I'm trying to write a front end to an API service with Node JS.
I'd like to be able to have a user point their browser at my node server and make a request. The node script would modify the input to the request, call the api service, then modify the output and pass back to the user.
I like the solution here (with Express JS and node-http-proxy) as it passes the cookies and headers directly from the user through my site to the api server.
proxy request in node.js / express
I see how to modify the input to the request, but i can't figure out how to modify the response. Any suggestions?
transformer-proxy could be useful here. I'm the author of this plugin and I'm answering here because I found this page when looking for the same question and wasn't satisfied with harmon as I don't want to manipulate HTML.
Maybe someone else is looking for this and finds it useful.
Harmon is designed to plug into node-http-proxy https://github.com/No9/harmon
It uses trumpet and so is stream based to work around any buffering problems.
It uses an element and attribute selector to enable manipulation of a response.
This can be used to modify output response.
See here: https://github.com/nodejitsu/node-http-proxy/issues/382#issuecomment-14895039
http-proxy-interceptor is a middleware I wrote for this very purpose. It allows you to modify the http response using one or more transform streams. There are tons of stream-based packages available (like trumpet, which harmon uses), and by using streams you can avoid buffering the entire response.
var httpProxy = require('http-proxy');
var modifyResponse = require('http-proxy-response-rewrite');
var proxy = httpProxy.createServer({
target:'target server IP here',
});
proxy.listen(8001);
proxy.on('error', function (err, req, res) {
res.writeHead(500, {
'Content-Type': 'text/plain'
});
res.end('Something went wrong. And we are reporting a custom error message.');
});
proxy.on('proxyRes', function (proxyRes, req, res) {
modifyResponse(res, proxyRes.headers['content-encoding'], function (body) {
if (body && (body.indexOf("<process-order-response>")!= -1)) {
var beforeTag = "</receipt-text>"; //tag after which u can add data to
// response
var beforeTagBody = body.substring(0,(body.indexOf(beforeTag) + beforeTag.length));
var requiredXml = " <ga-loyalty-rewards>\n"+
"<previousBalance>0</previousBalance>\n"+
"<availableBalance>0</availableBalance>\n"+
"<accuruedAmount>0</accuruedAmount>\n"+
"<redeemedAmount>0</redeemedAmount>\n"+
"</ga-loyalty-rewards>";
var afterTagBody = body.substring(body.indexOf(beforeTag)+ beforeTag.length)+
var res = [];
res.push(beforeTagBody, requiredXml, afterTagBody);
console.log(res.join(""));
return res.join("");
}
return body;
});
});
Related
I'm trying to use a cloudflare worker to dynamically set the origin based on the requesting IP (so we can serve a testing version of the website internally)
I have this
addEventListener('fetch', event => {
event.respondWith(handleRequest(event.request))
})
async function handleRequest(request) {
if (request.headers.get("cf-connecting-ip") == '185.X.X.X')
{
console.log('internal request change origin');
}
const response = await fetch(request)
console.log('Got response', response)
return response
}
I'm not sure what to set. The request object doesn't seem to have any suitable parameters to change.
Thanks
Normally, you should change the request's URL, like this:
// Parse the URL.
let url = new URL(request.url)
// Change the hostname.
url.hostname = "test-server.example.com"
// Construct a new request with the new URL
// and all other properties the same.
request = new Request(url, request)
Note that this will affect the Host header seen by the origin (it'll be test-server.example.com). Sometimes people want the Host header to remain the same. Cloudflare offers a non-standard extension to accomplish that:
// Tell Cloudflare to connect to `test-server.example.com`
// instead of the hostname specified in the URL.
request = new Request(request,
{cf: {resolveOverride: "test-server.example.com"}})
Note that for this to be allowed, test-server.example.com must be a hostname within your domain. However, you can of course configure that host to be a CNAME.
The resolveOverride feature is documented here: https://developers.cloudflare.com/workers/reference/apis/request/#the-cf-object
(The docs claim it is an "Enterprise only" feature, but this seems to be an error in the docs. Anyone can use this feature. I've filed a ticket to fix that...)
I'm a beginner in Amazon's Lambda-API implementations.
I'm just deploying a very simple API: a very simple lambda function with Python 2.7 printing "Hello World" that I trigger with API Gateway. However, when I click on the Invoke URL link, it tells me "{"message": "Internal server error"}".
Thus, I'm trying to see what is wrong here, so I click on the API itself and I can see the following being grey in my Method Execution: "Integration Response: Proxy integrations cannot be configured to transform responses."
I have tested many different configurations but I still face the same error. I have no idea why this step is grey.
I had the same problem when trying to integrate API gateway and lambda function. Basically, after spending a couple of hours, I figure out.
So when you were creating a new resource or method the Use Lambda Proxy integration was set by default.
So you need to remove this. Follow to Integration Request and untick the Use Lambda Proxy integration
you will see the following picture
Then in you Resources, Atction tab, choose Enable CORS
Once this done Deploy your API once again and test function. Also, this topic will explain what's happening under the hood.
Good luck...
The Lambda response should be in a specific format for API gateway to process. You could find details in the post. https://aws.amazon.com/premiumsupport/knowledge-center/malformed-502-api-gateway/
exports.handler = (event, context, callback) => {
var responseBody = {
"key3": "value3",
"key2": "value2",
"key1": "value1"
};
var response = {
"statusCode": 200,
"headers": {
"my_header": "my_value"
},
"body": JSON.stringify(responseBody),
"isBase64Encoded": false
};
callback(null, response);
My API was working in Postman but not locally when I was developing the front end. I was getting the same errors when trying to enable CORS on my resources for GET, POST and OPTIONS and after searching all over #aditya answer got me on the right track but I had to tweak my code slightly.
I needed to add the res.statusCodeand the two headers and it started working.
// GET
// get all myModel
app.get('/models/', (req, res) => {
const query = 'SELECT * FROM MyTable'
pool.query(query, (err, results, fields) => {
//...
const models = [...results]
const response = {
data: models,
message: 'All models successfully retrieved.',
}
//****** needed to add the next 3 lines
res.statusCode = 200;
res.setHeader('content-type', 'application/json');
res.setHeader('Access-Control-Allow-Origin', '*');
res.send(response)
})
})
If you re using terraform for aws resource provision you can set the
"aws_api_gateway_integration" type = "AWS" instead of "AWS_PROXY" and that should resolve your problem.
I want to use the request module in my express app, but I am not sure where the actual requests code goes.
Usage:
When a user loads a page, make a GET request and populate the page with data.
When a users clicks on a item from a table, make a GET request.
When a user fills out a form, POST.
I tried searching for answers but it seems to be implied that the developer knows where to place the code.
Example of a code snippet using request that I am unsure where to place in the express app:
var request = require('request');
request('http://www.google.com', function (error, response, body) {
if (!error && response.statusCode == 200) {
console.log(body) // Show the HTML for the Google homepage.
}
})
I am guessing that I should not place the code in the server.js file especially if I am going to be making many different calls, but that's what it looks like others are doing on StackOverflow.
Does the request belong in a model?
If you are doing this in response to a user interaction, like clicking on something you can just do it from the route handler. Below, I just return the results to the client, or I pass an error to the next handler in the chain.
var request = require('request');
var express = require('express');
var app = express();
app.get('/click', function(req, res, next){
request('http://www.google.com', function (error, response, body) {
if (error || response.statusCode != 200)
return next(err);
response.send(body) // return the html to the client
})
});
app.listen(3000);
In bigger apps you might move routes into separate modules.
Just finished breakfast and already hit a snag. I'm trying to call the salesforce REST api from my google sheets. I've written a working script locally in python, but converting it into JS, something went wrong:
function authenticateSF(){
var url = 'https://login.salesforce.com/services/oauth2/token';
var options = {
grant_type:'password',
client_id:'XXXXXXXXXXX',
client_secret:'111111111111',
username:'ITSME#smee.com',
password:'smee'
};
var results = UrlFetchApp.fetch(url, options);
}
Here is the error response:
Request failed for https://login.salesforce.com/services/oauth2/token
returned code 400. Truncated server response:
{"error_description":"grant type not
supported","error":"unsupported_grant_type"} (use muteHttpExceptions
option to examine full response) (line 12, file "Code")
Mind you, these exact parameters work fine in my local python script (putting the key values inside quotations).
Here are the relevant docs:
Google Script: Connecting to external API's
Salesforce: REST API guide
Thank you all!
Google's UrlFetchApp object automatically defaults to a GET request. To authenticate, you have to explicitly set in the options the method "post":
function authenticateSF(){
var url = 'https://login.salesforce.com/services/oauth2/token';
var payload = {
'grant_type':'password',
'client_id':'XXXXXXXXXXX',
'client_secret':'111111111111',
'username':'ITSME#smee.com',
'password':'smee'
};
var options = {
'method':'post',
'payload':payload
};
var results = UrlFetchApp.fetch(url, options);
}
I tried lot of examples available in the net using node module wcf.js. But could not get any appropriate result. I'm using the below url
https://webservice.kareo.com/services/soap/2.1/KareoServices.svc?wsdl
Any one who can explain me with the help of code will be really helpful. I want to know how to access the wsdl in node.js
Thanks.
Please have a look at wcf.js
In short you can follow these steps:
npm install wcf.js
Write your code like this:
code
var Proxy = require('wcf.js').Proxy;
var BasicHttpBinding = require('wcf.js').BasicHttpBinding;
var binding = new BasicHttpBinding();
//Ensure the proxy variable created below has a working wsdl link that actually loads wsdl
var proxy = new Proxy(binding, "http://YourHost/YourService.svc?wsdl");
/*Ensure your message below looks like a valid working SOAP UI request*/
var message = "<soapenv:Envelope xmlns:soapenv='http://schemas.xmlsoap.org/soap/envelope/' xmlns:sil='http://YourNamespace'>" +
"<soapenv:Header/>" +
"<soapenv:Body>" +
"<sil:YourMethod>" +
"<sil:YourParameter1>83015348-b9dc-41e5-afe2-85e19d3703f9</sil:YourParameter1>" +
"<sil:YourParameter2>IMUT</sil:YourParameter2>" +
"</sil:YourMethod>" +
"</soapenv:Body>" +
"</soapenv:Envelope>";
/*The message that you created above, ensure it works properly in SOAP UI rather copy a working request from SOAP UI*/
/*proxy.send's second argument is the soap action; you can find the soap action in your wsdl*/
proxy.send(message, "http://YourNamespace/IYourService/YourMethod", function (response, ctx) {
console.log(response);
/*Your response is in xml and which can either be used as it is of you can parse it to JSON etc.....*/
});
You don't have that many options.
You'll probably want to use one of:
node-soap
douche
soapjs
i tried node-soap to get INR USD rate with following code.
app.get('/getcurr', function(req, res) {
var soap = require('soap');
var args = {FromCurrency: 'USD', ToCurrency: 'INR'};
var url = "http://www.webservicex.net/CurrencyConvertor.asmx?WSDL";
soap.createClient(url, function(err, client) {
client.ConversionRate(args, function(err, result) {
console.log(result);
});
});
});
Code Project has got a neat sample which uses wcf.js for which api's are wcf like so no need to learn new paradigm.
I think that an alternative would be to:
use a tool such as SoapUI to record input and output xml messages
use node request to form input xml message to send (POST) the request to the web service (note that standard javascript templating mechanisms such as ejs or mustache could help you here) and finally
use an XML parser to deserialize response data to JavaScript objects
Yes, this is a rather dirty and low level approach but it should work without problems
You'll probably want to use one of:
node-soap
douche
soapjs
Aslo, there's an existing question.
In my case, I used https://www.npmjs.com/package/soap. By default forceSoap12Headers option was set to false which prevented node-soap to generate correct soap message according to SOAP 1.2. Check for more details: I am confused about SOAP namespaces. After I set it to true, I was able to make a call to .NET WCF service. Here is a TypeScript code snipper that worked for me.
import * as soap from 'soap';
import { IOptions } from 'soap';
// ...
const url = 'https://www.your-domain.com/stock.svc?wsdl';
const opt: IOptions = {
forceSoap12Headers: true,
};
soap.createClient(url, opt, (err, client: soap.Client) => {
if (err) {
throw err;
}
const wsSecurityOptions = {
hasTimeStamp: false,
};
const wsSecurity = new soap.WSSecurity('username', 'password', wsSecurityOptions);
client.setSecurity(wsSecurity);
client.addSoapHeader({ Action: 'http://tempuri.org/API/GetStockDetail' }, undefined, 'wsa', 'http://www.w3.org/2005/08/addressing');
client.addSoapHeader({ To: 'https://www.your-domain.com/stock.svc' }, undefined, 'wsa', 'http://www.w3.org/2005/08/addressing');
const args = {
symbol: 'GOOG',
};
client.GetStockDetail(
args,
(requestErr, result) => {
if (requestErr) {
throw requestErr;
}
console.log(result);
},
);
});
Here couple links to the documentation of node-soap usage:
https://github.com/vpulim/node-soap/tree/master/test
https://github.com/vpulim/node-soap