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Your bot code is executed in market update event, so if your active market refresh rate is set to 250 ms, then your bot is executed every 250 ms. For passive markets (default 10s) or markets added to bot executor tool the default settings is 1 second.

It means that when time is critical factor for your bot execution then you must set reasonable values for market update interval.

If you are using streaming for data update (that is relevant only for active and passive markets in Bet Event View and Open Markets view), then as updates are really streamed only when changes are detected, your bot can be executed in heart beat event only, set for active market to 1s and for passive markets to 15 seconds, keep that in mind!

Why is it implemented this way?

Well, because bot reacts on market data changes, and there is no reason to execute a bot when there are no market data changes.

I had already answered such question.

Please watch this video from my debugging of bot trigger code:

Debugging Bot Trigger Code

I set breakpoint, and add to watch view, selection and selection.BetPosition, so I could browse the watched object data, and see what properties are full with data.

The similar dialog I added couple month ago to bfexplorer so you can browse some market and market selection data, to learn about bfexplorer data, and how/what you can use in your bot trigger code.

Have a look at the line 34:

sprintf "%s: %A" selection.Name selection.BetPosition

selection.BetPosition object offers your bet position, so please browse data, put their break point when dubbing your bot trigger code.

Yes, exactly. You simply must use correct wording. “Bets” is plural, right? So it is collection, not one bet. On the object property that is bet, you could do so: bet.Price and so on.

I do not know what exactly you want to achieve as it is clear that you could have more unmatched bets on selection, so make reusable functions you could use/reuse in your bot triggers.

I wanted to explain in my sample bot trigger code, how you can work on bfexplorer domain objects, so I used direct code, but if you try to write:  unmatched .. Visual Studio will offer you all available functions/types and so available for you after you

open BeloSoft.Bfexplorer.Domain

so surprising it is offered for you:

isUnmatchedBet, unmatchedBetsExists, getBets, getUnmatchedBets, getUnmatchedBetsByBetType and so on and on.

So code I already had wrote and is reusable.

Then you could write:

let layUnmtached = market.Bets |> getUnmatchedBetsByBetType BetType.Lay

if not layUnmtached.IsEmpty

then

    let firstUnmatched = layUnmtached.Head

    firstUnmatched.Price

    ...

Any code, in any programming language is “sentence” expressed by programming language “words” and constructs you can make by programming, adds the language vocabulary.

So the vocabulary you can use to express your intentions in programming language is limited to couple words.

The above line of code:

let Stake = _selection.GetPriceSize(BetType.Lay)

In human sentence expresses:

 Selection, get PriceSize object for Lay side to stake!

As English have strict words order in sentence, to be grammatically correct, we command so exclamation mark at the end of sentence.

So you command selection to get PriceSize, and in this context it is Lay PriceSize offered. It is not bet, it is offer on this selection other bettors placed.

You can command bet object to get price or size to you, so odds or stake you placed a bet with.

So you must ask/command _selection.Bets to get all unmatched bets to you (to value), and then ask a bet to get you price, size and so on, like I did in my bot trigger code:

BetStatusBetCancellingBotOrchestrationBotTrigger.fsx

on the line 31.

*** 

Read further only when you want to learn some advance features of F# programming language.

***

I do not know in what context you use _selection, but please keep in mind that in F# underscore _ is used as intention to declare not used value, because in F# you must declare exact intention, so like in mathematics it does not make sense to express something what is not used.

Yes, in other programming languages, programmers used to declare object variables with _, but in F# it has different meaning, for instance here:

ShowPriceTradedVolume.fsx

On the line 52, where I declared construct for BetStatusBetCancellingBotOrchestrationBotTrigger type, I used _ for not used values, because in F# any input value/s in constructor are declared as well as object values you can access not only in constructor but in entire type.

On the line 106, you can see __ (two underscores), so in type member you must type __ to declare not used self-identifier of object. I use this as self-identifier, but you can use whatever word/character.

Ok, this underscore issue is for advance developers, you code will work whatever you will use.

***

Option value

***

For the option types/values it is similar like in C# for Nullable. So you can use anOptionValue.IsSome and if is some you can get value by: anOptionValue.Value, but better way is to use match expression or functions from Option module, like Option.iter.

In my code you can find maybe, computation expression I created, so for options you can type simplified expressions, for instance here:

ShowHorseData.fsx

Lines from 39 to 43, and then on line 40, let! ... actually evaluates if mySelection.MetaData.IsSome and continues only when it is assigning to metaData the value, otherwise returning None.

Such expression allows me to write less code. Programming is not about writing a lot of code, actually less code is always better approach.

Programming is about understanding of context in which you write the code, and so it is about interpreting of “words”.

Peter may I ask you to explain me by your own words, how do you understand this line of code?

let Stake = _selection.GetPriceSize(BetType.Lay)

As you may know, and now I speak not about programming languages, but about languages, my mother’s language is Slovak, and in many Slavic languages there is no such strict rule for word order like in English sentence.

That is the funny part in your question, because well my understanding of any language construct is a little bit different from the way only English people could read the code, the sentence.

Well, yes I understand what you want to try to do in your code, but the “words” you chose to do so are quite unclear for me.

this. is used to access object properties or methods.

You type your code as you would access static method or type. You must type object, so in this case maybe: market.MarketInfo.StartTime

You can access market’s bets or selection’s bets directly (line 76 and 31), and for matched bets you can access BetPosition property, the line 79 and 34.

BetPosition type/class allows you to calculate hedge stake and so on, have a look at on the type methods.

To cancel bets you can use TriggerResult.CancelBets, the line 150.

I already mentioned that the better way is to orchestrate existing bots to execute parts of your strategy, for instance you set trading bot and all bet placing/updating or cancelling your bets is then managed by this trading bot.

In my bot trigger I showed what you asked and created such simple bots’ orchestration:

BetStatusBetCancellingBotOrchestrationBotTrigger.fsx

Please watch my video. To show how to cancel bets, I set my action bot: “Back 1 tick better”, so bot offers 2 Euro back bet 1 tick over best offered price. When odds changes and are in allowed odds range Minimum/MaximumOdds, the bot updates its unmatched bet to always offer its back bet 1 tick over the best offered, set by the parameter: PriceImprovemnt.

Now, in my bot trigger I cancelled unmatched bet on my selection, the line 150. But what happened?

As the bet was placed by my action bot, and the bot is managing its bets itself, the bet was again placed.

What does it mean?

If you place your bets by action bots, you do not need to manage bets placed by the action bot, but of course if you do not want your unmatched bets be offered on the market anymore, you need to stop the action bot, and as the action bot managing its bets, the unmatched bets will cancel its bets when you end its execution, the line 160.

It is really better way to orchestrate action bots in your bot trigger than managing bet status in your bot trigger.

Well yes, if you want to place your bets directly then you can do so, you have got:

TriggerResult.PlaceBets

TriggerResult.CancelBets

Let’s say you have got strange trading strategy, where you setup the trading bot:

"Place Bet and Close Selection Bet Position"

To offer bet 3 ticks from best offered price, and close its bet position with profit of 3 ticks, or 5 ticks to lose.

You would setup two versions of this trading bot one offering back and the other one lay bet. In your bot trigger you would execute such pair of trading bots on 3 favourites when some conditions occurred.

Now imagine what you would have to program to manage such complex trading strategy in your bot trigger by directly placing your bets.

Here is my bot trigger code:

ShowPriceTradedVolume.fsx

Please watch video, showing how to use IntelliSense to browse available code.

Full market data are available in the active market, so in the only market open in Bet Event View or in Bet Event Trader View.

Why is it so?

Bfexplorer can monitor hundreds of markets so this way it is reasonably lower amount of data loaded from betfair servers.

Yes you can get matched volume only through PriceGridData, of course you must iterate through prices with traded volume, not all of 399 prices are traded.

If you run your bot in Bot Executor, then you can simply use the bot: “Execute at Time” and set the parameter: UseSetMarketInactive to True. So when executed in bot executes your action bot and set MonitoringStatus to Inactive, Bot Executor then removes such market from monitoring and opens it in Bet Event view, so your bot have them full market data available.

Of course there are other betfair api methods you can use to get traded data betfair uses in charts. You can see that in my post:

Lay the Field Strategy – Analyzing Data

Here is my bot trigger showing on ladders near BSP and after the race is turned at in-play the actual BSP:

HorseRacingShowStartPrices.fsx

Actually, there are such bot triggers:

HorseRacingSpFavouriteBotTrigger.fsx

HorseRacingSpBotTrigger.fsx

As an example you could create a bot trigger showing for active selections near BSP and actual BSP after race is turned at in-play. You can show prices on ladder, like in this example:

Horse Racing - Oddschecker Favourite Trigger

Yes, placing betfair sp bet returns matched bet with matched amount zero, as SP bet is fully matched only after race is turned at in-play and all betfair start price bets are processed.  This be cannot be cancelled I believe, well have never try that.

You can place normal bet with Take SP, such bet can be cancelled and unmatched part of bet is turned to SP at the moment race is turned at in-play.

Have a look at UpdateSpPricesMarketBot.fs if you want to update sp prices, but that is bot assembly, not bot trigger code. You have got access to betfair api in bot trigger code, so you need to study betfair documentation and then you can replicated code working with sp prices in bot trigger as well.

That is great Peter.

I would really suggest you to set breakpoint in your code and then debug it and browse available data offered by bfexplorer.

You must know what data you have got, visualize them in your head, and then you know what you can do with data.

Your approach for now is browsing existing code, so when you did not find similar one you cannot make progress, but data you have got, so working with data is the way to go.

On the line 3 of your code, there are set three values: startIndex, nextIndex, findFun

The findFun is function used to evaluate the place with empty offer. So when you want to place back bet, it must be checked lay offer and wise versa.

You change that code, therefore your findFun function returns true on offer with available offer. Actually in your code I cannot see logical problem because you start iterating through data on the best offer, so price must be set.

If you code does not go to the line 23, as you say price returned is always 0.0

Peter, how/where you execute your bot trigger?

The full market depth is updated only for active market, so for the market that is currently open in Bet Event/Trader.

It means that if you run your bot by Bot Executor tool you will get updates only for 3 best offered prices.

I would suggest you to debug code, only this way you can find your problem in the code.

Hint: There is function selection.PriceGridData.GetOfferedPriceData()

You can use to get all offered prices. I do not know what you want to make in your code, so this function: GetOfferedPriceData returns all offered prices, and you can filter whatever criteria you use.

Here is bot trigger code:

ShowOfferedPrices.fsx

Peter, please use VS debugger when testing your code.

I have just updated Bfexplorer BOT SDK source code adding MyFootballStrategy projects showing how to use Bfexplorer Plugin integration.

The MyFootballStrategy.App is working example. If you trade football matches on betfair you can use it to monitor all matches live score and match statistics.

https://github.com/StefanBelo/Bfexplorer-BOT-SDK/tree/master/MyFootballStrategy

If anyone wants to collaborate on this project adding new features, and is able to program, then of course you can clone entire Bfexplorer BOT SDK solution.

Those of you who just want to use this app, and are not able to build plugin from the source code, just contact me through support page and I will send you app/plugin files.

One of TriggerResult discriminated unions entry is:

TriggerResult.OpenAssociatedMarkets of string[] * (DataResult<Market list> -> unit)

Allowing requesting associated markets to the market you are running your bot on.

Every market is open as bet event on betfair, and you have got access to this information:

market.MarketInfo.BetEvent

So bfexplorer when you request TriggerResult.OpenAssociatedMarkets knows for which bet event id the associated markets should be queried.

Please have a look at on this bot trigger script:

HorseRacingWinToBePlacedData.fsx

Basically your bot has access to all betfair api methods:

myBfexplorer.BfexplorerService.BetfairServiceProvider

So you could be able to write any code against betfair api. The question is, is this approach practical?

Your bot is executed on exact type of market, for instance on horse racing win market, so what markets would you like to open in Bet Event view? Tennis match odds market, or football match odds market?

In any such scenario common sense dictates that you want to open associated market for bet event on which your bot is running, for instance place horse racing market, when your bot runs on win horse racing market and so on.

If you want to build your bespoke app on bfexplorer app, you can do so like I present in this article:

Bfexplorer Plugin Support

Peter, post on github your code you want to review, and please add to files extension, then github code preview can highlight the syntax, as from ending .fs, or ,fsx it is known that code is F#.

You can debug your code in Visual Studio, so you can really test each line of your bot trigger code, and so learn how your code works.