How to make multiple calls synchronous in elasticsearch? - ajax

Question

Im creating ajax calls to an elasticsearch server inside a "for" loop. The problem Im facing is that,the responses are not coming in proper sequence, (that is in the order which the clients are generated using for loop). How to make the calls and response synchronous? .

Answer 1

You could do something like this:
$(document).ready(function(){
function extendFuncChain(url, callback) {
func_chain_list.push(function() {
$.ajax({
url : url,
type: 'GET',
contentType:"application/json"
}).done(function(data) {
console.debug(data);
callback();
});
});
}
var func_chain_list = [function() {}];
for(var i=1; i<=4; i++) {
var url = "http://localhost:9200/test_index/doc/" + i;
var callback = func_chain_list.pop();
extendFuncChain(url, callback);
}
func_chain_list.pop()();
});
To test it I set up a simple index with 4 documents like this:
DELETE /test_index
PUT /test_index
POST /test_index/doc/_bulk
{"index":{"_id":1}}
{"name": "doc1"}
{"index":{"_id":2}}
{"name": "doc2"}
{"index":{"_id":3}}
{"name": "doc3"}
{"index":{"_id":4}}
{"name": "doc4"}
Then when I put the javascript in a web page and load it, I get this output in the console (I expanded the last one):
Hopefully you can see how to generalize this to do what you need. The call to extendFuncChain is important, because of the way closures work in JS, and it won't work if you take that out.