  40.   /**
  41.    * Extracts the username from the span element.
  42.    * This function looks for the username pattern in the badge label.
  43.    * @returns {string} - The extracted username or an empty string if not found.
  44.    */
  45.   function getUsername() {
  46.     const usernameElement = document.querySelector(".ui-badge-label"); // Select the username element
  47.     const match = usernameElement
  48.       ? usernameElement.textContent.match(/(\d{12}@\w{3})/)
  49.       : null; // Match the username pattern
  50.     return match ? match[0] : ""; // Return the matched username or empty string
  51.   }
  52.  
  53.   /**
  54.    * Solves the captcha by extracting numbers and performing the calculation.
  55.    * @param {string} text - The OCR result from the captcha image.
  56.    * @param {string} username - The username to be removed from the OCR text.
  57.    * @returns {number|null} - The result of the addition or null if not found.
  58.    */
  59.   function solveCaptcha(text, username) {
  60.     // Remove the username from the OCR text and trim whitespace
  61.     const cleanedText = text.replace(new RegExp(username, "gi"), "").trim();
  62.     // Match the addition pattern in the cleaned text
  63.     const match = cleanedText.match(/(\d+)\s*\+\s*(\d+)/);
  64.     // Return the sum of the two numbers if a match is found
  65.     return match ? parseInt(match[1], 10) + parseInt(match[2], 10) : null;
  66.   }
  67.  
  68.   /**
  69.    * Handles the captcha-solving process.
  70.    * This function orchestrates the overall captcha solving by coordinating image processing and user interactions.
  71.    */
  72.   async function handleCaptcha() {
  73.     // Get the captcha elements from the DOM
  74.     const captchaImage = document.querySelector("img[src*='data:image']");
  75.     const captchaInput = document.getElementById(CAPTCHA_INPUT);
  76.     const proceedBtn = document.getElementById(PROCEED_BTN);
  77.  
  78.     // Log an error and exit if any elements are not found
  79.     if (!captchaImage || !captchaInput || !proceedBtn) {
  80.       console.log("Captcha or input elements not found.");
  81.       return; // Stop execution
  82.     }
  83.  
  84.     // Get the username from the UI
  85.     const username = getUsername();
  86.     // Invert the colors of the captcha image for better OCR processing
  87.     const invertedImg = invertColors(captchaImage);
  88.  
  89.     try {
  90.       // Process the inverted image using Tesseract.js for OCR
  91.       const {
  92.         data: { text },
  93.       } = await Tesseract.recognize(invertedImg, "eng", {
  94.         whitelist:
  95.           "1234567890+=abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ@ ", // Allowed characters
  96.         psm: 6, // Page segmentation mode
  97.       });
  98.  
  99.       // Solve the Captcha using the OCR text and username
  100.       const result = solveCaptcha(text, username);
  101.       // Notify if the captcha could not be solved
  102.       if (result === null) {
  103.         console.log("Unable to solve Captcha. Please try again.");
  104.         return; // Stop execution
  105.       }
  106.       // Fill the captcha input with the calculated result
  107.       captchaInput.value = result;
  108.       // Click the submit button to proceed
  109.       proceedBtn.click();
  110.     } catch (error) {
  111.       // Log any errors encountered during the OCR process
  112.       console.error("Error processing captcha:", error);
  113.       alert(
  114.         "An error occurred while processing the captcha. Please try again."
  115.       ); // Notify user
  116.     }
  117.   }
  118.  
  119.   // Wait for the window to fully load before handling the captcha
  120.   window.addEventListener("load", handleCaptcha);
  121. })();