Using VB2008 to acccess the Betfair API: A tutorial

[Oldb]

Compresses Problem...

I am trying to get the latest BACK and LAY prices ( eg as i see it on the betfair web page)

Using uncompressed i am getting the figures all ok

BUT

When using the compressed option... as below

I am getting the figures i need but they are not consistantly in the same place in the array....

The lines start with the id and the m= ie 50/5

Code...


m = UBound(Field) \ 5 - 1 'm = number of prices - 1
ReDim .prices(m) : k = 0

POdds(i) = POdds(i) & m & " / "

For j = 0 To m ' eg m=5

.prices(j) = New PricesType

With .prices(j)
'Load the price array
.price = Val(Field(k + 0))
POdds(i) = POdds(i) & .price & " / "
.backAmount = Val(Field(k + 1))
.layAmount = Val(Field(k + 2))
.totalBspBackAmount = Val(Field(k + 3))
.totalBspLayAmount = Val(Field(k + 4))
k += 5
End With
Next

I am loading into Podds()

BUT the current Back and Lay are not allways at the end of the array Podds()


This is the output of Podds

4970766 @ 11 / 1.01 / 1.02 / 1.06 / 1.11 / 1.4 / 2.38 / 3.05 / 6 / 6.2 / 8 / 160 / 200 /
4970767 @ 12 / 1.01 / 1.02 / 1.06 / 1.11 / 1.4 / 2.68 / 2.76 / 6 / 7.2 / 8.2 / 10 / 75 / 990 /
4333840 @ 11 / 1.01 / 1.02 / 1.06 / 1.11 / 1.4 / 2.88 / 5.1 / 6 / 30 / 280 / 320 / 1000 /
4970764 @ 18 / 1.01 / 1.02 / 1.06 / 1.11 / 1.4 / 1.46 / 1.72 / 1.73 / 2 / 2.02 / 2.1 / 2.22 / 2.88 / 2.9 / 3 / 11 / 100 / 990 / 1000 /
4970765 @ 12 / 1.01 / 1.02 / 1.06 / 1.11 / 1.4 / 3 / 3.05 / 6 / 6.2 / 14.5 / 20 / 150 / 190 /
4935477 @ 11 / 1.01 / 1.02 / 1.06 / 1.11 / 1.4 / 2.18 / 2.98 / 6 / 27 / 40 / 50 / 990 /
4919959 @ 11 / 1.01 / 1.02 / 1.06 / 1.11 / 1.4 / 2.26 / 3.9 / 6 / 6.2 / 10 / 160 / 180 /
4970772 @ 14 / 1.01 / 1.02 / 1.06 / 1.11 / 1.33 / 1.4 / 2.14 / 2.5 / 6 / 6.2 / 7 / 10 / 65 / 90 / 990 /
4970771 @ 11 / 1.01 / 1.02 / 1.06 / 1.11 / 1.4 / 1.71 / 1.72 / 6 / 6.2 / 7 / 42 / 990 /
4970770 @ 12 / 1.01 / 1.02 / 1.06 / 1.11 / 1.4 / 2 / 2.02 / 6 / 6.2 / 9 / 55 / 170 / 1000 /
4970769 @ 10 / 1.01 / 1.02 / 1.06 / 1.11 / 1.4 / 2.64 / 4.3 / 6 / 16 / 150 / 230 /
4970768 @ 12 / 1.01 / 1.02 / 1.06 / 1.11 / 1.33 / 1.4 / 2.5 / 4.5 / 6 / 12 / 90 / 370 / 390 /

Regards
Oldb

[Peter Simple]

System.ServiceModel.CommunicationException

When i use the "getAllMarkets" method i am running in a problem when the API sends a large data file. Then it will cause a

System.ServiceModel.CommunicationException

because the MaxReceivedMessageSize (65536) is exceeded.

[Peter Simple]

Mumbles0

Thank you very much for this tutorial. It is extremely helpfull to make the first steps.

In Step 2 you define new Global Service object so

Dim BetfairGL As New BFGlobal.BFGlobalService

I used these declaration

Dim service As New Session_Manager.BFGlobalServiceClient

Session_Manager = BFGlobal, the difference is the "Client".

(even when your code was my guide my test app had an other structure). Was there an update of the API. The same happened when i wanted access to the exchange markets.

I have now tested various calls and it worked like it should.

[granted]

how do i access the oMarketResp.market.runners(i).selectionId from another sub

in lesson 29 we had the code below...how can i access the oMarketResp.market.runners(i).selectionId from another sub?

here is the code where its from:

Public Class MarketForm

Const PosLeft = 25 'Position of buttons from left edge of form
Const PosTop = 25 'Position of buttons from top of form
Const PosBut = 30 'Button spacing
Const Bwidth = 150 'Button width

Private Buttons As Button() 'The array of buttons

Sub AddRunnerButtons(ByVal oMarketResp As BFUK.GetMarketResp)
Dim Tpos As Integer = PosTop 'Top position of first button
Dim m As Integer = oMarketResp.market.runners.Length - 1 'Number of runners - 1

ReDim Buttons(m)
For i = 0 To m 'For each runner
Buttons(i) = New Button 'Create a new button object in the array element
With Buttons(i) 'Set button properties as required
.Left = PosLeft 'Set left position
.Text = oMarketResp.market.runners(i).name 'Set the text
.Tag = oMarketResp.market.runners(i).selectionId 'Save the selectionId in the button's Tag property
.TextAlign = ContentAlignment.MiddleLeft 'Set the text alignment
.Top = Tpos 'Set top position
.Width = Bwidth 'Set button width
End With
Controls.Add(Buttons(i)) 'Display this button on the form
AddHandler Buttons(i).Click, AddressOf RunnerButton_Click 'Assign the event handler for this button's click event
Tpos += PosBut 'Top position of the next button
Next

End Sub

'The 'Click' event handler

Private Sub RunnerButton_Click(ByVal sender As Object, ByVal e As System.EventArgs)
Dim RunnerButton As Button = sender 'A reference to the button that was clicked
With RunnerButton
MsgBox(.Tag & " " & .Text) 'Show the data for the clicked button
End With
End Sub

End Class

[Mumbles0]

Step 30. Saving your project’s settings.

A while back Welcometomylair1 asked a question about saving project settings so they would persist from one run to the next. In my reply I outlined a way to extend the existing SessToken.txt file to save project settings as well as the session token. G-Factor suggested a simpler way of doing this using VB’s inbuilt application settings facility. In this step we look at this.

1. Saving the value of a control’s property.

For example the Text property of a TextBox.

TextBoxes are handy controls which are commonly used to hold settings for your project, e.g. marketId, sample frequency, etc. For this exercise drag a TextBox from the ToolBox onto the TestForm and rename it to tParam (or anything you like).

With this TextBox selected so that its properties appear in the "Properties" widow, expand the (ApplicationSettings) node. Click on (PropertyBindings) then click (...) to show the "Applications Setting for tParam" form. Select the Text property then click (New...) in the property’s associated drop down list window to show the "New Application Setting" form. Enter these settings:

DefaultValue: 123
Name: Param1
Scope: User

Click OK, OK. With this procedure we have bound the tParam.Text property to an application setting we have created named Param1. Think of an application setting as being a special variable whose value is retained from one run to the next.

Now run the project. Notice that the default value we entered appears in the TextBox. Change this value to something else (e.g. 456), then close the form to stop the project running. Re-run the project and notice that the new value is now in the TextBox. Thus the TextBox always retains the most recently entered value. We have achieved this without writing any code.

2. Saving any value.

The application settings can be used to retain any value you like. You can create a new setting by clicking "BetfairX Properties" on the Project menu to show the Properties form. Select the "Settings" tab. Here you will see all the settings used by the project, including Param1 which we added above. You add a new setting by adding a new entry to the table. For example, add the name Param2, having value "This is Param2". This setting becomes a property of the My.Settings object and can be accessed from anywhere in you code with:

My.Settings.Param2

To demonstrate, put this code in Sub TestForm_Load:

  .....
  Print("Last run: " & My.Settings.Param2)  'Previous run time
  My.Settings.Param2 = Now              'Re-assign the setting 
  Print("This run: " & My.Settings.Param2)   'Current run time
  .....

and run the project a few times. You will see that Param2 initially holds the previous run time.

Note:

We could have used an application setting to hold the session token rather than storing it in the auxiliary file SessToken.txt.

Two "scopes" are available. With "User" scope the values of the settings apply only to the current (Windows) user. With "Application" scope the settings values apply to all users.

[Oldb]

Throttle Exceeded

Mumbles0

I probably did not do enough research to identify the throttle problem, sorry.

Will now alter my code accordingly.

I should have used the compressed function in the 1st place..!!!!!

Thanks again for all the free advice, much appreciated.

Regards Oldb

[Mumbles0]

I'm guessing that you should be placing your trimmed runners names into an array (to be sorted into alphabetical order) but perhaps don't know how to go about this.

Post some of your code so we can see what's happening.

[granted]

i trimmed the numbers from oMarketResp.market.runners(i).name and then wanted them sorted by name.....

they list out in order of their numbers even though i removed them but now i wanted to sort them alphabetically

[Mumbles0]

So NewString is a string, presumably containing a horse's name (e.g. "Sterling Prince").

It is quite meaningless to call Array.Sort to sort this single string. What are you trying to achieve?

It would work if the parameter was an array of strings, but you haven't got this.

[granted]

i trimmed those annoying numbers at the front of the aust. names using trim....
and then i did the following:

Dim NewString As String = MyString.TrimStart(MyChar)

newstring is the names without the numbers....

then i tried array.sort(newstring)

thats when everything goes pear-shaped

[Mumbles0]

Reply to Oldb (re: getMarketPrices)

You are calling getMarketPrices. This has a limit of only 10 calls/minute on the free API. It is better to call getMarketPricesCompressed because this has a higher limit of 60 calls/minute.

If you are using code similar to Step 7 it is easy to change this so that getMarketPricesCompressed is called instead of getMarketPrices:

[COLOR="Gray"]ShowMprices(BetFairAU.[COLOR="Black"]getMarketPricesCompressed[/COLOR](MpricesReq)) 'Get market prices
......[/COLOR]

[COLOR="Gray"]Function MpricesReq() As BFAU.[COLOR="Black"]GetMarketPricesCompressedReq[/COLOR]
  Dim oMPReq As New BFAU.[COLOR="Black"]GetMarketPricesCompressedReq[/COLOR]
  With oMPReq
    .header = oHeaderAU()
    .marketId = [i]an active market ID[/i]
  End With
  Return oMPReq
End Function

Sub ShowMprices(ByVal MpriceResp As BFAU.[COLOR="Black"]GetMarketPricesCompressedResp[/COLOR])
  Dim Lay, Back As String
  With MpriceResp
    CheckHeader(.header)
    Print("ErrorCode = " & .errorCode.ToString)
    If .errorCode = BFAU.GetMarketPricesErrorEnum.OK Then
      With [COLOR="Black"]New UnpackMarketPricesCompressed(.marketPrices)[/COLOR]
        Print("MarketID = " & .marketId)
        For i = 0 To .runnerPrices.Length - 1
          With .runnerPrices(i)

          .................
          .................

          End With
        Next
      End With
    End If
  End With
End Sub[/COLOR]

The class UnpackMarketPricesCompressed is given in Step 14

I don’t quite understand what your problem is with your GetRunners sub. If this calls getMarket, bear in mind that the free API limit is only 5 calls/minute.

[MrChameleon]

I'm a C# programmer, not VB.NET, but try this ...

myArray.Sort()

given ...

List<MyClass> myArray = new List<MyClass.()
myArray.Add(myObject);
etc.

Note also that you may define the the sort criterion by implementing IComparable<MyClass> on the class MyClass.

Not sure this will help you, but it can't harm

[Mumbles0]

What's in myarray ?

[granted]

array sorting problem

i keep getting an array sort error and i don't know why...anyone have any ideas..

i tried array.sort(myarray(i))

i tried array.sort(myarray)

and i always get the error

overload resolution failed...

what am i not doing right?

[Oldb]

Exceed Throttle

I have been using this program to retrieve odds for a year now, and really appreciate the code... its a life saver..

I have only one lingering item....


I am calling for odds every 10 seconds , but get an exceed throttle message., on occassions.

I am not 100% sure of the limitation of the free api. I thought i could do 60 calls per minute.?????

I have a timer running calling
ShowMprices(BetFairAU.getMarketPrices(MpricesReq)) 'Get market prices
every 10 seconds.....

This routine calls
GetRunners() 'Get the actual runner numbers and put into ActualRunners()

With .marketPrices
With .marketPrices

Really appreciate if someone could explain how this throttle limit would apply when using this vb2008 routines..

Regards Oldb................