我有2个async方法可以彼此独立运行。一旦完成，我想调用回调。我尝试过使用async.parallel()（npm），但这似乎适用于非异步方法。我该如何实现呢？
这是我的async.parallel call();请注意，asyncTasks是我的函数数组，其中函数是异步的。
async.parallel(asyncTasks, function(resultFinal){
console.log("--------->>>>> message: "+JSON.stringify(resultFinal));
console.log("");
callback(new RequestResponse(true, resultFinal));
});
简而言之，我真正想要的是一种并行执行多个异步方法的方法，并考虑在触发为该函数提供的回调时该方法完成。
更新
为了更好地理解，我已经包含了我正在使用的两个功能
getGroups
var getGroups = function (callback_async_1) { //get groups + members
pg.connect(datebasePath, function (err, client, done) {
var s = squel.select();
s.from("groups_members");
s.where("user_id = ?", userId);
console.log("query: " + s.toString());
client.query(s.toString(), function (err, result) { //get groups ids in which i am a member
if (err) {
console.error("error...1 " + err);
callback_async_1(responseData);
} else {
// console.log("init -- get from group_members " + JSON.stringify(result.rows));
var groupIds = [];
if (result.rows.length > 0) {
for (var i = 0; i < result.rows.length; i++) {
groupIds.push(result.rows[i].group_id); // create group ids list
}
// console.log("group ids : " + groupIds);
}
if (groupIds.length === 0) {
callback_async_1(responseData);
}
var s = squel.select();
s.from("groups");
s.where("id IN ?", groupIds);
client.query(s.toString(), function (err, result2) { // retrieve all the groups in which i take part
if (err) {
console.error("error...2 " + err);
callback_async_1(responseData);
return;
} else {
// var groupIds2 = [];
// console.log("init -- get from groups " + JSON.stringify(result2.rows));
var groups = [];
// var groups_members = [];
for (var i = 0; i < result2.rows.length; i++) {
groups.push(result2.rows[i]); // adding group info to list
// var groupId = result2.rows[i].id;
// groupIds2.push(groupId);
}
// console.log("");
//console.log(" ------->>>> " + JSON.stringify(groups));
// console.log("");
// responseData.groups = groups;
responseData.push({ //pushing groups into response
"groups": groups
});
var s = squel.select();
s.from("groups_members");
s.where("group_id IN ?", groupIds);
client.query(s.toString(), function (err, result3) { // get all the members in my groups
//console.log("get from group_members --- " + JSON.stringify(result3.rows));
var groupMembers = [];
for (var i = 0; i < result3.rows.length; i++) {
groupMembers.push({
groupMember: result3.rows[i] // pushing all the group members
});
}
//console.log("");
// console.log(" ------->>>> " + JSON.stringify(groupMembers));
// console.log("");
responseData.push({
"groupsMembers": groupMembers
});
// console.log("resulting json till now; Groups : " + JSON.stringify(responseData));
//fetching now events
var s = squel.select();
s.from("events");
s.where("group_id IN ?", groupIds);
client.query(s.toString(), function (err, result4) { //selecting all events that have my groups
if (err) {
console.error("error...3 " + err);
callback_async_1(responseData);
return;
} else {
var events = [];
for (var i = 0; i < result4.rows.length; i++) {
events.push(result4.rows[i]);
}
// responseData.events = events;
responseData.push({
"events": events
});
//responseData.push (events);
callback_async_1(responseData);
// asyncTasks[1](callback);
}
});
});
}
});
}
});
done();
});
};
getRegisteredContacts
var getRegisteredContacts = function (callback_async_2) { // get registered contacts
pg.connect(datebasePath, function (err, client, done) {
//get contacts that are registered
var s = squel.select();
s.from("users");
s.where("phone_number IN ?", arrayOfContacts);
client.query(s.toString(), function (err, result5) { // retriving registered contacts -- should be run with async parallel, it does not depend on the other calls
if (err) {
console.error(err);
callback_async_2(responseData);
} else {
if (result5.rows.length > 0) {
var contacts = [];
for (var i = 0; i < result5.rows.length; i++) {
contacts.push(result5.rows[i]);
}
responseData.push({
"registeredContacts": contacts
});
}
//console.log("");
//console.log(" ------->>>> " + JSON.stringify(events));
// console.log("");
// console.log("final ---> " + JSON.stringify(responseData));
callback_async_2(responseData);
}
});
done();
});
};
答案 0 :(得分：2)
你需要你的任务函数来获取一个参数，然后在完成任务时调用该参数
var task = function(callback){
console.log('Task');
callback(null);
};
当您在任务中执行异步操作时，您的任务看起来就像
var task = function(callback){
console.log('Task');
request.get('http://www.google.com', function (error, response, body){
console.log('Task - ' + response.statusCode);
callback(null);
});
};
示例
var async = require('async');
var request = require('request');
var task1 = function(callback){
console.log('Task 1');
callback(null);
};
var task2 = function(callback){
console.log('Task 2');
request.get('http://www.google.com', function (error, response, body){
console.log('Task 2 - ' + response.statusCode);
callback(null);
});
};
var asyncTasks = [task1, task2];
async.parallel(asyncTasks, function(err, result){
console.log('--DONE--');
});
输出
Task 1
Task 2
Task 2 - 200
--DONE--
答案 1 :(得分：0)
根据您的新代码列表，最明显的事情是done()对于您的两个任务都过早调用。它需要像
var getRegisteredContacts = function (callback_async_2) {
pg.connect(datebasePath, function (err, client, done) {
var s = squel.select();
s.from("users");
s.where("phone_number IN ?", arrayOfContacts);
client.query(s.toString(), function (err, result5) {
done(); // <---- done() to be here
if (err) {
//
} else {
//
}
callback_async_2();
});
});
};
你也应该lint你的代码。如果你有，你会注意到你没有检查回调err是否有pg.connect（并且还能更好地正确阅读）