How to force QueryTask to always POST requests?

Question

On ArcGIS API for JavaScript, how can we force QueryTask to always perform POST requests?

I know that I can force POST for esriRequest via the usePost options parameter. Perhaps a similar, undocumented, method exists for the rest of the API?

My application specifications require all requests to be performed via POST. So, a solution applicable to all ArcGIS API for JavaScript requests would be even better.

Answer 1

you can't control the request method which will be used artificially, but you could tack on a meaningless additional request parameter to ensure that the request exceeds 2000 characters and achieve the same thing.

var moreText = "%20AND%201%3D1%20";
var moreTextArray = [];
for (var i=0;i<125;i++) {
  moreTextArray.push(moreText);
}

query.where = "FIELD = 'value'" + moreTextArray.join("");
// resulting unencoded where clause: FIELD = 'value' AND 1=1 AND 1=1 AND ...

if you are attempting to POST across domains, standard Cross Origin rules apply, so you'll either need to ensure that the browser supports CORS or you have a proxy in place to help issue the request.

Answer 2

As of 2017-11 there is a way to do so in JSAPI 3.20. You can force to POST with the below line:

queryTask.requestOptions = {usePost:true}

Actually, it is documented in the JSAPI 4.X documentation, though not listed in 3.X, it still works.