I'm trying to put together a quick node.js/edge.js/C# bridge for a demo.
I have to use the ".Net calling Node.js" style, as the existing C# code uses a number of config values, which I can't add to node.exe.config as I will need to run several versions concurrently.
So I have this code:
private static async Task Start() {
Func<object, Task<object>> edge = EdgeJs.Edge.Func(#"
var login = require('login.js');
var edge = require('edge')
login({ email: 'user#example.com', password: 'shh' }, function callback(err, api) {
if (err) return console.error(err);
// This will keep listening until terminated
api.listen(function callback(err, message) {
if (err) return console.error(err);
// At this point I need to send the message back to this class so it can be processed..
console.log(message); // send the message to C#
// ... and then return the response via the api
api.send('response goes here');
});
});
return function (data, callback) {
callback(null, er...);
}
");
}
So, the code is waiting for messages in an event loop and responding. This all works with hardcoded values. But I need to submit the message back to the C# for processing, and I cannot work out how to communicate back and forth between edge.js and the C# app.
It must surely be via the callback, but I can't seem to start figure out how to structure it, and time is getting short. And I'm by no means a JavaScript expert.
How can I communicate between the edge code and the C# code from within the event loop using the callback?
You're right, it's via the callback. Since you're using async code, you have to wrap all your code inside the returned (edge) function, like this:
private static async Task Start() {
Func<object, Task<object>> edge = EdgeJs.Edge.Func(#"
// edge_callback is used to return values to the C# code
return function(data, edge_callback) {
var login = require('login.js');
var edge = require('edge')
login({
email: 'user#example.com',
password: 'shh'
}, function callback(err, api) {
if (err) return console.error(err);
// possible enhancement here by letting C# know there is an error
// edge_callback(err);
// This will keep listening until terminated
api.listen(function callback(err, message) {
if (err) return console.error(err);
// same thing here: edge_callback(err);
// At this point I need to send the message back to this class so it can be processed..
console.log(message); // send the message to C#
// use the callback, first param is error if there is any, second is the data
edge_callback(null, message);
// ... and then return the response via the api
api.send('response goes here');
});
});
}
");
}
I have ended up with something like this: there's a function defined on the data passed to edge, which edge then calls when a new message is received. That function then waits for the response, and passes it back to edge, which receives the result in (of course) another callback.
private static async Task Start() {
dynamic payload = new ExpandoObject();
payload.msgHook = NewMessage;
payload.login = new {
email,
password
};
var receive = Edge.Func(#"
return function(payload, edge_callback) {
var login = require('index.js');
login({
email: payload.login.email,
password: payload.login.password
}, function callback(err, api) {
if (err) {
edge_callback(err);
}
api.listen(function callback(err, message) {
if (err) { edge_callback(err); }
payload.msgHook(message,
function callback(err, result) {
if (err) {
edge_callback(err);
}
var msg = {
body: result.body,
url: result.url
}
api.sendMessage(msg, result.threadId);
});
});
});
}
");
var _ = await receive(payload) as IDictionary<string, object>;
}
private static Func<object, Task<object>> NewMessage {
get {
Func<object, Task<object>> hook = async m => {
string body, threadId;
if (!ProcessMessage(m as IDictionary<string, object>, out body, out threadId)) {
log.Error("Failed to process message: " + m.ToString());
}
api.SendMessage(body, threadId, phone);
var reply = await waitForReply(threadId);
var result = new {
body = reply
};
// Return the _result_ of the task.
return Task.FromResult<object>(result).Result;
};
return hook;
}
}
Related
I'm calling three functions, after the completion of these functions I want my script to close on it's own but it just hangs.
I've tried making the functions async/promise based, closing the database after each 'mongodb' type function, and using process.exit() within a function as a callback to the last called function.
Connecting to the (local - not Atlas) Database:
MongoClient.connect(local, {useNewUrlParser: true, useUnifiedTopology: true}, function(err, db) {
if (err) {
console.log(err)
}
else {
console.log('Connected to MongoDB...')
//Read in data from jsonfiles and store each file's contents into the database : This is where the functions are being called... within a successful connect to the MongoDB
insertJSON(db, jsonfiles, 'requests', jsonfilesSource)
insertJSON(db, issuedfiles, 'issuedLicenses', isssuedfilesSource)
insertLicenses(db)
}
db.close()
})
Function 1:
function insertJSON(db, dirBuf,collection, sourceFolder) {
var database = db.db('license-server')
var collection = database.collection(collection)
fs.readdir(dirBuf, function(err, files) {
if (err) {
console.log(err.message)
}
else {
files.forEach(function(filename) {
var text = fs.readFileSync(sourceFolder + filename);
var filecontents = JSON.parse(text)
//collection.insertOne(filecontents)
collection.findOne({"DisplayTitle" : filecontents.DisplayTitle, "NodeInformation" : filecontents.NodeInformation, "Date": filecontents.Date})
.then(function(result) {
if(result) {
console.log(`An Item could already be in the database: A file is unique if its display title, nodeinformation, and date are different.
the items display title is ${result.DisplayTitle}`)
return
}
else {
collection.insertOne(filecontents)
console.log(`Added ${filecontents.DisplayTitle} to database`)
}
})
.catch(function(error) {
console.log(error)
})
})
}
})
}
Function 2:
function insertLicenses(db) {
// Set up GridFS to import .lic and .licx files into the database
var database = db.db('license-server')
var collection = database.collection('fs.files')
var bucket = new mongodb.GridFSBucket(database);
var dirBuf = Buffer.from('../license-server/private/licenses')
fs.readdir(dirBuf, function(err, files) {
if (err) {
console.log(err.message)
}
else {
files.forEach(function(filename) {
collection.findOne({"filename": filename}).
then(function(result) {
if(result) {
console.log(`The file ${filename} is already in the database`)
return
}
else {
fs.createReadStream('./private/licenses/' + filename).
pipe(bucket.openUploadStream(filename)).
on('error', function(error) {
assert.ifError(error)
}).
on('finish', function() {
console.log(`Uploaded ${filename}`)
})
}
})
})
}
})
// I tried calling db.close() here since this is the last function to be called. No luck.
}
I'm guessing it has something to do with the mongodb functions having their own way to close themselves but I couldn't seem to find what I was looking for in previous attempts to resolve this issue.
The expected result should be the script closing itself, the actual result is a handing script.
All of these database calls are asynchronous -- the result of this code running is to immediately call db.close and then do the work in insertJSON and insertLicenses. If you were to rewrite this to use async/await (and you'd need to update your other functions as well) the db.close call would close the db, and that would allow the script to exit:
await insertJSON(db, jsonfiles, 'requests', jsonfilesSource)
await insertJSON(db, issuedfiles, 'issuedLicenses', isssuedfilesSource)
await insertLicenses(db)
db.close()
https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Asynchronous/Introducing
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function
I am trying to retrieve the access token from an API (https://github.com/Axosoft/node-axosoft/)
To receive an access token we have to follow this process:
var axo = nodeAxosoft(axosoftUrl, credentials);
axo.Api.getLoginUrl(function(url) {
// open browser using authorizationUrl and get code parameter from
//redirected Url after login
var code = 'code received from redirect';
axo.Api.exchangeCodeForToken(code);
});
As I did not understood exactly how to get the code following that example nor what is the url parameter on getLoginUrl, I did it on my own.
I have a login route that redirects the user to the axosoft website for authentication and redirects the user to the /authorization-process route on my application.
On the /authorization-process I get the code returned by the login and call a function that should get the access token by calling:
axo.Api.exchangeCodeForToken(code);
Code:
var axosoft_code = req.query.code;
console.log(axosoft_code);
var token = request.exchangeAuthCodeForAccessToken(axosoft_code)
.then(function(token)
{
res.send(token);
})
The Method:
var connection = nodeAxosoft(client_url, credentials);
return new Promise(function(resolve, reject){
console.log("CODE: ", axosoft_code)
var token = connection.Api.exchangeCodeForToken(axosoft_code, function(token){
console.log(token);
resolve(token)
})
The problem is that returns null
I had a look at the API lib api.js and found that:
https://github.com/Axosoft/node-axosoft/blob/master/lib/api.js
function exchangeCodeForToken(code, callback) {
_credentials.code = code;
_access_token = '';
_authenticateCredentails(function (err) {
if (!err) {
callback(null, _access_token);
} else {
callback(err);
}
})
}
So I have two questions:
Does anyone has an Idea what am I doing wrong?
What would be necessary to code the callback function?
The method expects a callback function but I don't really know how to do it.
EDIT:
return new Promise(function(resolve, reject){
var token = connection.Api.exchangeCodeForToken(axosoft_code, function(response,err){
if(!err){
console.log("token",response)
resolve(token);
}
else{
console.log("error",err)
resolve(token);
}
});
})
OR
var token = connection.Api.exchangeCodeForToken(axosoft_code, function(response,err){
if(!err){
console.log("token",response.body)
return response.body;
}
else{
console.log("error",err)
return err;
}
});
I am giving to my callback function two args (response and err), my problem is that I am falling at the else condition.
The output of err is something similar to a token though the documentation here shows that it should be like that:
{
"error" : "invalid_request",
"error_description" : "One or more parameters are missing: client_secret"
}
Another point is that the page is frozen waiting for something to happen but nothing happens.
Given that this is the input:
function exchangeCodeForToken(code, callback) {
_credentials.code = code;
_access_token = '';
_authenticateCredentails(function (err) {
if (!err) {
callback(null, _access_token);
} else {
callback(err);
}
})
}
You should format your call as:
exchangeCodeForToken(axosoft_code, function(err, response) {
if (err) {
// Deal with error
} else {
// Deal with response
}
}
Node functions often pass through error variables first so that you have to receive them, which is considered good practice.
I am attempting to send a text message when a user requests to reset their password. I would like to wait for the message to be sent to alert the user if it was successful or not. I am currently attempting to do it as follows:
async function sendResetPasswordTextMessage(req, res) {
let result = {};
let phoneNumber = req.body.phoneNumber;
if (phoneNumber === undefined) {
return sendInvalidParametersMessage(res);
}
phoneNumber = phoneNumber.toString();
const userProfile = await models.UserProfile.findOne({
where: {
phoneNumber: phoneNumber
}
});
************************** RELEVANT CODE TO ISSUE *************************
if (userProfile) {
const message = "Your username is:\n" + userProfile.username;
const sent = await AWSSNSClient.sendMessage(message, phoneNumber);
if (!sent) {
result.error = setTitleAndMessage("Error", "An error occurred");
} else {
result.success = setTitleAndMessage("Success", "Message sent");
}
}
return res.send(result);
***************************************************************************
}
In my other class AWSSNSClient, I have the following sendMessage function:
function sendMessage(message, phoneNumber) {
const params = {
Message: message,
MessageStructure: "string",
PhoneNumber: "+1" + phoneNumber
};
let sent = false;
sns.publish(params, function(err, data) {
if (err) {
console.log(err, err.stack); // an error occurred
}
else {
sent = true;
}
});
return sent;
}
I cannot figure out how to make sendMessage wait for sns.publish to return before it returns itself. I have tried making it an async method and adding await on sns.publish, but the function still returns before sent gets set to true.
I know that the messages are sending without error because I am receiving them and no console logs are printed.
Stumbled on this one via Google trying to figure this out myself today - short answer that I am now using:
You can now do this with Async/Await — and Call the AWS service (SNS for example) with a .promise() extension to tell aws-sdk to use the promise-ified version of that service function (SNS) instead of the call back based version.
The only caveat here is the containing function must ALSO be async to utilize the await syntax.
For example:
let snsResult = await sns.publish({
Message: snsPayload,
MessageStructure: 'json',
TargetArn: endPointArn
}, async function (err, data) {
if (err) {
console.log("SNS Push Failed:");
console.log(err.stack);
return;
}
console.log('SNS push suceeded: ' + data);
return data;
}).promise();
The important part is the .promise() on the end there. Full docs on using aws-sdk in an async / promise based manner can be found here: https://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/using-promises.html
In order to run another aws-sdk task you would similarly add await and the .promise() extension to that function (assuming that is available).
For anyone who runs into this thread and is actually looking to simply push multiple aws-sdk promises to an array and wait for that WHOLE array to finish (without regard to which promise executes first) I ended up with something like this:
let snsPromises = [] // declare array to hold promises
let snsResult = await sns.publish({
Message: snsPayload,
MessageStructure: 'json',
TargetArn: endPointArn
}, async function (err, data) {
if (err) {
console.log("Search Push Failed:");
console.log(err.stack);
return;
}
console.log('Search push suceeded: ' + data);
return data;
}).promise();
snsPromises.push(snsResult)
await Promise.all(snsPromises)
Hope that helps someone that randomly stumbles on this via google like I did!
stackdave will that actually wait?
Necevil "Search push suceeded will get logged twice" because you're mixing calling operations by passing a callback and using promises. You should only use one method of getting the result
let snsResult = await sns.publish({
Message: snsPayload,
MessageStructure: 'json',
TargetArn: endPointArn}).promise()
will do the trick
You can simply use callbacks for that. Modify your sendMessge like this
function sendMessage(message, phoneNumber, cb) {
const params = {
Message: message,
MessageStructure: "string",
PhoneNumber: "+1" + phoneNumber
};
sns.publish(params, cb);
}
then on your main file you can supply callback like this
if (userProfile) {
const message = "Your username is:\n" + userProfile.username;
AWSSNSClient.sendMessage(message, phoneNumber, (err, data) => {
if (err) {
result.error = setTitleAndMessage("Error", "An error occurred");
}
else {
result.success = setTitleAndMessage("Success", "Message sent");
}
res.send(result);
});
}
Here the right updated API, August 2018, Necevil answer send the sms twice.
// using config.env
AWS.config.region = 'eu-west-1';
AWS.config.update({
accessKeyId: process.env.AMAZON_SMS_ID,
secretAccessKey: process.env.AMAZON_SMS_TOKEN,
});
// parameters
let params = {
Message: contentSMS, // here your sms
PhoneNumber: mobile, // here the cellphone
};
const snsResult = await sns.publish(params, async (err, data) => {
if (err) {
console.log("ERROR", err.stack);
}
console.log('SNS ok: ' , JSON.stringify (data));
});
If you're having issues with duplicate SNS messages being sent, I fixed this issue by utilizing examples from AWS:
// Load the AWS SDK for Node.js
var AWS = require('aws-sdk');
// Set region
AWS.config.update({region: 'REGION'});
// Create publish parameters
var params = {
Message: 'MESSAGE_TEXT', /* required */
TopicArn: 'TOPIC_ARN'
};
// Create promise and SNS service object
var publishTextPromise = new AWS.SNS({apiVersion: '2010-03-31'}).publish(params).promise();
// Handle promise's fulfilled/rejected states
publishTextPromise.then(
function(data) {
console.log("Message ${params.Message} send sent to the topic ${params.TopicArn}");
console.log("MessageID is " + data.MessageId);
}).catch(
function(err) {
console.error(err, err.stack);
});
By utilizing a traditional .then() I was able to squash the duplicate message bug mentioned in comments above.
You can create a async function what use the promise method
async function sendMessage(message, phoneNumber){
const params = {
Message: message,
PhoneNumber: phoneNumber
};
return new Promise((resolve, reject) => {
SNS.publish(params, (err, data) => {
if (err) {
console.log("Search Push Failed:");
console.log(err.stack);
return reject(err);
} else {
console.log('Search push suceeded:' + phoneNumber);
return resolve(data);
}
})
});
}
and then you can call
var s= await sendMessage(message,phoneNumber);
I have written a node.js lambda function that triggers based on a dynamodb stream when new records are inserted into a particular table.
The function receives only new events, filters for inserted records, and then for each record, uses a couple of fields to retrieve data from other tables. Using this combined data a message is composed and sent via SNS to specific target ARN.
The function performs correctly. All the relevant data is retrieved, and a push notification is sent out.
However, for some reason the function appears to be called several times for the same stream, and processes the newly inserted records several times. The result is the target device receiving the same push notification several times.
Should I be placing the callback in a different place, or am I not calling on the context correctly?
This is the function:
'use strict';
var AWS = require("aws-sdk");
var dynamodb = new AWS.DynamoDB();
var sns = new AWS.SNS();
console.log('Loading function');
exports.handler = (event, context, callback) => {
console.log('Received event:', JSON.stringify(event, null, 2));
event.Records.forEach((record) => {
console.log(record.eventID);
console.log(record.eventName);
console.log('DynamoDB Record: %j', record.dynamodb);
if (record.eventName == 'INSERT') {
var matchId = record.dynamodb.NewImage.eventId.S;
var match_params = {
Key: {
"eventId": {
S: matchId
}
},
TableName: "xxxxxxxxxxx-mobilehub-xxxxxxx-Event"
};
//retrieve the match information from Event table
dynamodb.getItem(match_params, function(err, data) {
var match_description = "";
if (err) {
console.log(err, err.stack);
context.fail('No match event record found in Event table');
} else {
match_description = data.Item.description.S;
var uId = record.dynamodb.NewImage.participantUserId.S; //participantUserId
var user_params = {
Key: {
"userId": {
S: uId
}
},
TableName: "xxxxxxxxxxx-mobilehub-xxxxxxxxx-User"
};
//retrieve the user record from User table
dynamodb.getItem(user_params, function(err, data) {
if (err) {
console.log(err, err.stack); // an error occurred
context.fail('Error occurred. See log.');
} else {
console.log(data); // successful response
if (data.length === 0) {
console.log("No User Record Found.");
context.fail('No user found for participantUserId.');
} else {
var deviceARN = data.Item.device_arn.S;
if (deviceARN <= 1) {
console.log("User has not registered their device for push notifications.");
context.fail('User has not registered for notifications');
} else {
var json_message = JSON.stringify({
APNS_SANDBOX: JSON.stringify({
aps: {
alert: "You are playing in an upcoming match " + match_description,
badge: 1,
sound: 'default'
}
})
});
var snsparams = {
Message: json_message,
MessageStructure: 'json',
TargetArn: deviceARN
};
sns.publish(snsparams, function(err, data) {
if (err) {
console.log(err); // an error occurred
context.fail('SNS send failed. See log.');
} else {
console.log(data); // successful response
context.success('Push notification sent to user.');
}
});
}
}
}
});
}
});
}
});
callback(null, `Successfully processed ${event.Records.length} records.`);
};
In my case, I added the same event source multiple times.
Quote from the conversation with an AWS support engineer:
Using my internal tools, I noticed that the Lambda function xxxxxx has
the event source:
arn:aws:events:my_region:my_acct_id:rule/my_event_target
configured twice as push event source. This means that this might be the cause
why you are seeing two invokes at every minute. Would you please
confirm on your side if this event is configured twice for the $LATEST
version of your lambda and also confirm if it's intended?
I hope this could save someelse :)
In your lambda page at the bottom, try tweaking "Concurrency" Unreserved account concurrency to 1 and "Asynchronous invocation" Retry attempts to 0 . As a test try these and observe the behaviour. Might help.
I'm over my head at the moment.
I'm new to node and writing a passportjs module for Freshbooks. There's a Passport function I'm trying to implement that get's a user's profile.
This code uses Passport's OAuth foo to make a request.
this._oauth.post(url, token, tokenSecret, post_body, post_content_type, function (err, body, res) {
if (err) { return done(new InternalOAuthError('failed to fetch user profile', err)); }
try {
var parser = require('xml2json');
var json = parser.toJson(body); //returns a string containing the JSON structure by default
var util = require('util');
console.log(util.inspect(json));
var profile = { provider: 'freshbooks' };
profile.id = json.response.staff.staff_id;
profile.displayName = json.response.staff.first_name + ' ' + json.response.staff.last_name;
profile.name = { familyName: json.response.staff.last_name,
givenName: json.response.staff.first_name };
if (json.response.staff.email) { profile.emails = [{ value: json.response.staff.email }]; }
profile._raw = body;
profile._json = json;
console.log(util.inspect(json));
done(null, profile);
} catch(e) {
done(e);
}
});
I get a response. It's xml. I'm converting it to JSON, but I don't want that actually. I want a plain-old javascript object.
I looked at https://github.com/Leonidas-from-XIV/node-xml2js but the examples don't show how to get the result out.
var parseString = require('xml2js').parseString;
var xml = "<root>Hello xml2js!</root>"
parseString(xml, function (err, result) {
console.dir(result);
});
What do I do to block around this code till the call is complete and get result out? I'm not sure how to merge these two callbacks together.
you can ask xml2json to return object:
var json = parser.toJson(body, {object: true});
if you decide to use async parser then just put your done callback inside json result handler. There is no need to "block" async function:
var parseString = require('xml2js').parseString;
parseString(body, function(err, json) {
// handle error: return done(err)
// do your logic if no error
// ...
// profile._json = json;
// ...
//
// 'return' result
done(null, profile);
});