mirror of https://github.com/gchq/CyberChef.git
96 lines
3.3 KiB
JavaScript
96 lines
3.3 KiB
JavaScript
/**
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* @author n1474335 [n1474335@gmail.com]
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* @author mshwed [m@ttshwed.com]
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* @author Matt C [me@mitt.dev]
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* @copyright Crown Copyright 2019
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* @license Apache-2.0
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*/
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import Operation from "../Operation.mjs";
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import OperationError from "../errors/OperationError.mjs";
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import { isImage } from "../lib/FileType.mjs";
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import { toBase64 } from "../lib/Base64.mjs";
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import { isWorkerEnvironment } from "../Utils.mjs";
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import Tesseract from "tesseract.js";
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const { createWorker } = Tesseract;
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import process from "process";
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/**
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* Optical Character Recognition operation
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*/
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class OpticalCharacterRecognition extends Operation {
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/**
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* OpticalCharacterRecognition constructor
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*/
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constructor() {
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super();
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this.name = "Optical Character Recognition";
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this.module = "OCR";
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this.description = "Optical character recognition or optical character reader (OCR) is the mechanical or electronic conversion of images of typed, handwritten or printed text into machine-encoded text.<br><br>Supported image formats: png, jpg, bmp, pbm.";
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this.infoURL = "https://wikipedia.org/wiki/Optical_character_recognition";
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this.inputType = "ArrayBuffer";
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this.outputType = "string";
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this.args = [
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{
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name: "Show confidence",
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type: "boolean",
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value: true
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}
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];
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}
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/**
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* @param {ArrayBuffer} input
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* @param {Object[]} args
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* @returns {string}
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*/
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async run(input, args) {
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const [showConfidence] = args;
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if (!isWorkerEnvironment()) throw new OperationError("This operation only works in a browser");
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const type = isImage(input);
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if (!type) {
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throw new OperationError("Invalid File Type");
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}
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const assetDir = isWorkerEnvironment() ? `${self.docURL}/assets/` : `${process.cwd()}/src/core/vendor/`;
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try {
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self.sendStatusMessage("Spinning up Tesseract worker...");
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const image = `data:${type};base64,${toBase64(input)}`;
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const worker = createWorker({
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workerPath: `${assetDir}tesseract/worker.min.js`,
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langPath: `${assetDir}tesseract/lang-data`,
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corePath: `${assetDir}tesseract/tesseract-core.wasm.js`,
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logger: progress => {
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if (isWorkerEnvironment()) {
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self.sendStatusMessage(`Status: ${progress.status}${progress.status === "recognizing text" ? ` - ${(parseFloat(progress.progress)*100).toFixed(2)}%`: "" }`);
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}
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}
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});
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await worker.load();
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self.sendStatusMessage("Loading English language...");
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await worker.loadLanguage("eng");
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self.sendStatusMessage("Intialising Tesseract API...");
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await worker.initialize("eng");
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self.sendStatusMessage("Finding text...");
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const result = await worker.recognize(image);
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if (showConfidence) {
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return `Confidence: ${result.data.confidence}%\n\n${result.data.text}`;
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} else {
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return result.data.text;
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}
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} catch (err) {
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throw new OperationError(`Error performing OCR on image. (${err})`);
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}
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}
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}
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export default OpticalCharacterRecognition;
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