Extract the prompt metadata from a SD-WebUI .png file

scan.fsx

open System
open System.IO

let dumpParams f =
  let bytes = File.ReadAllBytes f
  // printfn "%A bytes" bytes.Length
  let rec readchunk index =
    // printfn "readchunk %A" index
    if index < bytes.Length then
      let field = [| bytes[index+3]; bytes[index+2]; bytes[index+1]; bytes[index] |]
      let length = BitConverter.ToInt32(field, 0)
      let chunk =  System.Text.Encoding.UTF8.GetString(bytes, index+4, 4)
      //printfn "%A %A" chunk length
      if chunk.Equals("tEXt") || chunk.Equals("iTXt")
      then
        let body = System.Text.Encoding.UTF8.GetString(bytes, index+19, length - 11)
        printfn "%s" body
      else
        readchunk (index + 12 + length)
  readchunk 8

let dump ((d:DateOnly), l) = 
  l
  |> Seq.iter  (fun (f:string) -> let fn = Path.GetFileName f
                                  printfn "  %A on %A" (fn.Substring(0,5)) (d.ToString("yyyy-MM-dd"))
                                  dumpParams f)


let scandir dir =
  printfn "%s" dir
  let files = Directory.GetFiles(dir, "?????-*.png")
  files
  |> Seq.groupBy (fun f -> (File.GetLastWriteTime f) |> DateOnly.FromDateTime)
  |> Seq.sortBy (fun (d,l) -> d)
  |> Seq.map (fun (d,l) -> (d, l |> Seq.sort))
  |> Seq.iter dump

let targets = Directory.GetDirectories(".", "*", SearchOption.AllDirectories )
targets
|> Seq.sort
|> Seq.iter scandir