Electron开发实战之记帐软件17——使用Lowdb存储数据

时间 2019-11-06

标签 electron 开发实战记帐软件使用 lowdb 存储数据繁體版

原文原文链接

代码仓库： https://github.com/hilanmiao/LanMiaoDesktophtml

请先阅读这位做者的文章，基本是按照他的思路作的。 https://molunerfinn.com/electron-vue-3/#lowdb%E5%AE%9E%E9%99%85%E4%BD%BF%E7%94%A8%E7%9A%84%E5%9D%91vue

lodash 中文文档 https://www.html.cn/doc/lodash/ http://lodash.think2011.net/assigngit

lodash-id 中文文档 https://www.helplib.com/GitHub/article_106283github

初始化

核心代码以下：sql

import Datastore from 'lowdb'
import LodashId from 'lodash-id'
import FileSync from 'lowdb/adapters/FileSync'
import path from 'path'
import fs from 'fs-extra'
// 引入remote模块
import { app, remote } from 'electron'
// package.json
import pkg from '../../package.json'

// 根据process.type来分辨在哪一种模式使用哪一种模块
const APP = process.type === 'renderer' ? remote.app : app

// 获取electron应用的用户目录
const STORE_PATH = APP.getPath('userData')
// console.log(STORE_PATH)
// C:\Users\JD\AppData\Roaming\Electron

if (process.type !== 'renderer') {
    // 若是不存在路径
    if (!fs.pathExistsSync(STORE_PATH)) {
        // 就建立
        fs.mkdirpSync(STORE_PATH)
    }
}

// 以同步的方式初始化lowdb读写的json文件名以及存储路径
const adapter = new FileSync(path.join(STORE_PATH, `/${pkg.name}_lowdb.json`))

// lowdb接管该文件
const db = Datastore(adapter)
// 经过._mixin()引入lodash_id惟一id插件
db._.mixin(LodashId)

// 初始化数据
if(!db.has('user').value()) {
    db.set('user',[{userId: 'admin', password: '123456'}]).write()
}

if(!db.has('category').value()) {
    db.set('category', []).write()
}

if(!db.has('assets').value()) {
    db.set('assets', []).write()
}

if(!db.has('incomeAndExpenditure').value()) {
    db.set('incomeAndExpenditure', []).write()
}

export default db // 暴露出去

效果：数据库

编写api并使用

结合vuetify的datatable组件作了个CRUD的例子，具体请查看源码。json

文件结构以下，api也能够放到renderer里，由于我主进程也可能会用到，因此我这边主要把它拿出来了，不必定合适，看我的习惯吧。api

核心代码以下，insert、upsert、removeWhere等其实都是lodash-id这个模块封装的，你能够点击看看，其实里面的代码仍是lodash的，你也能够封装本身的方法。数组

import db from '../datastore'

export function getCategoryById(id) {
    return new Promise((resolve, reject) => {
        try {
            const collection = db.get('category')
            const category = collection.getById(id).value()
            resolve({
                code: 200,
                data: category
            })
        } catch (err) {
            return reject({
                code: 400,
                message: err.message
            })
        }
    })
}

export function getCategoryWhere(attrs) {
    return new Promise((resolve, reject) => {
        try {
            const collection = db.get('category')
            const categoryList = collection.filter(attrs).value()
            resolve({
                code: 200,
                data: categoryList
            })
        } catch (err) {
            return reject({
                code: 400,
                message: err.message
            })
        }
    })
}

export function getCategoryAll() {
    return new Promise((resolve, reject) => {
        try {
            const collection = db.get('category')
            const categoryAll = collection.value()
            resolve({
                code: 200,
                data: categoryAll
            })
        } catch (err) {
            return reject({
                code: 400,
                message: err.message
            })
        }
    })
}

export function getCategoryPagination(pagination, whereAttrs) {
    return new Promise((resolve, reject) => {
        try {
            const collection = db.get('category')
            const total = collection.size().value()
            const categoryList = collection
                .filter(o => {
                    // 模糊查询
                    return o.category.match(whereAttrs.category)
                })
                .orderBy(pagination.sortBy, pagination.descending ? 'desc' : 'asc')
                .chunk(pagination.rowsPerPage === -1 ? total : pagination.rowsPerPage)
                .take(pagination.page)
                .last() // 由于上面用了chunk，是个二维数组，因此这里取最后一个
                .value()
            resolve({
                code: 200,
                data: {total: total, list: categoryList}
            })
        } catch (err) {
            return reject({
                code: 400,
                message: err.message
            })
        }
    })
}

export function postCategory(document) {
    return new Promise((resolve, reject) => {
        try {
            const collection = db.get('category')
            const category = collection.find({category: document.category}).value()
            if(category) {
                return reject({
                    code: 400,
                    message: 'This classification already exists'
                })
            }
            const newCategory = collection.insert(document).write()
            resolve({
                code: 200,
                data: newCategory
            })
        } catch (err) {
            return reject({
                code: 400,
                message: err.message
            })
        }
    })
}

export function postOrPutCategory(document) {
    return new Promise((resolve, reject) => {
        try {
            const collection = db.get('category')
            if(collection.find({category: document.category}).value()) {
                return reject({
                    code: 400,
                    message: 'This classification already exists'
                })
            }
            const newCategory = collection.upsert(document).write()
            resolve({
                code: 200,
                data: newCategory
            })
        } catch (err) {
            return reject({
                code: 400,
                message: err.message
            })
        }
    })
}

export function putCategoryById(id, attrs) {
    return new Promise((resolve, reject) => {
        try {
            const collection = db.get('category')
            if(collection.find({category: attrs.category}).value()) {
                return reject({
                    code: 400,
                    message: 'This classification already exists'
                })
            }
            const newCategory = collection.updateById(id, attrs).write()
            resolve({
                code: 200,
                data: newCategory
            })
        } catch (err) {
            return reject({
                code: 400,
                message: err.message
            })
        }
    })
}

export function putCategoryWhere(whereAttrs, attrs) {
    return new Promise((resolve, reject) => {
        try {
            const collection = db.get('category')
            if(collection.find({category: attrs.category}).value()) {
                return reject({
                    code: 400,
                    message: 'This classification already exists'
                })
            }
            const newCategory = collection.updateWhere(whereAttrs, attrs).write()
            resolve({
                code: 200,
                data: newCategory
            })
        } catch (err) {
            return reject({
                code: 400,
                message: err.message
            })
        }
    })
}

export function replaceCategoryById(id, attrs) {
    return new Promise((resolve, reject) => {
        try {
            const collection = db.get('category')
            const newCategory = collection.replaceById(id, attrs).write()
            resolve({
                code: 200,
                data: newCategory
            })
        } catch (err) {
            return reject({
                code: 400,
                message: err.message
            })
        }
    })
}

export function deleteCategoryById(id) {
    return new Promise((resolve, reject) => {
        try {
            const collection = db.get('category')
            collection.removeById(id).write()
            resolve({
                code: 200
            })
        } catch (err) {
            return reject({
                code: 400,
                message: err.message
            })
        }
    })
}

export function deleteCategoryByIds(ids) {
    return new Promise((resolve, reject) => {
        try {
            const collection = db.get('category')
            ids.forEach(id => {
                collection.removeById(id).write()
            })
            resolve({
                code: 200
            })
        } catch (err) {
            return reject({
                code: 400,
                message: err.message
            })
        }
    })
}

export function deleteCategoryWhere(whereAttrs) {
    return new Promise((resolve, reject) => {
        try {
            const collection = db.get('category')
            const categoryList = collection.removeWhere(whereAttrs).write()
            resolve({
                code: 200,
                data: categoryList
            })
        } catch (err) {
            return reject({
                code: 400,
                message: err.message
            })
        }
    })
}

说明

这种微小型数据库，不大可能支持G级，网友说也就是几百MB，因此若是数据量很大，请切换到sqlite。其实写个博客，作个单机小系统足够了，大不了分几个库，反正都是些文件，甚至能够按照日期一天一个文件，固然这样就麻烦了。
多表查询、分页，emmm，没有这些功能，全部的数据都已经在内存中了，随便折腾就行了......我代码中相似分页这种功能只是在模拟一些动做而已