@foreverrbum/ethsign/src/lib/helpers/download.js

This package will allow you to electronically sign documents within your application

import CryptoJS from 'crypto-js';
import fleekStorage from '@fleekhq/fleek-storage-js'
import { storeNotif } from './dashboard';

export const isFileWithPassword = async (fileHash) => {
    // TODO: integrate storageProvider
    if (!fileHash) return false;

    const myFile = await fleekStorage.getFileFromHash({
        hash: fileHash,
    })

    let decryptedDataArray;
    try {
        decryptedDataArray = decryptDataArrayFromStringAES(
            myFile,
            ""
        );
    } catch (error) {
        //doc has password
        return true;
    }
    //doc has no password
    return false;
}
const getFileArrayFL = async (password, fileHash, returnPromise, formatMessage) => {

    const myFile = await fleekStorage.getFileFromHash({
        hash: fileHash,
    })
    let decryptedDataArray;
    try {
        decryptedDataArray = decryptDataArrayFromStringAES(
            myFile,
            password
        );
    } catch (error) {
        storeNotif(formatMessage({id: 'INVALID_PASSWORD'}), formatMessage({id: 'PASSWORD_ENTERED_UNABLE_TO_DECRYPT'}), 'danger')
        return false;
    }
    if(returnPromise){
        return Promise.resolve(decryptedDataArray)
    }else{
        return decryptedDataArray
    }
}

export const getFileArray = async (password, fileHash, storageProvider, returnPromise, formatMessage) => {

    if (!fileHash) return false;

    if (storageProvider='FL'){
        const decryptedDataArray = await getFileArrayFL(password, fileHash, returnPromise, formatMessage);
        return(decryptedDataArray);
    }else if (storageProvider == 'IP'){
        // TODO: add getFileArrayIP code and add chinese transalations
    }else{
        storeNotif(formatMessage({id: 'ERROR'}), formatMessage({id: 'NO_DOCUMENT_FOUND'}), 'danger')
        return false;
    }
}

export const getCommentArrs = async (commentData, password, formatMessage) => {
    return Promise.all(commentData.map(comment => getFileArray(password, comment.commentHash, comment.provider, true, formatMessage)))
}

export const downloadFile = async (password, fileHash, name, close, storageProvider, formatMessage) => {
    const decryptedDataArray = await getFileArray(password, fileHash, storageProvider, false, formatMessage)
    if (decryptedDataArray != false) {
        createAndDownloadBlobFile(
            decryptedDataArray,
            name
        );
        storeNotif(formatMessage({id: 'DOWNLOAD'}), formatMessage({id: 'DOWNLOAD_STARTING'}), 'info')


        close();
    } else {
        return false;
    }
}

function decryptDataArrayFromStringAES(encryptedString, password) {
    if (password == undefined) password = "";
    const bytes = CryptoJS.AES.decrypt(encryptedString, password);
    const decrypted = JSON.parse(bytes.toString(CryptoJS.enc.Utf8));
    const decryptedDataArray = new Uint8Array(decrypted.data);
    return decryptedDataArray;
}

export const createAndDownloadBlobFile = (body, fileName) => {
    const blob = new Blob([body]);
    downloadBlob(blob, fileName);
}

export const downloadBlob = (blob, fileName) => {
    if (navigator.msSaveBlob) {
        // IE 10+
        navigator.msSaveBlob(blob, fileName);
    } else {
        const link = document.createElement('a');
        // Browsers that support HTML5 download attribute
        if (link.download !== undefined) {
            const url = URL.createObjectURL(blob);
            link.setAttribute('href', url);
            // link.setAttribute('download', fileName);
            link.setAttribute('target', '_blank');
            link.style.visibility = 'hidden';
            document.body.appendChild(link);
            link.click();
            document.body.removeChild(link);
        }
    }
}

export default { downloadFile, getFileArray, isFileWithPassword, downloadBlob}