@nasriya/cachify/dist/esm/core/persistence/helpers/streams/DecryptStream.js

A lightweight, extensible in-memory caching library for storing anything, with built-in TTL and customizable cache types.

import crypto from 'crypto';
import helpers from "../helpers.js";
import { Transform } from "stream";
class DecryptStream extends Transform {
    #_key;
    #_ivExtractHandler = helpers.createExtractIVHandler();
    #_chunkProcessor = helpers.createChunkProcessor();
    #_iv = null;
    #_decipher = null;
    #_handler = null;
    constructor(key) {
        super();
        if (key.length !== 32) {
            throw new Error('Key must be 32 bytes (256 bits) long');
        }
        this.#_key = key;
    }
    #decrept(data) {
        return this.#_decipher.update(data);
    }
    #setHandler(callback) {
        this.#_handler = helpers.createCallbackHandler(callback, this.#decrept.bind(this));
    }
    #processChunk(chunk) {
        return this.#_chunkProcessor(chunk, this.#_handler);
    }
    _transform(chunk, encoding, callback) {
        this.#setHandler(callback);
        try {
            if (Buffer.isBuffer(this.#_iv)) {
                return this.#processChunk(chunk);
            }
            const res = this.#_ivExtractHandler(chunk);
            if (!res.found) {
                return callback();
            }
            this.#_iv = res.iv;
            this.#_decipher = crypto.createDecipheriv('aes-256-cbc', this.#_key, this.#_iv);
            return this.#processChunk(res.rest);
        }
        catch (error) {
            callback(error);
        }
    }
    _flush(callback) {
        this.#setHandler(callback);
        try {
            if (!this.#_decipher) {
                // No data processed at all
                return callback();
            }
            this.#_chunkProcessor.flush(this.#_handler);
            const final = this.#_decipher.final();
            this.push(final);
        }
        catch (err) {
            callback(err);
        }
        finally {
            this.#_handler = null;
            this.#_iv = null;
            this.#_decipher = null;
        }
    }
}
export default DecryptStream;