every time i do an http request to any route in my app i got in my console the route method , execution time and and anther number that i have no idea what it means(will love to know) .
does anyone know how can i use this data? i want to record routes that takes more then x time so i can improve those routes.
i try do find from console. in the express framework as i assumed its coming from there but no luck
As I can see from the screenshot, you're probably using morgan middleware.
By default it logs all the requests in the dev format which is -
:method :url :status :response-time ms - :res[content-length]
So according to your screenshot -
Patch is the method.
/trades/ is the url path.
200 is the status code.
5.893 is the response time.
2 is content length of the response.
I think you were asking about content length. It's basically the size of your response body in bytes.
Looking at the source, Morgan keeps track of the request start / end times by adding instance properties to the request.
The request time looks like it's calculated when the response starts to write headers, as such you would need to follow the same pattern....but only after Morgan has been configured e.g.
import onHeaders from 'on-headers';
import logger from 'morgan';
app.use(logger()); // configure morgan
app.use((req, res, next) =>
onHeaders(res, () => {
console.log(logger['response-time'](req, res)); // this may work
// alternatively, use req._startAt / res._startAt to work it out (see source for implementation)
});
return next();
)
The other alternative of course is just do it yourself with custom middleware, or use something off the shelf like response-time
Related
I have a basic misunderstanding regarding asynchronic calls using express and middlewares and i would really appreciate some help understanding it.
Suppose we have this code:
var express = require('express')
var cookieParser = require('cookie-parser')
var app = require('express')
var router = express.Router()
app.use(function timeLog (req, res, next) {
req.requestTime = Date.now()
next()
})
app .use(express.json());
app .use(express.urlencoded());
app.use(cookieParser())
router.post('/hello', function (req, res) {
//write async to file
res.send('bye')
})
Now, when the client calls this endpoint "hello":
are the middlewares which defined in App-level called asynchronicaly? I understood that they do(because they are called "Callbacks" in the documentation... so basically before reaching the router: parsing cookies, parsing json to req.body and adding req.requestTime will run asynchronicaly and then will be routed to '/hello' end point.
after routing, is the callback will run asynchronicaly? if yes, then how in this case the request is not left hanging? i see that the response is being terminated inside a body of a callback... how this make any sense? :(
would somebody please explain to me this flow?
I will try to explain how I understood "async calls" through this code above: lets say alot of users trying to get this end point. all these calls added to the call stack, then because of these callbacks are async, then they are moved to event Queue/table and will be handled after the call stack will be "empty". if this is the case, how the first user will ever get a response? the requestTime done async, parsing the json done async and when reaching the router, the callback is done async.... so when the first user will ever get a repsone if all these async calls located inside the event Queue/table and they will be handled only after the callstack is empty? what am i missing here?
Thanks.
The middleware doesn't appear to be asynchronous of its own. In other words, as you said in your comment on another answer, it is not forcing each layer in the expressjs "stack" of middleware/handlers into a separate frame in the JavaScript event queue.
If you trace the next() function in a .use(), there are a couple of setImmediates fairly early on to handle "exit router" or "no more layers," but then you get into a while loop on a stack of handlers. This is happening at around this point in the code.
So if all your middleware was similar to this section, all middleware etc would happen in the same frame within the event queue:
app.use(function(req, res, next){
console.log('synchronous layer');
next();
});
Whereas a step like this next one would put the next into a separate frame in the event queue, and potentially allow the process to handle other frames that may be queued up.
app.use(function(req, res, next){
setImmediate(()=> {
console.log('setImmediate puts this next() into a separate frame in the event queue');
next();
});
});
I can't imagine this would normally be a problem. Most things that would happen in middleware that might take some time (a database call etc) are very likely all going to be happening asynchronously (in a way that puts the next into a new frame in the event queue). But it is something worth considering when you're adding middleware...
All those middleware are using the continuation passing style. So basically they COULD run asynchonous. But they don't have to. It depends on, whether those middlewares are doing some IO. You could take a look into the code to check how the functions behave exactly, but at least, this does not matter. Just keep in mind, that they COULD run asynchronous.
I'm trying to use Express Middleware to validate that users are authorized for some of my requests. But, some requests do not require any validation. In a router, I have something like this:
// Routes that end in /transactions
module.exports = function(router, isAuthenticated, acl) {
router.post('/transactions', isAuthenticated, acl.isAdminOrFrom, TransactionHandler.transactions.post);
// Get most recent transactios by general, category, or userId
router.get('/transactions/:timeStamp', isAuthenticated, TransactionHandler.transactions.findMostRecent);
router.get('/transactions/categories/:category/:timeStamp', isAuthenticated, TransactionHandler.transactions.category.findMostRecent);
router.get('/transactions/users/:user_id/:filter/public/:timeStamp', isAuthenticated, TransactionHandler.transactions.userId.findMostRecent);
// Get the total reps traded on Repcoin so far
router.get('/transactions/totaltraded', TransactionHandler.transactions.total.get);
Notice that the last route I've listed does not have isAuthenticated there. But, putting that middleware in the above routes has made it act in the last one as well. I also tried something like this:
router.use('/transactions/:timeStamp', TransactionHandler.transactions.findMostRecent);
router.get('/transactions/:timeStamp', TransactionHandler.transactions.findMostRecent);
But the middleware still seems to execute on anything that calls router.get(). How can I use my middleware on a per-route basis?
I think this could be because router.post('/transactions', ... matches before router.get('/transactions/totaltraded', .... You could try to change the ordering so that the latter route definition is before former and see if it makes any difference. Also try to debug which handlers it triggers on a given route.
I have an nodejs server with express and mongoose and I'd like to use method GET for search accoring to criteria which I'd like to provide as JSON object does anyone can help me how to implement it?
Or maybe should I use POST or PUT to make it?
http://hostname/modelname?criteria1=1&criteria2=2
router.route('/modelname')
.get(function (req, res, next) {
req.query.criteria1 === 1 // true
req.query.criteria2 === 2 // true
});
If you are unsure of what HTTP VERB you'd want to use,
POST - is primarily used for creating resources on the server
PUT - is used to update an existing resource
GET- to retrieve a resource
I would use GET in this case
GET http://myhost.com?q=word1+word2+word3+word4
app.get('*', function(req, res) {
// do something with the req.query.q array
});
You've got two options - using HTTP GET params or encoding whole criteria as JSON string and passing that string.
First option, by using params:
?crit[foo.bar][$eq]=abc&crit[foo.baz][$ne]=def
You can read it in nodejs/express via req.query.crit. But this is bad idea because there's no way of retaining data types. For example number 1 becomes string "1". Don't use it - MongoDB is data type sensitive so query {"foo.bar":{$eq:1}} is completely different from {"foo.bar":{$eq:"1"}}
Second option is to urlencode JSON criteria:
?critJSON=%7B%22foo.bar%22%3A%7B%22%24eq%22%3A%20%22abc%22%7D%2C%22foo.baz%22%3A%7B%22%24ne%22%3A%20%22def%22%7D%7D
And parse it on nodejs/express side:
var crit = JSON.parse(req.query.critJSON)
This way your data types are retained and it will work as expected.
Is there a clean way to handle key/value query params in Express 4 routes?
router.route('/some/route?category=:myCategory')
I want to detect the presence of 'myCategory' in this route and use router.param([name], callback) to handle the associated logic.
router.param('myCategory', function(req, res, next, id) {
/* some logic here... */
});
The above 'router.param()' works fine if I have a route like /some/route/:myCategory but fails if I use
router.route('/some/route?category=:myCategory')
Am I doing something wrong here, or is this not supported in the Express 4 router out of the box?
Express treats properties after a ? as query params. So for:
/some/route?mycategory=mine
you would have to use:
req.query.mycategory or req.query['mycategory']
See this for more examples.
I am fairly new to the express framework. I couldn't find the documentation for application.post() method in the express API reference. Can someone provide a few examples of all the possible parameters I can put in the function? I've read a couple sites with the following example, what does the first parameter mean?
I know the second parameter is the callback function, but what exactly do we put in the first parameter?
app.post('/', function(req, res){
Also, let's say we want the users to post(send data to our server) ID numbers with a certain format([{id:134123, url:www.qwer.com},{id:131211,url:www.asdf.com}]). We then want to extract the ID's and retrieves the data with those ID's from somewhere in our server. How would we write the app.post method that allows us to manipulate the input of an array of objects, so that we only use those object's ID(key) to retrieve the necessary info regardless of other keys in the objects. Given the description of the task, do we have to use app.get() method? If so, how would we write the app.get() function?
Thanks a lot for your inputs.
1. app.get('/', function(req, res){
This is telling express to listen for requests to / and run the function when it sees one.
The first argument is a pattern to match. Sometimes a literal URL fragment like '/' or '/privacy', you can also do substitutions as shown below. You can also match regexes if necessary as described here.
All the internal parts of Express follow the function(req, res, next) pattern. An incoming request starts at the top of the middleware chain (e.g. bodyParser) and gets passed along until something sends a response, or express gets to the end of the chain and 404's.
You usually put your app.router at the bottom of the chain. Once Express gets there it starts matching the request against all the app.get('path'..., app.post('path'... etc, in the order which they were set up.
Variable substitution:
// this would match:
// /questions/18087696/express-framework-app-post-and-app-get
app.get('/questions/:id/:slug', function(req, res, next){
db.fetch(req.params.id, function(err, question){
console.log('Fetched question: '+req.params.slug');
res.locals.question = question;
res.render('question-view');
});
});
next():
If you defined your handling functions as function(req, res, next){} you can call next() to yield, passing the request back into the middleware chain. You might do this for e.g. a catchall route:
app.all('*', function(req, res, next){
if(req.secure !== true) {
res.redirect('https://'+req.host+req.originalUrl);
} else {
next();
};
});
Again, order matters, you'll have to put this above the other routing functions if you want it to run before those.
I haven't POSTed json before but #PeterLyon's solution looks fine to me for that.
TJ annoyingly documents this as app.VERB(path, [callback...], callback in the express docs, so search the express docs for that. I'm not going to copy/paste them here. It's his unfriendly way of saying that app.get, app.post, app.put, etc all have the same function signature, and there are one of these methods for each supported method from HTTP.
To get your posted JSON data, use the bodyParser middleware:
app.post('/yourPath', express.bodyParser(), function (req, res) {
//req.body is your array of objects now:
// [{id:134123, url:'www.qwer.com'},{id:131211,url:'www.asdf.com'}]
});