Finnduplikater.fs

open System
open System.IO
open System.Collections.Generic
open System.Security.Cryptography

type CommandLineOptions = {
        startkatalog : DirectoryInfo
        minFilStorrelseIBytes : int64
    }

let filesInDirectory (dir:DirectoryInfo) =
    try
        // Kaster exception dersom ingen tilgang
        dir.EnumerateFiles()
    with
    | _ -> 
        printfn "Ingen tilgang til %s" dir.FullName
        // Ignorerer kataloger uten tilgang
        Seq.empty

let directoriesInDirectory (dir:DirectoryInfo) =
    try
        dir.EnumerateDirectories()
    with
    | _ -> Seq.empty // Ignorerer kataloger uten tilgang. dette er logget ifm enumerering av filer

let rec filer dir = 
    seq { yield! filesInDirectory dir
          yield! directoriesInDirectory dir |> Seq.collect filer }

let lagHash (fil:FileInfo) =
    use sha256 = SHA256.Create()
    try
        // Kaster exception dersom vi ikke har lesetilgang til filen
        use stream = fil.OpenRead()
        let hash = sha256.ComputeHash stream
        Some (Convert.ToBase64String(hash))
    with
    | _ -> None

// Her lagrer vi informasjon om filene vi har lest. Nøkkel er en hash av filen, verdien er fullt filnavn
let filLager = Dictionary<string, string>()

let finnDuplikat fil =
    let hashOption = lagHash fil
    match hashOption with
    | Some hash -> 
        if (filLager.ContainsKey(hash)) then
            printfn "Original fil: %s" filLager.[hash]
            printfn "Duplikat fil: %s" fil.FullName
            printfn ""
        else
            filLager.Add(hash, fil.FullName)
    | None -> printfn "Ingen tilgang til %s" fil.FullName

let PrintDuplikater options =
    filer options.startkatalog
    |> Seq.filter (fun fil -> fil.Length >= options.minFilStorrelseIBytes)
    |> Seq.iter (fun fil -> finnDuplikat fil)

let parseCommandLineOptions (args: string[]) = 
    match args with
    | [|bytes; katalog|] -> 
        let isLong, minFilStorrelseIBytes = Int64.TryParse(bytes)
        let katalogEksisterer = Directory.Exists katalog
        if isLong && katalogEksisterer then
            Some {
                startkatalog = DirectoryInfo(katalog)
                minFilStorrelseIBytes = minFilStorrelseIBytes
            }
        else
            None
    | _ -> None

[<EntryPoint>]
let Main(args) =
    let commandLineOptions = parseCommandLineOptions args
    match commandLineOptions with
    | Some options -> 
        PrintDuplikater options
        0
    | None -> 
        // Enkel feilmelding ved feil bruk
        printfn "Kalles fx. slik: %s 100000 C:\\Temp\\" (Environment.GetCommandLineArgs()).[0]
        -1

Andre implementasjoner:

• Erlend Wiig: https://gist.github.com/Erlord/1687483171981f6a120f
• Kristian Hellang: https://gist.github.com/khellang/3a1a49744f6825b6f401
• Tomas Jansson: https://gist.github.com/mastoj/83b0e0188fcec69cd3fb
• Bjørn Einar Bjartnes: https://gist.github.com/bjartwolf/d4d83eda3c2f18bf3ce7