Related
I am developing a RESTful API using NodeJS and Express.
I noticed that incoming requests sometimes lack of some expected variables, which cause the program to crash, saying it couldn't set the value of a variable, to an 'undefined' value - as no value arrived with the request.
Example:
The application is expecting variableY, but instead variableX is being sent:
formData: { variableX: 'valueX' }
The program is expecting to receive variableY, with the following code:
const checkVariables = Joi.validate({
variableY: req.body.variableY,
}, schema);
The application crashes with the following error:
TypeError: Cannot read property 'variableY' of undefined
I thought about a few ways to handle that, including declaration of variables upon application initiation and using them along, using try-catch.
Another way will be to use if-else, if-chaining, or case-switch, but as you understood of course I am looking for the cleanest way to achieve that.
Any ideas?
Thank you.
** EDIT **
Progressed and managed to achieve the result using the object only. Once trying to reach any of it's inner fields the error will be thrown anyway, example:
if(req.body.variableY == undefined){console.log('The expected variable is undefined');} //true
When the validation addresses a field inside the 'undefined' object:
if(req.body.variableY.dataId == undefined){console.log('The expected variable is undefined');} //crashes
The following error is being thrown again:
TypeError: Cannot read property 'variableX' of undefined
After doing some more digging around, found this Stackoverflow thread:
How to check if object property exists with a variable holding the property name?
Tried using hasOwnProperty, but the same kind of error is being thrown:
TypeError: Cannot read property 'hasOwnProperty' of undefined
Tried wrapping variable declaration using try-catch, still didn't work:
try{
var variableX = req.body.variableX
var variableXDataId = req.body.variableX.dataId
}
catch(e){
res.status(400).send('Wrong request error: Please check your request variables and try again');
}
As this is a really basic validation that should be addressed by most of the RESTful APIs (validating that you get the expected incoming variables inside the request, so the program won't crash by having errors it can't handle - what is the common solution for such problems (expected / unexpected request validation)?
Thank you.
You can take another approach, check req.body before you reach checkVariables:
let body = req.body;
// data - your req.body
// requiredKeys - is an array of strings , [ key1, key2 ... keyN] | string[]
const setKeys = ( data, requiredKeys )=>{
if( !typeof requiredKeys.length ){
requiredKeys = [];
}
if(requiredKeys.length) requiredKeys.forEach( k =>{
k = k.replace(/\+/g,'/');
let keysList = [];
if( /\/+/g.test(k)){
keysList = k.split('/');
}else{
keysList = [k];
}
let [firstKey, ...rest] = keysList;
if( typeof data[firstKey] === 'undefined' ){
data[firstKey] = {};
}
if( rest.length ){
data[firstKey] = setKeys(data[firstKey], [rest.join('/')] );
}
})
return data;
}
let checkedData= setKeys(body, ['variableT','variableP/noname/emptyObj','custom/object/does/not/exist/but/it/will/be/created/here']);
const checkVariables = Joi.validate(checkedData, schema);
UPDATE
Below you will find an working example on how things should work during a /(let's say /usersStatus/:id ) request:
const express = require('express')
const app = express()
const port = 3000
const setKeys = (data, requiredKeys) => {
if (!typeof requiredKeys.length) {
requiredKeys = [];
}
if (requiredKeys.length) requiredKeys.forEach(k => {
k = k.replace(/\+/g, '/');
let keysList = [];
if (/\/+/g.test(k)) {
keysList = k.split('/');
} else {
keysList = [k];
}
let [firstKey, ...rest] = keysList;
if (typeof data[firstKey] === 'undefined') {
data[firstKey] = {};
}
if (rest.length) {
data[firstKey] = setKeys(data[firstKey], [rest.join('/')]);
}
})
return data;
}
/**
* Mock some data
*/
const getUserData = (req, res, next) => {
if (typeof req.body === 'undefined') {
req.body = {};
}
req.body = {
variableY: {
someName: 23
},
variableZ: {
name: 3,
type: {
id: 5,
typeName: 'something',
tags: ['a', 'b', 'c']
}
}
};
console.log('Middleware 1 getUserData');
next();
}
/**
* 1. Setup our middleware for checking keys
* "requiredKeys" is an array of strings
*/
const middlewareSetKeys = (requiredKeys, wrappedMiddleware) => {
return (req, res, next) => {
console.log('Middleware 2 middlewareSetKeys');
if (typeof req.body === "undefined") {
console.log('Leaving Middleware 2 since we don\'t have req.body');
next();
}
/**
* Update "req.body" with keys that we want to have available
* in our next middleware
*/
req.body = setKeys(req.body, requiredKeys);
if (typeof wrappedMiddleware === 'function') {
return wrappedMiddleware.call(this, req, res, next);
} else {
next();
}
}
}
/**
* 2. Let's assume a "user status" situation
* 2.1. We need userInfo from database
* 2.2. Some info won't be retrieved, unless the user accesed some parts of the website to trigger some mechanisms that allows those fields to be exposed, therefore the lack of keys
* 2.3. But we know those keys/objects, and we still want to be present so our code won't crash.
*/
// lets call our getUserData
app.get(
'/', // this path is for some userInfo
getUserData, // this returns userInfo and appends it to `req.data`
middlewareSetKeys([
'userActivity/daily/jobs', // these won't exist in getUserData because the user is lazy and he didn't apply for any JOBS
'userStatus/active/two-weeks-ago', // these won't exist in getUserData because the user joined two days ago. BUT WE STILL NEED IT coz reazons.
]), // We set our desired-later-to-use keys
(req, res, next) => {
/**
* 3. Now our req.body will have our keys
* even if they didn't exist in the getUserData middleware
*/
console.log('Middleware 3 Your middleware');
console.log(req.body);
res.setHeader('Content-Type', 'application/json');
res.send(JSON.stringify(req.body, null, 2))
})
app.listen(port, () => console.log(`Example app listening on port ${port}!`))
you can use express validator https://www.npmjs.com/package/express-validator
to validate incoming request.Then add this to your controller where a,b,c ,d are parameters you want to valaidate
const nonEmptyFields = ['a', 'b', 'c', 'd'];
nonEmptyFields.forEach(field => req.assert(field, `${field} cannot be blank`).notEmpty());
const errors = req.validationErrors();
if (errors) {
return res.status(400).send(errors);
}
for validating a field inside a field you can try doing this
typeof(req.body && req.body.name !== undefined)
A solution will be to set a default empty object to replace undefined at a parent level:
// checking for body.variableX.variableZ with object destructuring ES6
const {body = {}} = request;
const {variableX = {}, variableY} = body;
const {variableZ} = variableX.variableZ;
// or prior ES6
var body = request.body || {};
var variableX = body.variableX || {};
var variableY = variableX.variableY;
// or in a statement
var variableY = request.body && request.body.variableX ? request.body.variableX.variableY : undefined;
Based on that you can create your own function like getValue(request, 'body.variableX.variableY') to return null if any parent or the end value is undefined:
// asumes the value in the path is either object or undefined
function getValue(rootObj, path = '') {
const parts = key.split('.');
let value = rootObj || {};
let part;
while ((part = parts.shift()) && value !== null) {
value = value[part] || null;
}
return value;
};
I am trying to use Node.js to programmatically build Jenkins jobs that take Git parameters.
I am sending the parameters as post data, as shown below. However, no matter what value I assign to ref, Jenkins runs the build with the default parameter value (specified in the job's configuration). I have tried passing in the parameters as query strings in the URL, but that also did not work.
I am using Jenkins v1.651.1 and Node v6.2.0.
var jobOptions = {
url: requestedJobObject.url + 'build',
method: 'POST',
port: 8080
};
// parameters = { "name": "ref", "value": "origin/master" }
if (!_.isEmpty(parameters)) {
var jsonParametersString = JSON.stringify({"parameter": parameters});
var parameterParam = encodeURIComponent(jsonParametersString);
parameters.json = parameterParam;
jobOptions.headers = {
'Content-Type': 'application/x-www-form-urlencoded',
'Content-Length': querystring.stringify(parameters).length
};
jobOptions.url += 'WithParameters';
postData = querystring.stringify(parameters);
}
// jobOptions contains auth field & separates url into hostname and path
// makes an http request to jobOptions and calls req.write(postData)
makeRequest(jobOptions, callback, responseCB, postData)
makeRequest makes an http request:
function makeRequest (object, callback, responseCB, postData) {
var accumulator = '';
var parsedUrl = u.parse('//' + object.url, true, true);
var options = {
hostname: parsedUrl.hostname,
port: object.port || 8080,
path: parsedUrl.path,
method: object.method || 'GET',
auth: getAuthByHost(parsedUrl.hostname)
};
if (object.headers) {
options.headers = object.headers;
}
var response = null;
var req = http.request(options, function(res) {
response = res;
res.on('data', function (data) {
accumulator = accumulator + data.toString();
res.resume();
});
res.on('close', function () {
// first assume accumulator is JSON object
var responseContent;
try {
responseContent = JSON.parse(accumulator);
}
// if not object, use accumulator as string
catch (err) {
responseContent = accumulator;
}
callback(responseContent, response.statusCode);
if (responseCB) {
responseCB(res);
}
});
});
req.on('close', function () {
// first assume accumulator is JSON object
var responseContent;
try {
responseContent = JSON.parse(accumulator);
}
catch (err) {
responseContent = accumulator;
}
callback(responseContent, response.statusCode);
if (responseCB) {
responseCB(response);
}
});
if (postData) {
req.write(postData);
}
req.end();
}
try this, it works for me:
var auth = 'Basic yourUserToken';
var jobOptions = {
url:'jenkinsHostName:8080/jenkins/job/jobName/' +'build',
method: 'POST',
port: 8080
};
var parameter = {"parameter": [{"name":"ref", "value":"origin/master"}]};
var postData;
if (!_.isEmpty(parameter)) {
var jsonParametersString = JSON.stringify(parameter);
jobOptions.headers = {
'Authorization':auth,
'Content-Type': 'application/x-www-form-urlencoded',
};
jobOptions.url += '?token=jobRemoteTriggerToken';
postData = "json="+jsonParametersString;
console.log("postData = " + postData);
}
var callback;
var responseCB;
makeRequest(jobOptions, callback, responseCB, postData) ;
It is based on your code. I removed the querystring - it seems that it returned an empty string when performed on the parameters object. I change /buildWithParameters to /build - it didn't work the other way.
In addition, verify that when you pass the 'Content-Length' in the header, it doesn't truncated your json parameters object (I removed it ).
also note that I used the user API token, that you can get at http://yourJenkinsUrl/me/configure and click the "Shown API Token" button.
Not sure about this, as I don't know Node.js -- but maybe this fits: the Jenkins remote access API indicates that the parameter entity in the json request must point to an array, even if there's just one parameter to be defined.
Does the change below fix the problem (note the angle brackets around parameters)?
[...]
var jsonParametersString = JSON.stringify({"parameter": [parameters]});
[...]
I want to write a test for this node.js funcion,This has two arguments request and response. I set the request variable . But dont know how to set response variable.
function addCustomerData(request, response) {
common.getCustomerByMobile(request.param('mobile_phone'), function (customerdata) {
if (!customerdata) {
var areaInterest = request.param('area_interest');
var customerInfo = {userType: request.param('userType'),
firstName : request.param('first_name'),
middleName : request.param('middle_name'),
lastName : request.param('last_name'),
email : request.param('email'),
mobilePhone : request.param('mobile_phone'),
uniqueName : request.param('user_name'),
company : request.param('company')
};
if(customerInfo.email){
customerInfo.email = customerInfo.email.toLowerCase();
}
if(customerInfo.uniqueName){
customerInfo.uniqueName = customerInfo.uniqueName.toLowerCase();
}
if(areaInterest) {
customerInfo.areaInterest = '{' + areaInterest + '}';
}else
areaInterest = null;
addCustomer(request, response, customerInfo, function (data) {
request.session.userId = data;
return response.send({success: true, message: 'Inserted successfully'});
}
);
} else {
return response.send({success: false, message: 'User with this mobile number already exists'});
}
});
}
I wrote the test as follows
describe('signup', function(){
describe('#addCustomer()', function(){
before(function (done) {
request = {};
request.data = {};
request.session = {};
request.data['userType'] = '3';
request.data['first_name'] = 'Shiji';
request.data['middle_name'] = '';
request.data['last_name'] = 'George';
request.data['email'] = 'shiji#lastplot.com';
request.data['mobile_phone'] = '5544332333';
request.data['user_name'] = 'shiji';
request.session['imageArray'] = [];
request.param=function(key){
// Look up key in data
return this.data[key];
};
request1 = {};
request1.data = {};
request1.session = {};
request1.data['area_interest']=["aluva","ernakulam"];
request1.data['userType'] = '1';
request1.data['first_name'] = 'Hari';
request1.data['middle_name'] = 'G';
request1.data['last_name'] = 'Ganesh';
request1.data['email'] = 'hari#lastplot.com';
request1.data['mobile_phone'] = '5544332321';
request1.data['user_name'] = 'hariganesh';
request1.data['company'] = 'HG Realestate';
request1.session['imageArray'] = [];
request1.param=function(key){
// Look up key in data
return this.data[key];
};
done();
});
it('It should list the matching properties', function(done){
async.parallel([
function(callback) {
signup.addCustomerData(request, response, function (result, err) {
should.not.exist(err);
should.exists(result);
callback();
});
},
function(callback) {
signup.addCustomerData(request1, response, function (result, err) {
should.not.exist(err);
should.exists(result);
callback();
});
}],function(){
done();
});
});
But i got the error as response has no method send()
Thanks in Advance.
Your addCustomerData function does not have a callback, it just calls respond.send(). You need to mock the response object, as well as the send method, and put your tests inside of it, but you won't be able to use async.parallel() as, like I already mentioned, your function does not have a callback parameter. If you're testing request/response functions, I suggest you look into Supertest https://github.com/visionmedia/supertest which is widely used for cases like this.
The standard says headers are case insensitive.
Ruby and node both force lower case headers.
We are using an outside server program that expects headers 'AuthToken' to be case sensitive, using .NET framework, and apparently both don't follow standards. We need headers to be up case in this instance.
At the time of writing, the following setHeader was copied from
the _http_outgoing page of node's core lib
var http = require('http');
http.OutgoingMessage.prototype.setHeader = function(name, value) {
if (arguments.length < 2) {
throw new Error('`name` and `value` are required for setHeader().');
}
if (this._header) {
throw new Error('Can\'t set headers after they are sent.');
}
// NO LOWER CASE
var key = name//.toLowerCase();
this._headers = this._headers || {};
this._headerNames = this._headerNames || {};
this._headers[key] = value;
this._headerNames[key] = name;
// Since we're re-defining the method, we can't use this part anymore
//if (automaticHeaders[key]) {
// this._removedHeader[key] = false;
//}
};
Commented out part for lowercase
So.. if you get this problem. require http and override this method with the version you're currently using.
It should then work properly. You could do a similar thing of overriding a method in ruby, but it won't be a quick and easy
Then this will work:
require('request')
request({url: 'http://myurl.com', headers: {UpperCaseWorks: 'Yay'}})
EDIT: here's for the newer version of node
OutgoingMessage.prototype.setHeader = function setHeader(name, value) {
if (this._header) {
throw new errors.Error('ERR_HTTP_HEADERS_SENT', 'set');
}
validateHeader(name, value);
if (!this[outHeadersKey])
this[outHeadersKey] = {};
// no more lower case
const key = name//.toLowerCase();
this[outHeadersKey][key] = [name, value];
switch (key.length) {
case 10:
if (key === 'connection')
this._removedConnection = false;
break;
case 14:
if (key === 'content-length')
this._removedContLen = false;
break;
case 17:
if (key === 'transfer-encoding')
this._removedTE = false;
break;
}
};
Looks like it calls this local method, which'll need to be defined as well
function validateHeader(name, value) {
let err;
if (typeof name !== 'string' || !name || !checkIsHttpToken(name)) {
err = new errors.TypeError('ERR_INVALID_HTTP_TOKEN', 'Header name', name);
} else if (value === undefined) {
err = new errors.TypeError('ERR_HTTP_INVALID_HEADER_VALUE', value, name);
} else if (checkInvalidHeaderChar(value)) {
debug('Header "%s" contains invalid characters', name);
err = new errors.TypeError('ERR_INVALID_CHAR', 'header content', name);
}
if (err !== undefined) {
Error.captureStackTrace(err, validateHeader);
throw err;
}
}
And this
const { outHeadersKey } = require('internal/http');
Anyway, check your version of node for what you are overriding
Piggybacking on Funkodebat's answer, here's my solution for Node 16:
const http = require('http');
// https://github.com/nodejs/node/blob/v16.x/lib/_http_outgoing.js#L574-L587
const { validateHeaderName, validateHeaderValue } = http;
http.OutgoingMessage.prototype.setHeader = function setHeader(name, value) {
if (this._header) {
throw new Error('Cannot set headers after they are sent to the client');
}
validateHeaderName(name);
validateHeaderValue(name, value);
// Extra logic to find kOutHeaders symbol in `this`
const kOutHeaders = Object.getOwnPropertySymbols(this).find(
(sym) => sym.toString() === 'Symbol(kOutHeaders)'
);
let headers = this[kOutHeaders];
if (headers === null) this[kOutHeaders] = headers = Object.create(null);
headers[name] = [name, value]; // toLowerCase removed from here
return this;
};
By looking at the source of NodeJS library on github, you do not need to override the OutgoingMessage.prototype.setHeader
Instead of passing the headers as an Object, you should send them as an Array. Here is a working example :
const http = require('http');
const postData = JSON.stringify({
'msg': 'Hello World!'
});
const options = {
hostname: 'www.google.com',
port: 80,
path: '/upload',
method: 'POST',
// use an Array instead of Object to avoid lowercase transformation
headers: [
['Host' ,'localhost' ],
['X-CustomHeaderFancy' , 'valueForFancyHeader'],
['Content-Type', 'application/json'],
['Content-Length', Buffer.byteLength(postData)]
}
};
const req = http.request(options, (res) => {
console.log(`STATUS: ${res.statusCode}`);
console.log(`HEADERS: ${JSON.stringify(res.headers)}`);
res.setEncoding('utf8');
res.on('data', (chunk) => {
console.log(`BODY: ${chunk}`);
});
res.on('end', () => {
console.log('No more data in response.');
});
});
req.on('error', (e) => {
console.error(`problem with request: ${e.message}`);
});
// Write data to request body
req.write(postData);
req.end();
inside the source code of https://github.com/nodejs/node/blob/v16.x/lib/_http_client.js#L249 there is a test to know if the headers are an array, if it is the case, then it bypass the lowercase transformation.
I do not know why it is not documented ? It's a very useful feature.
The title should be pretty self explanetory.
For debugging purposes, I would like express to print the response code and body for every request serviced. Printing the response code is easy enough, but printing the response body is trickier, since it seems the response body is not readily available as a property.
The following does NOT work:
var express = require('express');
var app = express();
// define custom logging format
express.logger.format('detailed', function (token, req, res) {
return req.method + ': ' + req.path + ' -> ' + res.statusCode + ': ' + res.body + '\n';
});
// register logging middleware and use custom logging format
app.use(express.logger('detailed'));
// setup routes
app.get(..... omitted ...);
// start server
app.listen(8080);
Of course, I could easily print the responses at the client who emitted the request, but I would prefer doing at the server side too.
PS: If it helps, all my responses are json, but hopefully there is a solution that works with general responses.
Not sure if it's the simplest solution, but you can write a middleware to intercept data written to the response. Make sure you disable app.compress().
function logResponseBody(req, res, next) {
var oldWrite = res.write,
oldEnd = res.end;
var chunks = [];
res.write = function (chunk) {
chunks.push(chunk);
return oldWrite.apply(res, arguments);
};
res.end = function (chunk) {
if (chunk)
chunks.push(chunk);
var body = Buffer.concat(chunks).toString('utf8');
console.log(req.path, body);
oldEnd.apply(res, arguments);
};
next();
}
app.use(logResponseBody);
I ran into an issue using the approach suggested by Laurent. Sometimes chunk is a string, and therefore causes problems in the call to Buffer.concat(). Anyways, I found a slight modification fixed things:
function logResponseBody(req, res, next) {
var oldWrite = res.write,
oldEnd = res.end;
var chunks = [];
res.write = function (chunk) {
chunks.push(new Buffer(chunk));
oldWrite.apply(res, arguments);
};
res.end = function (chunk) {
if (chunk)
chunks.push(new Buffer(chunk));
var body = Buffer.concat(chunks).toString('utf8');
console.log(req.path, body);
oldEnd.apply(res, arguments);
};
next();
}
app.use(logResponseBody);
The above accepted code has issues with ES6.
Use the below code
function logReqRes(req, res, next) {
const oldWrite = res.write;
const oldEnd = res.end;
const chunks = [];
res.write = (...restArgs) => {
chunks.push(Buffer.from(restArgs[0]));
oldWrite.apply(res, restArgs);
};
res.end = (...restArgs) => {
if (restArgs[0]) {
chunks.push(Buffer.from(restArgs[0]));
}
const body = Buffer.concat(chunks).toString('utf8');
console.log({
time: new Date().toUTCString(),
fromIP: req.headers['x-forwarded-for'] ||
req.connection.remoteAddress,
method: req.method,
originalUri: req.originalUrl,
uri: req.url,
requestData: req.body,
responseData: body,
referer: req.headers.referer || '',
ua: req.headers['user-agent']
});
// console.log(body);
oldEnd.apply(res, restArgs);
};
next();
}
module.exports = logReqRes;
You can use express-winston and configure using:
expressWinston.requestWhitelist.push('body');
expressWinston.responseWhitelist.push('body');
Example in coffeescript:
expressWinston.requestWhitelist.push('body')
expressWinston.responseWhitelist.push('body')
app.use(expressWinston.logger({
transports: [
new winston.transports.Console({
json: true,
colorize: true
})
],
meta: true, // optional: control whether you want to log the meta data about the request (default to true)
msg: "HTTP {{req.method}} {{req.url}}", // optional: customize the default logging message. E.g. "{{res.statusCode}} {{req.method}} {{res.responseTime}}ms {{req.url}}"
expressFormat: true, // Use the default Express/morgan request formatting, with the same colors. Enabling this will override any msg and colorStatus if true. Will only output colors on transports with colorize set to true
colorStatus: true, // Color the status code, using the Express/morgan color palette (default green, 3XX cyan, 4XX yellow, 5XX red). Will not be recognized if expressFormat is true
ignoreRoute: function (req, res) { return false; } // optional: allows to skip some log messages based on request and/or response
}));
This solution might not be heavyweight enough for some use cases, but I think it's the simplest. It's also typescript compatible. If you only want logging for JSON responses, all you have to do is substitute the send method with the json method in the code below. Note, I took inspiration from Jonathan Turnock's answer, but made it simpler.
app.use((req, res, next) => {
let send = res.send;
res.send = c => {
console.log(`Code: ${res.statusCode}`);
console.log("Body: ", c);
res.send = send;
return res.send(c);
}
next();
});
I found the simplest solution to this problem was to add a body property to the res object when sending the response, which can later be accessed by the logger. I add this to my own namespace that I maintain on the req and res objects to avoid naming collisions. e.g.
res[MY_NAMESPACE].body = ...
I have a utility method that formats all responses to my standardized API/JSON response, so adding this one liner there exposed the response body when the logging gets triggered by onFinished event of res.
Most of the suggestions seemed a little sledgehammer, Spent some time with this issue tonight and wrote up my findings after digging into a few libs to help make something bespoke.
//app.js
...
app.use(requestLoggerMiddleware({ logger: console.log }));
app.get(["/", "/api/health"], (req, res) => {
res.send({ message: "OK", uptime: process.uptime() });
...
});
// middleware.js
/**
* Interceptor function used to monkey patch the res.send until it is invoked
* at which point it intercepts the invokation, executes is logic such as res.contentBody = content
* then restores the original send function and invokes that to finalize the req/res chain.
*
* #param res Original Response Object
* #param send Original UNMODIFIED res.send function
* #return A patched res.send which takes the send content, binds it to contentBody on
* the res and then calls the original res.send after restoring it
*/
const resDotSendInterceptor = (res, send) => (content) => {
res.contentBody = content;
res.send = send;
res.send(content);
};
/**
* Middleware which takes an initial configuration and returns a middleware which will call the
* given logger with the request and response content.
*
* #param logger Logger function to pass the message to
* #return Middleware to perform the logging
*/
const requestLoggerMiddleware = ({ logger }) => (req, res, next) => {
logger("RECV <<<", req.method, req.url, req.hostname);
res.send = resDotSendInterceptor(res, res.send);
res.on("finish", () => {
logger("SEND >>>", res.contentBody);
});
next();
};
module.exports = { requestLoggerMiddleware };
Full working example and article in the git repo
https://github.com/JonathanTurnock/ReqResLoggingExample
I actually made this nifty little npm to solve this exact problem, hope you like it!
https://www.npmjs.com/package/morgan-body
May be this would help someone who is looking to get the response logged
So, we use the middleware to intercept the request just before being served to the client. Then if we are using res.send method to send the data, override the method in the middleware and make sure to console log the body. If you are planning to use res.send alone then this should work fine, but incase if you use res.end or res.sendFile, then overwrite those methods and log only the required things (obviously logging the entire octet stream of file should never be logged for perfomance purposes.
Here I use pino as the logger. Created it as singleton service.
// LoggingResponseRouter.js
var loggingResponseRouter = require('express').Router();
var loggingService = require('./../service/loggingService');
var appMethodInstance = require('./../constants/appMethod');
var path = require('path');
var fs = require('fs');
var timeZone = require('moment-timezone');
var pino = require('pino')();
loggingResponseRouter.use((req, res, next) => {
// set the fileName it needs to log
appMethodInstance.setFileName(__filename.substring(__filename.lastIndexOf(path.sep) + 1, __filename.length - 3));
//loggingService.debugAndInfolog().info('logging response body', appMethodInstance.getFileName());
let send = res.send;
res.send = function(body){
loggingService.debugAndInfolog().info('Response body before sending: ', body);
send.call(this, body);
}
next();
});
module.exports = loggingResponseRouter;
Main file - Main.js
const corsRouter = require('./app/modules/shared/router/corsRouter');
const logRequestRouter = require('./app/modules/shared/router/loggingRequestRouter');
const loggingResponseRouter = require('./app/modules/shared/router/loggingResponseRouter');
const express = require('express');
var path = require('path');
const app = express();
// define bodyparser middleware
const bodyParser = require('body-parser');
const port = process.env.PORT || 3000;
// Now use the middleware prior to any others
app.use(bodyParser.json());
// use this to read url form encoded values as wwell
app.use(bodyParser.urlencoded({extended:true}));
console.log('before calling cors router in main js');
app.use(corsRouter);
app.use(logRequestRouter);
app.use(loggingResponseRouter);
app.get('/api', (req, res) => {
console.log('inside api call');
res.send('aapi');
});
app.listen(port, () => {
console.log('starting the server');
});
And this is the loggingService - loggingService.js
var pino = require('pino');
var os = require('os');
var appMethodInstance = require('./../constants/appMethod');
var pinoPretty = require('pino-pretty');
var moment = require('moment');
var timeZone = require('moment-timezone');
class Logger{
constructor(){
this.appName = 'Feedback-backend';
this.filenameval = '';
}
getFileName(){
console.log('inside get filename');
console.log(appMethodInstance.getFileName());
if(appMethodInstance.getFileName() === null || appMethodInstance.getFileName() === undefined){
this.filenameval = 'bootstrapping...'
}else {
this.filenameval = appMethodInstance.getFileName();
}
console.log('end');
return this.filenameval;
}
debugAndInfolog(){
return pino({
name: 'feedback-backend',
base: {
pid: process.pid,
fileName: this.getFileName(),
moduleName: 'modulename',
timestamp: timeZone().tz('America/New_York').format('YYYY-MM-DD HH:mm:ss.ms'),
hostName: os.hostname()
},
level: 'info',
timestamp: timeZone().tz('America/New_York').format('YYYY-MM-DD HH:mm:ss.ms'),
messageKey: 'logMessage',
prettyPrint: {
messageKey: 'logMessage'
}
});
}
errorAndFatalLog(){
return pino({
name: 'feedback-backend',
base: {
pid: process.pid,
fileName: this.getFileName(),
moduleName: 'modulename',
timestamp: timeZone().tz('America/New_York').format('YYYY-MM-DD HH:mm:ss.ms'),
hostName: os.hostname()
},
level: 'error',
timestamp: timeZone().tz('America/New_York').format('YYYY-MM-DD HH:mm:ss.ms'),
prettyPrint: {
messageKey: 'FeedbackApp'
}
});
}
}
module.exports = new Logger();
Typescript solution based on Laurent's answer:
import { NextFunction, Request, Response } from 'express-serve-static-core';
//...
app.use(logResponseBody);
function logResponseBody(req: Request, res: Response, next: NextFunction | undefined) {
const [oldWrite, oldEnd] = [res.write, res.end];
const chunks: Buffer[] = [];
(res.write as unknown) = function(chunk) {
chunks.push(Buffer.from(chunk));
(oldWrite as Function).apply(res, arguments);
};
res.end = function(chunk) {
if (chunk) {
chunks.push(Buffer.from(chunk));
}
const body = Buffer.concat(chunks).toString('utf8');
console.log(new Date(), ` ↪ [${res.statusCode}]: ${body}`);
(oldEnd as Function).apply(res, arguments);
};
if (next) {
next();
}
}
I have similar need to this question.
Based on accepted answer, I modify it with proxy and trace response body only when it's json.
const traceMiddleware = (req, res, next) => {
const buffers = []
const proxyHandler = {
apply(target, thisArg, argumentsList) {
const contentType = res.getHeader('content-type')
if (
typeof contentType === 'string' && contentType.includes('json') && argumentsList[0]
) {
buffers.push(argumentsList[0])
}
return target.call(thisArg, ...argumentsList)
}
}
res.write = new Proxy(res.write, proxyHandler)
res.end = new Proxy(res.end, proxyHandler)
res.on('finish', () => {
// tracing logic inside
trace(req, res, Buffer.concat(buffers).toString('utf8'))
})
next()
}