Using VB2008 to acccess the Betfair API: A tutorial

[mbrylski]

BigSprout thank you for your answer now everything is working properly. I have one more question. How can I check current score of the game. Most interests me soccer

[BigSprout]

mbrylski,

at times there is no prices for the Back or Lay and this is the reason you are getting this error, try something like this to test that there is a price first:

                                    dgvField("FdBk", Rw).Value = If(.bestPricesToBack.Length > 0, Format(.bestPricesToBack(0).price, "   0.00"), "")    'Update best Back price
                                    dgvField("FdLay", Rw).Value = If(.bestPricesToLay.Length > 0, Format(.bestPricesToLay(0).price, "   0.00"), "")     'Update best Lay price

or

                                    If .bestPricesToBack.Length > 0 Then
                                        Field(Fd).Fld(Rw).ftBck = .bestPricesToBack(0).price                  'Update best Back price
                                        Field(Fd).Fld(Rw).ftbAmt = .bestPricesToBack(0).amountAvailable
                                    End If


                                    If .bestPricesToLay.Length > 0 Then
                                        Field(Fd).Fld(Rw).ftLay = .bestPricesToLay(0).price                   'Update best Lay price
                                        Field(Fd).Fld(Rw).ftlAmt = .bestPricesToLay(0).amountAvailable
                                    End If

Edit:
replace "dgvField("FdBk", Rw).Value" and "Field(Fd).Fld(Rw).ftBck" for your own variables

[mbrylski]

Hi All


Mumbles0 I found a bug in the procedure from Step 14. Generally it working very good except when market for back or lay is empty. When I tray use .bestPricesToBack(0).price Or .bestPricesTolay(0).price I receive the message “Index out of range”.

Can you correct this??


Maybe it is not a bug it is problem with function which display result. How can I check the range of bestPricesToBack or bestPricesTolay. I know the maximum is three, can I check the current range.

[beans]

Thanks for the replies. I had used WithEvents and got async calls working fine in one class, I just wasn't sure if I could use the service object in more than one class or if I would run into problems.

I found my applications became restricted when placing all the calls in one class as I couldn't deal with different responses how I wanted and everything was too generic. Therefore I have gone down the route of using a 'Session' class that handles the key and provides API headers, then another class to 'allocate' the data to custom objects. Then I have some worker classes that handle all the program logic. These worker class make all the calls so I needed each one to have it's own API object. I will probably run into problems with this method further down the line and end up changing the whole structure of my application .... But that wouldn't be the first time!

[NFLMAN]

This is fun. My bot is now placing bets for me :-)

One thing I need to be able to do is stop it from placing a second bet on the same selectionID when the bot loops back round. What's the best way to do this? I am looking at calling GetBetHistory and putting some logic in there against the returned selectionID's but if there's an easier way I'm all ears....

[Mumbles0]

Beans,

You can have as many instances of the BFGlobalService (or BFExchangeService) class as you want. Go ahead, it's fairly efficient, besides, you have lots of memory.

Looks like you have realized that, with async calls, you need a separate service object on each form (or class) which accesses the API, in order to handle the resulting "completed" events. (Of course each service object variable should be declared with the WithEvents keyword as BigSprout points out.)

Having said this, did you know that it’s possible to put all of your async API calls into a single class? Here, data from the API can be returned to the calling program using Event properties defined in this class. If you are interested I can show you how to do this.

[BigSprout]

Hi Beans,
you need to change this:

    Dim BetfairGL As New BFGlobal.BFGlobalService

to this to to be able to use Async on the global server

    Dim [B][COLOR="Red"]WithEvents[/COLOR][/B] BetfairGL As New BFGlobal.BFGlobalService

I converted most of my calls to Async mode and this was the only major change needed (please note, my naming of the global server may be different to Mumbles)

[beans]

Hi, back in step 2 we created the BetfairGL object for the BFGlobalService. I was just wondering if we are limited to only one of these objects in our application?
The reason I ask is I am trying to change my old application to an ASYNC capable version. I had classes for each type of call which shared a BFGlobalService stored in a module. Now I want to change to ASYNC I have a problem in that each class now needs it's own BFGlobalService object in order to 'Handle' the async response. Is this a problem? Does it use up lots of unnecessary memory or is it fine to create multiple versions of the service object?

[NFLMAN]

I think I can answer my own question here. I have found the reference guide :-) Looks like GetCompleteMarketPricesCompressed can do this. 60 calls/minute should be quick enough for my needs.

And I can confirm that the error was EXCEEDED_THROTTLE

[NFLMAN]

Thanks guys,

I'll test it out when I get home.

If this is indeed the case, are there any more 'throttle generous' calls I can make that will give me the SelectionID's I require?

Cheers

[Mumbles0]

NFLMAN,

I agree with BigSprout. Note that there are 2 errorCodes in the response object.

When oMarketResp.errorCode returns API_ERROR then the errorCode in the response header will give you more information. Try something like this

  With oMarketResp   
     
    Print("ErrorCode = " & .errorCode.ToString)
    If .errorCode = BFUK.GetMarketErrorEnum.API_ERROR Then Print("HeaderCode = " & .header.errorCode.ToString)

    ...........

or call the CheckHeader sub.

You will probably see that the API_ERROR is in fact EXCEEDED_THROTTLE.

[BigSprout]

Hi NFLMan,

on the free API, you are only allowed 5 calls per minute to "GetMarkets", this may be your problem.

How many correct prints do you get and is it consistent each minute?

Let us know how it goes

cheers

re-reading your code again:
You are making a call for every "womens tournament round matches" so you would be exceeding the throttle limits after 5 calls in every minute

[NFLMAN]

NFLMAN,

You can also look at the menuPath string. If you study this for a while you should see a pattern emerge and gain some insight into how Betfair name market groups.

A current example:

\Tennis\Group A\Wimbledon 2011\Mens Tournament\First Round Matches\A Murray v Gimeno Traver

You can filter this for "Mens Tournament" and "First Round Matches". This obviously won't work for "Second Round Matches", etc. but you refine the filter as you go along.

Thanks Mumbles.

I'm getting there......

I've added this after calling getAllMarkets:

'Unpack response into readable format and assign to AllMarkets
            Dim AllMarkets As New UnpackAllMarkets(oMarketsResp.marketData)
            With AllMarkets
                For i = 0 To .marketData.Length - 1 'Loop through all records in AllMrkets
                    With .marketData(i)
                        .marketName = "MATCH ODDS" 'Filter fo Match Odds markets
                        .noOfRunners = 2 'Filter for 2 participants (don't think this matters)
                        If InStr(.menuPath, "Round Matches") And InStr(.menuPath, "Womens Tournament") Then 'Further filters to find only ladies singles matches 
                            Print("MarketID=" & .marketId & " Event Start: " & .eventDate & " " & .menuPath)
                            Dim oMarketReq As New BFUK.GetMarketReq       'Create GetMarket request object
                            Dim oMarketResp As BFUK.GetMarketResp     'Create GetMarket response object
                            With oMarketReq
                                .header = oHeaderUK()
                                .marketId = AllMarkets.marketData(i).marketId
                        End With

                        
                            oMarketResp = BetFairUK.getMarket(oMarketReq)    'Call the API
                            With oMarketResp

                                Print("ErrorCode = " & .errorCode.ToString)
                                If .errorCode = BFUK.GetMarketErrorEnum.OK Then

                                    With .market
                                        If UCase(.name) = "MATCH ODDS" Then
                                            For j = 0 To .runners.Length - 1
                                                With .runners(j)
                                                    Print(.name & " Selection ID: " & .selectionId)
                                                End With
                                            Next j
                                        Else
                                            Print("NO BET")
                                        End If
                                    End With
                                End If
                            End With
                        End If
                    End With
                Next i
            End With

This will print something like this:

MarketID=102995053 Event Start: 21/06/2011 14:00:00 \Tennis\Group A\Wimbledon 2011\Womens Tournament\First Round Matches\Wozniacki v Parra Santonja
ErrorCode = OK
Caroline Wozniacki Selection ID: 2309522
Arantxa Parra Santonja Selection ID: 2309573

This is exactly what I want but after a few correct prints like this I start to get this:

MarketID=102995087 Event Start: 21/06/2011 17:30:00 \Tennis\Group A\Wimbledon 2011\Womens Tournament\First Round Matches\An Rodionova v Hlavackova
ErrorCode = API_ERROR

Once the errors start I do not get any correct data again. I was thinking I was throttling it but that's a different message, yes? I can't see any references to what this error means. Any ideas?

[MarkL]

Hi there. quick question. is it possible through for the api to retrieve all the matched bets of a market, one by one as it happens in a list, and not just my own but all the matched bets of a specific market. thanx

You're better off using one of the historical data services available to get that kind of information.

Try http://solutions.betfair.com and look for Historical Data.

[Mumbles0]

Bets matched on a market

karas,

No. you can only see your own bets with the bet status calls getMUBets, getBet, getCurrentBets etc.

However, if you analyse the data returned by getMarketTradedVolumeCompressed you can gain some insight into current betting matching on a market.