I'm using ReactJS to run my front-end and using Express for my back-end. I want to make a get request to my back-end using the "/paas" path to get a listing of all of my pods that are running inside my namespace in Rancher(Kubernetes).
The back-end then needs to be able to make an https request to my Rancher API endpoint and return the result to the front-end. I can make the successful call to Rancher API and see the data print to the screen on my back-end but I get lost when trying to send this data to the front-end and console log it out inside the browser.
Due to "pre-flight" errors, I can't just make a direct call to the Rancher endpoint inside of my App.js file. More info on this here. So I need to go the custom back-end route. I any case, it seems like this should be pretty straightforward. Any guidance would be appreciated.
App.js:
import React, { useEffect } from "react"
import axios from "axios"
function App() {
useEffect(() => {
const fecthPods = async () => {
try {
const response = await axios.get(`http://localhost:3001/paas`)
console.log(response.data)
} catch (err) {
if (err.response) {
// Not in the 200 response range
console.log(err.response.data)
console.log(err.response.status)
console.log(err.response.headers)
} else {
console.log(`Error: ${err.message}`)
}
}
}
fecthPods()
},[])
return (
<div>
Hello World!
</div>
);
}
export default App;
Back-end server.js:
import express from "express"
import cors from "cors"
import https from "https"
import bodyParser from "body-parser";
const app = express()
app.use(cors())
app.use("/data", (req, res) => {
res.json({ name: "Minion", favFood: "pizza"})
})
app.get("/paas", bodyParser.json(), (req, res) => {
const options = {
hostname: "k8.fqdn.com",
port: 443,
path: "/k8s/clusters/c-wwfc/v1/pods/mynamespace",
method: "GET",
headers: {
Authorization: "Bearer token:12345"
}
}
const request = https.get(options, (res) => {
let responseBody = ""
res.setEncoding("UTF-8")
res.on("data", (chunk) => {
console.log("---chunk", chunk.length);
responseBody += chunk;
});
res.on("end", () => {
let json = JSON.parse(responseBody)
// console.log(responseBody)
console.log("Response finished");
res.json({data: responseBody})
});
});
request.end()
res.json({ status: "complete", data: request.data})
})
app.listen(3001)
console.log("backend up on 3001")
I see a couple of errors on your backend code.
First, you are naming the res variable for the express middleware and also for the response received by the https module. In this way, you lose the possibility to access to the express response object in the on.('end') callback.
Secondly, you are triyng to respond to the client multiple times (inside the on.('end') callback and also directly inside the express middleware with the instruction res.json({ status: "complete", data: request.data}). Also, consider that the code you wrote is repliyng to the client before the call to the k8s cluster is made. And the response will always be a JSON with this data: { "status": "complete", "data": undefined}.
To fix all, try with this code (I will try to comment all edits):
app.get("/paas", bodyParser.json(), (req, res) => {
const options = {
hostname: "k8.fqdn.com",
port: 443,
path: "/k8s/clusters/c-wwfc/v1/pods/mynamespace",
method: "GET",
headers: {
Authorization: "Bearer token:12345"
}
}
const k8sRequest = https.get(options, (k8sResponse ) => { // as you can see I renamed request and res to k8sRequest and k8sResponse, to avoid loosing the scope on req and res express middleware variables
let responseBody = ""
res.setEncoding("UTF-8")
k8sResponse.on("data", (chunk) => { // here use k8sResponse to collect chunks
console.log("---chunk", chunk.length);
responseBody += chunk;
});
k8sResponse.on("end", () => { // here use k8sResponse again
let json = JSON.parse(responseBody)
// console.log(responseBody)
console.log("Response finished");
res.json({ status: "complete", data: responseBody}) // here use the express res variable, to reply to the client.
});
});
k8sRequest.end() // here use the k8sRequest variable to make the https call to the k8s cluster
// here I deleted the res.json instruction
})
The above code should just works. Anyway, I suggest you using axios also with your backend service. You are already using it with React, so you know how to use it. The syntax is minimal and easier and you can use the async/await approach.
Axios solution:
import axios from "axios"
app.get("/paas", bodyParser.json(), async (req, res) => {
try {
const url = 'https://k8.fqdn.com/k8s/clusters/c-wwfc/v1/pods/mynamespace'
const k8sResponse = await axios.get(url, headers: {
Authorization: "Bearer token:12345"
})
res.json({ status: "complete", data: k8sResponse.data })
} catch (e) {
res.json({status: "error", data: e.response.data})
}
})
You should wrap your axios call inside a try/catch block to properly handle errors like you are doing with your React implementation. Error handling should be also implemented if you still want you the native node.js https module
I am trying to write a function that creates an HTTPS request.
This is all part of an expressjs project with Typescript.
I can get the HTTPS request working and getting a response - but the response is encoded with GZIP. I am trying my best to follow the documentation. But no luck, the response stays zipped.
This is my code
private getData = (host, pathname): Promise<string> => {
return new Promise((resolve, reject) => {
const options = {
hostname: host,
path: pathname,
gzip: true,
method: 'GET',
headers: {'x-apikey': 'XXXX'}
}
const req = https.request(options, (res) => {
if (res.statusCode < 200 || res.statusCode >= 300) {
console.log('error!')
return reject(new Error('statusCode=' + res.statusCode));
}
let body = '';
res.on('data', function (chunk) {
body += chunk;
});
res.on('end', function () {
try {
console.log('res.headers', res.headers)
console.log('res.headers', body)
body = JSON.parse.toString();
resolve(body);
} catch (e) {
reject(e);
}
resolve(body);
});
req.on('error', (e) => {
reject(e.message);
});
// send the request
});
req.end();
});
}
The console log statement shows this
So obviously the JSONparsing is failing. What am I missing?
Thanks heaps for the help
https.request() does not natively support gzip compression. So, you will have to either add support for it yourself as shown here or use an https request library such as got() that already supports gzip (and also already supports promises too).
import got from 'got';
private getData = (host, pathname): Promise<string> => {
const options = {
method: 'GET',
headers: {'x-apikey': 'XXXX'}
}
return got(`https://${host}${pathname}`, options).json();
}
FYI, it's not clear in your question what type of response you are expecting. You attempt to use:
body = JSON.parse.toString();
which doesn't make any sense because JSON.parse.toString() is trying to get string version of the JSON.parse function without actually even calling that function - very odd. Perhaps you meant JSON.parse(body)? But, your typescript makes it look like you're expecting a promise that resolves to a string so that wouldn't usually be the result of JSON parsing.
If you are expecting a gzipped JSON response, then you would use the:
return got(`https://${host}${pathname}`, options).json();
I show above. If you are expecting just a string, not JSON, then you would change that line to:
return got(`https://${host}${pathname}`, options).text();
I trying to write node function to call third party API . I using the angular Fire Function for display the results in angular project. The issues is no data response;
Here is my node js code.
const request = require('request');
const UserDetail = () => {
const options ={
url: 'https://www.reddit.com/r/funny.json',
method: 'GET',
headers: {
'Accept': 'application/json',
'Accept-Charset': 'utf-8',
'User-Agent': 'my-reddit-client'
}
}
request(options, function(err, res, body) {
let json = JSON.parse(body);
console.log(json);
});
}
UserDetail();
Here is my firebase function code:
exports.userdetails = functions.https.onRequest(require('./api/user/userdetail'));
Here is my angular service calling firebase function code:
callUserDetails(){
const details = this.functions.httpsCallable('userdetails')({ text: 'Some Request Data' })
.pipe()
.subscribe(resp => {
console.log({ resp });
}, err => {
console.error({ err });
});
}
You are mixing up Callable Cloud Functions and HTTPS Cloud Functions.
By doing
exports.userdetails = functions.https.onRequest(...)
you define an HTTPS Cloud Function,
but by doing
this.functions.httpsCallable('userdetails')({ text: 'Some Request Data' })
in your front-end, you actually call a Callable Cloud Function.
You should either change your Cloud Function to a Callable one, or call the userdetails HTTPS Cloud Function by sending an HTTP Request to the Cloud Function URL.
I would advise the first approach because Callable brings several advantages over a "simmple" HTTPS one (see the doc).
In addition you need to note that request supports callback interfaces natively but does not return a Promise. And it is necessary to use Promises in order to manage the life cycle of a Callable Cloud Function (see the official video serie).
I would use Axios along the following lines (untested):
exports.userdetails = functions.https.onCall(async (data, context) => {
try {
const options = {
url: 'https://www.reddit.com/r/funny.json',
method: 'get',
headers: {
'Accept': 'application/json',
'Accept-Charset': 'utf-8',
'User-Agent': 'my-reddit-client'
}
}
const axiosResponse = await axios(options);
// Build the resp to be sent to the frontend by
// using axiosResponse.data .... up to you, see https://github.com/axios/axios#response-schema
return { resp: .... }
} catch (error) {
// See https://firebase.google.com/docs/functions/callable#handle_errors
}
});
Maybe you should call angular service like this:
// provider class
constructor(private http: HttpClient) {}
this.http.get(url, {params: {}, headers: {}}).subscribe(result => {
//// result
})
I'm trying to setup a Google-OAuth flow using serverless and AWS-Lambdas. To start, I have a button that kicks off the process by hitting a lambda endpoint. However, the page never actually redirects to the authentication page. Instead I get an error on the FE:
Request failed with status code 302
Frontend logic:
const redirectToGoogleOAuth = async (user) => {
try {
const endpoint = process.env.GOOGLE_PATH_ENDPOINT;
const response = await axios.get(endpoint, {
responseType: 'text',
headers: {
'Content-Type': 'application/json',
Authorization: `Bearer ${user}`,
},
});
// Expect redirect at this point
return response.data.data;
} catch (err) {
throw new Error(err.message);
}
};
Lambda Endpoint:
module.exports = async (event, context) => {
const responseType = 'code'
const googleAuthorizeURL = 'https://accounts.google.com/o/oauth2/v2/auth'
const scope = 'openid email https://www.googleapis.com/auth/contacts.readonly'
const accessType = 'offline'
try {
const params = [
`response_type=${responseType}`,
`client_id=${googleClientId}`,
`redirect_uri=${baseURL}`,
`scope=${scope}`,
`state="state"`,
`access_type=${accessType}`
]
const googleOAuthEndPath = `${googleAuthorizeURL}?${params.join('&')}`
const response = {
statusCode: 302,
body: '',
headers: {
location: googleOAuthEndPath
}
}
return response
} catch (err) {
return response(400, err.message)
}
}
In the lambda-response, I've added a header for location with the google-path. However, the frontend does not seem to consume the response correctly. The frontend interprets the 302 as in error instead of redirecting to the specific page. Any ideas on how I may resolve this so it actually redirects?
Axios uses XHR, which always follows redirects by itself and therefore Axios can't do anything about it (unless you rely on hacks, discussed in the same link).
You might have to use something other than Axios for this part, such as the Fetch API, which supports manual redirects.
GitHub user parties suggested the fetch() equivalent in the same Axios issue linked above:
fetch("/api/user", {
redirect: "manual"
}).then((res) => {
if (res.type === "opaqueredirect") {
window.location.href = res.url;
} else {
return res;
}
}).catch(handleFetchError);
I'm getting started with AWS Lambda and I'm trying to request an external service from my handler function. According to this answer, HTTP requests should work just fine, and I haven't found any documentation that says otherwise. (In fact, people have posted code that use the Twilio API to send SMS.)
My handler code is:
var http = require('http');
exports.handler = function(event, context) {
console.log('start request to ' + event.url)
http.get(event.url, function(res) {
console.log("Got response: " + res.statusCode);
}).on('error', function(e) {
console.log("Got error: " + e.message);
});
console.log('end request to ' + event.url)
context.done(null);
}
and I see the following 4 lines in my CloudWatch logs:
2015-02-11 07:38:06 UTC START RequestId: eb19c89d-b1c0-11e4-bceb-d310b88d37e2
2015-02-11 07:38:06 UTC eb19c89d-b1c0-11e4-bceb-d310b88d37e2 start request to http://www.google.com
2015-02-11 07:38:06 UTC eb19c89d-b1c0-11e4-bceb-d310b88d37e2 end request to http://www.google.com
2015-02-11 07:38:06 UTC END RequestId: eb19c89d-b1c0-11e4-bceb-d310b88d37e2
I'd expect another line in there:
2015-02-11 07:38:06 UTC eb19c89d-b1c0-11e4-bceb-d310b88d37e2 Got response: 302
but that's missing. If I'm using the essential part without the handler wrapper in node on my local machine, the code works as expected.
The inputfile.txt I'm using is for the invoke-async call is this:
{
"url":"http://www.google.com"
}
It seems like the part of the handler code that does the request is skipped entirely. I started out with the request lib and fell back to using plain http to create a minimal example. I've also tried to request a URL of a service I control to check the logs and there's no requests coming in.
I'm totally stumped. Is there any reason Node and/or AWS Lambda would not execute the HTTP request?
Of course, I was misunderstanding the problem. As AWS themselves put it:
For those encountering nodejs for the first time in Lambda, a common
error is forgetting that callbacks execute asynchronously and calling
context.done() in the original handler when you really meant to wait
for another callback (such as an S3.PUT operation) to complete, forcing
the function to terminate with its work incomplete.
I was calling context.done way before any callbacks for the request fired, causing the termination of my function ahead of time.
The working code is this:
var http = require('http');
exports.handler = function(event, context) {
console.log('start request to ' + event.url)
http.get(event.url, function(res) {
console.log("Got response: " + res.statusCode);
context.succeed();
}).on('error', function(e) {
console.log("Got error: " + e.message);
context.done(null, 'FAILURE');
});
console.log('end request to ' + event.url);
}
Update: starting 2017 AWS has deprecated the old Nodejs 0.10 and only the newer 4.3 run-time is now available (old functions should be updated). This runtime introduced some changes to the handler function. The new handler has now 3 parameters.
function(event, context, callback)
Although you will still find the succeed, done and fail on the context parameter, AWS suggest to use the callback function instead or null is returned by default.
callback(new Error('failure')) // to return error
callback(null, 'success msg') // to return ok
Complete documentation can be found at http://docs.aws.amazon.com/lambda/latest/dg/nodejs-prog-model-handler.html
Simple Working Example of Http request using node.
const http = require('https')
exports.handler = async (event) => {
return httprequest().then((data) => {
const response = {
statusCode: 200,
body: JSON.stringify(data),
};
return response;
});
};
function httprequest() {
return new Promise((resolve, reject) => {
const options = {
host: 'jsonplaceholder.typicode.com',
path: '/todos',
port: 443,
method: 'GET'
};
const req = http.request(options, (res) => {
if (res.statusCode < 200 || res.statusCode >= 300) {
return reject(new Error('statusCode=' + res.statusCode));
}
var body = [];
res.on('data', function(chunk) {
body.push(chunk);
});
res.on('end', function() {
try {
body = JSON.parse(Buffer.concat(body).toString());
} catch(e) {
reject(e);
}
resolve(body);
});
});
req.on('error', (e) => {
reject(e.message);
});
// send the request
req.end();
});
}
Yeah, awendt answer is perfect. I'll just show my working code... I had the context.succeed('Blah'); line right after the reqPost.end(); line. Moving it to where I show below solved everything.
console.log('GW1');
var https = require('https');
exports.handler = function(event, context) {
var body='';
var jsonObject = JSON.stringify(event);
// the post options
var optionspost = {
host: 'the_host',
path: '/the_path',
method: 'POST',
headers: {
'Content-Type': 'application/json',
}
};
var reqPost = https.request(optionspost, function(res) {
console.log("statusCode: ", res.statusCode);
res.on('data', function (chunk) {
body += chunk;
});
context.succeed('Blah');
});
reqPost.write(jsonObject);
reqPost.end();
};
I faced this issue on Node 10.X version.
below is my working code.
const https = require('https');
exports.handler = (event,context,callback) => {
let body='';
let jsonObject = JSON.stringify(event);
// the post options
var optionspost = {
host: 'example.com',
path: '/api/mypath',
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Authorization': 'blah blah',
}
};
let reqPost = https.request(optionspost, function(res) {
console.log("statusCode: ", res.statusCode);
res.on('data', function (chunk) {
body += chunk;
});
res.on('end', function () {
console.log("Result", body.toString());
context.succeed("Sucess")
});
res.on('error', function () {
console.log("Result Error", body.toString());
context.done(null, 'FAILURE');
});
});
reqPost.write(jsonObject);
reqPost.end();
};
Modern Async/Await Example
You need to prevent the lambda from finishing before the https request has completed. It makes code with multiple requests easier to read as well.
const https = require('https');
// Helper that turns https.request into a promise
function httpsRequest(options) {
return new Promise((resolve, reject) => {
const req = https.request(options, (res) => {
if (res.statusCode < 200 || res.statusCode >= 300) {
return reject(new Error('statusCode=' + res.statusCode));
}
var body = [];
res.on('data', function(chunk) {
body.push(chunk);
});
res.on('end', function() {
try {
body = JSON.parse(Buffer.concat(body).toString());
} catch(e) {
reject(e);
}
resolve(body);
});
});
req.on('error', (e) => {
reject(e.message);
});
req.end();
});
}
// Lambda starts executing here
exports.handler = async event => {
// --- GET example request
var options = {
method: 'GET',
hostname: 'postman-echo.com',
path: encodeURI('/get?foo1=bar1'),
headers: {
},
};
try {
const getBody = await httpsRequest(options);
// The console.log below will not run until the GET request above finishes
console.log('GET completed successfully! Response body:', getBody);
} catch (err) {
console.error('GET request failed, error:', err);
}
// --- POST example request
var options = {
method: 'POST',
hostname: 'postman-echo.com',
path: encodeURI('/hi/there?hand=wave'),
headers: {
},
};
try {
const postBody = await httpsRequest(options);
// The console.log below will not run until the POST request above finishes
console.log('POST response body:', postBody);
} catch (err) {
console.error('POST request failed, error:', err);
}
};
I had the very same problem and then I realized that programming in NodeJS is actually different than Python or Java as its based on JavaScript. I'll try to use simple concepts as there may be a few new folks that would be interested or may come to this question.
Let's look at the following code :
var http = require('http'); // (1)
exports.handler = function(event, context) {
console.log('start request to ' + event.url)
http.get(event.url, // (2)
function(res) { //(3)
console.log("Got response: " + res.statusCode);
context.succeed();
}).on('error', function(e) {
console.log("Got error: " + e.message);
context.done(null, 'FAILURE');
});
console.log('end request to ' + event.url); //(4)
}
Whenever you make a call to a method in http package (1) , it is created as event and this event gets it separate event. The 'get' function (2) is actually the starting point of this separate event.
Now, the function at (3) will be executing in a separate event, and your code will continue it executing path and will straight jump to (4) and finish it off, because there is nothing more to do.
But the event fired at (2) is still executing somewhere and it will take its own sweet time to finish. Pretty bizarre, right ?. Well, No it is not. This is how NodeJS works and its pretty important you wrap your head around this concept. This is the place where JavaScript Promises come to help.
You can read more about JavaScript Promises here. In a nutshell, you would need a JavaScript Promise to keep the execution of code inline and will not spawn new / extra threads.
Most of the common NodeJS packages have a Promised version of their API available, but there are other approaches like BlueBirdJS that address the similar problem.
The code that you had written above can be loosely re-written as follows.
'use strict';
console.log('Loading function');
var rp = require('request-promise');
exports.handler = (event, context, callback) => {
var options = {
uri: 'https://httpbin.org/ip',
method: 'POST',
body: {
},
json: true
};
rp(options).then(function (parsedBody) {
console.log(parsedBody);
})
.catch(function (err) {
// POST failed...
console.log(err);
});
context.done(null);
};
Please note that the above code will not work directly if you will import it in AWS Lambda. For Lambda, you will need to package the modules with the code base too.
I've found lots of posts across the web on the various ways to do the request, but none that actually show how to process the response synchronously on AWS Lambda.
Here's a Node 6.10.3 lambda function that uses an https request, collects and returns the full body of the response, and passes control to an unlisted function processBody with the results. I believe http and https are interchangable in this code.
I'm using the async utility module, which is easier to understand for newbies. You'll need to push that to your AWS Stack to use it (I recommend the serverless framework).
Note that the data comes back in chunks, which are gathered in a global variable, and finally the callback is called when the data has ended.
'use strict';
const async = require('async');
const https = require('https');
module.exports.handler = function (event, context, callback) {
let body = "";
let countChunks = 0;
async.waterfall([
requestDataFromFeed,
// processBody,
], (err, result) => {
if (err) {
console.log(err);
callback(err);
}
else {
const message = "Success";
console.log(result.body);
callback(null, message);
}
});
function requestDataFromFeed(callback) {
const url = 'https://put-your-feed-here.com';
console.log(`Sending GET request to ${url}`);
https.get(url, (response) => {
console.log('statusCode:', response.statusCode);
response.on('data', (chunk) => {
countChunks++;
body += chunk;
});
response.on('end', () => {
const result = {
countChunks: countChunks,
body: body
};
callback(null, result);
});
}).on('error', (err) => {
console.log(err);
callback(err);
});
}
};
Use promises with resolve reject. It worked for me!
Add above code in API gateway under GET-Integration Request> mapping section.
Yes, there's in fact many reasons why you can access AWS Lambda like and HTTP Endpoint.
The architecture of AWS Lambda
It's a microservice. Running inside EC2 with Amazon Linux AMI (Version 3.14.26–24.46.amzn1.x86_64) and runs with Node.js. The memory can be beetwen 128mb and 1gb. When the data source triggers the event, the details are passed to a Lambda function as parameter's.
What happen?
AWS Lambda run's inside a container, and the code is directly uploaded to this container with packages or modules. For example, we NEVER can do SSH for the linux machine running your lambda function. The only things that we can monitor are the logs, with CloudWatchLogs and the exception that came from the runtime.
AWS take care of launch and terminate the containers for us, and just run the code. So, even that you use require('http'), it's not going to work, because the place where this code runs, wasn't made for this.