我遇到了在异步调用完成之前分配值的问题,因此我选择使用 Promises(在本例中为 Bluebird)。我认为这可以解决问题,但鉴于我对 promises/or node 一点都不熟悉,它仍然在做同样的事情。
我将如何着手修改下面的代码,以正确使用 promises?并保持流程,以便我可以根据之前的 row
验证 modules
?
var Promise = require('bluebird');
var db = require('../shared/db');
var queryHelper = require('../shared/queryHelper');
var schemas = require('../schemas/schemas');
var _ = require('lodash');
var serverSettings = require('../shared/coreServerSettings');
// Create new instance of mysql module
var connection = new db();
var queryhelper = new queryHelper();
// Promised methods
var queryAndWait = Promise.promisify(connection.query);
..剪断..
queryAndWait(query + '; ' + queryFoundRows, params).then(function (result) {
var payload = [];
var site_access = [];
var module_access = [];
_.each(result[0], function (row) {
var sites = row.site_access.split(',');
_.each(sites, function (site_id) {
site_access.push(site_id);
});
row.site_access = site_access;
site_access = [];
queryAndWait(queryModules, [row.priv_id]).then(function (result) {
_.each(result, function (module) {
var modulePriv = {
priv_name: module.priv_name,
priv_num: module.priv_num,
enabled: module.enabled
};
module_access.push(modulePriv);
});
//console.log("am assigning " + JSON.stringify(module_access));
row.module_access = module_access;
module_access = []
});
payload.push(row);
});
});
澄清一下:
抱歉,模块是用户(行)有权访问的产品组,它们是动态计算的(按位 - 因此没有可用的连接和单独的查询),模块查询返回如下内容,然后我在返回有效负载之前循环并附加到行:
[{"priv_name":"INTERACT","priv_num":1,"enabled":1},{"priv_name":"STAFF_ADMIN","priv_num":32,"enabled":1},{"priv_name":"INT_EDIT","priv_num":64,"enabled":0},{"priv_name":"FAILED_LOGIN","priv_num":128,"enabled":0},{"priv_name":"INT_TAGS","priv_num":256,"enabled":0},{"priv_name":"NC","priv_num":512,"enabled":0},{"priv_name":"CC_TIMETABLE_MGR","priv_num":1024,"enabled":0}]
最佳答案
是的,内部 queryAndWait
将针对每一行独立运行,因为您没有链接 promise 。
因为你使用 bluebird,所以你需要这样的东西来维持流程
queryAndWait(query + '; ' + queryFoundRows, params).then(function (result) {
return Promise.map(result[0], function (row) {
var site_access = [];
var module_access = [];
var sites = row.site_access.split(',');
_.each(sites, function (site_id) {
site_access.push(site_id);
});
row.site_access = site_access;
return queryAndWait(queryModules, [row.priv_id]).then(function (result) {
_.each(result, function (module) {
var modulePriv = {
priv_name: module.priv_name,
priv_num: module.priv_num,
enabled: module.enabled
};
module_access.push(modulePriv);
});
row.module_access = module_access;
return row;
});
});
}).then(function(payload) {
console.log(payload);
}).catch(function(error) {
console.log(error);
});
关于javascript - 使用 Node (ES6)和 Bluebird promise 混淆,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/32735500/