1. FreeAgentCore.fs

#I @"packages"
#r @"Http.Fs\lib\net40\HttpClient.dll"
#r @"FSharp.Data\lib\net40\FSharp.Data.dll"

open HttpClient
open FSharp.Data

module Security =
    type RefreshTokenResponse = JsonProvider< """{
     "access_token":"ACCESS TOKEN",
     "token_type":"bearer",
     "expires_in":604800
    }""">
    
    let private contactTokenServer body =
        "https://api.freeagent.com/v2/token_endpoint"
        |> createRequest Post
        |> withBasicAuthentication clientId secret
        |> withHeader (ContentType "application/x-www-form-urlencoded")
        |> withHeader (RequestHeader.AcceptCharset "UTF-8")
        |> withBody body
        |> getResponseBody
    
    let private refreshToken = "REFRESH TOKEN GOES HERE"

    let private getFreshToken =
        sprintf "grant_type=refresh_token&refresh_token=%s"
        >> contactTokenServer
        >> RefreshTokenResponse.Parse
    
    let accessToken = getFreshToken refreshToken

module Communication =
    let private withFreeAgentAuth =
        sprintf "Bearer %s"
        >> Authorization
        >> withHeader
    let private withAuth = withFreeAgentAuth Security.accessToken.AccessToken
    
    let withStandardHeaders =
        withAuth
        >> withHeader (Accept "application/json")
        >> withHeader (ContentType "application/json")
        >> withHeader (UserAgent "fsharp interactive")

    let makeStandardRequest parser =
        createRequest Get
        >> withStandardHeaders
        >> getResponseBody
        >> parser

    let private getNextPageUri =
        let splitOn (text:string) (item:string) = item.Split([|text|], System.StringSplitOptions.RemoveEmptyEntries)
        fun (reponse:Response) ->
            reponse.Headers.[ResponseHeader.Link] |> splitOn ", "
            |> Seq.map (fun item ->
                let [|uri;direction|] = item |> splitOn "; "
                uri, (direction |> splitOn "=").[1].Trim '\'')
            |> Seq.tryFind (snd >> (=) "next")
            |> Option.map fst
            |> Option.map(fun s -> s.Trim('<', '>'))
    
    let createPagedRequest parser getCollection uri =
        let rec getNextPage uri =
            seq {
                let response = 
                    uri
                    |> createRequest Get
                    |> withStandardHeaders
                    |> getResponse
                match response.EntityBody with
                | Some body ->
                    let collection = body |> parser |> getCollection
                    yield! collection
                    let nextUri = getNextPageUri response
                    match nextUri with
                    | Some nextUri -> yield! getNextPage nextUri
                    | None -> ()
                | None -> ()
            }
        
        getNextPage (sprintf "%s%spage=1&per_page=100" uri (if uri.Contains "?" then "&" else "?"))

2. FreeAgentApi.fs

[<AutoOpen>]
module FreeAgent =
    type GetProjectsResponse = JsonProvider< """{ "projects":[
      {
        "url":"https://api.freeagent.com/v2/projects/1",
        "name":"Test Project",
        "contact":"https://api.freeagent.com/v2/contacts/1",
        "budget":0,
        "is_ir35":false,
        "status":"Active",
        "budget_units":"Hours",
        "normal_billing_rate":"0.0",
        "hours_per_day":"8.0",
        "uses_project_invoice_sequence":false,
        "currency":"GBP",
        "billing_period":"hour",
        "created_at":"2011-09-14T16:05:57Z",
        "updated_at":"2011-09-14T16:05:57Z"
      }
    ]}""">    
    
    type GetCustomersResponse = JsonProvider< """{ "contacts":[
      {
        "organisation_name":"foo",
        "url":"https://api.freeagent.com/v2/contacts/2",
        "first_name":"test",
        "last_name":"me",
        "contact_name_on_invoices":true,
        "country":"United Kingdom",
        "locale":"en",
        "account_balance":"-100.0",
        "uses_contact_invoice_sequence":false,
        "created_at":"2011-09-14T16:00:41Z",
        "updated_at":"2011-09-16T09:34:41Z"
      }
    ]}""">
    
    type GetTimeslipsResponse = JsonProvider< """{ "timeslips":[
      {
        "url":"https://api.freeagent.com/v2/timeslips/25",
        "user":"https://api.freeagent.com/v2/users/1",
        "project":"https://api.freeagent.com/v2/projects/1",
        "task":"https://api.freeagent.com/v2/tasks/1",
        "dated_on":"2011-08-15",
        "hours":"12.0",
        "updated_at":"2011-08-16T13:32:00Z",
        "created_at":"2011-08-16T13:32:00Z"
      }
    ]}""">
    
    type GetInvoicesResponse = JsonProvider< """{ "invoices": [ {
        "url":"https://api.freeagent.com/v2/invoices/1",
        "contact":"https://api.freeagent.com/v2/contacts/2",
        "dated_on":"2011-08-29T00:00:00+00:00",
        "due_on":"2011-09-28T00:00:00+00:00",
        "reference":"001",
        "currency":"GBP",
        "exchange_rate":"1.0",
        "net_value":"0.0",
        "sales_tax_value":"0.0",
        "total_value": "200.0",
        "paid_value": "50.0",
        "due_value": "150.0",
        "status":"Draft",
        "comments":"An example invoice comment.",
        "omit_header":false,
        "payment_terms_in_days":30,
        "ec_status":"EC Goods",
        "created_at":"2011-08-29T00:00:00Z",
        "updated_at":"2011-08-29T00:00:00Z"
      }
    ]}""">

    type GetExpensesResponse = JsonProvider< """{ "expenses":[
      {
        "url":"https://api.freeagent.com/v2/expenses/1",
        "user":"https://api.freeagent.com/v2/users/1",
        "category":"https://api.freeagent.com/v2/categories/285",
        "dated_on":"2011-08-24",
        "currency":"USD",
        "gross_value":"-20.0",
        "native_gross_value":"-12.0",
        "sales_tax_rate":"1.0",
        "sales_tax_value": "-0.2",
        "native_sales_tax_value": "-0.12",
        "description":"Some description",
        "manual_sales_tax_amount":"0.12",
        "updated_at":"2011-08-24T08:10:40Z",
        "created_at":"2011-08-24T08:10:40Z",
        "attachment":
          {
            "url":"https://api.freeagent.com/v2/attachments/3",
            "content_src":"https://s3.amazonaws.com/freeagent-dev/attachments/1/original.png?AWSAccessKeyId=1K3MW21E6T8KWBY84B02&Expires=1314281186&Signature=GFAKDo%2Bi%2FsUMTYEgg6ZWGysB4k4%3D",
            "content_type":"image/png",
            "file_name":"barcode.png",
            "file_size":7673
          }
      },
            {
        "url":"https://api.freeagent.com/v2/expenses/1",
        "user":"https://api.freeagent.com/v2/users/1",
        "category":"https://api.freeagent.com/v2/categories/285",
        "dated_on":"2011-08-24",
        "currency":"USD",
        "gross_value":"-20.0",
        "native_gross_value":"-12.0",
        "sales_tax_rate":"1.0",
        "sales_tax_value": "-0.2",
        "native_sales_tax_value": "-0.12",
        "description":"Some description",
        "manual_sales_tax_amount":"0.12",
        "updated_at":"2011-08-24T08:10:40Z",
        "created_at":"2011-08-24T08:10:40Z"
      }
    ]}""">

    type GetBillsResponse = JsonProvider< """{ "bills":[{
      "url":"https://api.freeagent.com/v2/bills/1",
      "contact":"https://api.freeagent.com/v2/contacts/1",
      "category":"https://api.freeagent.com/v2/categories/285",
      "reference":"acsad",
      "dated_on":"2011-07-28",
      "due_on":"2011-08-27",
      "total_value":"213.0",
      "paid_value":"200.0",
      "due_value":"13.0",
      "sales_tax_value":"-35.5",
      "sales_tax_rate":"20.0",
      "status":"Open",
      "updated_at":"2011-07-28T12:43:36Z",
      "created_at":"2011-07-28T12:43:36Z",
      "attachment":
        {
            "url":"https://api.freeagent.com/v2/attachments/3",
            "content_src":"https://s3.amazonaws.com/freeagent-dev/attachments/1/original.png?AWSAccessKeyId=1K3MW21E6T8KWBY84B02&Expires=1314281186&Signature=GFAKDo%2Bi%2FsUMTYEgg6ZWGysB4k4%3D",
            "content_type":"image/png",
            "file_name":"barcode.png",
            "file_size":7673
        }
      },
      {
      "url":"https://api.freeagent.com/v2/bills/1",
      "contact":"https://api.freeagent.com/v2/contacts/1",
      "category":"https://api.freeagent.com/v2/categories/285",
      "reference":"acsad",
      "dated_on":"2011-07-28",
      "due_on":"2011-08-27",
      "total_value":"213.0",
      "paid_value":"200.0",
      "due_value":"13.0",
      "sales_tax_value":"-35.5",
      "sales_tax_rate":"20.0",
      "status":"Open",
      "updated_at":"2011-07-28T12:43:36Z",
      "created_at":"2011-07-28T12:43:36Z"
      }
    ]}""">

    type GetBankAccountsResponse = JsonProvider< """{ "bank_accounts":[
      {
        "url":"https://api.freeagent.com/v2/bank_accounts/1",
        "opening_balance":"0.0",
        "type":"StandardBankAccount",
        "name":"Default bank account",
        "is_personal":false,
        "currency": "GBP",
        "current_balance": "0.0",
        "updated_at":"2011-07-28T11:25:20Z",
        "created_at":"2011-07-28T11:25:11Z"
      }
    ]}""">

    type GetBankTxnExplanationResponse = JsonProvider< """{ "bank_transaction_explanations": [
      {
        "url": "https://api.freeagent.com/v2/bank_transaction_explanations/20",
        "bank_transaction": "https://api.freeagent.com/v2/bank_transactions/20",
        "bank_account": "https://api.freeagent.com/v2/bank_accounts/1",
        "category": "https://api.freeagent.com/v2/categories/366",
        "dated_on": "2010-12-01",
        "description": "transform plug-and-play convergence",
        "gross_value": "-90.0",
        "attachment":
          {
            "url":"https://api.freeagent.com/v2/attachments/3",
            "content_src":"https://s3.amazonaws.com/freeagent-dev/attachments/2/original.pdf?AWSAccessKeyId=1K3MW21E6T8KWBY84B02&Expires=1316186571&Signature=tA4V5%2BJEE%2Fc3JTg5AiIO494m0cA%3D",
            "content_type":"application/pdf",
            "file_name":"About Stacks.pdf",
            "file_size":466028
          }
      },
      {
        "url": "https://api.freeagent.com/v2/bank_transaction_explanations/20",
        "bank_transaction": "https://api.freeagent.com/v2/bank_transactions/20",
        "bank_account": "https://api.freeagent.com/v2/bank_accounts/1",
        "category": "https://api.freeagent.com/v2/categories/366",
        "dated_on": "2010-12-01",
        "description": "transform plug-and-play convergence",
        "gross_value": "-90.0"
      }]
    }""">

    let buildUri = sprintf "https://api.freeagent.com/v2/%s"

    let Projects = 
        "projects"
        |> buildUri 
        |> Communication.createPagedRequest
            GetProjectsResponse.Parse
            (fun p -> p.Projects)
        |> Seq.cache
    
    let Customers = 
        "contacts"
        |> buildUri
        |> Communication.createPagedRequest
             GetCustomersResponse.Parse
             (fun t -> t.Contacts)
        |> Seq.map(fun x -> x.Url, x)
        |> Map.ofSeq

    let getTimeslips =
        sprintf "timeslips?project=%s"
        >> buildUri
        >> Communication.createPagedRequest
            GetTimeslipsResponse.Parse
            (fun t -> t.Timeslips)
                 
    let getInvoices =
        sprintf "invoices?project=%s"
        >> buildUri
        >> Communication.createPagedRequest
            GetInvoicesResponse.Parse
            (fun t -> t.Invoices)

    let getExpenses() =
        "expenses"
        |> buildUri
        |> Communication.createPagedRequest
            GetExpensesResponse.Parse
            (fun t -> t.Expenses)

    let getBills() =
        "bills"
        |> buildUri
        |> Communication.createPagedRequest
            GetBillsResponse.Parse
            (fun t -> t.Bills)

    let getBankAccounts() =
        "bank_accounts"
        |> buildUri
        |> Communication.createPagedRequest
            GetBankAccountsResponse.Parse
            (fun t -> t.BankAccounts)

    let getBankTxnExplanations =
        sprintf "bank_transaction_explanations?bank_account=%s"
        >> buildUri
        >> Communication.createPagedRequest
            GetBankTxnExplanationResponse.Parse
            (fun t -> t.BankTransactionExplanations)

3. DownloadAttachments.fs

let rootFolder = @"YOUR DOWNLOAD FOLDER"

open System
open System.IO

let whenExists getProp item = match getProp item with Some prop -> Some(item, prop) | None -> None
let buildPath rootFolder subFolder (date:System.DateTime) filename =
    let year = date.Year.ToString("0000")
    let month = date.Month.ToString("00")
    let dom = date.Day.ToString("00")
    Path.Combine(rootFolder, subFolder, year, month, dom, filename)
let downloadFile (path, uri) =
     async {
        let! contents =
            uri
            |> createRequest Get
            |> getResponseBytesAsync

        Directory.CreateDirectory(Path.GetDirectoryName(path)) |> ignore
        use s = File.Create(path)
        do! s.WriteAsync(contents, 0, contents.Length) |> Async.AwaitTask
        return path
    }
    
let bankTxns =
    getBankAccounts()
    |> Seq.collect(fun b -> getBankTxnExplanations b.Url)
    |> Seq.choose(whenExists(fun e -> e.Attachment))
    |> Seq.map(fun (e, attachment) -> buildPath rootFolder "BankTxns" e.DatedOn attachment.FileName, attachment.ContentSrc)
    |> Seq.map downloadFile
    |> Async.Parallel
    |> Async.RunSynchronously

let bills =
    getBills()
    |> Seq.choose(whenExists(fun e -> e.Attachment))
    |> Seq.map(fun (e, attachment) -> buildPath rootFolder "bills" e.DatedOn attachment.FileName, attachment.ContentSrc)
    |> Seq.map downloadFile
    |> Async.Parallel
    |> Async.RunSynchronously

let expenses =
    getExpenses()
    |> Seq.choose(whenExists(fun e -> e.Attachment))
    |> Seq.map(fun (e, attachment) -> buildPath rootFolder "expenses" e.DatedOn attachment.FileName, attachment.ContentSrc)
    |> Seq.map downloadFile
    |> Async.Parallel
    |> Async.RunSynchronously