Is there a difference between obtaining QUERY_STRING arguments via req.query[myParam]
and req.params.myParam
? If so, when should I use which?
This question is related to
node.js
query-string
Given this route
app.get('/hi/:param1', function(req,res){} );
and given this URL
http://www.google.com/hi/there?qs1=you&qs2=tube
You will have:
req.query
{
qs1: 'you',
qs2: 'tube'
}
req.params
{
param1: 'there'
}
Suppose you have defined your route name like this:
https://localhost:3000/user/:userid
which will become:
https://localhost:3000/user/5896544
Here, if you will print: request.params
{
userId : 5896544
}
so
request.params.userId = 5896544
so request.params is an object containing properties to the named route
and request.query comes from query parameters in the URL eg:
https://localhost:3000/user?userId=5896544
request.query
{
userId: 5896544
}
so
request.query.userId = 5896544
You should be able to access the query using dot notation now.
If you want to access say you are receiving a GET request at /checkEmail?type=email&utm_source=xxxx&email=xxxxx&utm_campaign=XX
and you want to fetch out the query used.
var type = req.query.type,
email = req.query.email,
utm = {
source: req.query.utm_source,
campaign: req.query.utm_campaign
};
Params are used for the self defined parameter for receiving request, something like (example):
router.get('/:userID/food/edit/:foodID', function(req, res){
//sample GET request at '/xavg234/food/edit/jb3552'
var userToFind = req.params.userID;//gets xavg234
var foodToSearch = req.params.foodID;//gets jb3552
User.findOne({'userid':userToFind}) //dummy code
.then(function(user){...})
.catch(function(err){console.log(err)});
});
I want to mention one important note regarding req.query
, because currently I am working on pagination functionality based on req.query
and I have one interesting example to demonstrate to you...
Example:
// Fetching patients from the database
exports.getPatients = (req, res, next) => {
const pageSize = +req.query.pageSize;
const currentPage = +req.query.currentPage;
const patientQuery = Patient.find();
let fetchedPatients;
// If pageSize and currentPage are not undefined (if they are both set and contain valid values)
if(pageSize && currentPage) {
/**
* Construct two different queries
* - Fetch all patients
* - Adjusted one to only fetch a selected slice of patients for a given page
*/
patientQuery
/**
* This means I will not retrieve all patients I find, but I will skip the first "n" patients
* For example, if I am on page 2, then I want to skip all patients that were displayed on page 1,
*
* Another example: if I am displaying 7 patients per page , I want to skip 7 items because I am on page 2,
* so I want to skip (7 * (2 - 1)) => 7 items
*/
.skip(pageSize * (currentPage - 1))
/**
* Narrow dont the amound documents I retreive for the current page
* Limits the amount of returned documents
*
* For example: If I got 7 items per page, then I want to limit the query to only
* return 7 items.
*/
.limit(pageSize);
}
patientQuery.then(documents => {
res.status(200).json({
message: 'Patients fetched successfully',
patients: documents
});
});
};
You will noticed +
sign in front of req.query.pageSize
and req.query.currentPage
Why? If you delete +
in this case, you will get an error, and that error will be thrown because we will use invalid type (with error message 'limit' field must be numeric).
Important: By default if you extracting something from these query parameters, it will always be a string, because it's coming the URL and it's treated as a text.
If we need to work with numbers, and convert query statements from text to number, we can simply add a plus sign in front of statement.
Source: Stackoverflow.com