Files
liberama/server/core/Reader/JembaReaderStorage.js

128 lines
3.9 KiB
JavaScript

const _ = require('lodash');
const utils = require('../utils');
const JembaConnManager = require('../../db/JembaConnManager');//singleton
const log = new (require('../AppLogger'))().log;//singleton
let instance = null;
//singleton
class JembaReaderStorage {
constructor() {
if (!instance) {
this.connManager = new JembaConnManager();
this.db = this.connManager.db['reader-storage'];
this.periodicCleanCache(3*3600*1000);//1 раз в 3 часа
instance = this;
}
return instance;
}
async doAction(act) {
try {
if (!_.isObject(act.items))
throw new Error('items is not an object');
let result = {};
switch (act.action) {
case 'check':
result = await this.checkItems(act.items);
break;
case 'get':
result = await this.getItems(act.items);
break;
case 'set':
result = await this.setItems(act.items, act.force);
break;
default:
throw new Error('Unknown action');
}
return result;
} catch (e) {
log(LM_ERR, `JembaReaderStorage: ${e.message}`);
throw e;
}
}
async checkItems(items) {
let result = {state: 'success', items: {}};
const db = this.db;
for (const id of Object.keys(items)) {
if (this.cache[id]) {
result.items[id] = this.cache[id];
} else {
const rows = await db.select({//SQL`SELECT rev FROM storage WHERE id = ${id}`
table: 'storage',
map: '(r) => ({rev: r.rev})',
where: `@@id(${db.esc(id)})`
});
const rev = (rows.length && rows[0].rev ? rows[0].rev : 0);
result.items[id] = {rev};
this.cache[id] = result.items[id];
}
}
return result;
}
async getItems(items) {
let result = {state: 'success', items: {}};
const db = this.db;
for (const id of Object.keys(items)) {
const rows = await db.select({//SQL`SELECT rev, data FROM storage WHERE id = ${id}`);
table: 'storage',
where: `@@id(${db.esc(id)})`
});
const rev = (rows.length && rows[0].rev ? rows[0].rev : 0);
const data = (rows.length && rows[0].data ? rows[0].data : '');
result.items[id] = {rev, data};
}
return result;
}
async setItems(items, force) {
let check = await this.checkItems(items);
//сначала проверим совпадение ревизий
for (const id of Object.keys(items)) {
if (!_.isString(items[id].data))
throw new Error('items.data is not a string');
if (!force && check.items[id].rev + 1 !== items[id].rev)
return {state: 'reject', items: check.items};
}
const db = this.db;
const newRev = {};
for (const id of Object.keys(items)) {
await db.insert({//SQL`INSERT OR REPLACE INTO storage (id, rev, time, data) VALUES (${id}, ${items[id].rev}, strftime('%s','now'), ${items[id].data})`);
table: 'storage',
replace: true,
rows: [{id, rev: items[id].rev, time: utils.toUnixTime(Date.now()), data: items[id].data}],
});
newRev[id] = {rev: items[id].rev};
}
Object.assign(this.cache, newRev);
return {state: 'success'};
}
periodicCleanCache(timeout) {
this.cache = {};
setTimeout(() => {
this.periodicCleanCache(timeout);
}, timeout);
}
}
module.exports = JembaReaderStorage;