Добавлен метод api /reader/storage и класс ReaderStorage

server/core/readerStorage.js

@@ -0,0 +1,92 @@
+const SQL = require('sql-template-strings');
+const _ = require('lodash');
+
+const connManager = require('../db/connManager');
+
+class ReaderStorage {
+    constructor() {
+        this.storagePool = connManager.pool.readerStorage;
+    }
+
+    async doAction(act) {
+        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;
+    }
+
+    async checkItems(items) {
+        let result = {state: 'success', items: {}};
+
+        const dbh = await this.storagePool.get();
+        try {
+            for (const id of Object.keys(items)) {
+                const rows = await dbh.all(SQL`SELECT rev FROM storage WHERE id = ${id}`);
+                const rev = (rows.length && rows[0].rev ? rows[0].rev : 0);
+                result.items[id] = {rev};
+            }
+        } finally {
+            dbh.ret();
+        }
+
+        return result;
+    }
+
+    async getItems(items) {
+        let result = {state: 'success', items: {}};
+
+        const dbh = await this.storagePool.get();
+        try {
+            for (const id of Object.keys(items)) {
+                const rows = await dbh.all(SQL`SELECT rev, data FROM storage WHERE id = ${id}`);                
+                const rev = (rows.length && rows[0].rev ? rows[0].rev : 0);
+                const data = (rows.length && rows[0].data ? rows[0].data : '');
+                result.items[id] = {rev, data};
+            }
+        } finally {
+            dbh.ret();
+        }
+
+        return result;
+    }
+
+    async setItems(items, force) {
+        let check = await this.checkItems(items);
+
+        //сначала проверим совпадение ревизий
+        for (const id of Object.keys(items)) {
+            if (!_.isString(items[id].data))
+                throw new Error('items.data is not a string');
+
+            if (!force && check.items[id].rev + 1 !== items[id].rev)
+                return {state: 'reject', items: check.items};
+        }
+
+        const dbh = await this.storagePool.get();
+        try {
+            for (const id of Object.keys(items)) {
+                await dbh.run(SQL`INSERT OR REPLACE INTO storage (id, rev, data) VALUES (${id}, ${items[id].rev}, ${items[id].data})`);
+            }
+        } finally {
+            dbh.ret();
+        }
+
+        return {state: 'success'};
+    }
+}
+
+const readerStorage = new ReaderStorage();
+
+module.exports = readerStorage;