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SkillRack Math Captcha Solver

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

当前为 2024-10-26 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/codeprogramgroup.xhtml
  9. // @icon         data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==
  10. // @require      https://cdn.jsdelivr.net/npm/tesseract.js@5/dist/tesseract.min.js
  11. // @grant        none
  12. // ==/UserScript==
  13.  
  14. (function () {
  15.     "use strict";
  16.  
  17.     // Define the IDs of the captcha image, input field, and proceed button
  18.     const CAPTCHA_IMAGE = "j_id_78";
  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 specified 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 ? usernameElement.textContent.match(/(\d{12}@\w{3})/) : null; // Match the username pattern
  48.         return match ? match[0] : ""; // Return the matched username or empty string
  49.     }
  50.  
  51.     /**
  52.      * Solves the captcha by extracting numbers and performing the calculation.
  53.      * @param {string} text - The OCR result from the captcha image.
  54.      * @param {string} username - The username to be removed from the OCR text.
  55.      * @returns {number|null} - The result of the addition or null if not found.
  56.      */
  57.     function solveCaptcha(text, username) {
  58.         // Remove the username from the OCR text and trim whitespace
  59.         const cleanedText = text.replace(new RegExp(username, "gi"), "").trim();
  60.         // Match the addition pattern in the cleaned text
  61.         const match = cleanedText.match(/(\d+)\s*\+\s*(\d+)/);
  62.         // Return the sum of the two numbers if a match is found
  63.         return match ? parseInt(match[1], 10) + parseInt(match[2], 10) : null;
  64.     }
  65.  
  66.     /**
  67.      * Handles the captcha-solving process.
  68.      * This function orchestrates the overall captcha solving by coordinating image processing and user interactions.
  69.      */
  70.     async function handleCaptcha() {
  71.         // Get the captcha elements from the DOM
  72.         const captchaImage = document.getElementById(CAPTCHA_IMAGE);
  73.         const captchaInput = document.getElementById(CAPTCHA_INPUT);
  74.         const proceedBtn = document.getElementById(PROCEED_BTN);
  75.  
  76.         // Log an error and exit if any elements are not found
  77.         if (!captchaImage || !captchaInput || !proceedBtn) {
  78.             alert("Captcha or input elements not found."); // Notify user
  79.             return; // Stop execution
  80.         }
  81.  
  82.         // Get the username from the UI
  83.         const username = getUsername();
  84.         // Invert the colors of the captcha image for better OCR processing
  85.         const invertedImg = invertColors(captchaImage);
  86.  
  87.         try {
  88.             // Process the inverted image using Tesseract.js for OCR
  89.             const { data: { text } } = await Tesseract.recognize(invertedImg, "eng", {
  90.                 whitelist: "1234567890+=abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ@ ", // Allowed characters
  91.                 psm: 6, // Page segmentation mode
  92.             });
  93.  
  94.             // Solve the Captcha using the OCR text and username
  95.             const result = solveCaptcha(text, username);
  96.             // Notify if the captcha could not be solved
  97.             if (result === null) {
  98.                 alert("Unable to solve Captcha. Please try again.");
  99.                 return; // Stop execution
  100.             }
  101.             // Fill the captcha input with the calculated result
  102.             captchaInput.value = result;
  103.             // Click the submit button to proceed
  104.             proceedBtn.click();
  105.         } catch (error) {
  106.             // Log any errors encountered during the OCR process
  107.             console.error("Error processing captcha:", error);
  108.             alert("An error occurred while processing the captcha. Please try again."); // Notify user
  109.         }
  110.     }
  111.  
  112.     // Wait for the window to fully load before handling the captcha
  113.     window.addEventListener("load", handleCaptcha);
  114. })();