motoboat/lib/helper.js

a powerful web framework, build on module http and https.

/**
    module router
    Copyright (C) 2019.08 BraveWang
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License , or
    (at your option) any later version.
 */

'use strict';

const crypto = require('crypto');
const fs = require('fs');

var helper = {};

/**
 * @param {string} filename 文件名称
 */
helper.extName = function (filename) {
    if (filename.indexOf(".") < 0) {
        return '';
    }
    var name_slice = filename.split('.');
    if (name_slice.length <= 0) {
        return '';
    }
    return '.' + name_slice[name_slice.length-1];
};

/**
 * @param {string} filename 文件名称
 * @param {string} pre_str 前缀字符串
 */
helper.genFileName = function(filename = '', pre_str='') {
    var org_name = `${pre_str}${Date.now()}`;
    var hash = crypto.createHash('sha1');
    hash.update(org_name);
    return hash.digest('hex') + ((filename=='') ? '' : helper.extName(filename));
};

/**
 * @param {object} ctx 请求上下文对象
 * @param {object} upf 通过getFile获取的文件对象
 * @param {options} 选项，包括target(目标文件名)和path(目标目录)
 */
helper.moveFile = async function (ctx, upf, options) {
    if (!options.filename) {
        options.filename = helper.genFileName(upf.filename,
            `${(Math.random()*10000).toFixed(0)}`);
    }
    var target = options.path + '/' + options.filename;
    try {
        let fd = await new Promise((rv, rj) => {
            fs.open(target, 'w+', 0o644, (err, fd) => {
                if (err) { rj(err); }
                else { rv(fd); }
            });
        });
        return new Promise((rv, rj) => {
            fs.write(fd, ctx.rawBody, upf.start, upf.length, 
                (err,bytesWritten,buffer) => {
                    if (err) { rj(err); }
                    else { rv(bytesWritten); }
                });
        })
        .then(d => {
            return {target:target, filename: options.filename};
        }, e => { throw e; })
        .finally(() => {
            fs.close(fd, (err) => {});
        });
    } catch (err) {
        throw err;
    }
};

/**
 * @param {string} filename 文件名
 * @param {string} encoding 文件编码
 */
helper.readFile = function (filename, encoding = 'utf8') {
    return new Promise((rv, rj) => {
        fs.readFile(filename, {encoding:encoding}, (err, data) => {
            if (err) {
                rj(err);
            } else {
                rv(data);
            }
        });
    });
};

/**
 * @param {string} extname 文件扩展名
 */
helper.imageType = function (extname) {
    switch (extname) {
        case '.png':
            return 'image/png';
        case '.jpg':
        case '.jpeg':
            return 'image/jpeg';
        case '.gif':
            return 'image/gif';

        default: return '';
    }
};

helper.aesEncrypt = function (data, key, options = {}) {
    var h = crypto.createCipher('aes-256-cbc', key, options);
    let hd = h.update(data, 'utf8', 'hex');
    hd += h.final('hex');
    return hd;
};

helper.aesDecrypt = function (data, key, options = {}) {
    var h = crypto.createDecipher('aes-256-cbc', key, options);
    let hd = h.update(data, 'hex', 'utf8');
    hd += h.final('utf8');
    return hd;
};

helper.md5 = function (data) {
    var h = crypto.createHash('md5');
    h.update(data);
    return h.digest('hex');
};

helper.sha1 = function (data) {
    var h = crypto.createHash('sha1');
    h.update(data);
    return h.digest('hex');
};

helper.sha512 = function (data) {
    var h = crypto.createHash('sha512');
    h.update(data);
    return h.digest('hex');
};

helper.makeSalt = function (length = 8) {
    var saltArr = [
        'a','b','c','d','e','f','g',
        'h','i','j','k','l','m','n',
        'o','p','q','r','s','t','u',
        'v','w','x','y','z','1','2',
        '3','4','5','6','7','8','9'
    ];

    let total = saltArr.length;
    let saltstr = '';
    let ind = 0;

    for(let i=0; i<length; i++) {
        ind = parseInt( Math.random() * 10000) % total;
        saltstr += saltArr[ ind ];
    }
    return saltstr;
};

helper.formatTime = function (t = null) {
    if (t == null) {
        t = new Date();
    }
    return `${t.getFullYear()}-${t.getMonth()+1}-${t.getDate()} ${t.getHours()}:${t.getMinutes()}:${t.getSeconds()}`;
};


module.exports = helper;