Obfuscate your ebook so that people who didn't pay can read it, partly

makebook_obfuscate.php

<?php

/*
 I wrote this function to progressively obfuscate text in MAKEbook.io. When it KINDA worked, I just used it.
 It can take a lot of improvement. I kinda just tweaked the values until it was good enough. It's not SO progressive though.
 
 It takes all the output of your PHP scripts via ob_start(), reroutes that to the obfuscation function.
 
 You should check if user paid for book or not, then either run ob_start or not!
 
 MIT license, do whatever you want with it!
 
 by Pieter Levels
*/

ob_start("progressivelyObfuscateText");

function progressivelyObfuscateText($text) {
  $constant=0;
  $exponent=2;
  $multiplier=10;

  srand('12318232372'); /* this is your random seed, to make sure the page doesn't obfuscate in a different way every load! */

  $chars=str_split($text);

  $alphabet='abcdefghijklmnopqrstuvwxyz';
  $alphabet=str_split($alphabet);

  $vowels='aeiouy';
  $vowels=str_split($vowels);

  $consonants='bcdfghjklmnpqrstvwxzw';
  $consonants=str_split($consonants);

  $obfuscatedText='';
  $i=0;
  $y=-1;
  $insideHTMLTag=false;
  foreach($chars as $char) {
    $i++;
    $y++;
    $progress=$i/1500*$multiplier + pow($i/1500,$exponent) -$constant;
    if($chars[$y-3].$chars[$y-2].$chars[$y-1].$chars[$y]=='<h1>') {
      // reset progress if we find <h1> because it means new chapter
      // so we progressively obfuscate again
      $i=0;
    }
    if($chars[$y-3].$chars[$y-2].$chars[$y-1].$chars[$y]=='<h2>') {
      // reset progress if we find <h2> because it means new head
      // so we progressively obfuscate again
      $i=0;
    }
    if($chars[$y-2].$chars[$y-1].$chars[$y]=='<b>') {
      $insideBoldTag=true;
      $obfuscatedText.=$char;
      continue;
    }
    if($chars[$y-3].$chars[$y-2].$chars[$y-1].$chars[$y]=='</b>') {
      $insideBoldTag=false;
      $obfuscatedText.=$char;
      continue;
    }
    if($char=='<') {
      $insideHTMLTag=true;
      $obfuscatedText.=$char;
      continue;
    }
    if($char=='>') {
      $insideHTMLTag=false;
      $obfuscatedText.=$char;
      continue;
    }
    if($insideHTMLTag || $insideHeaderTag || $insideBoldTag || $insideLinkTag) {
      $obfuscatedText.=$char;
      continue;
    }
    if($y<25000 || !ctype_alnum($char) || $char==' ' || $char=='"' || $char=='$' || $char=='/' || $char==',' || $char=='http://'  || $char=="'"  || $char=="\n" || $char=="\t" || $char=="\r") {
      $obfuscatedText.=$char;
      continue;
    }
    if(floor(1-rand(0,$progress))==1) {
      $obfuscatedText.=$char;
      continue;
    }
    if(in_array($char,$consonants)) $char=$consonants[array_rand($consonants)];
    if(in_array($char,$vowels)) $char=$vowels[array_rand($vowels)];

    $obfuscatedText.=$char;
  }


  return $obfuscatedText;
}


?>