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Saturday, December 25, 2010

Scala script to find duplicate files

Here is simple Scala script finding duplicate files and moving them to another directory. It searches album-with-duplicates for duplicates of files in main-album. All duplicates found are moved to copies directory in user's home.

If you have some ideas how to improve it, I'd appreciate if you share it in comments.

MD5 algorithm taken from here.
package com.blogspot.pawelstawicki.remove.duplicates

import java.security.MessageDigest
import java.io.{FileInputStream, File}
import org.apache.commons.io.{FilenameUtils, FileUtils, IOUtils}

/**
 * @author ${user.name}
 */
object App {
  
  def main(args : Array[String]) {
    val dir1 = new File("/photos/main-album,");
    val dir2 = new File("/photos/album-with-duplicates");

    val dir1Content = getAllFiles(dir1)
    val dir2Content = getAllFiles(dir2)

    var dir1Map = Map[String, File]()
    dir1Content.foreach(f => {
      val md5 = md5SumString(IOUtils.toByteArray(new FileInputStream(f)))
      println("md5 for " + f.getPath + ": " + md5)
      dir1Map = dir1Map + (md5 -> f)
    })

    var dir2Map = Map[String, File]()
    dir2Content.foreach(f => {
      val md5 = md5SumString(IOUtils.toByteArray(new FileInputStream(f)))
      println("md5 for " + f.getPath + ": " + md5)
      dir2Map = dir2Map + (md5 -> f)
    })

    for(md51 <- dir1Map.keys; md52 <- dir2Map.keys) {

      if (md51.equals(md52)) {
        val suspectedDuplicate = dir2Map(md52)
        val original = dir1Map(md52)

        if (checkDuplicate(original, suspectedDuplicate)) {
          println(suspectedDuplicate.getPath + " is duplicate of " + original.getPath)
          val copiesDir = new File(FileUtils.getUserDirectory + "/copies/" + FilenameUtils.getPathNoEndSeparator(original.getAbsolutePath()));
          println("Moving to " + copiesDir.getPath)
          FileUtils.moveFileToDirectory(suspectedDuplicate, copiesDir, true)
        }
      }
    }
  }

  def checkDuplicate(f1: File, f2: File): Boolean = {
    val bytes1 = new Array[Byte](1024*1024)
    val bytes2 = new Array[Byte](1024*1024)

    val input1 = new FileInputStream(f1)
    val input2 = new FileInputStream(f2)

    var bytesRead1 = input1.read(bytes1)
    while(bytesRead1 > 0) {
      val bytesRead2 = input2.read(bytes2)

      if (bytesRead1 != bytesRead2) {
        return false;
      }

      //Bytes read number the same
      if (!bytes1.sameElements(bytes2)) {
        return false
      }

      bytesRead1 = input1.read(bytes1)
    }

    //bytesRead1 is -1. Check if bytes read number from file2 is also -1
    if (input2.read(bytes2) == -1) {
      return true;
    } else {
      return false;
    }
  }

  def md5SumString(bytes : Array[Byte]) : String = {
    val md5 = MessageDigest.getInstance("MD5")
    md5.reset()
    md5.update(bytes)

    md5.digest().map(0xFF & _).map { "%02x".format(_) }.foldLeft(""){_ + _}
  }

  def getAllFiles(dir : File) : List[File] = {
    var l = List[File]()
    dir.listFiles.foreach(f => {
      if (f.isFile) {
        l = f :: l
      } else {
        l = l ::: getAllFiles(f)
      }
    })

    l
  }

}

7 comments:

Seth Tisue said...

def getAllFiles(dir: File): List[File] =
dir.listFiles.toList.flatMap{f =>
if(f.isFile) List(f)
else getAllFiles(f)
}

pawelstawicki said...

Thanks a lot Seth! I need just such comments.

Jason Mar said...

great post, I am beginning to learn scala and short and understandable working code like this is super helpful
This is actually a very commonly needed functionality if anonymous users are uploading junk files to an app all the time!

pawelstawicki said...

That's interesting. I used it to filter my photos collection, because while moving photos from some disks to another, from camera to PC etc. some of them become duplicated. It's great if someone else can use this code.

Danewan Williams said...
This comment has been removed by a blog administrator.
Danewan Williams said...
This comment has been removed by a blog administrator.
Angel Ikaz said...

i would suggest you to try DuplicateFilesDeleter , it can help resolve duplicate files issue.