I'm trying to create a route for the following URL:
http://localhost:5000/api/querystring?parameter1=value1¶meter2=value2
My route looks like this:
app.get('/api/:querystring/:parameter1?/:parameter2?', function(req, res) {
// do stuff
})
How can I create a route that matches the given URL?
You can't include query string parts in the route ... you will have to leave them off.
app.get('/api/querystring' ...
Then in the callback you can look at req.query to see the parameters. If you were to compare to the query, the order of the query string parameters would matter. It shouldn't.
If you want /api/querystring?parameter1=foo and /api/querystring?parameter2=bar to use different routes, you will have to handle this by calling separate functions within the app.get route callback above.
Related
If I have two REST endpoints:
app.get('/something/:id', ...handlers);
app.get('/something/else', ...handlers);
And I send a request to http://host:port/something/else
Is there a way to make Express router execute the endpoint with absolute path first (/something/else) before executing the one that matches the query params (/something/:id)?
I understand that I can reverse the order of invocation and specify the endpoint with query params last. But logically speaking, absolute path should take priority over query params and I believe that's the default behaviour for Koa.js
Just put the more specific route first and the wildcard route second. Routes are matched in order and the first one that matches handles the request and the others are not then processed. So, put the more specific route for /something/else before the /something/:id and you will see the /something/else route work properly when that's the URL.
// put wildcard route last and more specific route definitions first
// routes are matched in the order they are defined
app.get('/something/else', ...handlers);
app.get('/something/:id', ...handlers);
This does raise the question why you have designed this potential conflict into your URL scheme in the first place. You've essentially overloaded the id namespace and have reserved at least one id value for your own use. This can be managed by careful ordering of the route definitions, but it would generally be better if you didn't have this conflict in your URL design in the first place.
Is there a way to make Express router execute the endpoint with absolute path first ('/something/else') before executing the one that matches the query params ('/something/:id')?
Yes, define the more specific route first.
I understand that I can reverse the order of invocation and specify the endpoint with query params last. But logically speaking, absolute path should take priority over query params and I believe that's the default behaviour for Koa.js
You asked about Express. It matches routes in the order you've defined them. It doesn't try to guess which route it "thinks" you want to match first. It lets you define that exactly via the order of your route definitions.
I don't know Koa.js well, but there is this in the doc for Koa2: Middleware is now always run in the order declared by .use() (or .get(), etc.), which matches Express 4 API.
There are no specific route matching rules for express.js to match the routes.It goes and try to match every registered route with incoming request path and calls route handlers for all matched paths. Thus the following code will work.
app.get('/something/:id', (req, res, next) => {
console.log(`Calling with param ${req.params.id}`);
next(); // if you remove next from here it will not call the rest of the handlers
});
app.get('/something/else', (req, res, next) => {
console.log(`Calling with else`);
next();
});
Output:
Thus the only way to make sure the routes match exactly, define routes in their specific order.
app.get('/something/else', ...handlers);
app.get('/something/:id', ...handlers);
I am new to Express and Mongoose. I am currently working on my first project, that is not a tutorial, and I has run into a problem.
I have multiple routes, they are defined in the index.js like this:
app.use('/api/client',require('./routes/client'));
app.use('/api/host',require('./routes/host'));
In the routes, there are multiple verbs that work, like PUT and POST.
Here is the problematic route (I am trying to do more that what is presented here, but what is presented here, does not work as well):
router.get('/ama/:id', function (req, res, next) {
Ama.findById(req.params.id).then(function(Ama){
res.send(Ama);
});
});
This should work, right? It should return the document in the database, with that id. And I have checked if the document excists, probably around a 100 times.
Now, if I simplify the route greatly, removing the id, and make a simple response, the route works:
router.get('/ama', function (req, res, next) {
res.send({type:"GET"});
});
It's so wierd, that as soon as i add the parameter, i get a:
<pre>Cannot GET /api/host/ama</pre>
in Postman.
Any ideas? Mongod is running, my other routes are working.
It looks like you're trying to retrieve this URL:
/api/host/ama?id=SOMEID
However, you have a route declared for URL's that look like this:
/api/host/ama/SOMEID
In other words, the id is part of the path of the URL, and not passed as a query string parameter (that's what /:id means: it's a placeholder for a part of the URL that the route should match).
So either change the request-URL by adding the id to the path (/api/host/ama/58e395a8c6aaca2560089ce7), or rewrite your route handler to something like this:
router.get('/ama', function (req, res, next) {
Ama.findById(req.query.id).then(function(Ama){
res.send(Ama);
});
});
However, I would advise using the former (making the id part of the URL).
There are two problems here:
router.get('/ama/:id', function (req, res, next) {
Ama.findById(req.params.id).then(function(Ama){
res.send(Ama);
})
res.send(req.params.id)*/
});
First of all, res.send(req.params.id) will run before the res.send(Ama); and it will probably send the entire response. You are missing the .exec() method call (see the answer by Cédric De Dycker for details). The res.send() can only be reliably used once. Maybe you want res.write() instead if you want to wrte multiple things. Also you don't handle the promise rejection so you don't handle database errors. To know why you should always handle the promise rejections see this answer: Should I refrain from handling Promise rejection asynchronously?
The parameter should work fine but it seems you missed to add .exec to your query
Ama.findById(req.params.id).exec().then(function(Ama){
res.send(Ama);
})
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'}]
});
How can i get the URI and use it as params in nodejs. I am using express.
http://localhost:3000/getParams/param1/param2/param3/paramN
I want to get "/param1/param2/param3/paramN".
This is my current code:
app.get("/getParams/:params", test.params);
Thanks!
You can access the full path as one param, or you can access each segment as a separate param. To get as one param:
app.get('/mysvc/:input(*)', function(req, res)
{
console.log(req.params.input);
// ...
});
Notice the route which says everything (regex match of *) after /mysvc/ will be mapped to the input reques param. Then you can reference it via req.params
In this example, a request to /mysvc/foo/bar will output foo/bar
If you want to get each segment as a separate param then:
app.get('/mysvc/:param1/:param2'
access via req.params.param1, req.params.param2, etc...
In express parameters are available in the req object req.params.parameterName so in your case you can access it within the route like this req.params.params.
The params that you can access from the handler depends upon the route definitions. If you route is like
/my/:one/:two/:three
then you can access them as
req.params.one
req.params.two
req.params.three