IndexedDB使用（基本函数封到Angular2的service里）
IndexedDB使用
使用场景
- 具体使用场景：
存储用户浏览记录。
- 适合的使用场景:
- 处于安全性考虑，数据不能存储到服务器端。
- 数据为结构性数据或者数据量较大，不适合使用cookies。
- 希望数据不随着客户清理缓存而删除。此时我们一定一定要设计好清理浏览器端数据的时机。
相关站点
- MDN文档（中英） 访问
- IBM develoerWorks（中文） 访问
- 这个可能是最权威的了吧，W3C（英文）访问
ps:那么多好的资料了，为什么还写博客？
- 做笔记；
- 我用的Angular2，语法糖是ES6的啊。
代码段
代码段来自项目，当然是底层的与项目无关。这部分代码大部分是已有的，来自一个已经离开项目的同事，我写了一部分。在此我只是记录下而已。
// 项目使用的是Angular2,这是一个service。有关Angular2的写法我不做说明。
import { Injectable } from '@angular/core';
@Injectable()
export class WorkIndexedDBService {
// 声明一些属性，name：数据库名,version：数据库版本
// name和version发生变化，浏览器就会重新建一个新的indexedDB
private name: string = 'test-docView';
private version: number = 1;
private db: any = null;
constructor() { }
// 打开并创建数据库
public open(): Promise {
return new Promise((resolve, reject) => {
// 打开indexedDB
let req = indexedDB.open(this.name, this.version);
// 打开DB成功后的回调
req.onsuccess = function(event) {
this.db = event.target.result;
resolve();
}.bind(this);
// 此处说明.bind(this)，是为了把当前类的属性和方法传入req.onsuccess的这个function里。即：.bind(this)的this是指本类WorkIndexedDBService
// 打开DB失败后的回调
req.onerror = reject;
// 打开新的数据库时，会回调此函数，改变name和version均会建立新的DB，所以都会发生此回调。
req.onupgradeneeded = function(event) {
// 如果版本升级要记得删除旧的数据库表再建立新的。
this.db = event.target.result;
let storeNames = this.db.objectStoreNames;
if (storeNames && storeNames.length > 0) {
for (let i = 0 ; i < storeNames.length ; i++) {
this.db.deleteObjectStore(storeNames[i]);
console.log('deleteObjectStore', storeNames[i]);
}
}
// 创建数据库表
this.createViewDB();
}.bind(this);
});
}
// 关闭数据库
public close(): void {
this.db.close();
}
// 删除数据库
public deleteDB(): Promise {
return new Promise((resolve, reject) => {
// 先关闭连接再删
this.close();
let req = indexedDB.deleteDatabase(this.name);
req.onsuccess = function(event) {
this.db = null;
resolve();
}.bind(this);
req.onerror = reject;
});
}
// 添加数据
// 注意：使用事务来做操作比较快。
public insert(
storeName: string,
data: any
): Promise {
return new Promise((resolve, reject) => {
let transaction = this.db.transaction(storeName, 'readwrite');
let store = transaction.objectStore(storeName);
let req = store.add(data);
req.onsuccess = function(event) {
resolve(req.result);
};
req.onerror = reject;
});
}
// 批量添加数据
public batchInsert(
storeName: string,
data: any[]
): Promise {
if (!data || data.length === 0) {
return Promise.resolve();
}
let transaction = this.db.transaction(storeName, 'readwrite');
let store = transaction.objectStore(storeName);
return new Promise((resolve, reject) => {
data.forEach(row =>
store.add(row);
});
transaction.oncomplete = resolve;
transaction.onerror = reject;
})
.catch((error) => {
console.error('添加' + storeName + '表数据失败', error);
return Promise.reject(error);
});
}
// 删除数据
public workdelete(
storeName: string,
keyValue: any
): Promise {
return new Promise((resolve, reject) => {
let transaction = this.db.transaction(storeName, 'readwrite');
let store = transaction.objectStore(storeName);
let req = store.delete(keyValue);
req.onsuccess = resolve;
req.onerror = reject;
});
}
// 清楚全部数据
public clearAllData(): Promise {
let storeNameList: Array = new Array();
let storeNames = this.db.objectStoreNames;
if (storeNames && storeNames.length > 0) {
for (let i = 0 ; i < storeNames.length ; i++) {
storeNameList.push(storeNames[i]);
}
}
return Promise.all(
storeNameList.map((storeName) => {
return this.clear(storeName);
})
);
}
// 清空数据
public clear(
storeName: string
): Promise {
return new Promise((resolve, reject) => {
let transaction = this.db.transaction(storeName, 'readwrite');
let store = transaction.objectStore(storeName);
let req = store.clear();
req.onsuccess = resolve;
req.onerror = reject;
});
}
// 更新数据
public update(
storeName: string,
data: any
): Promise {
return new Promise((resolve, reject) => {
let transaction = this.db.transaction(storeName, 'readwrite');
let store = transaction.objectStore(storeName);
let req = store.put(data);
req.onsuccess = resolve;
req.onerror = reject;
});
}
// 根据Key取得数据
public selectByKey(
storeName: string,
keyValue: any
): Promise {
return new Promise((resolve, reject) => {
let transaction = this.db.transaction(storeName, 'readonly');
let store = transaction.objectStore(storeName);
let req = store.get(keyValue);
req.onsuccess = function() {
resolve(req.result);
}
req.onerror = reject;
});
}
// 根据索引取得数据
public selectByIndex(
storeName: string,
indexName: string,
indexValue: any
): Promise {
return new Promise((resolve, reject) => {
let transaction = this.db.transaction(storeName, 'readonly');
let store = transaction.objectStore(storeName);
let index = store.index(indexName);
let req = index.openCursor(indexValue);
let result: any[] = new Array();
req.onsuccess = function(event) {
let cursor = event.target.result;
if (cursor) {
result.push(cursor.value);
cursor.continue();
} else {
resolve(result);
}
}
req.onerror = reject;
});
}
// 批量合并数据
public batchMerge(
storeName: string,
data: any[],
delFlagColName?: string,
delFlagColName2?: string
): Promise {
if (!data || data.length === 0) {
return Promise.resolve();
}
let transaction = this.db.transaction(storeName, 'readwrite');
let store = transaction.objectStore(storeName);
return new Promise((resolve, reject) => {
data.forEach(row => {
let keyPath = store.keyPath;
let keyValue;
if (typeof keyPath === 'string') {
keyValue = row[keyPath];
} else {
keyValue = new Array();
keyPath.forEach(key => {
keyValue.push(row[key]);
});
}
store.delete(keyValue);
} else {
store.put(row);
}
});
transaction.oncomplete = resolve;
transaction.onerror = reject;
})
.catch((error) => {
console.error('更新' + storeName + '表数据失败', error);
return Promise.reject(error);
});
}
// 数据库初始化处理
private createDB(): void {
this.createConfigInfo();
this.createStoreUserInfo();
this.createStoreOrgInfo();
this.createStoreUserOrgInfo();
}
// 创建系统配置表及索引
private createConfigInfo(): void {
let store = this.db.createObjectStore(
'ConfigInfo',
{keyPath: 'key'}
);
}
// 创建用户表及索引
private createStoreUserInfo(): void {
let store = this.db.createObjectStore(
'UserInfo',
{keyPath: 'userId'}
);
}
// 创建组织表及索引
private createStoreOrgInfo(): void {
let store = this.db.createObjectStore(
'OrgInfo',
{keyPath: 'orgId'}
);
store.createIndex(
'parentOrgIdIndex',
['parentOrgId', 'displayOrder'],
{unique: false}
);
}
// 创建组织表及索引
private createStoreUserOrgInfo(): void {
let store = this.db.createObjectStore(
'UserOrgInfo',
// S zhuruifei 2017-08-14 通讯录数据结构变更
{keyPath: 'personRoleId'}
// E zhuruifei 2017-08-14 通讯录数据结构变更
);
store.createIndex(
'orgIdIndex',
'orgId',
{unique: false}
);
}
// 创建稿件浏览记录表
private createViewDB(): void{
let store = this.db.createObjectStore(
'viewedDoc',
{keyPath: 'docId'}
);
store.createIndex(
'viewedDoc',
'docId',
{unique: true}
);
}
// 批量查询稿件浏览信息
judgeIfWatched(
storeName: string,
data: any[]
):Promise{
if (!data || data.length === 0) {
return Promise.resolve();
}
return Promise.all(
data.map((data)=> {
return this.selectByKey(storeName,data.docId)
.then((res)=> {
if(res&&res.docId) {
data.viewed = "1";
}
return Promise.resolve();
})
})
)
.catch((error) => {
console.error(error);
return Promise.reject(error);
});
}
// 清除30天前的数据
cleanViewDB(){
this.open().then(()=>{
// 通过IDBDatabase得到IDBTransaction
let transaction = this.db.transaction('viewedDoc', 'readonly');
// 通过IDBTransaction得到IDBObjectStore
let objectStore = transaction.objectStore("viewedDoc");
// 打开游标，遍历customers中所有数据
objectStore.openCursor().onsuccess = function(event) {
let cursor = event.target.result;
if (cursor) {
let key = cursor.key;
let rowData = cursor.value;
var time1 = new Date(rowData.lastViewTime);
var time2 = new Date();
if(Math.abs(time2.getTime() - time1.getTime())>2592000000){// 清除三十天前的数据
this.workdelete('viewedDoc',cursor.key);
}
cursor.continue();
}
}.bind(this);
})
}
}
感谢您看到了这里，这里是结尾。如果对您有帮助，我深感欣慰。自己给自己做广告，不犯法吧？欢迎关注WeChat公众号
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