REST API call using nodejs on localhost - r

I have made a REST API using R language.
#* #get /mean
normalMean <- function(samples=10){
data <- rnorm(samples)
mean(data)
}
I started the R server and tested the API using the url- http://localhost:8000/mean and it is working.
However when I tried to invoke the API using nodejs it returns an error:
Error: socket hang up
at TLSSocket.onHangUp (_tls_wrap.js:1124:19)
at TLSSocket.g (events.js:292:16)
at emitNone (events.js:91:20)
at TLSSocket.emit (events.js:185:7)
at endReadableNT (_stream_readable.js:974:12)
at _combinedTickCallback (internal/process/next_tick.js:80:11)
Here is the nodejs code:
var https = require('https');
var optionsget = {
host : 'localhost', // here only the domain name
// (no http/https !)
port : 8000,
path : '/mean', // the rest of the url with parameters if needed
method : 'GET' // do GET
};
console.info('Options prepared:');
console.info(optionsget);
console.info('Do the GET call');
var reqGet = https.request(optionsget, function(res) {
console.log("statusCode: ", res.statusCode);
// uncomment it for header details
// console.log("headers: ", res.headers);
res.on('data', function(d) {
console.info('GET result:\n');
process.stdout.write(d);
console.info('\n\nCall completed');
});
});
I am not understanding where I am going wrong. I intend to make a put request in a similar manner after this.

It means that socket does not send connection end event within the timeout period. If you are getting the request via http.request (not http.get). You have to call request.end() to finish sending the request.
https.get('http://localhost:8000/mean', (resp) => {
console.log("statusCode: ", res.statusCode);
let result = 0;
// on succ
resp.on('data', (d) => {
result = d;
});
// on end
resp.on('end', () => {
console.log(result);
});
}).on("error", (err) => {
console.log("Error: " + err.message);
});

Related

Error while making request: socket hang up. Error code: ECONNRESET

I'm using node.js as a backend server for sending push notification from the Firebase Cloud Messaging service. The notifications are working fine with local server but on live server, I get this error:
Error while making request: socket hang up. Error code: ECONNRESET
Things to consider are that...
Number of users are in the thousands on live server
Firebase version is firebase-admin#6.5.1
Previously unregistered tokens are still there. But now registered tokens are being stored.
This is my code for sending notifications:
for (let c = 0; c < tokens.length; c++)
{
let notifyTo = tokens[c];
const platform = platforms[c];
let payload;
if (platform === "ios") {
payload = {
notification: {
title: "title",
subtitle :"messgae",
sound: "default",
badge: "1"
},
data: {
sendFrom: "",
notificationType: "",
flag: "true"
}
};
} else if (platform === "android") {
payload = {
data: {
title: "",
message : "",
flag: "true"
}
};
}
const registrationtoken = notifyTo;
await admin.messaging().sendToDevice(registrationtoken, payload)
.then(function (response) {
console.log("Successfully sent message:");
})
.catch(function (error) {
console.log("Error sending message: ");
});
}
Your issue is caused by your function taking too long to respond to the client (more than 60 seconds) and is caused by the following line:
await admin.messaging().sendToDevice(registrationtoken, payload)
Because you are waiting for each call of sendToDevice() individually, you are running your for-loop in synchronous sequential order, rather than asynchronously in parallel.
To avoid this, you want to make use of array mapping and Promise.all() which will allow you to build a queue of sendToDevice() requests. As in your current code, any failed messages will be silently ignored, but we will also count them.
Your current code makes use of two arrays, tokens and platforms, so in the code below I use a callback for Array.prototype.map() that takes two arguments - the current mapped value (from tokens) and it's index (your for-loop's c value). The index is then used to get the correct platform entry.
let fcmPromisesArray = tokens.map((token, idx) => {
let platform = platforms[idx];
if (platform === "ios") {
payload = {
notification: {
title: "title",
subtitle :"messgae",
sound: "default",
badge: "1"
},
data: {
sendFrom: "",
notificationType: "",
flag: "true"
}
};
} else if (platform === "android") {
payload = {
data: {
title: "",
message : "",
flag: "true"
}
};
}
return admin.messaging().sendToDevice(token, payload) // note: 'await' was changed to 'return' here
.then(function (response) {
return true; // success
})
.catch(function (error) {
console.log("Error sending message to ", token);
return false; // failed
});
});
let results = await Promise.all(fcmPromisesArray); // wait here for all sendToDevice() requests to finish or fail
let successCount = results.reduce((acc, v) => v ? acc + 1 : acc, 0); // this minified line just counts the number of successful results
console.log(`Successfully sent messages to ${successCount}/${results.length} devices.`);
After this snippet has run, don't forget to send a result back to the client using res.send(...) or similar.

Meteor HTTP.POST call on same machine (for testing)

I have created a server side route (using iron-router). Code is as follows :
Router.route( "/apiCall/:username", function(){
var id = this.params.username;
},{ where: "server" } )
.post( function(req, res) {
// If a POST request is made, create the user's profile.
//check for legit request
console.log('post detected')
var userId = Meteor.users.findOne({username : id})._id;
})
.delete( function() {
// If a DELETE request is made, delete the user's profile.
});
This app is running on port 3000 on my local. Now I have created another dummy app running on port 5000. Frrom the dummy app, I am firing a http.post request and then listening it on the app on 3000 port. I fire the http.post request via dummy app using the below code :
apiTest : function(){
console.log('apiTest called')
HTTP.post("http://192.168.1.5:3000/apiCall/testUser", {
data: [
{
"name" : "test"
}
]
}, function (err, res) {
if(!err)
console.log("succesfully posted"); // 4
else
console.log('err',err)
});
return true;
}
But I get the following error on the callback :
err { [Error: socket hang up] code: 'ECONNRESET' }
Not able to figure out whats the problem here.
The server side route is successfully called, but the .post() method is not being entered.
Using meteor version 1.6
192.168.1.5 is my ip addr
Okay so if I use Router.map function, the issue is resolved.
Router.map(function () {
this.route("apiRoute", {path: "/apiCall/:username",
where: "server",
action: function(){
// console.log('------------------------------');
// console.log('apiRoute');
// console.log((this.params));
// console.log(this.request.body);
var id = this.params.username;
this.response.writeHead(200, {
'Content-Type': 'application/json',
'Access-Control-Allow-Origin': '*'
});
if (this.request.method == 'POST') {
// console.log('POST');
var user = Meteor.users.findOne({username : id});
// console.log(user)
if(!user){
return 'no user found'
}
else{
var userId = user._id;
}
}
});
});
It looks like the content type is not set the application/json. So you should do that...
Setting the "Content-Type" header in HTTP.call on client side in Meteor

'end' undefined for this.response in Iron Router for Meteor

I have created an HTTP POST endpoint for my Meteor server using Iron Router. I would like to send a response back to the requestor with a JSON of the status and some other metadata.
Here is the code for the endpoint:
Router.route('/new_video', {where: 'server'})
.post(function(){
var body = this.request.body;
this.response.setHeader('Content-Type', 'application/json');
var filename = body.filename;
console.log('New video uploaded for: ' + filename);
Meteor.call('newUpload', filename, function(error, results){
if (error){
throw new Meteor.Error("new-video-upload-failed", "New video could not be uploaded.");
var message = {
url: '/new_video',
status: 'success'
};
}
else{
var videoId = results;
console.log('Returned video id: ' + videoId);
var message = {
url: '/new_video',
status: 'failure'
};
}
this.response.end(JSON.stringify(message));
});
});
The Meteor console is printing:
=> Meteor server restarted
I20151002-15:51:26.311(-4)? New recording for: 1422776235,43.46756387,-80.54130886.mp4
I20151002-15:51:26.515(-4)? Returned video id: QiHXxZSb2sn9aNRPs
I20151002-15:51:26.569(-4)? Exception in delivering result of invoking 'newRecording': TypeError: Cannot call method 'end' of undefined
I20151002-15:51:26.569(-4)? at shared/routes.js:79:17
It's a common pitfall of JS where the value of this is modified due to the introduction of another function callback in the Meteor.call.
If you're using Meteor 1.2 which comes with ES2015 arrow functions you can solve the issue using this function declaration syntax instead :
Meteor.call('newUpload', filename, (error, results) => {
// here 'this' will keep referencing the POST route context
// so you can safely use this.response
});
If you're not using Meteor 1.2, use this syntax instead :
Meteor.call('newUpload', filename, function(error, results) {
// inner function is bound to parent function 'this'
}.bind(this));

How to listen to node http-proxy traffic?

I am using node-http-proxy. However, in addition to relaying HTTP requests, I also need to listen to the incoming and outgoing data.
Intercepting the response data is where I'm struggling. Node's ServerResponse object (and more generically the WritableStream interface) doesn't broadcast a 'data' event. http-proxy seems to create it's own internal request, which produces a ClientResponse object (which does broadcast the 'data' event) however this object is not exposed publically outside the proxy.
Any ideas how to solve this without monkey-patching node-http-proxy or creating a wrapper around the response object?
Related issue in issues of node-http-proxy on Github seems to imply this is not possible. For future attempts by others, here is how I hacked the issue:
you'll quickly find out that the proxy is only calling writeHead(), write() and end() methods of the res object
since res is already an EventEmitter, you can start emitting new custom events
listen for these new events to assemble the response data and then use it
var eventifyResponse = function(res) {
var methods = ['writeHead', 'write', 'end'];
methods.forEach(function(method){
var oldMethod = res[method]; // remember original method
res[method] = function() { // replace with a wrapper
oldMethod.apply(this, arguments); // call original method
arguments = Array.prototype.slice.call(arguments, 0);
arguments.unshift("method_" + method);
this.emit.apply(this, arguments); // broadcast the event
};
});
};
res = eventifyResponse(res), outputData = '';
res.on('method_writeHead', function(statusCode, headers) { saveHeaders(); });
res.on('method_write', function(data) { outputData += data; });
res.on('method_end', function(data) { use_data(outputData + data); });
proxy.proxyRequest(req, res, options)
This is a simple proxy server sniffing the traffic and writing it to console:
var http = require('http'),
httpProxy = require('http-proxy');
//
// Create a proxy server with custom application logic
//
var proxy = httpProxy.createProxyServer({});
// assign events
proxy.on('proxyRes', function (proxyRes, req, res) {
// collect response data
var proxyResData='';
proxyRes.on('data', function (chunk) {
proxyResData +=chunk;
});
proxyRes.on('end',function () {
var snifferData =
{
request:{
data:req.body,
headers:req.headers,
url:req.url,
method:req.method},
response:{
data:proxyResData,
headers:proxyRes.headers,
statusCode:proxyRes.statusCode}
};
console.log(snifferData);
});
// console.log('RAW Response from the target', JSON.stringify(proxyRes.headers, true, 2));
});
proxy.on('proxyReq', function(proxyReq, req, res, options) {
// collect request data
req.body='';
req.on('data', function (chunk) {
req.body +=chunk;
});
req.on('end', function () {
});
});
proxy.on('error',
function(err)
{
console.error(err);
});
// run the proxy server
var server = http.createServer(function(req, res) {
// every time a request comes proxy it:
proxy.web(req, res, {
target: 'http://localhost:4444'
});
});
console.log("listening on port 5556")
server.listen(5556);
I tried your hack but it didn't work for me. My use case is simple: I want to log the in- and outgoing traffic from an Android app to our staging server which is secured by basic auth.
https://github.com/greim/hoxy/
was the solution for me. My node-http-proxy always returned 500 (while the direct request to stage did not). Maybe the authorization headers would not be forwarded correctly or whatever.
Hoxy worked fine right from the start.
npm install hoxy [-g]
hoxy --port=<local-port> --stage=<your stage host>:<port>
As rules for logging I specified:
request: $aurl.log()
request: #log-headers()
request: $method.log()
request: $request-body.log()
response: $url.log()
response: $status-code.log()
response: $response-body.log()
Beware, this prints any binary content.

Express / NodeJS Can't send headers after they are sent caused by http requests

First time working with NodeJS (yes, it's awesome) and also using Express as well. Got the web app / service working great but I run in to problems when trying to make more than one http request. Here's a video of how the app causes 2 http requests - http://screencast.com/t/yFKdIajs0XD - as you can see I click on 'articles' it loads an rss feed, then click videos and it loads a youtube feed - both work just fine but after the second call is made it throws an exception. I get the following when I attempt two separate http requests using node's http module:
http.js:527
throw new Error("Can't set headers after they are sent.");
^
Error: Can't set headers after they are sent.
at ServerResponse.<anonymous> (http.js:527:11)
at ServerResponse.setHeader (/Users/rickblalock/node/auti_node/node_modules/express/node_modules/connect/lib/patch.js:47:22)
at /Users/rickblalock/node/auti_node/node_modules/express/node_modules/connect/lib/middleware/errorHandler.js:72:19
at [object Object].<anonymous> (fs.js:107:5)
at [object Object].emit (events.js:61:17)
at afterRead (fs.js:878:12)
at wrapper (fs.js:245:17)
Sample code provided here:
Using my controller module to render the request - http://pastie.org/2317698
One of the tabs (article tab) - the video code is identical minus referencing a video feed: http://pastie.org/2317731
try using the "end" event not "data" like this:
var data = "";
app.get('/', function(req, res){
var options = {
host: 'http://www.engadget.com',
path: '/rss.xml',
method: 'GET'
};
if (data === "") {
var myReq = http.request(options, function(myRes) {
myRes.setEncoding('utf8');
myRes.on('data', function(chunk) {
console.log("request on data ");
data += chunk;
});
myRes.on('end', function () {
console.log("request on END");
res.render('index', {
title: 'Express',
data: data
});
});
});
myReq.write('data\n');
myReq.end();
}
else {
res.render('index', {
title: 'Express',
data: data
});
}
});
old answer
i also think that this is the culprit:
var req = http.request(options, function(res) {
res.setEncoding('utf8');
res.on('data', function(chunk) {
parseArticle(chunk);
});
});
req.write('data\n');
req.end();
the first line is async so everything inside the callback is called after you do req.write() and req.end()
put these two lines into the callback.

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