Express js get parameters from root of URL (Not as simple as req.params)

Question

I've made an api and I've routed it as follows:

In the main routes file:

  //with sub-route
  app.use('/api/test/:test', require('./api/test'));

  //Without sub-route
  app.use('/api/test2/:test', function(req, res){
    console.log('in test', req.params, req.body);
    return res.status(200).json({params: req.params, body: req.body});
  });

Accessing the second route displays the :test in req.params, as expected.

In the modular routes folder ('./api/test') I have a sub-router (index.js) which looks like this:

router.get('/:test2', controller.getItem);

with a handler:

exports.getItem = function getItem(req, res) {
  console.log('in getItem \nreq.params', req.params, '\nreq.body: ', req.body);
  return res.status(200).json({yes: 'yes', params: req.params, body: req.body});
};

So the first url, which has no sub-routing is: /api/test2/:test and logs out whatever you put in place of :test in req.params.

The second url, which has sub-routing is: /api/test/:test/:test2, but when you send your get request only :test2 appears in req.params.

It seems that if you use this pattern any variables in the 'root' of the route (ie in the primary router) are not picked up.

Is there a way to fix this?

Thanks

Amberlamps · Accepted Answer · 2015-07-21 06:04:24Z

2

You will need a middleware to fix this for you:

function paramFix(req, res, next) {
    req._params = req.params;
    next();
}
app.use('/api/test/:test', paramFix, require('./api/test'));

And then use req._params.test in your last callback function.

So reflect multiple levels of mounting you can extend your middleware like this:

function paramFix(req, res, next) {
    req._params = req._params || {};
    for (var key in req.params) {
        if (req.params.hasOwnProperty(key)) {
            req._params[key] = req.params[key];
        }
    }
    next();
}
app.use('/api/test/:test', paramFix, require('./api/test'));

edited Jul 21, 2015 at 6:04

answered Jul 20, 2015 at 21:26

Amberlamps

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3 Comments

Plato Over a year ago

I suggest you do req._params = req._params || [] then req._params.push(req.params). This way it works with multiple levels of mounting.

user1775718 Over a year ago

Thanks. :) I heard they're going to fix this up in a future release; I really hope so...

Amberlamps Over a year ago

@Plato: But then you have an array of objects and you cannot access req._params.test anymore. I updated my answer to reflect multiple levels of mounting.

Subrat · Accepted Answer · 2020-04-20 06:54:34Z

1

express.js (>= v4.5.0+) provides a direct solution without having to implement middleware. https://expressjs.com/en/api.html#express.router

While creating the router, pass the mergeParams flag.

var router = express.Router({ mergeParams: true })

mergeParams preserves the req.params values from the parent router. If the parent and the child have conflicting param names, the child’s value takes precedence.

edited Apr 20, 2020 at 6:54

answered Apr 18, 2020 at 4:35

Subrat

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