mediareuqest_special_chars.scala

import java.net.URLDecoder
import java.net.URLEncoder
import org.apache.spark.sql.functions._ 

val urlDecoder = (u: String) => URLDecoder.decode(u.replaceAll("%(?![0-9a-fA-F]{2})", "%25").replaceAll("\\+", "%2B"), "UTF-8")
val urlEncoder = (u: String) => URLEncoder.encode(u, "UTF-8")
val countSlashes = (u: String) => u.count(_ == '/')

spark.sql("SET spark.sql.shuffle.partitions = 1024")

spark.udf.register("url_decode", urlDecoder)
spark.udf.register("url_encode", urlEncoder)
spark.udf.register("count_slashes", countSlashes)


val df = spark.read.parquet("/wmf/data/wmf/mediarequest/year=2019/month=9")

val d = df.selectExpr("replace(base_name, '%20', '_') as bn").distinct
val d2 = d.selectExpr("bn", "url_decode(bn) as dbn").cache()
val d3 = d2.selectExpr("bn", "dbn", "replace(url_encode(dbn), '%2F', '/') as ebn")


val replacements = Map(
  "%21" -> "!",
  "%22" -> "\"",
  "%23" -> "#",
  "%24" -> "\\$",
  "%25" -> "%",
  "%26" -> "&",
  "%27" -> "'",
  "%28" -> "(",
  "%29" -> ")",
  "%2B" -> "+",
  "%3A" -> ":",
  "%3B" -> ";",
  "%3C" -> "<",
  "%3D" -> "=",
  "%3E" -> ">",
  "%3F" -> "?",
  "%40" -> "@",
  "%5B" -> "[",
  "%5C" -> "\\\\",
  "%5D" -> "]",
  "%5E" -> "^",
  "%60" -> "`",
  "%7B" -> "\\{",
  "%7C" -> "\\|",
  "%7D" -> "\\}",
  "%7E" -> "~"
)
val replace = (u: String) => replacements.foldLeft(u)((s, r) => s.replaceAll(r._1, r._2))
spark.udf.register("my_replace", replace)
val d4 = d3.selectExpr("bn", "my_replace(ebn) as fbn")
val findFirstDiff = (s1: String, s2: String) => s1 diff s2
spark.udf.register("diff", findFirstDiff)
val ddiff = d4.where("fbn <> bn").cache()
ddiff.count
ddiff.selectExpr("diff(bn, fbn)", "bn", "fbn").distinct.show(10, false)