118 lines
3.5 KiB
JavaScript
118 lines
3.5 KiB
JavaScript
const SQL = require('sql-template-strings');
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const _ = require('lodash');
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const connManager = require('../db/connManager');
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class ReaderStorage {
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constructor() {
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this.storagePool = connManager.pool.readerStorage;
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this.periodicCleanCache(3*3600*1000);//1 раз в 3 часа
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}
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async doAction(act) {
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if (!_.isObject(act.items))
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throw new Error('items is not an object');
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let result = {};
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switch (act.action) {
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case 'check':
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result = await this.checkItems(act.items);
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break;
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case 'get':
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result = await this.getItems(act.items);
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break;
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case 'set':
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result = await this.setItems(act.items, act.force);
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break;
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default:
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throw new Error('Unknown action');
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}
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return result;
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}
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async checkItems(items) {
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let result = {state: 'success', items: {}};
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const dbh = await this.storagePool.get();
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try {
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for (const id of Object.keys(items)) {
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if (this.cache[id]) {
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result.items[id] = this.cache[id];
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} else {
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const rows = await dbh.all(SQL`SELECT rev FROM storage WHERE id = ${id}`);
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const rev = (rows.length && rows[0].rev ? rows[0].rev : 0);
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result.items[id] = {rev};
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this.cache[id] = result.items[id];
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}
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}
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} finally {
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dbh.ret();
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}
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return result;
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}
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async getItems(items) {
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let result = {state: 'success', items: {}};
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const dbh = await this.storagePool.get();
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try {
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for (const id of Object.keys(items)) {
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const rows = await dbh.all(SQL`SELECT rev, data FROM storage WHERE id = ${id}`);
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const rev = (rows.length && rows[0].rev ? rows[0].rev : 0);
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const data = (rows.length && rows[0].data ? rows[0].data : '');
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result.items[id] = {rev, data};
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}
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} finally {
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dbh.ret();
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}
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return result;
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}
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async setItems(items, force) {
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let check = await this.checkItems(items);
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//сначала проверим совпадение ревизий
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for (const id of Object.keys(items)) {
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if (!_.isString(items[id].data))
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throw new Error('items.data is not a string');
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if (!force && check.items[id].rev + 1 !== items[id].rev)
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return {state: 'reject', items: check.items};
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}
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const dbh = await this.storagePool.get();
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await dbh.run('BEGIN');
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try {
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const newRev = {};
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for (const id of Object.keys(items)) {
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await dbh.run(SQL`INSERT OR REPLACE INTO storage (id, rev, time, data) VALUES (${id}, ${items[id].rev}, strftime('%s','now'), ${items[id].data})`);
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newRev[id] = {rev: items[id].rev};
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}
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await dbh.run('COMMIT');
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Object.assign(this.cache, newRev);
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} catch (e) {
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await dbh.run('ROLLBACK');
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throw e;
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} finally {
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dbh.ret();
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}
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return {state: 'success'};
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}
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periodicCleanCache(timeout) {
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this.cache = {};
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setTimeout(() => {
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this.periodicCleanCache(timeout);
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}, timeout);
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}
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}
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const readerStorage = new ReaderStorage();
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module.exports = readerStorage; |