CsvUtil.fs

namespace CsvHelperfs

(*
  FILE    : CsvUtil.fs
  AUTHOR  : callmekohei
  LICENSE :
  DESC    :
*)

module CsvUtil =

  open System
  open System.Collections.Generic
  open System.Dynamic
  open System.Reflection
  open CsvHelper


  let csvHeaderValidate<'T,'U> (args: HeaderValidatedArgs) =
    let requiredHeaders =
      // The value__ field is removed by specifying we only want the public, static fields.
      typeof<'T>.GetFields(BindingFlags.Public ||| BindingFlags.Static)
      |> Array.filter(fun fieldInfo -> isNull (Attribute.GetCustomAttribute(fieldInfo,typeof<'U>)))
      |> Array.map(fun x -> x.Name)
    let optionalHeaders =
      // The value__ field is removed by specifying we only want the public, static fields.
      typeof<'T>.GetFields(BindingFlags.Public ||| BindingFlags.Static)
      |> Array.filter(fun fieldInfo -> isNull (Attribute.GetCustomAttribute(fieldInfo,typeof<'U>)) |> not )
      |> Array.map(fun x -> x.Name)
    let headers = args.Context.Parser.Record
    let missingHeaders = requiredHeaders |> Array.except headers |> Array.except optionalHeaders
    let unexpectedHeaders = headers |> Array.except requiredHeaders |> Array.except optionalHeaders
    if (Seq.isEmpty missingHeaders && Seq.isEmpty unexpectedHeaders) |> not
    then failwith <| $"""(Invalid Header) short: {String.Join(" ",missingHeaders)}. invalid: {String.Join(" ",unexpectedHeaders)}"""


  let skipRows (csv: CsvReader) i =
    let skipRow _ =
      async {
        return! csv.ReadAsync() |> Async.AwaitTask
      }

    let sequential = Async.Sequential >> Async.Ignore

    async {
      do!
        seq { 1..i }
        |> Seq.map skipRow
        |> sequential
    }


  // Idictionary => ExpandoObject.IDictionary
  let asExpandoIDictionary (idic:IDictionary<string,obj>)  =
    let expando = new ExpandoObject()
    let expandoIDic = expando :> IDictionary<string,obj>
    idic.Keys |> Seq.iter(fun k -> expandoIDic.Add(k,idic.Item(k)))
    expandoIDic