Streaming API with VB.NET

[GeorgeDev]

Hi!

I have used the book "Programming for Betfair" by James Buttler to create my program in VB.Net. Everything works fine with the API-NG. I have been trying for a while now to implement the Streaming API. I know that there are SWAGGER / C# samples available, and I had a look at these, but it led to a complexity in the code, which is a bit beyond my programming skills.

I am using the following function without any problems with the API-NG :

Public Function SendSportsReq(ByVal jsonString As String)
Try

Dim testJsonString as String = ""

If testJsonString <> "" then
jsonString = testJsonString
End if

Dim request As HttpWebRequest = WebRequest.Create("https://api.betfair.com/exchange/betting/json-rpc/v1")

Dim byteArray As Byte() = Encoding.UTF8.GetBytes(jsonString)

Dim responseFromServer As String = ""

request.Method = "POST"
request.ContentType = "application/json"
request.ContentLength = byteArray.Length
request.Headers.Add("X-Application: APP_KEY")
request.Headers.Add("X-Authentication: " & SESSION_TOKEN)
request.AutomaticDecompression = DecompressionMethods.GZip OrElse DecompressionMethods.Deflate
request.ServicePoint.Expect100Continue = False
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12
request.Timeout = 2000

Dim dataStream As Stream = request.GetRequestStream()
dataStream.Write(byteArray, 0, byteArray.Length)

Dim response As WebResponse = request.GetResponse()
dataStream = response.GetResponseStream()

Dim reader As New StreamReader(dataStream)
responseFromServer = reader.ReadToEnd()

reader.Dispose()
dataStream.Dispose()
response.Dispose()
Return responseFromServer

Catch e As WebException

Debug.Print("SendSportsReq Error: " & e.Message & " - " & e.StackTrace.ToString & " - " & e.Source.ToString & " - " & e.TargetSite.ToString)
Return "Error:" & e.Message

End Try

End Function

I have tried to update/change the Function to get it running with the Streaming API:


Public Function SendStreamReq(ByVal jsonString As String)
Try

Dim testJsonString as String = "{""op"":""authentication"", ""id"": 1, ""appKey"":""APP_KEY"", ""session"": ""SESSION_TOKEN""}" & vbCrLf

If testJsonString <> "" then
jsonString = testJsonString
End if

Dim request As HttpWebRequest = WebRequest.Create("https://stream-api.betfair.com:443")

Dim byteArray As Byte() = Encoding.UTF8.GetBytes(jsonString)

Dim responseFromServer As String = ""

request.Method = "POST"
request.ContentType = "application/json"
request.ContentLength = byteArray.Length
request.Headers.Add("X-Application: APP_KEY")
request.Headers.Add("X-Authentication: " & SESSION_TOKEN)
request.AutomaticDecompression = DecompressionMethods.GZip OrElse DecompressionMethods.Deflate
request.ServicePoint.Expect100Continue = False
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12
request.Timeout = 2000

Dim dataStream As Stream = request.GetRequestStream()
dataStream.Write(byteArray, 0, byteArray.Length)

Dim response As WebResponse = request.GetResponse()
dataStream = response.GetResponseStream()

Dim reader As New StreamReader(dataStream)
responseFromServer = reader.ReadToEnd()

reader.Dispose()
dataStream.Dispose()
response.Dispose()
Return responseFromServer

Catch e As WebException

Debug.Print("SendSportsReq Error: " & e.Message & " - " & e.StackTrace.ToString & " - " & e.Source.ToString & " - " & e.TargetSite.ToString)
Return "Error:" & e.Message

End Try

End Function

I have tried the "SendStreamReq"
- several variants of the testJsonString
- with and without the request.Headers.Add("X-Application: APP_KEY") and request.Headers.Add("X-Authentication: " & SESSION_TOKEN)
- the live stream API "stream-api.betfair.com" and also the integration-API
- with the vbCrLf and without

It always ends up with an error in the "Dim response As WebResponse = request.GetResponse()" line. The error message is "Received an invalid status line: '{"op":"connection","connectionId":"209-130925203907-1936646"}'."

Any help would be very much appreciated

Thanks

George

[bfexplorer]

My code looks something like this one:

image.png

[GeorgeDev]

My code looks something like this one:

image.png

Thanks a lot! That helped me to find the issue.