Introduction

Blocktrail does not provide a .NET implementation of their SDK so I decided to build one on my own (feel free to contribute!). This .NET SDK is written in F# and tries to keep it as C# friendly as possible, keep this in mind when contributing as it is a vital requirement. The client implements some of the same methods as the official ones. The idea was to differ in some ways.

E.G.: implementing the request for unconfirmed transactions of an address as a method on the Address object instead of an API call from the client module.

We start the tutorial by setting up the API. The first thing to notice is that it's built in F# modules which are basically statis classes. This might change in the future, but at this moment it is not possible to use multiple API keys.

If you don't have a Blocktrail API key yet go get one at Blocktrail.com, it's free!

Basics

Copy the snippet below and replace the APIKey placeholder with your api key you requested.

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#r "BlocktrailSdk.dll"
open BlocktrailSdk
open BlocktrailSdk.Models

BlocktrailSdk.Config.ApiKey <- "INSERT_YOUR_API_KEY";

let transaction = BlocktrailSdk.Client.GetTransaction "c326105f7fbfa4e8fe971569ef8858f47ee7e4aa5e8e7c458be8002be3d86aad"

Relational properties and methods

This will retrieve the the transaction of that specific hash. After retrieving it you can print and use it's values as shown in the next snippet.

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printfn "Hash: %s" transaction.Hash
printfn "Confirmations: %i" transaction.Confirmations

Or do more advanced stuff and retrieve the Block where this particular transaction resides in.

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let block = transaction.Block
printfn "Block height: %i" block.Height
printfn "Block mined by: %s" block.MiningpoolName

Pagination

And why stop there... let's retrieve the next block and a page of it's transactions. Remember that responses that contains lists are often paginated. That means the reponse is sliced into the size you request (or the default size of 20). But don't worry, retrieving the next page is simple!

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let nextBlock = BlocktrailSdk.Client.GetBlock block.NextBlock

let transactions = nextBlock.GetTransactions(1, 20, "asc")

// Print out the hashes
transactions |> Seq.iteri (fun i x -> printfn "Transaction[%i]: %s" i x.Hash)

let nextLoadOfTransactions = transactions.NextPage()

// Print out the hashes of the 2nd page of transactions
nextLoadOfTransactions |> Seq.iteri (fun i x -> printfn "Transaction[%i]: %s" i x.Hash)

This was the starting point of using the SDK, there is more to be found within this project. Go explore the blockchain on your own and be sure to file any issues or suggestions.

namespace BlocktrailSdk

namespace BlocktrailSdk.Models

module Config

from BlocktrailSdk

val mutable ApiKey : string

Full name: BlocktrailSdk.Config.ApiKey

val transaction : Transaction

Full name: Tutorial.transaction

module Client

from BlocktrailSdk

val GetTransaction : trans:string -> Transaction

Full name: BlocktrailSdk.Client.GetTransaction

val printfn : format:Printf.TextWriterFormat<'T> -> 'T

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.printfn

property Transaction.Hash: string

property Transaction.Confirmations: int

val block : Block

Full name: Tutorial.block

property Transaction.Block: Block

property Block.Height: int

property Block.MiningpoolName: string

val nextBlock : Block

Full name: Tutorial.nextBlock

val GetBlock : block:string -> Block

Full name: BlocktrailSdk.Client.GetBlock

property Block.NextBlock: string

val transactions : PagingResponse<RelatedTransaction>

Full name: Tutorial.transactions

member Block.GetTransactions : page:int * limit:int * sort_dir:string -> PagingResponse<RelatedTransaction>

module Seq

from Microsoft.FSharp.Collections

val iteri : action:(int -> 'T -> unit) -> source:seq<'T> -> unit

Full name: Microsoft.FSharp.Collections.Seq.iteri

val i : int

val x : RelatedTransaction

property RelatedTransaction.Hash: string

val nextLoadOfTransactions : PagingResponse<RelatedTransaction>

Full name: Tutorial.nextLoadOfTransactions

member PagingResponse.NextPage : unit -> PagingResponse<'T>