Response Time Query

[only1jake]

Hey everyone,
I'm currently developing a program/bot for the Betfair API and have a question. I am still currently on the Delayed app key, however I was wondering about response times.

This is my code in VB.NET:
(Mostly taken from an example)

Function CreateRequest(AppKey As String, SessToken As String, postData As String)


        Dim Url As String = "https://api.betfair.com/exchange/betting/json-rpc/v1/"
        Dim request As WebRequest = Nothing
        Dim dataStream As Stream = Nothing
        Dim response As WebResponse = Nothing
        Dim strResponseStatus As String = ""
        Dim reader As StreamReader = Nothing
        Dim responseFromServer As String = ""
        Try
            Dim TimerStart As DateTime
            TimerStart = Now
            request = WebRequest.Create(New Uri(Url))
            request.Method = "POST"
            request.ContentType = "application/json-rpc"
            request.Headers.Add(HttpRequestHeader.AcceptCharset, "utf-8")
            request.Headers.Add("X-Application", AppKey)
            request.Headers.Add("X-Authentication", SessToken)
            
            Dim byteArray As Byte() = Encoding.UTF8.GetBytes(postData)
            
            request.ContentLength = byteArray.Length
            
            dataStream = request.GetRequestStream()
            
            dataStream.Write(byteArray, 0, byteArray.Length)
            
            dataStream.Close()
           
            response = request.GetResponse()
            
            strResponseStatus = CType(response, HttpWebResponse).StatusDescription
            
            dataStream = response.GetResponseStream()
            
            reader = New StreamReader(dataStream)
            

            responseFromServer = reader.ReadToEnd()
            Dim TimeSpent As System.TimeSpan
            TimeSpent = Now.Subtract(TimerStart)
            BetBotMainForm.oddschanging.Add("DL TIME: " + TimeSpent.TotalSeconds.ToString)
            
        Catch ex As Exception
            
            MsgBox("CreateRequest Error" & ex.Message)
        End Try
        Return responseFromServer   '~~> Function Output
        
        reader.Close()
        dataStream.Close()
        response.Close()
    End Function

I'm finding using the timer its taking around 1.9 seconds to get a response from the server. I need this to be faster. Is it because I am using the delayed app key or because this is a slow method?

Is there a way to speed things up?

Thanks for your help!

[gr33d]

You aren't measuring the server response time in that code, you're actually measuring the time to construct the message, encode it, send it to betfair, get the response and read the response fully.

[only1jake]

Reason I did it like that is because all the other actions take a relatively low time in comparison to the request.GetRequestStream(). I just get a varying response time between 0.8 and 2.0 seconds. Just seems odd and I'm wondering if its the delay key or if there is a faster way to request/receive.

Is there a faster way to request listmarketbook for example?

[Mr Magoo]

The response time might be very high if this is a new connection. Establishing a SSL connection to the server can be very time-consuming, however once this is done, you can send many API requests on the same underlying HTTPS connection.

I don't know VB, so I've no idea how its web libraries share and pool connections, but try sending one request out and then timing the next one - it should take much less time. Or try timing ten requests in a row - there will still be the 1-2 second set up time but the ten requests should then complete very quickly.

[gr33d]

The response time might be very high if this is a new connection. Establishing a SSL connection to the server can be very time-consuming, however once this is done, you can send many API requests on the same underlying HTTPS connection.

I don't know VB, so I've no idea how its web libraries share and pool connections, but try sending one request out and then timing the next one - it should take much less time. Or try timing ten requests in a row - there will still be the 1-2 second set up time but the ten requests should then complete very quickly.

Good point.

Jake, you'll probably need to add something like the following, but I am also not a VB expert, but this is how I'd expect to do it:

request.Headers.Add("Connection", "Keep-Alive");

[only1jake]

Thanks for the help guys. All makes sense.
I've done some more research and played around a little and found that's the case.
Cheers