I am new to node js and I am trying to use async module to eliminate the setTimeouts. Here I am facing a problem. It is not working as expected. It calls the second function even before the first function completes execution. I searched for answers and tried multiple ways. But it doesn't seem to work. It prints "Inside db insert in async series" even before the async.forEach finishes. Can anyone please check the code and tell me where I'm going wrong?
setTimeout(function() {
async.series([function(callback1) {
console.log("Inside async series");
try {
var msg = "";
var datas = [];
for (var i = 0; i < service_name.length; i++) {
console.log("Inside for loop service names");
var child = {
"space_guid": space_guid,
"name": service_name[i],
"service_plan_guid": service_plan_guid[i]
};
datas.push(child);
console.log("datas array===" + JSON.stringify(datas))
}
async.forEach(datas, function(data1, callback) {
console.log("Inside async task");
var data = JSON.stringify(data1);
console.log("data value===" + JSON.stringify(data));
var options = {
host: 'api.ng.bluemix.net',
path: '/v2/service_instances' +
'?accepts_incomplete=true',
method: 'POST',
headers: {
'Authorization': full_token_new
}
};
console.log("options is" + JSON.stringify(options));
var reqst = http.request(options, function(res) {
console.log("Sent for request");
res.setEncoding('utf8');
res.on('data', function(chunk) {
msg += chunk;
});
res.on('end', function() {
try {
console.log("message =======", msg);
console.log("-----------------------------------------");
msg = JSON.stringify(msg);
msg1 = JSON.parse(msg);
console.log("printing msg--" + msg1);
console.log("-----------------------------------------");
console.log("here i am", i);
console.log(service_name.length - 1);
callback();
} catch (err) {
console.log(err);
}
});
});
reqst.on('error', function(e) {
console.log(e);
});
reqst.write(data);
reqst.end();
}, function(err) {
console.log("for each error" + err);
});
callback1(null, null);
} catch (err) {
console.log(err);
}
},
function(callback1) {
console.log("Inside db insert in async series")
db_insert(service_name, solnName, full_token_new, uname, version);
callback1(null, null);
}
],
function(err, results) {
if (err) {
console.log("There's an error" + err);
} else {
console.log("result of async", results);
}
})
}, 3000)
You are mixing try...catch with asynchronous code, this is bad practice and almost impossible to do right.
Also, your error stem from the fact you are calling callback just after async.forEach, which don't finish, and go to the next step.
Also, what do you mean by "eliminate the timeout"? Your whole code is in it, you can remove it whenever you want.
'use strict';
async.series([
(callback) => {
let msg = "",
datas = [],
i = 0;
while(i < service_name.length) {
let child = {
"space_guid": space_guid,
"name": service_name[i],
"service_plan_guid": service_plan_guid[i]
};
datas.push(child);
i = i + 1;
}
async.forEach(datas, (data1, callback) => {
let data = JSON.stringify(data1),
options = {
host: 'api.ng.bluemix.net',
path: '/v2/service_instances?accepts_incomplete=true',
method: 'POST',
headers: {
'Authorization': full_token_new
}
},
reqst = http.request(options, (res) => {
res.setEncoding('utf8');
res.on('data', (chunk) => {
msg += chunk;
});
res.on('end', () => {
msg = JSON.stringify(msg);
msg1 = JSON.parse(msg);
callback();
});
});
reqst.on('error', (error) => {
callback(error);
});
reqst.write(data);
reqst.end();
}, (error) => {
callback(error);
});
},
(callback) => {
db_insert(service_name, solnName, full_token_new, uname, version);
callback();
}
],
(error, results) => {
if (error) {
console.log("There's an error" + error);
} else {
console.log("result of async", results);
}
});
Since this smell heavily like a plssendzecode question, I've removed every console.log and gone ES6 to make sure you will not be able to use it as such and need to read the change I made.
I simplify code a little.
datas and processData aren't good names.
setTimeout(onTimer, 3000);
function onTimer() {
var datas = service_name.map(function(name, i) {
return {
space_guid: space_guid,
name: name,
service_plan_guid: service_plan_guid[i]
}
});
function processData(data, callback) {
var options = {
host: 'api.ng.bluemix.net',
path: '/v2/service_instances?accepts_incomplete=true',
method: 'POST',
headers: {
'Authorization': full_token_new
}
};
var reqst = http.request(options, function(res) {
var msg = '';
res.setEncoding('utf8');
res.on('data', function(chunk) {
msg += chunk;
});
res.on('end', function() {
try {
msg = JSON.parse(msg);
callback(null, msg);
} catch (err) {
callback(err);
}
});
});
reqst.on('error', callback);
reqst.write(JSON.stringify(data));
reqst.end();
}
async.map(datas, processData, function(err, results) {
if (err);
return console.log(err);
// process msg of each request db_insert(...);
});
};
Related
I am calling a javascript function , which in turn calls a web service;The response of this service is used to call another function which also calls a service. At end of both services we set session attributes. This code gives no errors, but the callback gets called before the service has returned data. The main motive of this code is to set the session attributes before return of flow from this code, when the callback gets called before the service has returned values the session attributes are not set and the requirement of the code is not fulfilled.
'use strict';
function close(sessionAttributes, fulfillmentState, message) {
return {
sessionAttributes,
dialogAction: {
type: 'Close',
fulfillmentState,
message : 'For security purpose answer these questions '
},
};
}
function getSecurityQuestions(intentRequest, context, post_options, callback){
const sessionAttributes = intentRequest.sessionAttributes || {};
var policynumber = sessionAttributes.policynumber;
var interactionID = sessionAttributes.interactionID;
var body = "";
var body2;
const http = require('https');
const promise = new Promise((resolve, reject) => {
const post_data = JSON.stringify({"Purpose":"SecurityQuestions", "InteractionID":interactionID, "SearchStringAcctNum":policynumber});
//ignores SSL
process.env.NODE_TLS_REJECT_UNAUTHORIZED = "0";
var post_request = http.request(post_options, function(res) {
res.on('data', function(chunk) {
body += chunk;
});
res.on('end', function() {
context.done(body);
resolve(body);
});
res.on('error', function(e) {
reject(Error(e.message));
context.fail('error:' + e.message);
});
});
// post the data
post_request.write(post_data);
post_request.end();
});
callback( promise.then((body) => {
body2 = JSON.parse(body);
sessionAttributes.question1 = body2.SecurityDetails[0].Question;
close(sessionAttributes, 'Fulfilled');
}, (error) => {
console.log(error.message);
})
);
}
function getInteraction(intentRequest, context, callback) {
const slots = intentRequest.currentIntent.slots;
var policynumber = "PA"+slots.PolicyNumber;
var questionOne = slots.questionOne;
var questionTwo = slots.questionTwo;
const sessionAttributes = intentRequest.sessionAttributes || {};
console.log("policy number : "+policynumber + "question 1 : "+questionOne + "question 2 : "+questionTwo);
sessionAttributes.policynumber = policynumber;
var body = "";
var body2;
// An object of options to indicate where to post to
var post_options = {
host: 'example.com',
protocol: 'https:',
port: '3000',
path: '/hiddenPath',
method: 'POST',
headers: {
'Content-Type': 'application/json'
}
};
const http = require('https');
const promise = new Promise((resolve, reject) => {
const post_data = JSON.stringify({"Purpose":"CreateInteraction"});
//ignores SSL
process.env.NODE_TLS_REJECT_UNAUTHORIZED = "0";
var post_request = http.request(post_options, function(res) {
res.on('data', function(chunk) {
body += chunk;
});
res.on('end', function() {
context.done(body);
resolve(body);
});
res.on('error', function(e) {
console.log("rejected here");
reject(Error(e.message));
context.fail('error:' + e.message);
});
});
// post the data
post_request.write(post_data);
post_request.end();
});
callback( promise.then((body) => {
body2 = JSON.parse(body);
console.log("interaction ID : "+body2.InteractionID);
sessionAttributes.interactionID = body2.InteractionID;
getSecurityQuestions(intentRequest, context, post_options, callback);
}, (error) => {
console.log('Promise rejected.');
console.log(error.message);
}));
}
// --------------- Intents -----------------------
/**
* Called when the user specifies an intent for this skill.
*/
function dispatch(intentRequest, context, callback) {
const intentName = intentRequest.currentIntent.name;
if (intentName === 'currIntent') {
return getInteraction(intentRequest, context, callback);
}
throw new Error(`Intent with name ${intentName} not supported`);
}
// --------------- Main handler -----------------------
function loggingCallback(response, originalCallback) {
console.log("logging callback called......");
originalCallback(null, response);
}
exports.handler = (event, context, callback) => {
try {
dispatch(event, context, (response) => loggingCallback(response, callback));
} catch (err) {
callback(err);
}
};
You should resolve your promise only after the request ends.. Have updated your sample below. Hope it helps. Also, you were sending an invalid object as your post body. Fixed that as well.
function getValue(context, post_options, callback) {
var body = "";
var body2;
const http = require('http');
const promise = new Promise((resolve, reject) => {
// INVALID OBJECT
//const post_data = JSON.stringify({"something"});
const post_data = JSON.stringify({
something: "something"
});
//ignores SSL
process.env.NODE_TLS_REJECT_UNAUTHORIZED = "0";
var post_request = http.request(post_options, function(res) {
res.on('data', function(chunk) {
body += chunk;
console.log("inside " + JSON.stringify(body));
// DONT RESOLVE HERE, REQUEST IS NOT COMPLETE
//resolve(body);
});
res.on('end', function() {
context.done(body);
//RESOLVE HERE INSTEAD
resolve(body);
});
res.on('error', function(e) {
reject(Error(e.message));
context.fail('error:' + e.message);
});
});
// post the data
post_request.write(post_data);
post_request.end();
});
promise.then((body) => {
console.log("response data " + JSON.stringify(body));
body2 = JSON.parse(body);
callback(delegate(sessionAttributes, intentRequest.currentIntent.slots));
}, (error) => {
console.log('Promise rejected.');
console.log(error.message);
});
}
I am trying to use a callback to indicate when all the async workers are complete, but I am getting the dreaded
TypeError: callback is not a function.
I would like to individually process each element in data, and on completion, have queue.drain to send the callback(data) to refresh Data on completion. I have been readying the async documentation, but clearly i am not getting something.
function refreshData(postData, callback) {
var options = {
host: 'www.myhost.com',
port: 443,
path: '/pulldata,
method: 'POST',
headers: {
"Content-Type": "application/json"
}
};
var req = https.request(options, function(res) {
var headers = res.headers
var d = '';
res.setEncoding('utf8');
res.on('data', function (chunk) {
d = d + chunk;
});
res.on('end', function() {
if (res.statusCode == '200') {
data = JSON.parse(d);
queue = async.queue(function (task, cb) {
processData(task,cb);
},1);
//this is were the errors are
queue.drain = function() {
callback(data)
};
for(i=0; i<data.length; i++) {
queue.push(data[i],'');
}
} else {
callback(false)
}
});
});
req.on('error', function(e) {
console.log('problem with request: ' + e.message);
});
// write data to request body
req.write(postData);
req.end();
}
Any assistance would be greatly appreciated!
Edit, added some pseudo code to demonstrate how refreshData is being used:
Node https.createServer(req,res) {
req.on(){
read userData
}
req.end(){
validateUser(userData, function(callbackData) {
if(callbackData==false) {
//bad user or error with request
res.writeHead(404);
res.end('bye');
} else {
//good user and responses
res.writeHead(200);
res.end(callbackData);
}
})
}
}
function validateUser(userData,callback) {
//do some stuff to validate
if(userData is good) {
//call refreshData if user
refreshData(userData,callback)
} else {
callback(false)
}
}
[EDIT] Added a callback
As given in the documentation you pointed to , change this line
queue.push(data[i],'');
to
queue.push(data[i], function(err){
// handle error
});
Try it here async-queue-callback
i have an application which needs a data.json file in order to draw a d3-graph. However i need to update that file on an onClick-Event:
d3.select("#updatebutton").on("click", function(e) {
try{
$.get('https://localhost:4444/data', function(data) {
});
}
catch (e) {
alert('Error: ' + e);
}
});
Above is the update-Button with the jquery-call. In my app.js File I am using it like this:
app.get('/data', function(req, res, next) {
try{
getJSON();
}
catch(e) {
alert('Error');
}
});
The getJSON()-Function is received Data over an https-Request, processes that data and saves it to data.json:
function getJSON() {
var req = https.get(options, function(response) {
// handle the response
var res_data = '';
response.on('data', function(chunk) {
res_data += chunk;
});
response.on('end', function() {
//process data
// save to file
fs.writeFile(filePath, JSON.stringify(finalJson), function(err) {
if (err)
throw err;
});
});
});
}
However if i click on my updateButton repeatedly after seconds, it seems that data.json is not overwritten but the file gets bigger and bigger, means that data is added to the file instead of overwritten.
What am I doing wrong?
Thanks for help.
Since you use app.get as your route, I guess you are using express.
In your routes definition:
var getData = (function() {
var callbacks = [];
function executeCallbacks(err, data) {
for (var i = 0; i < callbacks.length; i++) {
callbacks[i](err, data);
}
callbacks = [];
}
return function(cb) {
callbacks.push(cb);
if( callbacks.length === 1 ) {
var req = https.get(options, function(response) {
// handle the response
var res_data = '';
response.on('data', function(chunk) {
res_data += chunk;
});
response.once('end', function() {
// process data here
// save to file
fs.writeFile(filePath, JSON.stringify(finalJson), function(err) {
if (err) {
// call error handler
return executeCallbacks(err);
}
executeCallbacks(null, body);
});
});
response.once('error', function() {
return executeCallbacks(err);
});
}
req.end();
}
};
})();
app.get('/data', function(req, res, next) {
getData(function(err, data) {
if(err) {
return next(err);
}
return data;
});
});
In your browser js file:
d3.select("#updatebutton").on("click", function(e) {
$.get( 'https://localhost:4444/data', function(data) {
alert( "success" );
var json = JSON.parse(data);
})
.fail(function() {
alert( "error" );
});
});
I see you use try / catch around callback functions. The callback function fires after the original function completes. So don't use Try / Catch around callback function.
Read: https://strongloop.com/strongblog/async-error-handling-expressjs-es7-promises-generators/
I'm trying to get data from the kanbanery rest api and verything works but after a while the https.request function doesn't work anymore. I don't get any error's just no ouput after 10 times or so
here's my code:
setInterval( function() {
console.log('get tasks');
var req = https.request(options, function(res) {
console.log('STATUS: ' + res.statusCode);
//console.log('HEADERS: ' + JSON.stringify(res.headers));
res.setEncoding('utf8');
res.on('data', function (chunk) {
temp = JSON.parse(chunk);
tasks = [];
for (var i = 0; i < temp.length; i++) {
tasks[i] = {
label: temp[i]['title'],
value: indexOfRowContainingId(temp[i]['task_type_id'],tasks2)
};
}
console.log(tasks);
send_event('tasks', { items: tasks });
});
});
req.on('error', function(error){
console.log("Error: "+error);
});
req.end();
}, 10 * 1000);
Does anybody see the problem?
function die(err) {
console.log('Uh oh: ' + err);
process.exit(1);
}
var box, cmds, next = 0, cb = function(err) {
if (err)
die(err);
else if (next < cmds.length)
cmds[next++].apply(this, Array.prototype.slice.call(arguments).slice(1));
};
cmds = [
function() { imap.connect(cb); },
function() { imap.openBox('INBOX', false, cb); },
function(result) { box = result; imap.search([ 'UNSEEN', ['SINCE', 'April 5, 2011'] ], cb); },
function(results) {
var msgCache = {},
fetch = imap.fetch(results, { request: { headers: ['from', 'to', 'subject', 'date'] } });
console.log('Now fetching headers!');
fetch.on('message', function(msg) {
msg.on('end', function() {
msgCache[msg.id] = { headers: msg.headers };
console.log(msg.headers.date[0]);
console.log(msg.headers.to[0]);
console.log(msg.headers.from[0]);
console.log(msg.headers.subject[0]);
var from = /(.*)?<(.*?)>/.exec(msg.headers.from[0]);
console.log(from[1]); // nome from
console.log(from[2]); // from
});
});
fetch.on('end', function() {
console.log('Done fetching headers!');
console.log('Now fetching bodies!');
fetch = imap.fetch(results, { request: { headers: false, body: '1' } });
fetch.on('message', function(msg) {
msg.data = '';
msg.on('data', function(chunk) {
msg.data += chunk;
});
msg.on('end', function() {
msgCache[msg.id].body = msg.data;
console.log(msg.data);
});
});
fetch.on('end', function() {
console.log('Done fetching bodies!');
cb(undefined, msgCache);
});
});
},
function(msgs) {
// Do something here with msgs, which contains the headers and
// body (parts) of all the messages you fetched
// console.log(msgs);
//imap.logout(cb);
imap.on('mail', function () {
// body...
console.log("New Email Has Arrived!");
next = 0;
cb();
})
}
];
cb();
When a new e-mail arrives imap.on('mail', function () I want it to run the cb() function again. However, it doesn't do anything after the console.log.
What am I doing wrong?
Thanks
reset your next counter, and your imap.on('mail', ... should be outside of cmds so that it's not bound again, and again, and again...
There are some modules around for "flattening" async operations to not end in callback hell.
e.g.: async
Maybe this could help you.