limit number of concurrent HTTP connections (requests) made from javascript

[oleksandrdarchu]

Hello,

API proxy has to split incoming JSON and make a number of HTTP requests to the back-end (sort of batch API). Additionally there is a need to limit number of simultaneous HTTP connections to that back-end.

This has been implemented in javascript policy in the following way.

First iterate until reach defined connection limit value and make httpClient.send with onComplete function. In onComplete recursively call same httpClient.send with the same onComplete.

function onComplete(res,err) {
	//... process response
	//... prepare next request
	sendRequest(req)
}


function sendRequest(req) {
	httpClient.send(req, onComplete(res,err))
}


for (i=0; i< poolSize; i++) {
 //... prepare initial request
  sendRequest(req)
 
 }

A few questions in regards to that

1) Are there better (more optimal, more efficient) ways to achieve the same? I failed to make promise/await or generator/yield code even deployed.

2) For higher numbers javascript returns error "too many Callbak calls". Is it possible to overcome this anyhow?

Any suggestions/comments are appreciated.

Thank you