Use the websocket API in synchronous mode

chbailly

What is the best way to get a price snapshot synchronously.

What I would like:

ws.send(request)

result = ws.recv()

The problem is that I can receive different messages (ping for instance..).

Do I have to necessarily implement a logic to filter the answers ?

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Accepted answers

Gurpreet

@chbailly The websocket is a connection oriented API, and there is minimal housekeeping that has to be performed - like login before making a data request, and responding to ping requests. These have to be done, regardless of request for snapshot or streaming data.

We don't have a synchronous access helper for it, but might consider providing such "ease of use library" in future. For now, please see the implementation details in the provided code samples.

All comments

chbailly

I realised that I was not in snapshot mode..

So now I think I do not have to filter the answers, I am supposed to receive the answer directly, no need to filter (no ping for instance)

Gurpreet

We don't have a synchronous access helper for it, but might consider providing such "ease of use library" in future. For now, please see the implementation details in the provided code samples.

chbailly

Thanks for your answer.

Are you saying that potentially I can receive a ping even in snapshot mode ?

The code is not straightforward.. We have to match the correct request, the error management is also made more complicated. What do we do if we do not fintd the matching request, how do we set a timeout..; This is really easy to write an incorrect code even if it looks simple.

An helper would really be a good idea imho. Sometimes, we just need to write simple and basic code. 2 lines, the send followed by the rcv...

Gurpreet

Yes, as long as the connection is held open, ping messages are sent to asset that TCP connection is still open. This would happen regardless of snapshot or any request for data.

The websockets is a protocol specification, rather than an API, and protocol requires that application start with a login and maintain ping/pong messages.

chbailly

I agree, it makes sense; thanks

ranjit.talukdar

Hhi - just checking to see if any decision had been made on a synchronous access helper as yet and iff there was any potential eta for it?

Many thanks

Ranjit

Gurpreet

@ranjit.talukdar You can take a look for Websocket examples in the TR API Samples github repository - specifically the Quote Widget, which uses the TRWebsocketController. This controller sample is in Javascript and can be used as a helper object in your own implementations.